Ticket #2504: 2504_http_response_and_conditional_middleware.patch

django/http/__init__.py

@@ -18 +18 @@
 class Http404(Exception):
     pass
 
+class UnknownSize(Exception):
+    pass
+
 class HttpRequest(object):
     "A basic HTTP request"
 
@@ -314 +317 @@
 
     def _get_content(self):
         if self.has_header('Content-Encoding'):
-            return ''.join(self._container)
-        return smart_str(''.join(self._container), self._charset)
+            content = ''.join(self._container)
+        else:
+            content = smart_str(''.join(self._container), self._charset)
+        # cache generated output
+        self.content = content
+        return content
 
     def _set_content(self, value):
         self._container = [value]
         self._is_string = True
 
+    def get_content_length(self):
+        # try to determin the length of the file
+        #
+        if isinstance(self._container, file):
+            if os.path.exists(self._container.name):
+                return os.path.getsize(self._container.name)
+            else:
+                raise UnknownSize, "size of file can't be determined"
+        return len(self.content)
+
+
     content = property(_get_content, _set_content)
 
     def __iter__(self):

django/middleware/http.py

@@ -11 +11 @@
     def process_response(self, request, response):
         response['Date'] = http_date()
         if not response.has_header('Content-Length'):
-            response['Content-Length'] = str(len(response.content))
+            try:
+                clength = response.get_content_length()
+                response['Content-Length'] = str(clength)
+            except http.UnknownSize:
+                # FIXME we could switch to chunked transfer encoding if
+                # self.META['SERVER_PROTOCOL'] == "HTTP/1.1"
+                # don't sending a Content-Length is legal and EOF
+                # of tcp connection determins end of stream
+                pass
 
         if response.has_header('ETag'):
             if_none_match = request.META.get('HTTP_IF_NONE_MATCH', None)

tests/regressiontests/httpwrappers/tests.py

@@ -391 +391 @@
 >>> q.getlist('foo')
 [u'bar', u'\ufffd']
 
+>>> r = HttpResponse()
+>>> r.get_content_length()
+0
+
+>>> r = HttpResponse('foo')
+>>> r.get_content_length()
+3
+
+>>> r = HttpResponse('foo')
+>>> r.write('bar')
+>>> r.get_content_length()
+6
+
+>>> r = HttpResponse(['foo', 'bar', 'foobar'])
+>>> r.get_content_length()
+12
+
+>>> r = HttpResponse(file(__file__))
+>>> assert r.get_content_length() > 0
+
+>>> import os, os.path
+>>> if os.path.isfile("/bin/echo"):
+...    fp = os.popen2("echo")
+...    r = HttpResponse(fp[1])
+...    r.get_content_length()
+Traceback (most recent call last):
+  ...
+UnknownSize: size of file can't be determined
+
+>>> def ten_foos():
+...     for i in range(10): yield 'foo'
+
+>>> r = HttpResponse(ten_foos())
+>>> r.get_content_length()
+30
+>>> print r.content
+foofoofoofoofoofoofoofoofoofoo
+
 """
 
-from django.http import QueryDict
+from django.http import QueryDict, HttpResponse
 
 if __name__ == "__main__":
     import doctest

docs/request_response.txt

@@ -431 +431 @@
 ``write(content)``, ``flush()`` and ``tell()``
     These methods make an ``HttpResponse`` instance a file-like object.
 
+``get_content_length``
+    **(New in Django development version)** 
+    Returns the length of the content. 
+    If the content of HttpResponse is a Filepointer to a file, the filesize is returned. 
+    It the Filepointer is a pipe, django.http.UnknownSize exception is raised.
+
 .. _HTTP Status code: http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10
 
 HttpResponse subclasses