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1 """ |
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2 Helper functions for creating Form classes from Django models |
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3 and database field objects. |
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4 """ |
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5 |
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6 from django.utils.encoding import smart_unicode |
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7 from django.utils.datastructures import SortedDict |
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8 from django.utils.text import get_text_list, capfirst |
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9 from django.utils.translation import ugettext_lazy as _ |
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10 |
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11 from util import ValidationError, ErrorList |
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12 from forms import BaseForm, get_declared_fields |
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13 from fields import Field, ChoiceField, IntegerField, EMPTY_VALUES |
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14 from widgets import Select, SelectMultiple, HiddenInput, MultipleHiddenInput |
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15 from widgets import media_property |
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16 from formsets import BaseFormSet, formset_factory, DELETION_FIELD_NAME |
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17 |
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18 try: |
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19 set |
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20 except NameError: |
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21 from sets import Set as set # Python 2.3 fallback |
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22 |
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23 __all__ = ( |
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24 'ModelForm', 'BaseModelForm', 'model_to_dict', 'fields_for_model', |
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25 'save_instance', 'form_for_fields', 'ModelChoiceField', |
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26 'ModelMultipleChoiceField', |
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27 ) |
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28 |
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29 |
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30 def save_instance(form, instance, fields=None, fail_message='saved', |
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31 commit=True, exclude=None): |
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32 """ |
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33 Saves bound Form ``form``'s cleaned_data into model instance ``instance``. |
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34 |
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35 If commit=True, then the changes to ``instance`` will be saved to the |
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36 database. Returns ``instance``. |
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37 """ |
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38 from django.db import models |
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39 opts = instance._meta |
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40 if form.errors: |
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41 raise ValueError("The %s could not be %s because the data didn't" |
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42 " validate." % (opts.object_name, fail_message)) |
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43 cleaned_data = form.cleaned_data |
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44 for f in opts.fields: |
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45 if not f.editable or isinstance(f, models.AutoField) \ |
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46 or not f.name in cleaned_data: |
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47 continue |
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48 if fields and f.name not in fields: |
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49 continue |
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50 if exclude and f.name in exclude: |
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51 continue |
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52 f.save_form_data(instance, cleaned_data[f.name]) |
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53 # Wrap up the saving of m2m data as a function. |
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54 def save_m2m(): |
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55 opts = instance._meta |
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56 cleaned_data = form.cleaned_data |
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57 for f in opts.many_to_many: |
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58 if fields and f.name not in fields: |
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59 continue |
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60 if f.name in cleaned_data: |
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61 f.save_form_data(instance, cleaned_data[f.name]) |
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62 if commit: |
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63 # If we are committing, save the instance and the m2m data immediately. |
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64 instance.save() |
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65 save_m2m() |
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66 else: |
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67 # We're not committing. Add a method to the form to allow deferred |
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68 # saving of m2m data. |
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69 form.save_m2m = save_m2m |
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70 return instance |
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71 |
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72 def make_model_save(model, fields, fail_message): |
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73 """Returns the save() method for a Form.""" |
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74 def save(self, commit=True): |
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75 return save_instance(self, model(), fields, fail_message, commit) |
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76 return save |
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77 |
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78 def make_instance_save(instance, fields, fail_message): |
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79 """Returns the save() method for a Form.""" |
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80 def save(self, commit=True): |
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81 return save_instance(self, instance, fields, fail_message, commit) |
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82 return save |
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83 |
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84 def form_for_fields(field_list): |
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85 """ |
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86 Returns a Form class for the given list of Django database field instances. |
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87 """ |
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88 fields = SortedDict([(f.name, f.formfield()) |
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89 for f in field_list if f.editable]) |
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90 return type('FormForFields', (BaseForm,), {'base_fields': fields}) |
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91 |
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92 |
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93 # ModelForms ################################################################# |
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94 |
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95 def model_to_dict(instance, fields=None, exclude=None): |
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96 """ |
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97 Returns a dict containing the data in ``instance`` suitable for passing as |
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98 a Form's ``initial`` keyword argument. |
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99 |
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100 ``fields`` is an optional list of field names. If provided, only the named |
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101 fields will be included in the returned dict. |
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102 |
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103 ``exclude`` is an optional list of field names. If provided, the named |
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104 fields will be excluded from the returned dict, even if they are listed in |
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105 the ``fields`` argument. |
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106 """ |
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107 # avoid a circular import |
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108 from django.db.models.fields.related import ManyToManyField, OneToOneField |
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109 opts = instance._meta |
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110 data = {} |
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111 for f in opts.fields + opts.many_to_many: |
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112 if not f.editable: |
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113 continue |
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114 if fields and not f.name in fields: |
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115 continue |
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116 if exclude and f.name in exclude: |
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117 continue |
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118 if isinstance(f, ManyToManyField): |
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119 # If the object doesn't have a primry key yet, just use an empty |
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120 # list for its m2m fields. Calling f.value_from_object will raise |
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121 # an exception. |
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122 if instance.pk is None: |
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123 data[f.name] = [] |
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124 else: |
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125 # MultipleChoiceWidget needs a list of pks, not object instances. |
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126 data[f.name] = [obj.pk for obj in f.value_from_object(instance)] |
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127 else: |
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128 data[f.name] = f.value_from_object(instance) |
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129 return data |
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130 |
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131 def fields_for_model(model, fields=None, exclude=None, formfield_callback=lambda f: f.formfield()): |
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132 """ |
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133 Returns a ``SortedDict`` containing form fields for the given model. |
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134 |
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135 ``fields`` is an optional list of field names. If provided, only the named |
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136 fields will be included in the returned fields. |
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137 |
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138 ``exclude`` is an optional list of field names. If provided, the named |
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139 fields will be excluded from the returned fields, even if they are listed |
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140 in the ``fields`` argument. |
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141 """ |
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142 # TODO: if fields is provided, it would be nice to return fields in that order |
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143 field_list = [] |
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144 opts = model._meta |
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145 for f in opts.fields + opts.many_to_many: |
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146 if not f.editable: |
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147 continue |
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148 if fields and not f.name in fields: |
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149 continue |
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150 if exclude and f.name in exclude: |
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151 continue |
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152 formfield = formfield_callback(f) |
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153 if formfield: |
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154 field_list.append((f.name, formfield)) |
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155 return SortedDict(field_list) |
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156 |
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157 class ModelFormOptions(object): |
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158 def __init__(self, options=None): |
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159 self.model = getattr(options, 'model', None) |
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160 self.fields = getattr(options, 'fields', None) |
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161 self.exclude = getattr(options, 'exclude', None) |
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162 |
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163 |
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164 class ModelFormMetaclass(type): |
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165 def __new__(cls, name, bases, attrs): |
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166 formfield_callback = attrs.pop('formfield_callback', |
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167 lambda f: f.formfield()) |
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168 try: |
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169 parents = [b for b in bases if issubclass(b, ModelForm)] |
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170 except NameError: |
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171 # We are defining ModelForm itself. |
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172 parents = None |
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173 declared_fields = get_declared_fields(bases, attrs, False) |
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174 new_class = super(ModelFormMetaclass, cls).__new__(cls, name, bases, |
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175 attrs) |
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176 if not parents: |
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177 return new_class |
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178 |
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179 if 'media' not in attrs: |
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180 new_class.media = media_property(new_class) |
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181 opts = new_class._meta = ModelFormOptions(getattr(new_class, 'Meta', None)) |
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182 if opts.model: |
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183 # If a model is defined, extract form fields from it. |
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184 fields = fields_for_model(opts.model, opts.fields, |
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185 opts.exclude, formfield_callback) |
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186 # Override default model fields with any custom declared ones |
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187 # (plus, include all the other declared fields). |
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188 fields.update(declared_fields) |
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189 else: |
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190 fields = declared_fields |
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191 new_class.declared_fields = declared_fields |
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192 new_class.base_fields = fields |
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193 return new_class |
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194 |
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195 class BaseModelForm(BaseForm): |
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196 def __init__(self, data=None, files=None, auto_id='id_%s', prefix=None, |
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197 initial=None, error_class=ErrorList, label_suffix=':', |
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198 empty_permitted=False, instance=None): |
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199 opts = self._meta |
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200 if instance is None: |
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201 # if we didn't get an instance, instantiate a new one |
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202 self.instance = opts.model() |
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203 object_data = {} |
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204 else: |
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205 self.instance = instance |
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206 object_data = model_to_dict(instance, opts.fields, opts.exclude) |
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207 # if initial was provided, it should override the values from instance |
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208 if initial is not None: |
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209 object_data.update(initial) |
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210 super(BaseModelForm, self).__init__(data, files, auto_id, prefix, object_data, |
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211 error_class, label_suffix, empty_permitted) |
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212 def clean(self): |
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213 self.validate_unique() |
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214 return self.cleaned_data |
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215 |
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216 def validate_unique(self): |
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217 from django.db.models.fields import FieldDoesNotExist |
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218 |
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219 # Gather a list of checks to perform. Since this is a ModelForm, some |
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220 # fields may have been excluded; we can't perform a unique check on a |
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221 # form that is missing fields involved in that check. |
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222 unique_checks = [] |
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223 for check in self.instance._meta.unique_together[:]: |
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224 fields_on_form = [field for field in check if field in self.fields] |
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225 if len(fields_on_form) == len(check): |
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226 unique_checks.append(check) |
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227 |
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228 form_errors = [] |
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229 |
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230 # Gather a list of checks for fields declared as unique and add them to |
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231 # the list of checks. Again, skip fields not on the form. |
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232 for name, field in self.fields.items(): |
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233 try: |
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234 f = self.instance._meta.get_field_by_name(name)[0] |
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235 except FieldDoesNotExist: |
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236 # This is an extra field that's not on the ModelForm, ignore it |
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237 continue |
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238 # MySQL can't handle ... WHERE pk IS NULL, so make sure we |
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239 # don't generate queries of that form. |
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240 is_null_pk = f.primary_key and self.cleaned_data[name] is None |
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241 if name in self.cleaned_data and f.unique and not is_null_pk: |
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242 unique_checks.append((name,)) |
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243 |
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244 # Don't run unique checks on fields that already have an error. |
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245 unique_checks = [check for check in unique_checks if not [x in self._errors for x in check if x in self._errors]] |
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246 |
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247 bad_fields = set() |
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248 for unique_check in unique_checks: |
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249 # Try to look up an existing object with the same values as this |
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250 # object's values for all the unique field. |
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251 |
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252 lookup_kwargs = {} |
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253 for field_name in unique_check: |
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254 lookup_kwargs[field_name] = self.cleaned_data[field_name] |
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255 |
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256 qs = self.instance.__class__._default_manager.filter(**lookup_kwargs) |
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257 |
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258 # Exclude the current object from the query if we are editing an |
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259 # instance (as opposed to creating a new one) |
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260 if self.instance.pk is not None: |
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261 qs = qs.exclude(pk=self.instance.pk) |
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262 |
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263 # This cute trick with extra/values is the most efficient way to |
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264 # tell if a particular query returns any results. |
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265 if qs.extra(select={'a': 1}).values('a').order_by(): |
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266 model_name = capfirst(self.instance._meta.verbose_name) |
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267 |
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268 # A unique field |
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269 if len(unique_check) == 1: |
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270 field_name = unique_check[0] |
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271 field_label = self.fields[field_name].label |
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272 # Insert the error into the error dict, very sneaky |
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273 self._errors[field_name] = ErrorList([ |
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274 _(u"%(model_name)s with this %(field_label)s already exists.") % \ |
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275 {'model_name': unicode(model_name), |
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276 'field_label': unicode(field_label)} |
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277 ]) |
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278 # unique_together |
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279 else: |
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280 field_labels = [self.fields[field_name].label for field_name in unique_check] |
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281 field_labels = get_text_list(field_labels, _('and')) |
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282 form_errors.append( |
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283 _(u"%(model_name)s with this %(field_label)s already exists.") % \ |
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284 {'model_name': unicode(model_name), |
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285 'field_label': unicode(field_labels)} |
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286 ) |
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287 |
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288 # Mark these fields as needing to be removed from cleaned data |
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289 # later. |
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290 for field_name in unique_check: |
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291 bad_fields.add(field_name) |
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292 |
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293 for field_name in bad_fields: |
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294 del self.cleaned_data[field_name] |
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295 if form_errors: |
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296 # Raise the unique together errors since they are considered |
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297 # form-wide. |
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298 raise ValidationError(form_errors) |
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299 |
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300 def save(self, commit=True): |
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301 """ |
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302 Saves this ``form``'s cleaned_data into model instance |
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303 ``self.instance``. |
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304 |
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305 If commit=True, then the changes to ``instance`` will be saved to the |
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306 database. Returns ``instance``. |
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307 """ |
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308 if self.instance.pk is None: |
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309 fail_message = 'created' |
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310 else: |
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311 fail_message = 'changed' |
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312 return save_instance(self, self.instance, self._meta.fields, fail_message, commit) |
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313 |
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314 class ModelForm(BaseModelForm): |
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315 __metaclass__ = ModelFormMetaclass |
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316 |
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317 def modelform_factory(model, form=ModelForm, fields=None, exclude=None, |
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318 formfield_callback=lambda f: f.formfield()): |
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319 # HACK: we should be able to construct a ModelForm without creating |
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320 # and passing in a temporary inner class |
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321 class Meta: |
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322 pass |
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323 setattr(Meta, 'model', model) |
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324 setattr(Meta, 'fields', fields) |
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325 setattr(Meta, 'exclude', exclude) |
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326 class_name = model.__name__ + 'Form' |
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327 return ModelFormMetaclass(class_name, (form,), {'Meta': Meta, |
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328 'formfield_callback': formfield_callback}) |
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329 |
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330 |
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331 # ModelFormSets ############################################################## |
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332 |
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333 class BaseModelFormSet(BaseFormSet): |
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334 """ |
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335 A ``FormSet`` for editing a queryset and/or adding new objects to it. |
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336 """ |
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337 model = None |
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338 |
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339 def __init__(self, data=None, files=None, auto_id='id_%s', prefix=None, |
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340 queryset=None, **kwargs): |
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341 self.queryset = queryset |
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342 defaults = {'data': data, 'files': files, 'auto_id': auto_id, 'prefix': prefix} |
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343 defaults['initial'] = [model_to_dict(obj) for obj in self.get_queryset()] |
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344 defaults.update(kwargs) |
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345 super(BaseModelFormSet, self).__init__(**defaults) |
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346 |
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347 def _construct_form(self, i, **kwargs): |
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348 if i < self._initial_form_count: |
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349 kwargs['instance'] = self.get_queryset()[i] |
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350 return super(BaseModelFormSet, self)._construct_form(i, **kwargs) |
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351 |
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352 def get_queryset(self): |
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353 if not hasattr(self, '_queryset'): |
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354 if self.queryset is not None: |
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355 qs = self.queryset |
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356 else: |
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357 qs = self.model._default_manager.get_query_set() |
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358 if self.max_num > 0: |
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359 self._queryset = qs[:self.max_num] |
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360 else: |
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361 self._queryset = qs |
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362 return self._queryset |
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363 |
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364 def save_new(self, form, commit=True): |
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365 """Saves and returns a new model instance for the given form.""" |
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366 return save_instance(form, self.model(), exclude=[self._pk_field.name], commit=commit) |
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367 |
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368 def save_existing(self, form, instance, commit=True): |
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369 """Saves and returns an existing model instance for the given form.""" |
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370 return save_instance(form, instance, exclude=[self._pk_field.name], commit=commit) |
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371 |
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372 def save(self, commit=True): |
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373 """Saves model instances for every form, adding and changing instances |
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374 as necessary, and returns the list of instances. |
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375 """ |
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376 if not commit: |
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377 self.saved_forms = [] |
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378 def save_m2m(): |
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379 for form in self.saved_forms: |
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380 form.save_m2m() |
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381 self.save_m2m = save_m2m |
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382 return self.save_existing_objects(commit) + self.save_new_objects(commit) |
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383 |
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384 def save_existing_objects(self, commit=True): |
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385 self.changed_objects = [] |
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386 self.deleted_objects = [] |
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387 if not self.get_queryset(): |
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388 return [] |
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389 |
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390 # Put the objects from self.get_queryset into a dict so they are easy to lookup by pk |
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391 existing_objects = {} |
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392 for obj in self.get_queryset(): |
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393 existing_objects[obj.pk] = obj |
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394 saved_instances = [] |
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395 for form in self.initial_forms: |
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396 obj = existing_objects[form.cleaned_data[self._pk_field.name]] |
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397 if self.can_delete and form.cleaned_data[DELETION_FIELD_NAME]: |
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398 self.deleted_objects.append(obj) |
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399 obj.delete() |
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400 else: |
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401 if form.changed_data: |
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402 self.changed_objects.append((obj, form.changed_data)) |
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403 saved_instances.append(self.save_existing(form, obj, commit=commit)) |
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404 if not commit: |
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405 self.saved_forms.append(form) |
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406 return saved_instances |
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407 |
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408 def save_new_objects(self, commit=True): |
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409 self.new_objects = [] |
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410 for form in self.extra_forms: |
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411 if not form.has_changed(): |
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412 continue |
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413 # If someone has marked an add form for deletion, don't save the |
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414 # object. |
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415 if self.can_delete and form.cleaned_data[DELETION_FIELD_NAME]: |
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416 continue |
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417 self.new_objects.append(self.save_new(form, commit=commit)) |
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418 if not commit: |
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419 self.saved_forms.append(form) |
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420 return self.new_objects |
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421 |
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422 def add_fields(self, form, index): |
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423 """Add a hidden field for the object's primary key.""" |
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424 from django.db.models import AutoField |
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425 self._pk_field = pk = self.model._meta.pk |
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426 if pk.auto_created or isinstance(pk, AutoField): |
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427 form.fields[self._pk_field.name] = IntegerField(required=False, widget=HiddenInput) |
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428 super(BaseModelFormSet, self).add_fields(form, index) |
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429 |
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430 def modelformset_factory(model, form=ModelForm, formfield_callback=lambda f: f.formfield(), |
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431 formset=BaseModelFormSet, |
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432 extra=1, can_delete=False, can_order=False, |
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433 max_num=0, fields=None, exclude=None): |
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434 """ |
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435 Returns a FormSet class for the given Django model class. |
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436 """ |
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437 form = modelform_factory(model, form=form, fields=fields, exclude=exclude, |
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438 formfield_callback=formfield_callback) |
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439 FormSet = formset_factory(form, formset, extra=extra, max_num=max_num, |
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440 can_order=can_order, can_delete=can_delete) |
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441 FormSet.model = model |
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442 return FormSet |
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443 |
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444 |
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445 # InlineFormSets ############################################################# |
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446 |
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447 class BaseInlineFormSet(BaseModelFormSet): |
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448 """A formset for child objects related to a parent.""" |
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449 def __init__(self, data=None, files=None, instance=None, |
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450 save_as_new=False, prefix=None): |
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451 from django.db.models.fields.related import RelatedObject |
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452 self.instance = instance |
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453 self.save_as_new = save_as_new |
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454 # is there a better way to get the object descriptor? |
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455 self.rel_name = RelatedObject(self.fk.rel.to, self.model, self.fk).get_accessor_name() |
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456 super(BaseInlineFormSet, self).__init__(data, files, prefix=prefix or self.rel_name) |
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457 |
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458 def _construct_forms(self): |
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459 if self.save_as_new: |
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460 self._total_form_count = self._initial_form_count |
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461 self._initial_form_count = 0 |
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462 super(BaseInlineFormSet, self)._construct_forms() |
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463 |
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464 def _construct_form(self, i, **kwargs): |
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465 form = super(BaseInlineFormSet, self)._construct_form(i, **kwargs) |
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466 if self.save_as_new: |
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467 # Remove the primary key from the form's data, we are only |
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468 # creating new instances |
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469 form.data[form.add_prefix(self._pk_field.name)] = None |
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470 return form |
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471 |
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472 def get_queryset(self): |
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473 """ |
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474 Returns this FormSet's queryset, but restricted to children of |
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475 self.instance |
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476 """ |
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477 kwargs = {self.fk.name: self.instance} |
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478 return self.model._default_manager.filter(**kwargs) |
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479 |
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480 def save_new(self, form, commit=True): |
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481 kwargs = {self.fk.get_attname(): self.instance.pk} |
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482 new_obj = self.model(**kwargs) |
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483 return save_instance(form, new_obj, exclude=[self._pk_field.name], commit=commit) |
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484 |
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485 def add_fields(self, form, index): |
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486 super(BaseInlineFormSet, self).add_fields(form, index) |
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487 if self._pk_field == self.fk: |
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488 form.fields[self._pk_field.name] = IntegerField(required=False, widget=HiddenInput) |
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489 |
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490 def _get_foreign_key(parent_model, model, fk_name=None): |
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491 """ |
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492 Finds and returns the ForeignKey from model to parent if there is one. |
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493 If fk_name is provided, assume it is the name of the ForeignKey field. |
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494 """ |
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495 # avoid circular import |
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496 from django.db.models import ForeignKey |
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497 opts = model._meta |
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498 if fk_name: |
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499 fks_to_parent = [f for f in opts.fields if f.name == fk_name] |
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500 if len(fks_to_parent) == 1: |
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501 fk = fks_to_parent[0] |
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502 if not isinstance(fk, ForeignKey) or \ |
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503 (fk.rel.to != parent_model and |
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504 fk.rel.to not in parent_model._meta.get_parent_list()): |
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505 raise Exception("fk_name '%s' is not a ForeignKey to %s" % (fk_name, parent_model)) |
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506 elif len(fks_to_parent) == 0: |
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507 raise Exception("%s has no field named '%s'" % (model, fk_name)) |
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508 else: |
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509 # Try to discover what the ForeignKey from model to parent_model is |
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510 fks_to_parent = [ |
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511 f for f in opts.fields |
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512 if isinstance(f, ForeignKey) |
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513 and (f.rel.to == parent_model |
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514 or f.rel.to in parent_model._meta.get_parent_list()) |
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515 ] |
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516 if len(fks_to_parent) == 1: |
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517 fk = fks_to_parent[0] |
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518 elif len(fks_to_parent) == 0: |
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519 raise Exception("%s has no ForeignKey to %s" % (model, parent_model)) |
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520 else: |
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521 raise Exception("%s has more than 1 ForeignKey to %s" % (model, parent_model)) |
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522 return fk |
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523 |
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524 |
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525 def inlineformset_factory(parent_model, model, form=ModelForm, |
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526 formset=BaseInlineFormSet, fk_name=None, |
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527 fields=None, exclude=None, |
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528 extra=3, can_order=False, can_delete=True, max_num=0, |
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529 formfield_callback=lambda f: f.formfield()): |
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530 """ |
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531 Returns an ``InlineFormSet`` for the given kwargs. |
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532 |
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533 You must provide ``fk_name`` if ``model`` has more than one ``ForeignKey`` |
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534 to ``parent_model``. |
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535 """ |
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536 fk = _get_foreign_key(parent_model, model, fk_name=fk_name) |
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537 # enforce a max_num=1 when the foreign key to the parent model is unique. |
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538 if fk.unique: |
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539 max_num = 1 |
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540 if exclude is not None: |
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541 exclude = list(exclude) |
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542 exclude.append(fk.name) |
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543 else: |
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544 exclude = [fk.name] |
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545 kwargs = { |
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546 'form': form, |
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547 'formfield_callback': formfield_callback, |
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548 'formset': formset, |
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549 'extra': extra, |
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550 'can_delete': can_delete, |
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551 'can_order': can_order, |
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552 'fields': fields, |
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553 'exclude': exclude, |
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554 'max_num': max_num, |
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555 } |
|
556 FormSet = modelformset_factory(model, **kwargs) |
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557 FormSet.fk = fk |
|
558 return FormSet |
|
559 |
|
560 |
|
561 # Fields ##################################################################### |
|
562 |
|
563 class ModelChoiceIterator(object): |
|
564 def __init__(self, field): |
|
565 self.field = field |
|
566 self.queryset = field.queryset |
|
567 |
|
568 def __iter__(self): |
|
569 if self.field.empty_label is not None: |
|
570 yield (u"", self.field.empty_label) |
|
571 if self.field.cache_choices: |
|
572 if self.field.choice_cache is None: |
|
573 self.field.choice_cache = [ |
|
574 self.choice(obj) for obj in self.queryset.all() |
|
575 ] |
|
576 for choice in self.field.choice_cache: |
|
577 yield choice |
|
578 else: |
|
579 for obj in self.queryset.all(): |
|
580 yield self.choice(obj) |
|
581 |
|
582 def choice(self, obj): |
|
583 if self.field.to_field_name: |
|
584 # FIXME: The try..except shouldn't be necessary here. But this is |
|
585 # going in just before 1.0, so I want to be careful. Will check it |
|
586 # out later. |
|
587 try: |
|
588 key = getattr(obj, self.field.to_field_name).pk |
|
589 except AttributeError: |
|
590 key = getattr(obj, self.field.to_field_name) |
|
591 else: |
|
592 key = obj.pk |
|
593 return (key, self.field.label_from_instance(obj)) |
|
594 |
|
595 |
|
596 class ModelChoiceField(ChoiceField): |
|
597 """A ChoiceField whose choices are a model QuerySet.""" |
|
598 # This class is a subclass of ChoiceField for purity, but it doesn't |
|
599 # actually use any of ChoiceField's implementation. |
|
600 default_error_messages = { |
|
601 'invalid_choice': _(u'Select a valid choice. That choice is not one of' |
|
602 u' the available choices.'), |
|
603 } |
|
604 |
|
605 def __init__(self, queryset, empty_label=u"---------", cache_choices=False, |
|
606 required=True, widget=None, label=None, initial=None, |
|
607 help_text=None, to_field_name=None, *args, **kwargs): |
|
608 self.empty_label = empty_label |
|
609 self.cache_choices = cache_choices |
|
610 |
|
611 # Call Field instead of ChoiceField __init__() because we don't need |
|
612 # ChoiceField.__init__(). |
|
613 Field.__init__(self, required, widget, label, initial, help_text, |
|
614 *args, **kwargs) |
|
615 self.queryset = queryset |
|
616 self.choice_cache = None |
|
617 self.to_field_name = to_field_name |
|
618 |
|
619 def _get_queryset(self): |
|
620 return self._queryset |
|
621 |
|
622 def _set_queryset(self, queryset): |
|
623 self._queryset = queryset |
|
624 self.widget.choices = self.choices |
|
625 |
|
626 queryset = property(_get_queryset, _set_queryset) |
|
627 |
|
628 # this method will be used to create object labels by the QuerySetIterator. |
|
629 # Override it to customize the label. |
|
630 def label_from_instance(self, obj): |
|
631 """ |
|
632 This method is used to convert objects into strings; it's used to |
|
633 generate the labels for the choices presented by this object. Subclasses |
|
634 can override this method to customize the display of the choices. |
|
635 """ |
|
636 return smart_unicode(obj) |
|
637 |
|
638 def _get_choices(self): |
|
639 # If self._choices is set, then somebody must have manually set |
|
640 # the property self.choices. In this case, just return self._choices. |
|
641 if hasattr(self, '_choices'): |
|
642 return self._choices |
|
643 |
|
644 # Otherwise, execute the QuerySet in self.queryset to determine the |
|
645 # choices dynamically. Return a fresh QuerySetIterator that has not been |
|
646 # consumed. Note that we're instantiating a new QuerySetIterator *each* |
|
647 # time _get_choices() is called (and, thus, each time self.choices is |
|
648 # accessed) so that we can ensure the QuerySet has not been consumed. This |
|
649 # construct might look complicated but it allows for lazy evaluation of |
|
650 # the queryset. |
|
651 return ModelChoiceIterator(self) |
|
652 |
|
653 choices = property(_get_choices, ChoiceField._set_choices) |
|
654 |
|
655 def clean(self, value): |
|
656 Field.clean(self, value) |
|
657 if value in EMPTY_VALUES: |
|
658 return None |
|
659 try: |
|
660 key = self.to_field_name or 'pk' |
|
661 value = self.queryset.get(**{key: value}) |
|
662 except self.queryset.model.DoesNotExist: |
|
663 raise ValidationError(self.error_messages['invalid_choice']) |
|
664 return value |
|
665 |
|
666 class ModelMultipleChoiceField(ModelChoiceField): |
|
667 """A MultipleChoiceField whose choices are a model QuerySet.""" |
|
668 widget = SelectMultiple |
|
669 hidden_widget = MultipleHiddenInput |
|
670 default_error_messages = { |
|
671 'list': _(u'Enter a list of values.'), |
|
672 'invalid_choice': _(u'Select a valid choice. %s is not one of the' |
|
673 u' available choices.'), |
|
674 } |
|
675 |
|
676 def __init__(self, queryset, cache_choices=False, required=True, |
|
677 widget=None, label=None, initial=None, |
|
678 help_text=None, *args, **kwargs): |
|
679 super(ModelMultipleChoiceField, self).__init__(queryset, None, |
|
680 cache_choices, required, widget, label, initial, help_text, |
|
681 *args, **kwargs) |
|
682 |
|
683 def clean(self, value): |
|
684 if self.required and not value: |
|
685 raise ValidationError(self.error_messages['required']) |
|
686 elif not self.required and not value: |
|
687 return [] |
|
688 if not isinstance(value, (list, tuple)): |
|
689 raise ValidationError(self.error_messages['list']) |
|
690 final_values = [] |
|
691 for val in value: |
|
692 try: |
|
693 obj = self.queryset.get(pk=val) |
|
694 except self.queryset.model.DoesNotExist: |
|
695 raise ValidationError(self.error_messages['invalid_choice'] % val) |
|
696 else: |
|
697 final_values.append(obj) |
|
698 return final_values |