author | Lennard de Rijk <ljvderijk@gmail.com> |
Mon, 13 Jul 2009 00:53:42 +0200 | |
changeset 2616 | 9321e100a7fb |
parent 109 | 620f9b141567 |
permissions | -rw-r--r-- |
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=============================== |
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Forms, fields, and manipulators |
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=============================== |
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Forwards-compatibility note |
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=========================== |
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The legacy forms/manipulators system described in this document is going to be |
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replaced in the next Django release. If you're starting from scratch, we |
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strongly encourage you not to waste your time learning this. Instead, learn and |
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use the django.newforms system, which we have begun to document in the |
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`newforms documentation`_. |
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If you have legacy form/manipulator code, read the "Migration plan" section in |
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that document to understand how we're making the switch. |
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.. _newforms documentation: ../newforms/ |
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Introduction |
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============ |
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Once you've got a chance to play with Django's admin interface, you'll probably |
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wonder if the fantastic form validation framework it uses is available to user |
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code. It is, and this document explains how the framework works. |
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We'll take a top-down approach to examining Django's form validation framework, |
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because much of the time you won't need to use the lower-level APIs. Throughout |
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this document, we'll be working with the following model, a "place" object:: |
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from django.db import models |
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PLACE_TYPES = ( |
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(1, 'Bar'), |
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(2, 'Restaurant'), |
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(3, 'Movie Theater'), |
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(4, 'Secret Hideout'), |
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) |
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class Place(models.Model): |
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name = models.CharField(maxlength=100) |
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address = models.CharField(maxlength=100, blank=True) |
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city = models.CharField(maxlength=50, blank=True) |
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state = models.USStateField() |
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zip_code = models.CharField(maxlength=5, blank=True) |
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place_type = models.IntegerField(choices=PLACE_TYPES) |
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class Admin: |
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pass |
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def __str__(self): |
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return self.name |
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Defining the above class is enough to create an admin interface to a ``Place``, |
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but what if you want to allow public users to submit places? |
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Automatic Manipulators |
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====================== |
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The highest-level interface for object creation and modification is the |
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**automatic Manipulator** framework. An automatic manipulator is a utility |
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class tied to a given model that "knows" how to create or modify instances of |
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that model and how to validate data for the object. Automatic Manipulators come |
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in two flavors: ``AddManipulators`` and ``ChangeManipulators``. Functionally |
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they are quite similar, but the former knows how to create new instances of the |
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model, while the latter modifies existing instances. Both types of classes are |
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automatically created when you define a new class:: |
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>>> from mysite.myapp.models import Place |
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>>> Place.AddManipulator |
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<class 'django.models.manipulators.AddManipulator'> |
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>>> Place.ChangeManipulator |
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<class 'django.models.manipulators.ChangeManipulator'> |
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Using the ``AddManipulator`` |
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---------------------------- |
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We'll start with the ``AddManipulator``. Here's a very simple view that takes |
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POSTed data from the browser and creates a new ``Place`` object:: |
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from django.shortcuts import render_to_response |
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from django.http import Http404, HttpResponse, HttpResponseRedirect |
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from django import forms |
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from mysite.myapp.models import Place |
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def naive_create_place(request): |
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"""A naive approach to creating places; don't actually use this!""" |
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# Create the AddManipulator. |
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manipulator = Place.AddManipulator() |
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# Make a copy of the POSTed data so that do_html2python can |
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# modify it in place (request.POST is immutable). |
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new_data = request.POST.copy() |
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# Convert the request data (which will all be strings) into the |
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# appropriate Python types for those fields. |
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manipulator.do_html2python(new_data) |
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# Save the new object. |
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new_place = manipulator.save(new_data) |
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# It worked! |
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return HttpResponse("Place created: %s" % new_place) |
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The ``naive_create_place`` example works, but as you probably can tell, this |
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view has a number of problems: |
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* No validation of any sort is performed. If, for example, the ``name`` field |
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isn't given in ``request.POST``, the save step will cause a database error |
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because that field is required. Ugly. |
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* Even if you *do* perform validation, there's still no way to give that |
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information to the user in any sort of useful way. |
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113 |
|
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114 |
* You'll have to separately create a form (and view) that submits to this |
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115 |
page, which is a pain and is redundant. |
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116 |
|
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117 |
Let's dodge these problems momentarily to take a look at how you could create a |
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118 |
view with a form that submits to this flawed creation view:: |
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119 |
|
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120 |
def naive_create_place_form(request): |
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"""Simplistic place form view; don't actually use anything like this!""" |
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# Create a FormWrapper object that the template can use. Ignore |
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# the last two arguments to FormWrapper for now. |
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form = forms.FormWrapper(Place.AddManipulator(), {}, {}) |
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return render_to_response('places/naive_create_form.html', {'form': form}) |
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126 |
|
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127 |
(This view, as well as all the following ones, has the same imports as in the |
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128 |
first example above.) |
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129 |
|
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The ``forms.FormWrapper`` object is a wrapper that templates can |
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easily deal with to create forms. Here's the ``naive_create_form.html`` |
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132 |
template:: |
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133 |
|
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{% extends "base.html" %} |
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135 |
|
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{% block content %} |
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<h1>Create a place:</h1> |
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138 |
|
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139 |
<form method="post" action="../do_new/"> |
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<p><label for="id_name">Name:</label> {{ form.name }}</p> |
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<p><label for="id_address">Address:</label> {{ form.address }}</p> |
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<p><label for="id_city">City:</label> {{ form.city }}</p> |
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<p><label for="id_state">State:</label> {{ form.state }}</p> |
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<p><label for="id_zip_code">Zip:</label> {{ form.zip_code }}</p> |
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<p><label for="id_place_type">Place type:</label> {{ form.place_type }}</p> |
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146 |
<input type="submit" /> |
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</form> |
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148 |
{% endblock %} |
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149 |
|
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150 |
Before we get back to the problems with these naive set of views, let's go over |
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151 |
some salient points of the above template: |
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152 |
|
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153 |
* Field "widgets" are handled for you: ``{{ form.field }}`` automatically |
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154 |
creates the "right" type of widget for the form, as you can see with the |
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155 |
``place_type`` field above. |
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156 |
|
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157 |
* There isn't a way just to spit out the form. You'll still need to define |
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158 |
how the form gets laid out. This is a feature: Every form should be |
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159 |
designed differently. Django doesn't force you into any type of mold. |
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160 |
If you must use tables, use tables. If you're a semantic purist, you can |
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161 |
probably find better HTML than in the above template. |
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162 |
|
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163 |
* To avoid name conflicts, the ``id`` values of form elements take the |
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164 |
form "id_*fieldname*". |
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165 |
|
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166 |
By creating a creation form we've solved problem number 3 above, but we still |
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167 |
don't have any validation. Let's revise the validation issue by writing a new |
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168 |
creation view that takes validation into account:: |
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169 |
|
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170 |
def create_place_with_validation(request): |
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171 |
manipulator = Place.AddManipulator() |
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172 |
new_data = request.POST.copy() |
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173 |
|
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174 |
# Check for validation errors |
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175 |
errors = manipulator.get_validation_errors(new_data) |
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176 |
manipulator.do_html2python(new_data) |
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177 |
if errors: |
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178 |
return render_to_response('places/errors.html', {'errors': errors}) |
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179 |
else: |
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180 |
new_place = manipulator.save(new_data) |
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181 |
return HttpResponse("Place created: %s" % new_place) |
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182 |
|
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183 |
In this new version, errors will be found -- ``manipulator.get_validation_errors`` |
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184 |
handles all the validation for you -- and those errors can be nicely presented |
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185 |
on an error page (templated, of course):: |
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186 |
|
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187 |
{% extends "base.html" %} |
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188 |
|
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189 |
{% block content %} |
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190 |
|
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191 |
<h1>Please go back and correct the following error{{ errors|pluralize }}:</h1> |
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192 |
<ul> |
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193 |
{% for e in errors.items %} |
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194 |
<li>Field "{{ e.0 }}": {{ e.1|join:", " }}</li> |
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195 |
{% endfor %} |
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196 |
</ul> |
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197 |
|
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198 |
{% endblock %} |
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199 |
|
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200 |
Still, this has its own problems: |
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201 |
|
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202 |
* There's still the issue of creating a separate (redundant) view for the |
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203 |
submission form. |
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204 |
|
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205 |
* Errors, though nicely presented, are on a separate page, so the user will |
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206 |
have to use the "back" button to fix errors. That's ridiculous and unusable. |
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207 |
|
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208 |
The best way to deal with these issues is to collapse the two views -- the form |
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209 |
and the submission -- into a single view. This view will be responsible for |
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210 |
creating the form, validating POSTed data, and creating the new object (if the |
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211 |
data is valid). An added bonus of this approach is that errors and the form will |
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212 |
both be available on the same page, so errors with fields can be presented in |
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213 |
context. |
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214 |
|
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215 |
.. admonition:: Philosophy: |
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216 |
|
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217 |
Finally, for the HTTP purists in the audience (and the authorship), this |
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218 |
nicely matches the "true" meanings of HTTP GET and HTTP POST: GET fetches |
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219 |
the form, and POST creates the new object. |
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220 |
|
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221 |
Below is the finished view:: |
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222 |
|
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223 |
def create_place(request): |
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manipulator = Place.AddManipulator() |
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225 |
|
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if request.method == 'POST': |
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# If data was POSTed, we're trying to create a new Place. |
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new_data = request.POST.copy() |
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229 |
|
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230 |
# Check for errors. |
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errors = manipulator.get_validation_errors(new_data) |
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manipulator.do_html2python(new_data) |
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233 |
|
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234 |
if not errors: |
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235 |
# No errors. This means we can save the data! |
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new_place = manipulator.save(new_data) |
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237 |
|
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238 |
# Redirect to the object's "edit" page. Always use a redirect |
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239 |
# after POST data, so that reloads don't accidently create |
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# duplicate entires, and so users don't see the confusing |
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# "Repost POST data?" alert box in their browsers. |
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return HttpResponseRedirect("/places/edit/%i/" % new_place.id) |
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243 |
else: |
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# No POST, so we want a brand new form without any data or errors. |
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errors = new_data = {} |
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246 |
|
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# Create the FormWrapper, template, context, response. |
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form = forms.FormWrapper(manipulator, new_data, errors) |
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return render_to_response('places/create_form.html', {'form': form}) |
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250 |
|
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and here's the ``create_form`` template:: |
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252 |
|
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{% extends "base.html" %} |
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254 |
|
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{% block content %} |
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256 |
<h1>Create a place:</h1> |
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257 |
|
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{% if form.has_errors %} |
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<h2>Please correct the following error{{ form.error_dict|pluralize }}:</h2> |
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260 |
{% endif %} |
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261 |
|
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262 |
<form method="post" action="."> |
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263 |
<p> |
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<label for="id_name">Name:</label> {{ form.name }} |
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{% if form.name.errors %}*** {{ form.name.errors|join:", " }}{% endif %} |
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266 |
</p> |
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267 |
<p> |
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268 |
<label for="id_address">Address:</label> {{ form.address }} |
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269 |
{% if form.address.errors %}*** {{ form.address.errors|join:", " }}{% endif %} |
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270 |
</p> |
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271 |
<p> |
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272 |
<label for="id_city">City:</label> {{ form.city }} |
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{% if form.city.errors %}*** {{ form.city.errors|join:", " }}{% endif %} |
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274 |
</p> |
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275 |
<p> |
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276 |
<label for="id_state">State:</label> {{ form.state }} |
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277 |
{% if form.state.errors %}*** {{ form.state.errors|join:", " }}{% endif %} |
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278 |
</p> |
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279 |
<p> |
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280 |
<label for="id_zip_code">Zip:</label> {{ form.zip_code }} |
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281 |
{% if form.zip_code.errors %}*** {{ form.zip_code.errors|join:", " }}{% endif %} |
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282 |
</p> |
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283 |
<p> |
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284 |
<label for="id_place_type">Place type:</label> {{ form.place_type }} |
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285 |
{% if form.place_type.errors %}*** {{ form.place_type.errors|join:", " }}{% endif %} |
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286 |
</p> |
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287 |
<input type="submit" /> |
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288 |
</form> |
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289 |
{% endblock %} |
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290 |
|
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291 |
The second two arguments to ``FormWrapper`` (``new_data`` and ``errors``) |
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292 |
deserve some mention. |
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293 |
|
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294 |
The first is any "default" data to be used as values for the fields. Pulling |
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295 |
the data from ``request.POST``, as is done above, makes sure that if there are |
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296 |
errors, the values the user put in aren't lost. If you try the above example, |
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297 |
you'll see this in action. |
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298 |
|
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299 |
The second argument is the error list retrieved from |
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300 |
``manipulator.get_validation_errors``. When passed into the ``FormWrapper``, |
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301 |
this gives each field an ``errors`` item (which is a list of error messages |
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302 |
associated with the field) as well as a ``html_error_list`` item, which is a |
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303 |
``<ul>`` of error messages. The above template uses these error items to |
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304 |
display a simple error message next to each field. The error list is saved as |
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305 |
an ``error_dict`` attribute of the ``FormWrapper`` object. |
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306 |
|
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307 |
Using the ``ChangeManipulator`` |
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308 |
------------------------------- |
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309 |
|
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310 |
The above has covered using the ``AddManipulator`` to create a new object. What |
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311 |
about editing an existing one? It's shockingly similar to creating a new one:: |
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312 |
|
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313 |
def edit_place(request, place_id): |
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314 |
# Get the place in question from the database and create a |
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315 |
# ChangeManipulator at the same time. |
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316 |
try: |
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317 |
manipulator = Place.ChangeManipulator(place_id) |
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318 |
except Place.DoesNotExist: |
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319 |
raise Http404 |
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320 |
|
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321 |
# Grab the Place object in question for future use. |
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322 |
place = manipulator.original_object |
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323 |
|
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|
324 |
if request.method == 'POST': |
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325 |
new_data = request.POST.copy() |
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326 |
errors = manipulator.get_validation_errors(new_data) |
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327 |
manipulator.do_html2python(new_data) |
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328 |
if not errors: |
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329 |
manipulator.save(new_data) |
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330 |
|
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331 |
# Do a post-after-redirect so that reload works, etc. |
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332 |
return HttpResponseRedirect("/places/edit/%i/" % place.id) |
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333 |
else: |
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|
334 |
errors = {} |
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335 |
# This makes sure the form accurate represents the fields of the place. |
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336 |
new_data = manipulator.flatten_data() |
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|
337 |
|
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|
338 |
form = forms.FormWrapper(manipulator, new_data, errors) |
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|
339 |
return render_to_response('places/edit_form.html', {'form': form, 'place': place}) |
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|
340 |
|
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|
341 |
The only real differences are: |
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|
342 |
|
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|
343 |
* We create a ``ChangeManipulator`` instead of an ``AddManipulator``. |
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|
344 |
The argument to a ``ChangeManipulator`` is the ID of the object |
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|
345 |
to be changed. As you can see, the initializer will raise an |
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|
346 |
``ObjectDoesNotExist`` exception if the ID is invalid. |
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|
347 |
|
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348 |
* ``ChangeManipulator.original_object`` stores the instance of the |
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349 |
object being edited. |
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|
350 |
|
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|
351 |
* We set ``new_data`` based upon ``flatten_data()`` from the manipulator. |
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|
352 |
``flatten_data()`` takes the data from the original object under |
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353 |
manipulation, and converts it into a data dictionary that can be used |
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|
354 |
to populate form elements with the existing values for the object. |
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|
355 |
|
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|
356 |
* The above example uses a different template, so create and edit can be |
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357 |
"skinned" differently if needed, but the form chunk itself is completely |
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358 |
identical to the one in the create form above. |
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|
359 |
|
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|
360 |
The astute programmer will notice the add and create functions are nearly |
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|
361 |
identical and could in fact be collapsed into a single view. This is left as an |
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|
362 |
exercise for said programmer. |
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|
363 |
|
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|
364 |
(However, the even-more-astute programmer will take heed of the note at the top |
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|
365 |
of this document and check out the `generic views`_ documentation if all she |
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|
366 |
wishes to do is this type of simple create/update.) |
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|
367 |
|
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|
368 |
Custom forms and manipulators |
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|
369 |
============================= |
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|
370 |
|
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|
371 |
All the above is fine and dandy if you just want to use the automatically |
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|
372 |
created manipulators. But the coolness doesn't end there: You can easily create |
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|
373 |
your own custom manipulators for handling custom forms. |
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|
374 |
|
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|
375 |
Custom manipulators are pretty simple. Here's a manipulator that you might use |
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|
376 |
for a "contact" form on a website:: |
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|
377 |
|
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|
378 |
from django import forms |
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|
379 |
|
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|
380 |
urgency_choices = ( |
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|
381 |
(1, "Extremely urgent"), |
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|
382 |
(2, "Urgent"), |
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|
383 |
(3, "Normal"), |
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|
384 |
(4, "Unimportant"), |
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|
385 |
) |
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|
386 |
|
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|
387 |
class ContactManipulator(forms.Manipulator): |
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|
388 |
def __init__(self): |
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|
389 |
self.fields = ( |
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|
390 |
forms.EmailField(field_name="from", is_required=True), |
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|
391 |
forms.TextField(field_name="subject", length=30, maxlength=200, is_required=True), |
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parents:
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|
392 |
forms.SelectField(field_name="urgency", choices=urgency_choices), |
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|
393 |
forms.LargeTextField(field_name="contents", is_required=True), |
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parents:
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|
394 |
) |
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|
395 |
|
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|
396 |
A certain similarity to Django's models should be apparent. The only required |
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parents:
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|
397 |
method of a custom manipulator is ``__init__`` which must define the fields |
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parents:
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|
398 |
present in the manipulator. See the ``django.forms`` module for |
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parents:
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|
399 |
all the form fields provided by Django. |
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parents:
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changeset
|
400 |
|
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parents:
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changeset
|
401 |
You use this custom manipulator exactly as you would use an auto-generated one. |
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parents:
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changeset
|
402 |
Here's a simple function that might drive the above form:: |
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parents:
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|
403 |
|
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parents:
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|
404 |
def contact_form(request): |
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parents:
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changeset
|
405 |
manipulator = ContactManipulator() |
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parents:
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|
406 |
if request.method == 'POST': |
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parents:
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changeset
|
407 |
new_data = request.POST.copy() |
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parents:
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changeset
|
408 |
errors = manipulator.get_validation_errors(new_data) |
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parents:
diff
changeset
|
409 |
manipulator.do_html2python(new_data) |
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parents:
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changeset
|
410 |
if not errors: |
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parents:
diff
changeset
|
411 |
|
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parents:
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changeset
|
412 |
# Send e-mail using new_data here... |
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parents:
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changeset
|
413 |
|
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parents:
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changeset
|
414 |
return HttpResponseRedirect("/contact/thankyou/") |
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parents:
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changeset
|
415 |
else: |
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parents:
diff
changeset
|
416 |
errors = new_data = {} |
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parents:
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changeset
|
417 |
form = forms.FormWrapper(manipulator, new_data, errors) |
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parents:
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changeset
|
418 |
return render_to_response('contact_form.html', {'form': form}) |
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parents:
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changeset
|
419 |
|
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parents:
diff
changeset
|
420 |
Implementing ``flatten_data`` for custom manipulators |
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parents:
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|
421 |
------------------------------------------------------ |
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parents:
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|
422 |
|
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parents:
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changeset
|
423 |
It is possible (although rarely needed) to replace the default automatically |
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parents:
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changeset
|
424 |
created manipulators on a model with your own custom manipulators. If you do |
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
425 |
this and you are intending to use those models in generic views, you should |
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
426 |
also define a ``flatten_data`` method in any ``ChangeManipulator`` replacement. |
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parents:
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changeset
|
427 |
This should act like the default ``flatten_data`` and return a dictionary |
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parents:
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changeset
|
428 |
mapping field names to their values, like so:: |
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parents:
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changeset
|
429 |
|
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parents:
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changeset
|
430 |
def flatten_data(self): |
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parents:
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changeset
|
431 |
obj = self.original_object |
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parents:
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changeset
|
432 |
return dict( |
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parents:
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changeset
|
433 |
from = obj.from, |
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parents:
diff
changeset
|
434 |
subject = obj.subject, |
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parents:
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|
435 |
... |
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Load ../../google_appengine into trunk/thirdparty/google_appengine.
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parents:
diff
changeset
|
436 |
) |
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Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
437 |
|
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Load ../../google_appengine into trunk/thirdparty/google_appengine.
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parents:
diff
changeset
|
438 |
In this way, your new change manipulator will act exactly like the default |
620f9b141567
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
439 |
version. |
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parents:
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changeset
|
440 |
|
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Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
441 |
``FileField`` and ``ImageField`` special cases |
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parents:
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|
442 |
============================================== |
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
443 |
|
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Load ../../google_appengine into trunk/thirdparty/google_appengine.
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parents:
diff
changeset
|
444 |
Dealing with ``FileField`` and ``ImageField`` objects is a little more |
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parents:
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changeset
|
445 |
complicated. |
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parents:
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changeset
|
446 |
|
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parents:
diff
changeset
|
447 |
First, you'll need to make sure that your ``<form>`` element correctly defines |
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parents:
diff
changeset
|
448 |
the ``enctype`` as ``"multipart/form-data"``, in order to upload files:: |
620f9b141567
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parents:
diff
changeset
|
449 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
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parents:
diff
changeset
|
450 |
<form enctype="multipart/form-data" method="post" action="/foo/"> |
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
451 |
|
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
452 |
Next, you'll need to treat the field in the template slightly differently. A |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
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parents:
diff
changeset
|
453 |
``FileField`` or ``ImageField`` is represented by *two* HTML form elements. |
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parents:
diff
changeset
|
454 |
|
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
455 |
For example, given this field in a model:: |
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
456 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
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parents:
diff
changeset
|
457 |
photo = model.ImageField('/path/to/upload/location') |
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parents:
diff
changeset
|
458 |
|
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Load ../../google_appengine into trunk/thirdparty/google_appengine.
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parents:
diff
changeset
|
459 |
You'd need to display two formfields in the template:: |
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
460 |
|
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
461 |
<p><label for="id_photo">Photo:</label> {{ form.photo }}{{ form.photo_file }}</p> |
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parents:
diff
changeset
|
462 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
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parents:
diff
changeset
|
463 |
The first bit (``{{ form.photo }}``) displays the currently-selected file, |
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
464 |
while the second (``{{ form.photo_file }}``) actually contains the file upload |
620f9b141567
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parents:
diff
changeset
|
465 |
form field. Thus, at the validation layer you need to check the ``photo_file`` |
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
466 |
key. |
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parents:
diff
changeset
|
467 |
|
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
468 |
Finally, in your view, make sure to access ``request.FILES``, rather than |
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parents:
diff
changeset
|
469 |
``request.POST``, for the uploaded files. This is necessary because |
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parents:
diff
changeset
|
470 |
``request.POST`` does not contain file-upload data. |
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
471 |
|
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Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
472 |
For example, following the ``new_data`` convention, you might do something like |
620f9b141567
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parents:
diff
changeset
|
473 |
this:: |
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parents:
diff
changeset
|
474 |
|
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
475 |
new_data = request.POST.copy() |
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Todd Larsen <tlarsen@google.com>
parents:
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changeset
|
476 |
new_data.update(request.FILES) |
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parents:
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changeset
|
477 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
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parents:
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changeset
|
478 |
Validators |
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parents:
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changeset
|
479 |
========== |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
480 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
481 |
One useful feature of manipulators is the automatic validation. Validation is |
620f9b141567
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
482 |
done using a simple validation API: A validator is a callable that raises a |
620f9b141567
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
483 |
``ValidationError`` if there's something wrong with the data. |
620f9b141567
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
484 |
``django.core.validators`` defines a host of validator functions (see below), |
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
485 |
but defining your own couldn't be easier:: |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
486 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
487 |
from django.core import validators |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
488 |
from django import forms |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
489 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
490 |
class ContactManipulator(forms.Manipulator): |
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
491 |
def __init__(self): |
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Todd Larsen <tlarsen@google.com>
parents:
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changeset
|
492 |
self.fields = ( |
620f9b141567
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
493 |
# ... snip fields as above ... |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
494 |
forms.EmailField(field_name="to", validator_list=[self.isValidToAddress]) |
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
495 |
) |
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Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
496 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
497 |
def isValidToAddress(self, field_data, all_data): |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
498 |
if not field_data.endswith("@example.com"): |
620f9b141567
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
499 |
raise validators.ValidationError("You can only send messages to example.com e-mail addresses.") |
620f9b141567
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
500 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
501 |
Above, we've added a "to" field to the contact form, but required that the "to" |
620f9b141567
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Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
502 |
address end with "@example.com" by adding the ``isValidToAddress`` validator to |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
503 |
the field's ``validator_list``. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
504 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
505 |
The arguments to a validator function take a little explanation. ``field_data`` |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
506 |
is the value of the field in question, and ``all_data`` is a dictionary of all |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
507 |
the data being validated. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
508 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
509 |
.. admonition:: Note:: |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
510 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
511 |
At the point validators are called all data will still be |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
512 |
strings (as ``do_html2python`` hasn't been called yet). |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
513 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
514 |
Also, because consistency in user interfaces is important, we strongly urge you |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
515 |
to put punctuation at the end of your validation messages. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
516 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
517 |
When are validators called? |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
518 |
--------------------------- |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
519 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
520 |
After a form has been submitted, Django first checks to see that all the |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
521 |
required fields are present and non-empty. For each field that passes that |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
522 |
test *and if the form submission contained data* for that field, all the |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
523 |
validators for that field are called in turn. The emphasized portion in the |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
524 |
last sentence is important: if a form field is not submitted (because it |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
525 |
contains no data -- which is normal HTML behavior), the validators are not |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
526 |
run against the field. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
527 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
528 |
This feature is particularly important for models using |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
529 |
``models.BooleanField`` or custom manipulators using things like |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
530 |
``forms.CheckBoxField``. If the checkbox is not selected, it will not |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
531 |
contribute to the form submission. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
532 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
533 |
If you would like your validator to run *always*, regardless of whether its |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
534 |
attached field contains any data, set the ``always_test`` attribute on the |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
535 |
validator function. For example:: |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
536 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
537 |
def my_custom_validator(field_data, all_data): |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
538 |
# ... |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
539 |
my_custom_validator.always_test = True |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
540 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
541 |
This validator will always be executed for any field it is attached to. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
542 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
543 |
Ready-made validators |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
544 |
--------------------- |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
545 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
546 |
Writing your own validator is not difficult, but there are some situations |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
547 |
that come up over and over again. Django comes with a number of validators |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
548 |
that can be used directly in your code. All of these functions and classes |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
549 |
reside in ``django/core/validators.py``. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
550 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
551 |
The following validators should all be self-explanatory. Each one provides a |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
552 |
check for the given property: |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
553 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
554 |
* isAlphaNumeric |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
555 |
* isAlphaNumericURL |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
556 |
* isSlug |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
557 |
* isLowerCase |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
558 |
* isUpperCase |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
559 |
* isCommaSeparatedIntegerList |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
560 |
* isCommaSeparatedEmailList |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
561 |
* isValidIPAddress4 |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
562 |
* isNotEmpty |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
563 |
* isOnlyDigits |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
564 |
* isNotOnlyDigits |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
565 |
* isInteger |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
566 |
* isOnlyLetters |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
567 |
* isValidANSIDate |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
568 |
* isValidANSITime |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
569 |
* isValidEmail |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
570 |
* isValidImage |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
571 |
* isValidImageURL |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
572 |
* isValidPhone |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
573 |
* isValidQuicktimeVideoURL |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
574 |
* isValidURL |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
575 |
* isValidHTML |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
576 |
* isWellFormedXml |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
577 |
* isWellFormedXmlFragment |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
578 |
* isExistingURL |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
579 |
* isValidUSState |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
580 |
* hasNoProfanities |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
581 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
582 |
There are also a group of validators that are slightly more flexible. For |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
583 |
these validators, you create a validator instance, passing in the parameters |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
584 |
described below. The returned object is a callable that can be used as a |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
585 |
validator. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
586 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
587 |
For example:: |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
588 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
589 |
from django.core import validators |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
590 |
from django import forms |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
591 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
592 |
power_validator = validators.IsAPowerOf(2) |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
593 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
594 |
class InstallationManipulator(forms.Manipulator) |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
595 |
def __init__(self): |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
596 |
self.fields = ( |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
597 |
... |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
598 |
forms.IntegerField(field_name = "size", validator_list=[power_validator]) |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
599 |
) |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
600 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
601 |
Here, ``validators.IsAPowerOf(...)`` returned something that could be used as |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
602 |
a validator (in this case, a check that a number was a power of 2). |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
603 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
604 |
Each of the standard validators that take parameters have an optional final |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
605 |
argument (``error_message``) that is the message returned when validation |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
606 |
fails. If no message is passed in, a default message is used. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
607 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
608 |
``AlwaysMatchesOtherField`` |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
609 |
Takes a field name and the current field is valid if and only if its value |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
610 |
matches the contents of the other field. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
611 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
612 |
``ValidateIfOtherFieldEquals`` |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
613 |
Takes three parameters: ``other_field``, ``other_value`` and |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
614 |
``validator_list``, in that order. If ``other_field`` has a value of |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
615 |
``other_value``, then the validators in ``validator_list`` are all run |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
616 |
against the current field. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
617 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
618 |
``RequiredIfOtherFieldNotGiven`` |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
619 |
Takes the name of the other field and this field is only required if the |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
620 |
other field has no value. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
621 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
622 |
``RequiredIfOtherFieldsNotGiven`` |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
623 |
Similar to ``RequiredIfOtherFieldNotGiven``, except that it takes a list |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
624 |
of field names and if any one of the supplied fields does not have a value |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
625 |
provided, the field being validated is required. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
626 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
627 |
``RequiredIfOtherFieldEquals`` and ``RequiredIfOtherFieldDoesNotEqual`` |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
628 |
Each of these validator classes takes a field name and a value (in that |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
629 |
order). If the given field does (or does not have, in the latter case) the |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
630 |
given value, then the current field being validated is required. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
631 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
632 |
An optional ``other_label`` argument can be passed which, if given, is used |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
633 |
in error messages instead of the value. This allows more user friendly error |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
634 |
messages if the value itself is not descriptive enough. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
635 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
636 |
Note that because validators are called before any ``do_html2python()`` |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
637 |
functions, the value being compared against is a string. So |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
638 |
``RequiredIfOtherFieldEquals('choice', '1')`` is correct, whilst |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
639 |
``RequiredIfOtherFieldEquals('choice', 1)`` will never result in the |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
640 |
equality test succeeding. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
641 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
642 |
``IsLessThanOtherField`` |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
643 |
Takes a field name and validates that the current field being validated |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
644 |
has a value that is less than (or equal to) the other field's value. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
645 |
Again, comparisons are done using strings, so be cautious about using |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
646 |
this function to compare data that should be treated as another type. The |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
647 |
string "123" is less than the string "2", for example. If you don't want |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
648 |
string comparison here, you will need to write your own validator. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
649 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
650 |
``NumberIsInRange`` |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
651 |
Takes two boundary numbers, ``lower`` and ``upper``, and checks that the |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
652 |
field is greater than ``lower`` (if given) and less than ``upper`` (if |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
653 |
given). |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
654 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
655 |
Both checks are inclusive. That is, ``NumberIsInRange(10, 20)`` will allow |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
656 |
values of both 10 and 20. This validator only checks numeric values |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
657 |
(e.g., float and integer values). |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
658 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
659 |
``IsAPowerOf`` |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
660 |
Takes an integer argument and when called as a validator, checks that the |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
661 |
field being validated is a power of the integer. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
662 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
663 |
``IsValidFloat`` |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
664 |
Takes a maximum number of digits and number of decimal places (in that |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
665 |
order) and validates whether the field is a float with less than the |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
666 |
maximum number of digits and decimal place. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
667 |
|
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
668 |
``MatchesRegularExpression`` |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
669 |
Takes a regular expression (a string) as a parameter and validates the |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
Todd Larsen <tlarsen@google.com>
parents:
diff
changeset
|
670 |
field value against it. |
620f9b141567
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parents:
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changeset
|
671 |
|
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parents:
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changeset
|
672 |
``AnyValidator`` |
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parents:
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changeset
|
673 |
Takes a list of validators as a parameter. At validation time, if the |
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parents:
diff
changeset
|
674 |
field successfully validates against any one of the validators, it passes |
620f9b141567
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parents:
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changeset
|
675 |
validation. The validators are tested in the order specified in the |
620f9b141567
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parents:
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changeset
|
676 |
original list. |
620f9b141567
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parents:
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changeset
|
677 |
|
620f9b141567
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parents:
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changeset
|
678 |
``URLMimeTypeCheck`` |
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parents:
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changeset
|
679 |
Used to validate URL fields. Takes a list of MIME types (such as |
620f9b141567
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parents:
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changeset
|
680 |
``text/plain``) at creation time. At validation time, it verifies that the |
620f9b141567
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Todd Larsen <tlarsen@google.com>
parents:
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changeset
|
681 |
field is indeed a URL and then tries to retrieve the content at the URL. |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
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parents:
diff
changeset
|
682 |
Validation succeeds if the content could be retrieved and it has a content |
620f9b141567
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parents:
diff
changeset
|
683 |
type from the list used to create the validator. |
620f9b141567
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parents:
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changeset
|
684 |
|
620f9b141567
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parents:
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changeset
|
685 |
``RelaxNGCompact`` |
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Todd Larsen <tlarsen@google.com>
parents:
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changeset
|
686 |
Used to validate an XML document against a Relax NG compact schema. Takes |
620f9b141567
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parents:
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changeset
|
687 |
a file path to the location of the schema and an optional root element |
620f9b141567
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parents:
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changeset
|
688 |
(which is wrapped around the XML fragment before validation, if supplied). |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
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parents:
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changeset
|
689 |
At validation time, the XML fragment is validated against the schema using |
620f9b141567
Load ../../google_appengine into trunk/thirdparty/google_appengine.
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parents:
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changeset
|
690 |
the executable specified in the ``JING_PATH`` setting (see the settings_ |
620f9b141567
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parents:
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changeset
|
691 |
document for more details). |
620f9b141567
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parents:
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changeset
|
692 |
|
620f9b141567
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parents:
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|
693 |
.. _`generic views`: ../generic_views/ |
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parents:
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|
694 |
.. _`models API`: ../model_api/ |
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parents:
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|
695 |
.. _settings: ../settings/ |