EVOLUTION-MANAGER

Edit File: fixers.py

# -*- coding: utf-8 -*- """ werkzeug.contrib.fixers ~~~~~~~~~~~~~~~~~~~~~~~ .. versionadded:: 0.5 This module includes various helpers that fix bugs in web servers. They may be necessary for some versions of a buggy web server but not others. We try to stay updated with the status of the bugs as good as possible but you have to make sure whether they fix the problem you encounter. If you notice bugs in webservers not fixed in this module consider contributing a patch. :copyright: Copyright 2009 by the Werkzeug Team, see AUTHORS for more details. :license: BSD, see LICENSE for more details. """ try: from urllib import unquote except ImportError: from urllib.parse import unquote from werkzeug.http import parse_options_header, parse_cache_control_header, \ parse_set_header from werkzeug.useragents import UserAgent from werkzeug.datastructures import Headers, ResponseCacheControl class CGIRootFix(object): """Wrap the application in this middleware if you are using FastCGI or CGI and you have problems with your app root being set to the cgi script's path instead of the path users are going to visit .. versionchanged:: 0.9 Added `app_root` parameter and renamed from `LighttpdCGIRootFix`. :param app: the WSGI application :param app_root: Defaulting to ``'/'``, you can set this to something else if your app is mounted somewhere else. """ def __init__(self, app, app_root='/'): self.app = app self.app_root = app_root def __call__(self, environ, start_response): # only set PATH_INFO for older versions of Lighty or if no # server software is provided. That's because the test was # added in newer Werkzeug versions and we don't want to break # people's code if they are using this fixer in a test that # does not set the SERVER_SOFTWARE key. if 'SERVER_SOFTWARE' not in environ or \ environ['SERVER_SOFTWARE'] < 'lighttpd/1.4.28': environ['PATH_INFO'] = environ.get('SCRIPT_NAME', '') + \ environ.get('PATH_INFO', '') environ['SCRIPT_NAME'] = self.app_root.strip('/') return self.app(environ, start_response) # backwards compatibility LighttpdCGIRootFix = CGIRootFix class PathInfoFromRequestUriFix(object): """On windows environment variables are limited to the system charset which makes it impossible to store the `PATH_INFO` variable in the environment without loss of information on some systems. This is for example a problem for CGI scripts on a Windows Apache. This fixer works by recreating the `PATH_INFO` from `REQUEST_URI`, `REQUEST_URL`, or `UNENCODED_URL` (whatever is available). Thus the fix can only be applied if the webserver supports either of these variables. :param app: the WSGI application """ def __init__(self, app): self.app = app def __call__(self, environ, start_response): for key in 'REQUEST_URL', 'REQUEST_URI', 'UNENCODED_URL': if key not in environ: continue request_uri = unquote(environ[key]) script_name = unquote(environ.get('SCRIPT_NAME', '')) if request_uri.startswith(script_name): environ['PATH_INFO'] = request_uri[len(script_name):] \ .split('?', 1)[0] break return self.app(environ, start_response) class ProxyFix(object): """This middleware can be applied to add HTTP proxy support to an application that was not designed with HTTP proxies in mind. It sets `REMOTE_ADDR`, `HTTP_HOST` from `X-Forwarded` headers. If you have more than one proxy server in front of your app, set `num_proxies` accordingly. Do not use this middleware in non-proxy setups for security reasons. The original values of `REMOTE_ADDR` and `HTTP_HOST` are stored in the WSGI environment as `werkzeug.proxy_fix.orig_remote_addr` and `werkzeug.proxy_fix.orig_http_host`. :param app: the WSGI application :param num_proxies: the number of proxy servers in front of the app. """ def __init__(self, app, num_proxies=1): self.app = app self.num_proxies = num_proxies def get_remote_addr(self, forwarded_for): """Selects the new remote addr from the given list of ips in X-Forwarded-For. By default it picks the one that the `num_proxies` proxy server provides. Before 0.9 it would always pick the first. .. versionadded:: 0.8 """ if len(forwarded_for) >= self.num_proxies: return forwarded_for[-1 * self.num_proxies] def __call__(self, environ, start_response): getter = environ.get forwarded_proto = getter('HTTP_X_FORWARDED_PROTO', '') forwarded_for = getter('HTTP_X_FORWARDED_FOR', '').split(',') forwarded_host = getter('HTTP_X_FORWARDED_HOST', '') environ.update({ 'werkzeug.proxy_fix.orig_wsgi_url_scheme': getter('wsgi.url_scheme'), 'werkzeug.proxy_fix.orig_remote_addr': getter('REMOTE_ADDR'), 'werkzeug.proxy_fix.orig_http_host': getter('HTTP_HOST') }) forwarded_for = [x for x in [x.strip() for x in forwarded_for] if x] remote_addr = self.get_remote_addr(forwarded_for) if remote_addr is not None: environ['REMOTE_ADDR'] = remote_addr if forwarded_host: environ['HTTP_HOST'] = forwarded_host if forwarded_proto: environ['wsgi.url_scheme'] = forwarded_proto return self.app(environ, start_response) class HeaderRewriterFix(object): """This middleware can remove response headers and add others. This is for example useful to remove the `Date` header from responses if you are using a server that adds that header, no matter if it's present or not or to add `X-Powered-By` headers:: app = HeaderRewriterFix(app, remove_headers=['Date'], add_headers=[('X-Powered-By', 'WSGI')]) :param app: the WSGI application :param remove_headers: a sequence of header keys that should be removed. :param add_headers: a sequence of ``(key, value)`` tuples that should be added. """ def __init__(self, app, remove_headers=None, add_headers=None): self.app = app self.remove_headers = set(x.lower() for x in (remove_headers or ())) self.add_headers = list(add_headers or ()) def __call__(self, environ, start_response): def rewriting_start_response(status, headers, exc_info=None): new_headers = [] for key, value in headers: if key.lower() not in self.remove_headers: new_headers.append((key, value)) new_headers += self.add_headers return start_response(status, new_headers, exc_info) return self.app(environ, rewriting_start_response) class InternetExplorerFix(object): """This middleware fixes a couple of bugs with Microsoft Internet Explorer. Currently the following fixes are applied: - removing of `Vary` headers for unsupported mimetypes which causes troubles with caching. Can be disabled by passing ``fix_vary=False`` to the constructor. see: http://support.microsoft.com/kb/824847/en-us - removes offending headers to work around caching bugs in Internet Explorer if `Content-Disposition` is set. Can be disabled by passing ``fix_attach=False`` to the constructor. If it does not detect affected Internet Explorer versions it won't touch the request / response. """ # This code was inspired by Django fixers for the same bugs. The # fix_vary and fix_attach fixers were originally implemented in Django # by Michael Axiak and is available as part of the Django project: # http://code.djangoproject.com/ticket/4148 def __init__(self, app, fix_vary=True, fix_attach=True): self.app = app self.fix_vary = fix_vary self.fix_attach = fix_attach def fix_headers(self, environ, headers, status=None): if self.fix_vary: header = headers.get('content-type', '') mimetype, options = parse_options_header(header) if mimetype not in ('text/html', 'text/plain', 'text/sgml'): headers.pop('vary', None) if self.fix_attach and 'content-disposition' in headers: pragma = parse_set_header(headers.get('pragma', '')) pragma.discard('no-cache') header = pragma.to_header() if not header: headers.pop('pragma', '') else: headers['Pragma'] = header header = headers.get('cache-control', '') if header: cc = parse_cache_control_header(header, cls=ResponseCacheControl) cc.no_cache = None cc.no_store = False header = cc.to_header() if not header: headers.pop('cache-control', '') else: headers['Cache-Control'] = header def run_fixed(self, environ, start_response): def fixing_start_response(status, headers, exc_info=None): headers = Headers(headers) self.fix_headers(environ, headers, status) return start_response(status, headers.to_wsgi_list(), exc_info) return self.app(environ, fixing_start_response) def __call__(self, environ, start_response): ua = UserAgent(environ) if ua.browser != 'msie': return self.app(environ, start_response) return self.run_fixed(environ, start_response)