GZIP files served by the development server.

mojo/devtools/common/devtoolslib/http_server.py

 # Copyright 2015 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.
 
 import atexit
 import datetime
 import email.utils
 import errno
+import gzip
 import hashlib
 import logging
 import math
 import os.path
+import shutil
 import socket
 import threading
 
 import SimpleHTTPServer
 import SocketServer
 
 _ZERO = datetime.timedelta(0)
 
 
 class UTC_TZINFO(datetime.tzinfo):
@@ skipping 90 matching lines @@
           if last_modified <= ims:
             self.send_response(304)
             return None
 
       return SimpleHTTPServer.SimpleHTTPRequestHandler.send_head(self)
 
     def end_headers(self):
       path = self.translate_path(self.path)
 
       if os.path.isfile(path):
+        self.send_header('Content-Encoding', 'gzip')
         etag = self.get_etag()
         if etag:
           self.send_header('ETag', etag)
           self.send_header('Cache-Control', 'must-revalidate')
 
       return SimpleHTTPServer.SimpleHTTPRequestHandler.end_headers(self)
 
     def translate_path(self, path):
       # Parent translate_path() will strip away the query string and fragment
       # identifier, but also will prepend the cwd to the path. relpath() gives
       # us the relative path back.
       normalized_path = os.path.relpath(
           SimpleHTTPServer.SimpleHTTPRequestHandler.translate_path(self, path))
 
       for prefix, local_base_path in mappings:
         if normalized_path.startswith(prefix):
-          return os.path.join(local_base_path, normalized_path[len(prefix):])
+          result = os.path.join(local_base_path, normalized_path[len(prefix):])
+          if os.path.isfile(result):
+            gz_result = result + '.gz'
+            if (not os.path.isfile(gz_result) or
+                os.path.getmtime(gz_result) <= os.path.getmtime(result)):
+              with open(result, 'rb') as f:
+                with gzip.open(gz_result, 'wb') as zf:
+                  shutil.copyfileobj(f, zf)
+            result = gz_result
+          return result
 
       # This class is only used internally, and we're adding a catch-all ''
       # prefix at the end of |mappings|.
       assert False
 
     def guess_type(self, path):
       # This is needed so that Sky files without shebang can still run thanks to
       # content-type mappings.
       # TODO(ppi): drop this part once we can rely on the Sky files declaring
       # correct shebang.
@@ skipping 44 matching lines @@
     return httpd.server_address
   except socket.error as v:
     error_code = v[0]
     print 'Failed to start http server for %s on port %d: %s.' % (
         local_dir_path, host_port, os.strerror(error_code))
     if error_code == errno.EADDRINUSE:
       print ('  Run `fuser %d/tcp` to find out which process is using the port.'
              % host_port)
     print '---'
     raise