CNS seek tests for <video>.

media/tools/constrained_network_server/cns.py

 #!/usr/bin/env python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Constrained Network Server. Serves files with supplied network constraints.
 
 The CNS exposes a web based API allowing network constraints to be imposed on
 file serving.
 
@@ skipping 167 matching lines @@
 
     Args:
       options: optparse based class returned by ParseArgs()
       port_allocator: A port allocator instance.
     """
     self._options = options
     self._port_allocator = port_allocator
 
   @cherrypy.expose
   def ServeConstrained(self, f=None, bandwidth=None, latency=None, loss=None,
-                       new_port=False):
+                       new_port=False, no_cache=False, **kwargs):
     """Serves the requested file with the requested constraints.
 
     Subsequent requests for the same constraints from the same IP will share the
     previously created port unless new_port equals True. If no constraints
     are provided the file is served as is.
 
     Args:
       f: path relative to http root of file to serve.
       bandwidth: maximum allowed bandwidth for the provided port (integer
           in kbit/s).
       latency: time to add to each packet (integer in ms).
       loss: percentage of packets to drop (integer, 0-100).
       new_port: whether to use a new port for this request or not.
+      no_cache: Set reponse's cache-control to no-cache.
     """
     cherrypy.log('Got request for %s, bandwidth=%s, latency=%s, loss=%s, '
-                 'new_port=%s' % (f, bandwidth, latency, loss, new_port))
+                 'new_port=%s, no_cache=%s, kwargs=%s' %
+                 (f, bandwidth, latency, loss, new_port, no_cache, kwargs))
+    if no_cache:
+      response = cherrypy.response
+      response.headers['Pragma'] = 'no-cache'
+      response.headers['Cache-Control'] = 'no-cache'
+
     # CherryPy is a bit wonky at detecting parameters, so just make them all
     # optional and validate them ourselves.
     if not f:
       raise cherrypy.HTTPError(400, 'Invalid request. File must be specified.')
 
     # Sanitize and check the path to prevent www-root escapes.
     sanitized_path = os.path.abspath(os.path.join(self._options.www_root, f))
     if not sanitized_path.startswith(self._options.www_root):
       raise cherrypy.HTTPError(403, 'Invalid file requested.')
 
@@ skipping 24 matching lines @@
         interface=self._options.interface, bandwidth=bandwidth, latency=latency,
         loss=loss, new_port=new_port)
     end_time = time.time()
 
     if not constrained_port:
       raise cherrypy.HTTPError(503, 'Service unavailable. Out of ports.')
 
     cherrypy.log('Time to set up port %d = %ssec.' %
                  (constrained_port, end_time - start_time))
 
-    # Build constrained URL. Only pass on the file parameter.
-    constrained_url = '%s?f=%s' % (
+    # Build constrained URL using the constrained port and original URL
+    # parameters except the network constraints (bandwidth, latency, and loss).
+    constrained_url = '%s?f=%s&no_cache=%s&%s' % (
         cherrypy.url().replace(
             ':%d' % self._options.port, ':%d' % constrained_port),
-        f)
+        f,
+        no_cache,
+        '&'.join(['%s=%s' % (key, kwargs[key]) for key in kwargs]))
 
     # Redirect request to the constrained port.
     cherrypy.lib.cptools.redirect(constrained_url, internal=False)
 
   def _ParseIntParameter(self, param, msg, check):
     """Returns integer value of param and verifies it satisfies the check.
 
     Args:
       param: Parameter name to check.
       msg: Message in error if raised.
@@ skipping 96 matching lines @@
   try:
     cherrypy.quickstart(ConstrainedNetworkServer(options, pa))
   finally:
     # Disable Ctrl-C handler to prevent interruption of cleanup.
     signal.signal(signal.SIGINT, lambda signal, frame: None)
     pa.Cleanup(options.interface, all_ports=True)
 
 
 if __name__ == '__main__':
   Main()