Imported from SVN by Bitbucket

Paste-1.7.5.1-py2.6.egg/paste/gzipper.py

@@ -0,0 +1,111 @@
+# (c) 2005 Ian Bicking and contributors; written for Paste (http://pythonpaste.org)
+# Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
+
+# (c) 2005 Ian Bicking and contributors; written for Paste (http://pythonpaste.org)
+# Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
+
+"""
+WSGI middleware
+
+Gzip-encodes the response.
+"""
+
+import gzip
+from paste.response import header_value, remove_header
+from paste.httpheaders import CONTENT_LENGTH
+
+try:
+    from cStringIO import StringIO
+except ImportError:
+    from StringIO import StringIO
+
+class GzipOutput(object):
+    pass
+
+class middleware(object):
+
+    def __init__(self, application, compress_level=6):
+        self.application = application
+        self.compress_level = int(compress_level)
+
+    def __call__(self, environ, start_response):
+        if 'gzip' not in environ.get('HTTP_ACCEPT_ENCODING', ''):
+            # nothing for us to do, so this middleware will
+            # be a no-op:
+            return self.application(environ, start_response)
+        response = GzipResponse(start_response, self.compress_level)
+        app_iter = self.application(environ,
+                                    response.gzip_start_response)
+        if app_iter is not None:
+            response.finish_response(app_iter)
+
+        return response.write()
+
+class GzipResponse(object):
+
+    def __init__(self, start_response, compress_level):
+        self.start_response = start_response
+        self.compress_level = compress_level
+        self.buffer = StringIO()
+        self.compressible = False
+        self.content_length = None
+
+    def gzip_start_response(self, status, headers, exc_info=None):
+        self.headers = headers
+        ct = header_value(headers,'content-type')
+        ce = header_value(headers,'content-encoding')
+        self.compressible = False
+        if ct and (ct.startswith('text/') or ct.startswith('application/')) \
+            and 'zip' not in ct:
+            self.compressible = True
+        if ce:
+            self.compressible = False
+        if self.compressible:
+            headers.append(('content-encoding', 'gzip'))
+        remove_header(headers, 'content-length')
+        self.headers = headers
+        self.status = status
+        return self.buffer.write
+
+    def write(self):
+        out = self.buffer
+        out.seek(0)
+        s = out.getvalue()
+        out.close()
+        return [s]
+
+    def finish_response(self, app_iter):
+        if self.compressible:
+            output = gzip.GzipFile(mode='wb', compresslevel=self.compress_level,
+                fileobj=self.buffer)
+        else:
+            output = self.buffer
+        try:
+            for s in app_iter:
+                output.write(s)
+            if self.compressible:
+                output.close()
+        finally:
+            if hasattr(app_iter, 'close'):
+                app_iter.close()
+        content_length = self.buffer.tell()
+        CONTENT_LENGTH.update(self.headers, content_length)
+        self.start_response(self.status, self.headers)
+
+def filter_factory(application, **conf):
+    import warnings
+    warnings.warn(
+        'This function is deprecated; use make_gzip_middleware instead',
+        DeprecationWarning, 2)
+    def filter(application):
+        return middleware(application)
+    return filter
+
+def make_gzip_middleware(app, global_conf, compress_level=6):
+    """
+    Wrap the middleware, so that it applies gzipping to a response
+    when it is supported by the browser and the content is of
+    type ``text/*`` or ``application/*``
+    """
+    compress_level = int(compress_level)
+    return middleware(app, compress_level=compress_level)