1# (c) 2005 Ian Bicking and contributors; written for Paste (http://pythonpaste.org) 2# Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php 3 4# (c) 2005 Ian Bicking and contributors; written for Paste (http://pythonpaste.org) 5# Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php 6 7""" 8WSGI middleware 9 10Gzip-encodes the response. 11""" 12 13import gzip 14from paste.response import header_value, remove_header 15from paste.httpheaders import CONTENT_LENGTH 16import six 17 18class GzipOutput(object): 19 pass 20 21class middleware(object): 22 23 def __init__(self, application, compress_level=6): 24 self.application = application 25 self.compress_level = int(compress_level) 26 27 def __call__(self, environ, start_response): 28 if 'gzip' not in environ.get('HTTP_ACCEPT_ENCODING', ''): 29 # nothing for us to do, so this middleware will 30 # be a no-op: 31 return self.application(environ, start_response) 32 response = GzipResponse(start_response, self.compress_level) 33 app_iter = self.application(environ, 34 response.gzip_start_response) 35 if app_iter is not None: 36 response.finish_response(app_iter) 37 38 return response.write() 39 40class GzipResponse(object): 41 42 def __init__(self, start_response, compress_level): 43 self.start_response = start_response 44 self.compress_level = compress_level 45 self.buffer = six.BytesIO() 46 self.compressible = False 47 self.content_length = None 48 49 def gzip_start_response(self, status, headers, exc_info=None): 50 self.headers = headers 51 ct = header_value(headers,'content-type') 52 ce = header_value(headers,'content-encoding') 53 self.compressible = False 54 if ct and (ct.startswith('text/') or ct.startswith('application/')) \ 55 and 'zip' not in ct: 56 self.compressible = True 57 if ce: 58 self.compressible = False 59 if self.compressible: 60 headers.append(('content-encoding', 'gzip')) 61 remove_header(headers, 'content-length') 62 self.headers = headers 63 self.status = status 64 return self.buffer.write 65 66 def write(self): 67 out = self.buffer 68 out.seek(0) 69 s = out.getvalue() 70 out.close() 71 return [s] 72 73 def finish_response(self, app_iter): 74 if self.compressible: 75 output = gzip.GzipFile(mode='wb', compresslevel=self.compress_level, 76 fileobj=self.buffer) 77 else: 78 output = self.buffer 79 try: 80 for s in app_iter: 81 output.write(s) 82 if self.compressible: 83 output.close() 84 finally: 85 if hasattr(app_iter, 'close'): 86 app_iter.close() 87 content_length = self.buffer.tell() 88 CONTENT_LENGTH.update(self.headers, content_length) 89 self.start_response(self.status, self.headers) 90 91def filter_factory(application, **conf): 92 import warnings 93 warnings.warn( 94 'This function is deprecated; use make_gzip_middleware instead', 95 DeprecationWarning, 2) 96 def filter(application): 97 return middleware(application) 98 return filter 99 100def make_gzip_middleware(app, global_conf, compress_level=6): 101 """ 102 Wrap the middleware, so that it applies gzipping to a response 103 when it is supported by the browser and the content is of 104 type ``text/*`` or ``application/*`` 105 """ 106 compress_level = int(compress_level) 107 return middleware(app, compress_level=compress_level) 108