Ticket #7894: file_wrapper_response2.diff

django/http/__init__.py

@@ -424 +424 @@
     def __init__(self, *args, **kwargs):
         HttpResponse.__init__(self, *args, **kwargs)
 
+
+class FileWrapper(object):
+    def __init__(self, file_path, block_size, byte_count, offset):
+        self.__dict__.update(locals())
+
+    def __iter__(self):
+        self.file = open(self.file_path, 'rb')
+        self.close = self.file.close
+        if self.offset:
+            self.file.seek(self.offset)
+        self.bytes_left = self.byte_count
+        return self
+        
+    def next(self):
+        if self.bytes_left > 0:
+            data_size = min(self.block_size, self.bytes_left)
+            data = self.file.read(data_size)
+            if data:
+                self.bytes_left -= data_size
+                return data
+        raise StopIteration
+
+
+class HttpResponseFileWrapper(HttpResponse):
+    def __init__(self, file_path, block_size=8192, length=None, offset=0, **kwargs):
+        content_length = length or os.path.getsize(file_path)
+        HttpResponse.__init__(self, content=FileWrapper(file_path, block_size, content_length, offset), **kwargs)
+        self.file_path = file_path
+        self.block_size = block_size
+        self.length = length
+        self.offset = offset
+        self['Content-Length'] = content_length
+
+
 # A backwards compatible alias for HttpRequest.get_host.
 def get_host(request):
     return request.get_host()

django/core/servers/basehttp.py

@@ -312 +312 @@
         in the event loop to iterate over the data, and to call
         'self.close()' once the response is finished.
         """
-        if not self.result_is_file() and not self.sendfile():
+        if not self.result_is_file() or not self.sendfile():
             for data in self.result:
                 self.write(data)
             self.finish_content()

django/core/handlers/wsgi.py

@@ -1 +1 @@
 from threading import Lock
+import os
 from pprint import pformat
 try:
     from cStringIO import StringIO
@@ -194 +195 @@
     initLock = Lock()
     request_class = WSGIRequest
 
+    def wsgi_adaptor_honours_content_length(self, environ):
+        return 'mod_wsgi.callable_object' in environ
+    
     def __call__(self, environ, start_response):
         from django.conf import settings
 
@@ -232 +236 @@
         for c in response.cookies.values():
             response_headers.append(('Set-Cookie', str(c.output(header=''))))
         start_response(status, response_headers)
-        return response
+        if (isinstance(response, http.HttpResponseFileWrapper) and
+            'wsgi.file_wrapper'in environ and
+            (response.length is None or
+             self.wsgi_adaptor_honours_content_length(environ) or
+             response.length == os.path.getsize(response.file_path))):
+            f = open(response.file_path, 'rb')
+            if response.offset:
+                f.seek(response.offset)
+            return environ['wsgi.file_wrapper'](f, response.block_size)
+        else:
+            return response
 

django/core/handlers/modpython.py

@@ -199 +199 @@
             req.headers_out.add('Set-Cookie', c.output(header=''))
         req.status = response.status_code
         try:
-            for chunk in response:
-                req.write(chunk)
+            if isinstance(response, http.HttpResponseFileWrapper):
+                if response.length is None:
+                    length = -1
+                else:
+                    length = response.length
+                req.sendfile(response.file_path, response.offset, length)
+            else:
+                for chunk in response:
+                    req.write(chunk)
         finally:
             response.close()
-
         return 0 # mod_python.apache.OK
 
 def handler(req):

tests/regressiontests/httpwrappers/tests.py

@@ -426 +426 @@
 Traceback (most recent call last):
 ...
 UnicodeEncodeError: ..., HTTP response headers must be in US-ASCII format
- 
+
+
+###########################
+# HttpResponseFileWrapper # 
+###########################
+
+Get the path of the test file
+
+>>> import os
+>>> test_file_path = os.path.join(os.path.dirname(__file__), 'test_file.txt')
+
+Create a response with the file path
+
+>>> r = HttpResponseFileWrapper(test_file_path, mimetype='text/plain')
+
+The response's content defaults to an iterator over the file data
+
+>>> ''.join(list(r))
+'123456789 Heres some data!'
+
+An offset and length can be provided limit the data read from the file
+
+>>> r = HttpResponseFileWrapper(test_file_path, offset=2, length=5)
+>>> ''.join(list(r))
+'34567'
+
+A block_size can also be passed in as a suggestion for the block size to read
+
+>>> r = HttpResponseFileWrapper(test_file_path, offset=2, length=5, block_size=4024)
+
+Handler can choose to deliver the file's data using alternative means by using the response's properties rather than treating it as an iterator
+
+>>> r.file_path == test_file_path
+True
+
+>>> r.offset
+2
+
+>>> r.length
+5
+
+>>> r.block_size
+4024
+
 """
 
-from django.http import QueryDict, HttpResponse
+from django.http import QueryDict, HttpResponse, HttpResponseFileWrapper
 
 if __name__ == "__main__":
     import doctest