source: publico/il.spdo/trunk/Paste-1.7.5.1-py2.6.egg/paste/gzipper.py @ 5327

Última Alteração nesse arquivo desde 5327 foi 5327, incluída por fabianosantos, 8 anos atrás

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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
16
17try:
18    from cStringIO import StringIO
19except ImportError:
20    from StringIO import StringIO
21
22class GzipOutput(object):
23    pass
24
25class middleware(object):
26
27    def __init__(self, application, compress_level=6):
28        self.application = application
29        self.compress_level = int(compress_level)
30
31    def __call__(self, environ, start_response):
32        if 'gzip' not in environ.get('HTTP_ACCEPT_ENCODING', ''):
33            # nothing for us to do, so this middleware will
34            # be a no-op:
35            return self.application(environ, start_response)
36        response = GzipResponse(start_response, self.compress_level)
37        app_iter = self.application(environ,
38                                    response.gzip_start_response)
39        if app_iter is not None:
40            response.finish_response(app_iter)
41
42        return response.write()
43
44class GzipResponse(object):
45
46    def __init__(self, start_response, compress_level):
47        self.start_response = start_response
48        self.compress_level = compress_level
49        self.buffer = StringIO()
50        self.compressible = False
51        self.content_length = None
52
53    def gzip_start_response(self, status, headers, exc_info=None):
54        self.headers = headers
55        ct = header_value(headers,'content-type')
56        ce = header_value(headers,'content-encoding')
57        self.compressible = False
58        if ct and (ct.startswith('text/') or ct.startswith('application/')) \
59            and 'zip' not in ct:
60            self.compressible = True
61        if ce:
62            self.compressible = False
63        if self.compressible:
64            headers.append(('content-encoding', 'gzip'))
65        remove_header(headers, 'content-length')
66        self.headers = headers
67        self.status = status
68        return self.buffer.write
69
70    def write(self):
71        out = self.buffer
72        out.seek(0)
73        s = out.getvalue()
74        out.close()
75        return [s]
76
77    def finish_response(self, app_iter):
78        if self.compressible:
79            output = gzip.GzipFile(mode='wb', compresslevel=self.compress_level,
80                fileobj=self.buffer)
81        else:
82            output = self.buffer
83        try:
84            for s in app_iter:
85                output.write(s)
86            if self.compressible:
87                output.close()
88        finally:
89            if hasattr(app_iter, 'close'):
90                app_iter.close()
91        content_length = self.buffer.tell()
92        CONTENT_LENGTH.update(self.headers, content_length)
93        self.start_response(self.status, self.headers)
94
95def filter_factory(application, **conf):
96    import warnings
97    warnings.warn(
98        'This function is deprecated; use make_gzip_middleware instead',
99        DeprecationWarning, 2)
100    def filter(application):
101        return middleware(application)
102    return filter
103
104def make_gzip_middleware(app, global_conf, compress_level=6):
105    """
106    Wrap the middleware, so that it applies gzipping to a response
107    when it is supported by the browser and the content is of
108    type ``text/*`` or ``application/*``
109    """
110    compress_level = int(compress_level)
111    return middleware(app, compress_level=compress_level)
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