diff -r 5ff1fc726848 -r c6bca38c1cbf parts/django/docs/ref/request-response.txt
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/parts/django/docs/ref/request-response.txt	Sat Jan 08 11:20:57 2011 +0530
@@ -0,0 +1,646 @@
+============================
+Request and response objects
+============================
+
+.. module:: django.http
+   :synopsis: Classes dealing with HTTP requests and responses.
+
+Quick overview
+==============
+
+Django uses request and response objects to pass state through the system.
+
+When a page is requested, Django creates an :class:`HttpRequest` object that
+contains metadata about the request. Then Django loads the appropriate view,
+passing the :class:`HttpRequest` as the first argument to the view function.
+Each view is responsible for returning an :class:`HttpResponse` object.
+
+This document explains the APIs for :class:`HttpRequest` and
+:class:`HttpResponse` objects.
+
+HttpRequest objects
+===================
+
+.. class:: HttpRequest
+
+Attributes
+----------
+
+All attributes except ``session`` should be considered read-only.
+
+.. attribute:: HttpRequest.path
+
+    A string representing the full path to the requested page, not including
+    the domain.
+
+    Example: ``"/music/bands/the_beatles/"``
+
+.. attribute:: HttpRequest.path_info
+
+    Under some web server configurations, the portion of the URL after the host
+    name is split up into a script prefix portion and a path info portion
+    (this happens, for example, when using the ``django.root`` option
+    with the :ref:`modpython handler from Apache <howto-deployment-modpython>`).
+    The ``path_info`` attribute always contains the path info portion of the
+    path, no matter what web server is being used. Using this instead of
+    attr:`~HttpRequest.path` can make your code much easier to move between test
+    and deployment servers.
+
+    For example, if the ``django.root`` for your application is set to 
+    ``"/minfo"``, then ``path`` might be ``"/minfo/music/bands/the_beatles/"``
+    and ``path_info`` would be ``"/music/bands/the_beatles/"``.
+
+.. attribute:: HttpRequest.method
+
+    A string representing the HTTP method used in the request. This is
+    guaranteed to be uppercase. Example::
+
+        if request.method == 'GET':
+            do_something()
+        elif request.method == 'POST':
+            do_something_else()
+
+.. attribute:: HttpRequest.encoding
+
+    A string representing the current encoding used to decode form submission
+    data (or ``None``, which means the :setting:`DEFAULT_CHARSET` setting is
+    used). You can write to this attribute to change the encoding used when
+    accessing the form data. Any subsequent attribute accesses (such as reading
+    from ``GET`` or ``POST``) will use the new ``encoding`` value.  Useful if
+    you know the form data is not in the :setting:`DEFAULT_CHARSET` encoding.
+
+.. attribute:: HttpRequest.GET
+
+    A dictionary-like object containing all given HTTP GET parameters. See the
+    :class:`QueryDict` documentation below.
+
+.. attribute:: HttpRequest.POST
+
+    A dictionary-like object containing all given HTTP POST parameters. See the
+    :class:`QueryDict` documentation below.
+
+    It's possible that a request can come in via POST with an empty ``POST``
+    dictionary -- if, say, a form is requested via the POST HTTP method but
+    does not include form data. Therefore, you shouldn't use ``if request.POST``
+    to check for use of the POST method; instead, use ``if request.method ==
+    "POST"`` (see above).
+
+    Note: ``POST`` does *not* include file-upload information. See ``FILES``.
+
+.. attribute:: HttpRequest.REQUEST
+
+    For convenience, a dictionary-like object that searches ``POST`` first,
+    then ``GET``. Inspired by PHP's ``$_REQUEST``.
+
+    For example, if ``GET = {"name": "john"}`` and ``POST = {"age": '34'}``,
+    ``REQUEST["name"]`` would be ``"john"``, and ``REQUEST["age"]`` would be
+    ``"34"``.
+
+    It's strongly suggested that you use ``GET`` and ``POST`` instead of
+    ``REQUEST``, because the former are more explicit.
+
+.. attribute:: HttpRequest.COOKIES
+
+    A standard Python dictionary containing all cookies. Keys and values are
+    strings.
+
+.. attribute:: HttpRequest.FILES
+
+    A dictionary-like object containing all uploaded files. Each key in
+    ``FILES`` is the ``name`` from the ``<input type="file" name="" />``. Each
+    value in ``FILES`` is an :class:`UploadedFile` as described below.
+
+    See :doc:`/topics/files` for more information.
+
+    Note that ``FILES`` will only contain data if the request method was POST
+    and the ``<form>`` that posted to the request had
+    ``enctype="multipart/form-data"``. Otherwise, ``FILES`` will be a blank
+    dictionary-like object.
+
+    .. versionchanged:: 1.0
+
+    In previous versions of Django, ``request.FILES`` contained simple ``dict``
+    objects representing uploaded files. This is no longer true -- files are
+    represented by :class:`UploadedFile` objects.
+
+    These :class:`UploadedFile` objects will emulate the old-style ``dict``
+    interface, but this is deprecated and will be removed in the next release
+    of Django.
+
+.. attribute:: HttpRequest.META
+
+    A standard Python dictionary containing all available HTTP headers.
+    Available headers depend on the client and server, but here are some
+    examples:
+
+        * ``CONTENT_LENGTH``
+        * ``CONTENT_TYPE``
+        * ``HTTP_ACCEPT_ENCODING``
+        * ``HTTP_ACCEPT_LANGUAGE``
+        * ``HTTP_HOST`` -- The HTTP Host header sent by the client.
+        * ``HTTP_REFERER`` -- The referring page, if any.
+        * ``HTTP_USER_AGENT`` -- The client's user-agent string.
+        * ``QUERY_STRING`` -- The query string, as a single (unparsed) string.
+        * ``REMOTE_ADDR`` -- The IP address of the client.
+        * ``REMOTE_HOST`` -- The hostname of the client.
+        * ``REMOTE_USER`` -- The user authenticated by the Web server, if any.
+        * ``REQUEST_METHOD`` -- A string such as ``"GET"`` or ``"POST"``.
+        * ``SERVER_NAME`` -- The hostname of the server.
+        * ``SERVER_PORT`` -- The port of the server.
+
+    With the exception of ``CONTENT_LENGTH`` and ``CONTENT_TYPE``, as given
+    above, any HTTP headers in the request are converted to ``META`` keys by
+    converting all characters to uppercase, replacing any hyphens with
+    underscores and adding an ``HTTP_`` prefix to the name. So, for example, a
+    header called ``X-Bender`` would be mapped to the ``META`` key
+    ``HTTP_X_BENDER``.
+
+.. attribute:: HttpRequest.user
+
+    A ``django.contrib.auth.models.User`` object representing the currently
+    logged-in user. If the user isn't currently logged in, ``user`` will be set
+    to an instance of ``django.contrib.auth.models.AnonymousUser``. You
+    can tell them apart with ``is_authenticated()``, like so::
+
+        if request.user.is_authenticated():
+            # Do something for logged-in users.
+        else:
+            # Do something for anonymous users.
+
+    ``user`` is only available if your Django installation has the
+    ``AuthenticationMiddleware`` activated. For more, see
+    :doc:`/topics/auth`.
+
+.. attribute:: HttpRequest.session
+
+    A readable-and-writable, dictionary-like object that represents the current
+    session. This is only available if your Django installation has session
+    support activated. See the :doc:`session documentation
+    </topics/http/sessions>` for full details.
+
+.. attribute:: HttpRequest.raw_post_data
+
+    The raw HTTP POST data. This is only useful for advanced processing. Use
+    ``POST`` instead.
+
+.. attribute:: HttpRequest.urlconf
+
+    Not defined by Django itself, but will be read if other code (e.g., a custom
+    middleware class) sets it. When present, this will be used as the root
+    URLconf for the current request, overriding the :setting:`ROOT_URLCONF`
+    setting. See :ref:`how-django-processes-a-request` for details.
+
+Methods
+-------
+
+.. method:: HttpRequest.get_host()
+
+    Returns the originating host of the request using information from the
+    ``HTTP_X_FORWARDED_HOST`` and ``HTTP_HOST`` headers (in that order). If
+    they don't provide a value, the method uses a combination of
+    ``SERVER_NAME`` and ``SERVER_PORT`` as detailed in `PEP 333`_.
+
+    .. _PEP 333: http://www.python.org/dev/peps/pep-0333/
+
+    Example: ``"127.0.0.1:8000"``
+
+    .. note:: The :meth:`~HttpRequest.get_host()` method fails when the host is
+        behind multiple proxies. One solution is to use middleware to rewrite
+        the proxy headers, as in the following example::
+
+            class MultipleProxyMiddleware(object):
+                FORWARDED_FOR_FIELDS = [
+                    'HTTP_X_FORWARDED_FOR',
+                    'HTTP_X_FORWARDED_HOST',
+                    'HTTP_X_FORWARDED_SERVER',
+                ]
+
+                def process_request(self, request):
+                    """
+                    Rewrites the proxy headers so that only the most
+                    recent proxy is used.
+                    """
+                    for field in self.FORWARDED_FOR_FIELDS:
+                        if field in request.META:
+                            if ',' in request.META[field]:
+                                parts = request.META[field].split(',')
+                                request.META[field] = parts[-1].strip()
+
+
+.. method:: HttpRequest.get_full_path()
+
+   Returns the ``path``, plus an appended query string, if applicable.
+
+   Example: ``"/music/bands/the_beatles/?print=true"``
+
+.. method:: HttpRequest.build_absolute_uri(location)
+
+   Returns the absolute URI form of ``location``. If no location is provided,
+   the location will be set to ``request.get_full_path()``.
+
+   If the location is already an absolute URI, it will not be altered.
+   Otherwise the absolute URI is built using the server variables available in
+   this request.
+
+   Example: ``"http://example.com/music/bands/the_beatles/?print=true"``
+
+.. method:: HttpRequest.is_secure()
+
+   Returns ``True`` if the request is secure; that is, if it was made with
+   HTTPS.
+
+.. method:: HttpRequest.is_ajax()
+
+   Returns ``True`` if the request was made via an ``XMLHttpRequest``, by
+   checking the ``HTTP_X_REQUESTED_WITH`` header for the string
+   ``'XMLHttpRequest'``. Most modern JavaScript libraries send this header.
+   If you write your own XMLHttpRequest call (on the browser side), you'll
+   have to set this header manually if you want ``is_ajax()`` to work.
+
+
+UploadedFile objects
+====================
+
+.. class:: UploadedFile
+
+
+Attributes
+----------
+
+.. attribute::  UploadedFile.name
+
+    The name of the uploaded file.
+
+.. attribute:: UploadedFile.size
+
+    The size, in bytes, of the uploaded file.
+
+Methods
+----------
+
+.. method:: UploadedFile.chunks(chunk_size=None)
+
+    Returns a generator that yields sequential chunks of data.
+
+.. method:: UploadedFile.read(num_bytes=None)
+
+    Read a number of bytes from the file.
+
+
+
+QueryDict objects
+=================
+
+.. class:: QueryDict
+
+In an :class:`HttpRequest` object, the ``GET`` and ``POST`` attributes are instances
+of ``django.http.QueryDict``. :class:`QueryDict` is a dictionary-like
+class customized to deal with multiple values for the same key. This is
+necessary because some HTML form elements, notably
+``<select multiple="multiple">``, pass multiple values for the same key.
+
+``QueryDict`` instances are immutable, unless you create a ``copy()`` of them.
+That means you can't change attributes of ``request.POST`` and ``request.GET``
+directly.
+
+Methods
+-------
+
+:class:`QueryDict` implements all the standard dictionary methods, because it's
+a subclass of dictionary. Exceptions are outlined here:
+
+.. method:: QueryDict.__getitem__(key)
+
+    Returns the value for the given key. If the key has more than one value,
+    ``__getitem__()`` returns the last value. Raises
+    ``django.utils.datastructures.MultiValueDictKeyError`` if the key does not
+    exist. (This is a subclass of Python's standard ``KeyError``, so you can
+    stick to catching ``KeyError``.)
+
+.. method:: QueryDict.__setitem__(key, value)
+
+    Sets the given key to ``[value]`` (a Python list whose single element is
+    ``value``). Note that this, as other dictionary functions that have side
+    effects, can only be called on a mutable ``QueryDict`` (one that was created
+    via ``copy()``).
+
+.. method:: QueryDict.__contains__(key)
+
+    Returns ``True`` if the given key is set. This lets you do, e.g., ``if "foo"
+    in request.GET``.
+
+.. method:: QueryDict.get(key, default)
+
+    Uses the same logic as ``__getitem__()`` above, with a hook for returning a
+    default value if the key doesn't exist.
+
+.. method:: QueryDict.setdefault(key, default)
+
+    Just like the standard dictionary ``setdefault()`` method, except it uses
+    ``__setitem__()`` internally.
+
+.. method:: QueryDict.update(other_dict)
+
+    Takes either a ``QueryDict`` or standard dictionary. Just like the standard
+    dictionary ``update()`` method, except it *appends* to the current
+    dictionary items rather than replacing them. For example::
+
+          >>> q = QueryDict('a=1')
+          >>> q = q.copy() # to make it mutable
+          >>> q.update({'a': '2'})
+          >>> q.getlist('a')
+          [u'1', u'2']
+          >>> q['a'] # returns the last
+          [u'2']
+
+.. method:: QueryDict.items()
+
+    Just like the standard dictionary ``items()`` method, except this uses the
+    same last-value logic as ``__getitem__()``. For example::
+
+           >>> q = QueryDict('a=1&a=2&a=3')
+           >>> q.items()
+           [(u'a', u'3')]
+
+.. method:: QueryDict.iteritems()
+
+    Just like the standard dictionary ``iteritems()`` method. Like
+    :meth:`QueryDict.items()` this uses the same last-value logic as
+    :meth:`QueryDict.__getitem__()`.
+
+.. method:: QueryDict.iterlists()
+
+    Like :meth:`QueryDict.iteritems()` except it includes all values, as a list,
+    for each member of the dictionary.
+
+.. method:: QueryDict.values()
+
+    Just like the standard dictionary ``values()`` method, except this uses the
+    same last-value logic as ``__getitem__()``. For example::
+
+           >>> q = QueryDict('a=1&a=2&a=3')
+           >>> q.values()
+           [u'3']
+
+.. method:: QueryDict.itervalues()
+
+    Just like :meth:`QueryDict.values()`, except an iterator.
+
+In addition, ``QueryDict`` has the following methods:
+
+.. method:: QueryDict.copy()
+
+    Returns a copy of the object, using ``copy.deepcopy()`` from the Python
+    standard library. The copy will be mutable -- that is, you can change its
+    values.
+
+.. method:: QueryDict.getlist(key)
+
+    Returns the data with the requested key, as a Python list. Returns an
+    empty list if the key doesn't exist. It's guaranteed to return a list of
+    some sort.
+
+.. method:: QueryDict.setlist(key, list_)
+
+    Sets the given key to ``list_`` (unlike ``__setitem__()``).
+
+.. method:: QueryDict.appendlist(key, item)
+
+    Appends an item to the internal list associated with key.
+
+.. method:: QueryDict.setlistdefault(key, default_list)
+
+    Just like ``setdefault``, except it takes a list of values instead of a
+    single value.
+
+.. method:: QueryDict.lists()
+
+    Like :meth:`items()`, except it includes all values, as a list, for each
+    member of the dictionary. For example::
+
+         >>> q = QueryDict('a=1&a=2&a=3')
+         >>> q.lists()
+         [(u'a', [u'1', u'2', u'3'])]
+
+.. method:: QueryDict.urlencode()
+
+    Returns a string of the data in query-string format.
+    Example: ``"a=2&b=3&b=5"``.
+
+HttpResponse objects
+====================
+
+.. class:: HttpResponse
+
+In contrast to :class:`HttpRequest` objects, which are created automatically by
+Django, :class:`HttpResponse` objects are your responsibility. Each view you
+write is responsible for instantiating, populating and returning an
+:class:`HttpResponse`.
+
+The :class:`HttpResponse` class lives in the :mod:`django.http` module.
+
+Usage
+-----
+
+Passing strings
+~~~~~~~~~~~~~~~
+
+Typical usage is to pass the contents of the page, as a string, to the
+:class:`HttpResponse` constructor::
+
+    >>> response = HttpResponse("Here's the text of the Web page.")
+    >>> response = HttpResponse("Text only, please.", mimetype="text/plain")
+
+But if you want to add content incrementally, you can use ``response`` as a
+file-like object::
+
+    >>> response = HttpResponse()
+    >>> response.write("<p>Here's the text of the Web page.</p>")
+    >>> response.write("<p>Here's another paragraph.</p>")
+
+Passing iterators
+~~~~~~~~~~~~~~~~~
+
+Finally, you can pass ``HttpResponse`` an iterator rather than passing it
+hard-coded strings. If you use this technique, follow these guidelines:
+
+    * The iterator should return strings.
+    * If an :class:`HttpResponse` has been initialized with an iterator as its
+      content, you can't use the class:`HttpResponse` instance as a file-like
+      object. Doing so will raise ``Exception``.
+
+Setting headers
+~~~~~~~~~~~~~~~
+
+To set or remove a header in your response, treat it like a dictionary::
+
+    >>> response = HttpResponse()
+    >>> response['Cache-Control'] = 'no-cache'
+    >>> del response['Cache-Control']
+
+Note that unlike a dictionary, ``del`` doesn't raise ``KeyError`` if the header
+doesn't exist.
+
+.. versionadded:: 1.1
+
+HTTP headers cannot contain newlines. An attempt to set a header containing a
+newline character (CR or LF) will raise ``BadHeaderError``
+
+Telling the browser to treat the response as a file attachment
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+To tell the browser to treat the response as a file attachment, use the
+``mimetype`` argument and set the ``Content-Disposition`` header. For example,
+this is how you might return a Microsoft Excel spreadsheet::
+
+    >>> response = HttpResponse(my_data, mimetype='application/vnd.ms-excel')
+    >>> response['Content-Disposition'] = 'attachment; filename=foo.xls'
+
+There's nothing Django-specific about the ``Content-Disposition`` header, but
+it's easy to forget the syntax, so we've included it here.
+
+Attributes
+----------
+
+.. attribute:: HttpResponse.content
+
+    A normal Python string representing the content, encoded from a Unicode
+    object if necessary.
+
+.. attribute:: HttpResponse.status_code
+
+    The `HTTP Status code`_ for the response.
+
+Methods
+-------
+
+.. method:: HttpResponse.__init__(content='', mimetype=None, status=200, content_type=DEFAULT_CONTENT_TYPE)
+
+    Instantiates an ``HttpResponse`` object with the given page content (a
+    string) and MIME type. The :setting:`DEFAULT_CONTENT_TYPE` is
+    ``'text/html'``.
+
+    ``content`` can be an iterator or a string. If it's an iterator, it should
+    return strings, and those strings will be joined together to form the
+    content of the response.
+
+    ``status`` is the `HTTP Status code`_ for the response.
+
+    ``content_type`` is an alias for ``mimetype``. Historically, this parameter
+    was only called ``mimetype``, but since this is actually the value included
+    in the HTTP ``Content-Type`` header, it can also include the character set
+    encoding, which makes it more than just a MIME type specification.
+    If ``mimetype`` is specified (not ``None``), that value is used.
+    Otherwise, ``content_type`` is used. If neither is given, the
+    :setting:`DEFAULT_CONTENT_TYPE` setting is used.
+
+.. method:: HttpResponse.__setitem__(header, value)
+
+    Sets the given header name to the given value. Both ``header`` and
+    ``value`` should be strings.
+
+.. method:: HttpResponse.__delitem__(header)
+
+    Deletes the header with the given name. Fails silently if the header
+    doesn't exist. Case-insensitive.
+
+.. method:: HttpResponse.__getitem__(header)
+
+    Returns the value for the given header name. Case-insensitive.
+
+.. method:: HttpResponse.has_header(header)
+
+    Returns ``True`` or ``False`` based on a case-insensitive check for a
+    header with the given name.
+
+.. method:: HttpResponse.set_cookie(key, value='', max_age=None, expires=None, path='/', domain=None, secure=None)
+
+    Sets a cookie. The parameters are the same as in the `cookie Morsel`_
+    object in the Python standard library.
+
+        * ``max_age`` should be a number of seconds, or ``None`` (default) if
+          the cookie should last only as long as the client's browser session.
+        * ``expires`` should be a string in the format
+          ``"Wdy, DD-Mon-YY HH:MM:SS GMT"``.
+        * Use ``domain`` if you want to set a cross-domain cookie. For example,
+          ``domain=".lawrence.com"`` will set a cookie that is readable by
+          the domains www.lawrence.com, blogs.lawrence.com and
+          calendars.lawrence.com. Otherwise, a cookie will only be readable by
+          the domain that set it.
+
+    .. _`cookie Morsel`: http://docs.python.org/library/cookie.html#Cookie.Morsel
+
+.. method:: HttpResponse.delete_cookie(key, path='/', domain=None)
+
+    Deletes the cookie with the given key. Fails silently if the key doesn't
+    exist.
+
+    Due to the way cookies work, ``path`` and ``domain`` should be the same
+    values you used in ``set_cookie()`` -- otherwise the cookie may not be
+    deleted.
+
+.. method:: HttpResponse.write(content)
+
+    This method makes an :class:`HttpResponse` instance a file-like object.
+
+.. method:: HttpResponse.flush()
+
+    This method makes an :class:`HttpResponse` instance a file-like object.
+
+.. method:: HttpResponse.tell()
+
+    This method makes an :class:`HttpResponse` instance a file-like object.
+
+.. _HTTP Status code: http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10
+
+
+.. _ref-httpresponse-subclasses:
+
+HttpResponse subclasses
+-----------------------
+
+Django includes a number of ``HttpResponse`` subclasses that handle different
+types of HTTP responses. Like ``HttpResponse``, these subclasses live in
+:mod:`django.http`.
+
+.. class:: HttpResponseRedirect
+
+    The constructor takes a single argument -- the path to redirect to. This
+    can be a fully qualified URL (e.g. ``'http://www.yahoo.com/search/'``) or
+    an absolute path with no domain (e.g. ``'/search/'``). Note that this
+    returns an HTTP status code 302.
+
+.. class:: HttpResponsePermanentRedirect
+
+    Like :class:`HttpResponseRedirect`, but it returns a permanent redirect
+    (HTTP status code 301) instead of a "found" redirect (status code 302).
+
+.. class:: HttpResponseNotModified
+
+    The constructor doesn't take any arguments. Use this to designate that a
+    page hasn't been modified since the user's last request (status code 304).
+
+.. class:: HttpResponseBadRequest
+
+    Acts just like :class:`HttpResponse` but uses a 400 status code.
+
+.. class:: HttpResponseNotFound
+
+    Acts just like :class:`HttpResponse` but uses a 404 status code.
+
+.. class:: HttpResponseForbidden
+
+    Acts just like :class:`HttpResponse` but uses a 403 status code.
+
+.. class:: HttpResponseNotAllowed
+
+    Like :class:`HttpResponse`, but uses a 405 status code. Takes a single,
+    required argument: a list of permitted methods (e.g. ``['GET', 'POST']``).
+
+.. class:: HttpResponseGone
+
+    Acts just like :class:`HttpResponse` but uses a 410 status code.
+
+.. class:: HttpResponseServerError
+
+    Acts just like :class:`HttpResponse` but uses a 500 status code.