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Diffstat (limited to 'flup/middleware/gzip.py')
| -rw-r--r-- | flup/middleware/gzip.py | 279 |
1 files changed, 0 insertions, 279 deletions
diff --git a/flup/middleware/gzip.py b/flup/middleware/gzip.py deleted file mode 100644 index 59a800d..0000000 --- a/flup/middleware/gzip.py +++ /dev/null @@ -1,279 +0,0 @@ -# Copyright (c) 2005 Allan Saddi <allan@saddi.com> -# All rights reserved. -# -# Redistribution and use in source and binary forms, with or without -# modification, are permitted provided that the following conditions -# are met: -# 1. Redistributions of source code must retain the above copyright -# notice, this list of conditions and the following disclaimer. -# 2. Redistributions in binary form must reproduce the above copyright -# notice, this list of conditions and the following disclaimer in the -# documentation and/or other materials provided with the distribution. -# -# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND -# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE -# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE -# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE -# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL -# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS -# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) -# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT -# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY -# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF -# SUCH DAMAGE. -# -# $Id$ - -"""WSGI response gzipper middleware. - -This gzip middleware component differentiates itself from others in that -it (hopefully) follows the spec more closely. Namely with regard to the -application iterator and buffering. (It doesn't buffer.) See -`Middleware Handling of Block Boundaries`_. - -Of course this all comes with a price... just LOOK at this mess! :) - -The inner workings of gzip and the gzip file format were gleaned from gzip.py. - -.. _Middleware Handling of Block Boundaries: http://www.python.org/dev/peps/pep-0333/#middleware-handling-of-block-boundaries -""" - -__author__ = 'Allan Saddi <allan@saddi.com>' -__version__ = '$Revision$' - - -import struct -import time -import zlib -import re - - -__all__ = ['GzipMiddleware'] - - -def _gzip_header(): - """Returns a gzip header (with no filename).""" - # See GzipFile._write_gzip_header in gzip.py - return '\037\213' \ - '\010' \ - '\0' + \ - struct.pack('<L', long(time.time())) + \ - '\002' \ - '\377' - - -class _GzipIterWrapper(object): - """gzip application iterator wrapper. - - It ensures that: the application iterator's ``close`` method (if any) is - called by the parent server; and at least one value is yielded each time - the application's iterator yields a value. - - If the application's iterator yields N values, this iterator will yield - N+1 values. This is to account for the gzip trailer. - """ - - def __init__(self, app_iter, gzip_middleware): - self._g = gzip_middleware - self._next = iter(app_iter).next - - self._last = False # True if app_iter has yielded last value. - self._trailer_sent = False - - if hasattr(app_iter, 'close'): - self.close = app_iter.close - - def __iter__(self): - return self - - # This would've been a lot easier had I used a generator. But then I'd have - # to wrap the generator anyway to ensure that any existing close() method - # was called. (Calling it within the generator is not the same thing, - # namely it does not ensure that it will be called no matter what!) - def next(self): - if not self._last: - # Need to catch StopIteration here so we can append trailer. - try: - data = self._next() - except StopIteration: - self._last = True - - if not self._last: - if self._g.gzip_ok: - return self._g.gzip_data(data) - else: - return data - else: - # See if trailer needs to be sent. - if self._g.header_sent and not self._trailer_sent: - self._trailer_sent = True - return self._g.gzip_trailer() - # Otherwise, that's the end of this iterator. - raise StopIteration - - -class _GzipMiddleware(object): - """The actual gzip middleware component. - - Holds compression state as well implementations of ``start_response`` and - ``write``. Instantiated before each call to the underlying application. - - This class is private. See ``GzipMiddleware`` for the public interface. - """ - - def __init__(self, start_response, mime_types, compress_level): - self._start_response = start_response - self._mime_types = mime_types - - self.gzip_ok = False - self.header_sent = False - - # See GzipFile.__init__ and GzipFile._init_write in gzip.py - self._crc = zlib.crc32('') - self._size = 0 - self._compress = zlib.compressobj(compress_level, - zlib.DEFLATED, - -zlib.MAX_WBITS, - zlib.DEF_MEM_LEVEL, - 0) - - def gzip_data(self, data): - """Compresses the given data, prepending the gzip header if necessary. - - Returns the result as a string. - """ - if not self.header_sent: - self.header_sent = True - out = _gzip_header() - else: - out = '' - - # See GzipFile.write in gzip.py - length = len(data) - if length > 0: - self._size += length - self._crc = zlib.crc32(data, self._crc) - out += self._compress.compress(data) - return out - - def gzip_trailer(self): - """Returns the gzip trailer.""" - # See GzipFile.close in gzip.py - return self._compress.flush() + \ - struct.pack('<l', self._crc) + \ - struct.pack('<L', self._size & 0xffffffffL) - - def start_response(self, status, headers, exc_info=None): - """WSGI ``start_response`` implementation.""" - self.gzip_ok = False - - # Scan the headers. Only allow gzip compression if the Content-Type - # is one that we're flagged to compress AND the headers do not - # already contain Content-Encoding. - for name,value in headers: - name = name.lower() - if name == 'content-type': - value = value.split(';')[0].strip() - for p in self._mime_types: - if p.match(value) is not None: - self.gzip_ok = True - break # NB: Breaks inner loop only - elif name == 'content-encoding': - self.gzip_ok = False - break - - if self.gzip_ok: - # Remove Content-Length, if present, because compression will - # most surely change it. (And unfortunately, we can't predict - # the final size...) - headers = [(name,value) for name,value in headers - if name.lower() != 'content-length'] - headers.append(('Content-Encoding', 'gzip')) - - _write = self._start_response(status, headers, exc_info) - - if self.gzip_ok: - def write_gzip(data): - _write(self.gzip_data(data)) - return write_gzip - else: - return _write - - -class GzipMiddleware(object): - """WSGI middleware component that gzip compresses the application's - response (if the client supports gzip compression - gleaned from the - ``Accept-Encoding`` request header). - """ - - def __init__(self, application, mime_types=None, compress_level=9): - """Initializes this GzipMiddleware. - - ``mime_types`` - A list of Content-Types that are OK to compress. Regular - expressions are accepted. Defaults to ``[text/.*]`` if not - specified. - - ``compress_level`` - The gzip compression level, an integer from 1 to 9; 1 is the - fastest and produces the least compression, and 9 is the slowest, - producing the most compression. The default is 9. - """ - if mime_types is None: - mime_types = ['text/', r'''application/(?:.+\+)?xml$'''] - - self._application = application - self._mime_types = [re.compile(m) for m in mime_types] - self._compress_level = compress_level - - def __call__(self, environ, start_response): - """WSGI application interface.""" - # If the client doesn't support gzip encoding, just pass through - # directly to the application. - if 'gzip' not in environ.get('HTTP_ACCEPT_ENCODING', ''): - return self._application(environ, start_response) - - # All of the work is done in _GzipMiddleware and _GzipIterWrapper. - g = _GzipMiddleware(start_response, self._mime_types, - self._compress_level) - - result = self._application(environ, g.start_response) - - # See if it's a length 1 iterable... - try: - shortcut = len(result) == 1 - except: - shortcut = False - - if shortcut: - # Special handling if application returns a length 1 iterable: - # also return a length 1 iterable! - try: - i = iter(result) - # Hmmm, if we get a StopIteration here, the application's - # broken (__len__ lied!) - data = i.next() - if g.gzip_ok: - return [g.gzip_data(data) + g.gzip_trailer()] - else: - return [data] - finally: - if hasattr(result, 'close'): - result.close() - - return _GzipIterWrapper(result, g) - - -if __name__ == '__main__': - def app(environ, start_response): - start_response('200 OK', [('Content-Type', 'text/html')]) - yield 'Hello World!\n' - - from wsgiref import validate - app = validate.validator(app) - app = GzipMiddleware(app) - app = validate.validator(app) - - from flup.server.ajp import WSGIServer - import logging - WSGIServer(app, loggingLevel=logging.DEBUG).run() |