# -*- test-case-name: twisted.web.test.test_cgi -*- # Copyright (c) Twisted Matrix Laboratories. # See LICENSE for details. """ I hold resource classes and helper classes that deal with CGI scripts. """ # System Imports import os import urllib # Twisted Imports from twisted.internet import protocol from twisted.logger import Logger from twisted.python import filepath from twisted.spread import pb from twisted.web import http, resource, server, static class CGIDirectory(resource.Resource, filepath.FilePath): def __init__(self, pathname): resource.Resource.__init__(self) filepath.FilePath.__init__(self, pathname) def getChild(self, path, request): fnp = self.child(path) if not fnp.exists(): return static.File.childNotFound elif fnp.isdir(): return CGIDirectory(fnp.path) else: return CGIScript(fnp.path) return resource.NoResource() def render(self, request): notFound = resource.NoResource( "CGI directories do not support directory listing.") return notFound.render(request) class CGIScript(resource.Resource): """ L{CGIScript} is a resource which runs child processes according to the CGI specification. The implementation is complex due to the fact that it requires asynchronous IPC with an external process with an unpleasant protocol. """ isLeaf = 1 def __init__(self, filename, registry=None, reactor=None): """ Initialize, with the name of a CGI script file. """ self.filename = filename if reactor is None: # This installs a default reactor, if None was installed before. # We do a late import here, so that importing the current module # won't directly trigger installing a default reactor. from twisted.internet import reactor self._reactor = reactor def render(self, request): """ Do various things to conform to the CGI specification. I will set up the usual slew of environment variables, then spin off a process. @type request: L{twisted.web.http.Request} @param request: An HTTP request. """ scriptName = b"/" + b"/".join(request.prepath) serverName = request.getRequestHostname().split(b':')[0] env = {"SERVER_SOFTWARE": server.version, "SERVER_NAME": serverName, "GATEWAY_INTERFACE": "CGI/1.1", "SERVER_PROTOCOL": request.clientproto, "SERVER_PORT": str(request.getHost().port), "REQUEST_METHOD": request.method, "SCRIPT_NAME": scriptName, "SCRIPT_FILENAME": self.filename, "REQUEST_URI": request.uri} ip = request.getClientAddress().host if ip is not None: env['REMOTE_ADDR'] = ip pp = request.postpath if pp: env["PATH_INFO"] = "/" + "/".join(pp) if hasattr(request, "content"): # 'request.content' is either a StringIO or a TemporaryFile, and # the file pointer is sitting at the beginning (seek(0,0)) request.content.seek(0, 2) length = request.content.tell() request.content.seek(0, 0) env['CONTENT_LENGTH'] = str(length) try: qindex = request.uri.index(b'?') except ValueError: env['QUERY_STRING'] = '' qargs = [] else: qs = env['QUERY_STRING'] = request.uri[qindex+1:] if '=' in qs: qargs = [] else: qargs = [urllib.unquote(x) for x in qs.split('+')] # Propagate HTTP headers for title, header in request.getAllHeaders().items(): envname = title.replace(b'-', b'_').upper() if title not in (b'content-type', b'content-length', b'proxy'): envname = b"HTTP_" + envname env[envname] = header # Propagate our environment for key, value in os.environ.items(): if key not in env: env[key] = value # And they're off! self.runProcess(env, request, qargs) return server.NOT_DONE_YET def runProcess(self, env, request, qargs=[]): """ Run the cgi script. @type env: A L{dict} of L{str}, or L{None} @param env: The environment variables to pass to the process that will get spawned. See L{twisted.internet.interfaces.IReactorProcess.spawnProcess} for more information about environments and process creation. @type request: L{twisted.web.http.Request} @param request: An HTTP request. @type qargs: A L{list} of L{str} @param qargs: The command line arguments to pass to the process that will get spawned. """ p = CGIProcessProtocol(request) self._reactor.spawnProcess(p, self.filename, [self.filename] + qargs, env, os.path.dirname(self.filename)) class FilteredScript(CGIScript): """ I am a special version of a CGI script, that uses a specific executable. This is useful for interfacing with other scripting languages that adhere to the CGI standard. My C{filter} attribute specifies what executable to run, and my C{filename} init parameter describes which script to pass to the first argument of that script. To customize me for a particular location of a CGI interpreter, override C{filter}. @type filter: L{str} @ivar filter: The absolute path to the executable. """ filter = '/usr/bin/cat' def runProcess(self, env, request, qargs=[]): """ Run a script through the C{filter} executable. @type env: A L{dict} of L{str}, or L{None} @param env: The environment variables to pass to the process that will get spawned. See L{twisted.internet.interfaces.IReactorProcess.spawnProcess} for more information about environments and process creation. @type request: L{twisted.web.http.Request} @param request: An HTTP request. @type qargs: A L{list} of L{str} @param qargs: The command line arguments to pass to the process that will get spawned. """ p = CGIProcessProtocol(request) self._reactor.spawnProcess(p, self.filter, [self.filter, self.filename] + qargs, env, os.path.dirname(self.filename)) class CGIProcessProtocol(protocol.ProcessProtocol, pb.Viewable): handling_headers = 1 headers_written = 0 headertext = b'' errortext = b'' _log = Logger() # Remotely relay producer interface. def view_resumeProducing(self, issuer): self.resumeProducing() def view_pauseProducing(self, issuer): self.pauseProducing() def view_stopProducing(self, issuer): self.stopProducing() def resumeProducing(self): self.transport.resumeProducing() def pauseProducing(self): self.transport.pauseProducing() def stopProducing(self): self.transport.loseConnection() def __init__(self, request): self.request = request def connectionMade(self): self.request.registerProducer(self, 1) self.request.content.seek(0, 0) content = self.request.content.read() if content: self.transport.write(content) self.transport.closeStdin() def errReceived(self, error): self.errortext = self.errortext + error def outReceived(self, output): """ Handle a chunk of input """ # First, make sure that the headers from the script are sorted # out (we'll want to do some parsing on these later.) if self.handling_headers: text = self.headertext + output headerEnds = [] for delimiter in b'\n\n', b'\r\n\r\n', b'\r\r', b'\n\r\n': headerend = text.find(delimiter) if headerend != -1: headerEnds.append((headerend, delimiter)) if headerEnds: # The script is entirely in control of response headers; # disable the default Content-Type value normally provided by # twisted.web.server.Request. self.request.defaultContentType = None headerEnds.sort() headerend, delimiter = headerEnds[0] self.headertext = text[:headerend] # This is a final version of the header text. linebreak = delimiter[:len(delimiter)//2] headers = self.headertext.split(linebreak) for header in headers: br = header.find(b': ') if br == -1: self._log.error( 'ignoring malformed CGI header: {header!r}', header=header) else: headerName = header[:br].lower() headerText = header[br+2:] if headerName == b'location': self.request.setResponseCode(http.FOUND) if headerName == b'status': try: # "XXX " sometimes happens. statusNum = int(headerText[:3]) except: self._log.error("malformed status header") else: self.request.setResponseCode(statusNum) else: # Don't allow the application to control # these required headers. if headerName.lower() not in (b'server', b'date'): self.request.responseHeaders.addRawHeader( headerName, headerText) output = text[headerend+len(delimiter):] self.handling_headers = 0 if self.handling_headers: self.headertext = text if not self.handling_headers: self.request.write(output) def processEnded(self, reason): if reason.value.exitCode != 0: self._log.error("CGI {uri} exited with exit code {exitCode}", uri=self.request.uri, exitCode=reason.value.exitCode) if self.errortext: self._log.error("Errors from CGI {uri}: {errorText}", uri=self.request.uri, errorText=self.errortext) if self.handling_headers: self._log.error("Premature end of headers in {uri}: {headerText}", uri=self.request.uri, headerText=self.headertext) self.request.write( resource.ErrorPage(http.INTERNAL_SERVER_ERROR, "CGI Script Error", "Premature end of script headers.").render(self.request)) self.request.unregisterProducer() self.request.finish()