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Diffstat (limited to 'cherrypy/_cpwsgi.py')
| -rwxr-xr-x | cherrypy/_cpwsgi.py | 347 |
1 files changed, 347 insertions, 0 deletions
diff --git a/cherrypy/_cpwsgi.py b/cherrypy/_cpwsgi.py new file mode 100755 index 0000000..aa4b763 --- /dev/null +++ b/cherrypy/_cpwsgi.py @@ -0,0 +1,347 @@ +"""WSGI interface (see PEP 333 and 3333). + +Note that WSGI environ keys and values are 'native strings'; that is, +whatever the type of "" is. For Python 2, that's a byte string; for Python 3, +it's a unicode string. But PEP 3333 says: "even if Python's str type is +actually Unicode "under the hood", the content of native strings must +still be translatable to bytes via the Latin-1 encoding!" +""" + +import sys as _sys + +import cherrypy as _cherrypy +from cherrypy._cpcompat import BytesIO +from cherrypy import _cperror +from cherrypy.lib import httputil + + +def downgrade_wsgi_ux_to_1x(environ): + """Return a new environ dict for WSGI 1.x from the given WSGI u.x environ.""" + env1x = {} + + url_encoding = environ[u'wsgi.url_encoding'] + for k, v in environ.items(): + if k in [u'PATH_INFO', u'SCRIPT_NAME', u'QUERY_STRING']: + v = v.encode(url_encoding) + elif isinstance(v, unicode): + v = v.encode('ISO-8859-1') + env1x[k.encode('ISO-8859-1')] = v + + return env1x + + +class VirtualHost(object): + """Select a different WSGI application based on the Host header. + + This can be useful when running multiple sites within one CP server. + It allows several domains to point to different applications. For example:: + + root = Root() + RootApp = cherrypy.Application(root) + Domain2App = cherrypy.Application(root) + SecureApp = cherrypy.Application(Secure()) + + vhost = cherrypy._cpwsgi.VirtualHost(RootApp, + domains={'www.domain2.example': Domain2App, + 'www.domain2.example:443': SecureApp, + }) + + cherrypy.tree.graft(vhost) + """ + default = None + """Required. The default WSGI application.""" + + use_x_forwarded_host = True + """If True (the default), any "X-Forwarded-Host" + request header will be used instead of the "Host" header. This + is commonly added by HTTP servers (such as Apache) when proxying.""" + + domains = {} + """A dict of {host header value: application} pairs. + The incoming "Host" request header is looked up in this dict, + and, if a match is found, the corresponding WSGI application + will be called instead of the default. Note that you often need + separate entries for "example.com" and "www.example.com". + In addition, "Host" headers may contain the port number. + """ + + def __init__(self, default, domains=None, use_x_forwarded_host=True): + self.default = default + self.domains = domains or {} + self.use_x_forwarded_host = use_x_forwarded_host + + def __call__(self, environ, start_response): + domain = environ.get('HTTP_HOST', '') + if self.use_x_forwarded_host: + domain = environ.get("HTTP_X_FORWARDED_HOST", domain) + + nextapp = self.domains.get(domain) + if nextapp is None: + nextapp = self.default + return nextapp(environ, start_response) + + +class InternalRedirector(object): + """WSGI middleware that handles raised cherrypy.InternalRedirect.""" + + def __init__(self, nextapp, recursive=False): + self.nextapp = nextapp + self.recursive = recursive + + def __call__(self, environ, start_response): + redirections = [] + while True: + environ = environ.copy() + try: + return self.nextapp(environ, start_response) + except _cherrypy.InternalRedirect, ir: + sn = environ.get('SCRIPT_NAME', '') + path = environ.get('PATH_INFO', '') + qs = environ.get('QUERY_STRING', '') + + # Add the *previous* path_info + qs to redirections. + old_uri = sn + path + if qs: + old_uri += "?" + qs + redirections.append(old_uri) + + if not self.recursive: + # Check to see if the new URI has been redirected to already + new_uri = sn + ir.path + if ir.query_string: + new_uri += "?" + ir.query_string + if new_uri in redirections: + ir.request.close() + raise RuntimeError("InternalRedirector visited the " + "same URL twice: %r" % new_uri) + + # Munge the environment and try again. + environ['REQUEST_METHOD'] = "GET" + environ['PATH_INFO'] = ir.path + environ['QUERY_STRING'] = ir.query_string + environ['wsgi.input'] = BytesIO() + environ['CONTENT_LENGTH'] = "0" + environ['cherrypy.previous_request'] = ir.request + + +class ExceptionTrapper(object): + """WSGI middleware that traps exceptions.""" + + def __init__(self, nextapp, throws=(KeyboardInterrupt, SystemExit)): + self.nextapp = nextapp + self.throws = throws + + def __call__(self, environ, start_response): + return _TrappedResponse(self.nextapp, environ, start_response, self.throws) + + +class _TrappedResponse(object): + + response = iter([]) + + def __init__(self, nextapp, environ, start_response, throws): + self.nextapp = nextapp + self.environ = environ + self.start_response = start_response + self.throws = throws + self.started_response = False + self.response = self.trap(self.nextapp, self.environ, self.start_response) + self.iter_response = iter(self.response) + + def __iter__(self): + self.started_response = True + return self + + def next(self): + return self.trap(self.iter_response.next) + + def close(self): + if hasattr(self.response, 'close'): + self.response.close() + + def trap(self, func, *args, **kwargs): + try: + return func(*args, **kwargs) + except self.throws: + raise + except StopIteration: + raise + except: + tb = _cperror.format_exc() + #print('trapped (started %s):' % self.started_response, tb) + _cherrypy.log(tb, severity=40) + if not _cherrypy.request.show_tracebacks: + tb = "" + s, h, b = _cperror.bare_error(tb) + if self.started_response: + # Empty our iterable (so future calls raise StopIteration) + self.iter_response = iter([]) + else: + self.iter_response = iter(b) + + try: + self.start_response(s, h, _sys.exc_info()) + except: + # "The application must not trap any exceptions raised by + # start_response, if it called start_response with exc_info. + # Instead, it should allow such exceptions to propagate + # back to the server or gateway." + # But we still log and call close() to clean up ourselves. + _cherrypy.log(traceback=True, severity=40) + raise + + if self.started_response: + return "".join(b) + else: + return b + + +# WSGI-to-CP Adapter # + + +class AppResponse(object): + """WSGI response iterable for CherryPy applications.""" + + def __init__(self, environ, start_response, cpapp): + if environ.get(u'wsgi.version') == (u'u', 0): + environ = downgrade_wsgi_ux_to_1x(environ) + self.environ = environ + self.cpapp = cpapp + try: + self.run() + except: + self.close() + raise + r = _cherrypy.serving.response + self.iter_response = iter(r.body) + self.write = start_response(r.output_status, r.header_list) + + def __iter__(self): + return self + + def next(self): + return self.iter_response.next() + + def close(self): + """Close and de-reference the current request and response. (Core)""" + self.cpapp.release_serving() + + def run(self): + """Create a Request object using environ.""" + env = self.environ.get + + local = httputil.Host('', int(env('SERVER_PORT', 80)), + env('SERVER_NAME', '')) + remote = httputil.Host(env('REMOTE_ADDR', ''), + int(env('REMOTE_PORT', -1) or -1), + env('REMOTE_HOST', '')) + scheme = env('wsgi.url_scheme') + sproto = env('ACTUAL_SERVER_PROTOCOL', "HTTP/1.1") + request, resp = self.cpapp.get_serving(local, remote, scheme, sproto) + + # LOGON_USER is served by IIS, and is the name of the + # user after having been mapped to a local account. + # Both IIS and Apache set REMOTE_USER, when possible. + request.login = env('LOGON_USER') or env('REMOTE_USER') or None + request.multithread = self.environ['wsgi.multithread'] + request.multiprocess = self.environ['wsgi.multiprocess'] + request.wsgi_environ = self.environ + request.prev = env('cherrypy.previous_request', None) + + meth = self.environ['REQUEST_METHOD'] + + path = httputil.urljoin(self.environ.get('SCRIPT_NAME', ''), + self.environ.get('PATH_INFO', '')) + qs = self.environ.get('QUERY_STRING', '') + rproto = self.environ.get('SERVER_PROTOCOL') + headers = self.translate_headers(self.environ) + rfile = self.environ['wsgi.input'] + request.run(meth, path, qs, rproto, headers, rfile) + + headerNames = {'HTTP_CGI_AUTHORIZATION': 'Authorization', + 'CONTENT_LENGTH': 'Content-Length', + 'CONTENT_TYPE': 'Content-Type', + 'REMOTE_HOST': 'Remote-Host', + 'REMOTE_ADDR': 'Remote-Addr', + } + + def translate_headers(self, environ): + """Translate CGI-environ header names to HTTP header names.""" + for cgiName in environ: + # We assume all incoming header keys are uppercase already. + if cgiName in self.headerNames: + yield self.headerNames[cgiName], environ[cgiName] + elif cgiName[:5] == "HTTP_": + # Hackish attempt at recovering original header names. + translatedHeader = cgiName[5:].replace("_", "-") + yield translatedHeader, environ[cgiName] + + +class CPWSGIApp(object): + """A WSGI application object for a CherryPy Application.""" + + pipeline = [('ExceptionTrapper', ExceptionTrapper), + ('InternalRedirector', InternalRedirector), + ] + """A list of (name, wsgiapp) pairs. Each 'wsgiapp' MUST be a + constructor that takes an initial, positional 'nextapp' argument, + plus optional keyword arguments, and returns a WSGI application + (that takes environ and start_response arguments). The 'name' can + be any you choose, and will correspond to keys in self.config.""" + + head = None + """Rather than nest all apps in the pipeline on each call, it's only + done the first time, and the result is memoized into self.head. Set + this to None again if you change self.pipeline after calling self.""" + + config = {} + """A dict whose keys match names listed in the pipeline. Each + value is a further dict which will be passed to the corresponding + named WSGI callable (from the pipeline) as keyword arguments.""" + + response_class = AppResponse + """The class to instantiate and return as the next app in the WSGI chain.""" + + def __init__(self, cpapp, pipeline=None): + self.cpapp = cpapp + self.pipeline = self.pipeline[:] + if pipeline: + self.pipeline.extend(pipeline) + self.config = self.config.copy() + + def tail(self, environ, start_response): + """WSGI application callable for the actual CherryPy application. + + You probably shouldn't call this; call self.__call__ instead, + so that any WSGI middleware in self.pipeline can run first. + """ + return self.response_class(environ, start_response, self.cpapp) + + def __call__(self, environ, start_response): + head = self.head + if head is None: + # Create and nest the WSGI apps in our pipeline (in reverse order). + # Then memoize the result in self.head. + head = self.tail + for name, callable in self.pipeline[::-1]: + conf = self.config.get(name, {}) + head = callable(head, **conf) + self.head = head + return head(environ, start_response) + + def namespace_handler(self, k, v): + """Config handler for the 'wsgi' namespace.""" + if k == "pipeline": + # Note this allows multiple 'wsgi.pipeline' config entries + # (but each entry will be processed in a 'random' order). + # It should also allow developers to set default middleware + # in code (passed to self.__init__) that deployers can add to + # (but not remove) via config. + self.pipeline.extend(v) + elif k == "response_class": + self.response_class = v + else: + name, arg = k.split(".", 1) + bucket = self.config.setdefault(name, {}) + bucket[arg] = v + |