Merge

doc/modules/wsgi.rst

@@ -21,5 +21,41 @@ To launch a wsgi server, simply create a socket and call :func:`eventlet.wsgi.se
 You can find a slightly more elaborate version of this code in the file
 ``examples/wsgi.py``.
 
+Non-Standard Extension to Support Post Hooks
+--------------------------------------------
+Eventlet's WSGI server supports a non-standard extension to the WSGI
+specification where :samp:`env['eventlet.posthooks']` contains an array of
+`post hooks` that will be called after fully sending a response. Each post hook
+is a tuple of :samp:`(func, args, kwargs)` and the `func` will be called with
+the WSGI environment dictionary, followed by the `args` and then the `kwargs`
+in the post hook.
+
+For example::
+
+    from eventlet import wsgi
+    import eventlet
+
+    def hook(env, arg1, arg2, kwarg3=None, kwarg4=None):
+        print 'Hook called: %s %s %s %s %s' % (env, arg1, arg2, kwarg3, kwarg4)
+    
+    def hello_world(env, start_response):
+        env['eventlet.posthooks'].append(
+            (hook, ('arg1', 'arg2'), {'kwarg3': 3, 'kwarg4': 4}))
+        start_response('200 OK', [('Content-Type', 'text/plain')])
+        return ['Hello, World!\r\n']
+    
+    wsgi.server(eventlet.listen(('', 8090)), hello_world)
+
+The above code will print the WSGI environment and the other passed function
+arguments for every request processed.
+
+Post hooks are useful when code needs to be executed after a response has been
+fully sent to the client (or when the client disconnects early). One example is
+for more accurate logging of bandwidth used, as client disconnects use less
+bandwidth than the actual Content-Length.
+
+API
+---
+
 .. automodule:: eventlet.wsgi
 	:members:

eventlet/wsgi.py

@@ -376,6 +376,9 @@ class HttpProtocol(BaseHTTPServer.BaseHTTPRequestHandler):
                         pass
             finish = time.time()
 
+            for hook, args, kwargs in self.environ['eventlet.posthooks']:
+                hook(self.environ, *args, **kwargs)
+
             self.server.log_message(self.server.log_format % dict(
                 client_ip=self.get_client_ip(),
                 date_time=self.log_date_time_string(),
@@ -442,6 +445,7 @@ class HttpProtocol(BaseHTTPServer.BaseHTTPRequestHandler):
         env['wsgi.input'] = env['eventlet.input'] = Input(
             self.rfile, length, wfile=wfile, wfile_line=wfile_line,
             chunked_input=chunked)
+        env['eventlet.posthooks'] = []
 
         return env
 

tests/wsgi_test.py

@@ -818,6 +818,60 @@ class TestHttpd(_TestBase):
                 pass # TODO: should test with OpenSSL
             greenthread.kill(g)
 
+    def test_029_posthooks(self):
+        posthook1_count = [0]
+        posthook2_count = [0]
+        def posthook1(env, value, multiplier=1):
+            self.assertEquals(env['local.test'], 'test_029_posthooks')
+            posthook1_count[0] += value * multiplier
+        def posthook2(env, value, divisor=1):
+            self.assertEquals(env['local.test'], 'test_029_posthooks')
+            posthook2_count[0] += value / divisor
+
+        def one_posthook_app(env, start_response):
+            env['local.test'] = 'test_029_posthooks'
+            if 'eventlet.posthooks' not in env:
+                start_response('500 eventlet.posthooks not supported',
+                               [('Content-Type', 'text/plain')])
+            else:
+                env['eventlet.posthooks'].append(
+                    (posthook1, (2,), {'multiplier': 3}))
+                start_response('200 OK', [('Content-Type', 'text/plain')])
+            yield ''
+        self.site.application = one_posthook_app
+        sock = eventlet.connect(('localhost', self.port))
+        fp = sock.makefile('rw')
+        fp.write('GET / HTTP/1.1\r\nHost: localhost\r\n\r\n')
+        fp.flush()
+        self.assertEquals(fp.readline(), 'HTTP/1.1 200 OK\r\n')
+        fp.close()
+        sock.close()
+        self.assertEquals(posthook1_count[0], 6)
+        self.assertEquals(posthook2_count[0], 0)
+
+        def two_posthook_app(env, start_response):
+            env['local.test'] = 'test_029_posthooks'
+            if 'eventlet.posthooks' not in env:
+                start_response('500 eventlet.posthooks not supported',
+                               [('Content-Type', 'text/plain')])
+            else:
+                env['eventlet.posthooks'].append(
+                    (posthook1, (4,), {'multiplier': 5}))
+                env['eventlet.posthooks'].append(
+                    (posthook2, (100,), {'divisor': 4}))
+                start_response('200 OK', [('Content-Type', 'text/plain')])
+            yield ''
+        self.site.application = two_posthook_app
+        sock = eventlet.connect(('localhost', self.port))
+        fp = sock.makefile('rw')
+        fp.write('GET / HTTP/1.1\r\nHost: localhost\r\n\r\n')
+        fp.flush()
+        self.assertEquals(fp.readline(), 'HTTP/1.1 200 OK\r\n')
+        fp.close()
+        sock.close()
+        self.assertEquals(posthook1_count[0], 26)
+        self.assertEquals(posthook2_count[0], 25)
+
     def test_zero_length_chunked_response(self):
         def zero_chunked_app(env, start_response):
             start_response('200 OK', [('Content-type', 'text/plain')])