web.py 学习（二）Worker
Rocket Server 启动一个线程监听客户端的连接，收到连接将连接放置到队列中。线程池中的Worker会以这个连接进行初始化。Rocket中Worker的基类是：
class Worker(Thread): """The Worker class is a base class responsible for receiving connections and (a subclass) will run an application to process the the connection """ def __init__(self, app_info, active_queue, monitor_queue, *args, **kwargs): Thread.__init__(self, *args, **kwargs) # Instance Variables self.app_info = app_info self.active_queue = active_queue self.monitor_queue = monitor_queue self.size = 0 self.status = "200 OK" self.closeConnection = True self.request_line = "" self.protocol = 'HTTP/1.1' # Request Log self.req_log = logging.getLogger('Rocket.Requests') self.req_log.addHandler(NullHandler()) # Error Log self.err_log = logging.getLogger('Rocket.Errors.' + self.getName()) self.err_log.addHandler(NullHandler()) def _handleError(self, typ, val, tb): if typ == SSLError: if 'timed out' in str(val.args[0]): typ = SocketTimeout if typ == SocketTimeout: if __debug__: self.err_log.debug('Socket timed out') self.monitor_queue.put(self.conn) return True if typ == SocketClosed: self.closeConnection = True if __debug__: self.err_log.debug('Client closed socket') return False if typ == BadRequest: self.closeConnection = True if __debug__: self.err_log.debug('Client sent a bad request') return True if typ == socket.error: self.closeConnection = True if val.args[0] in IGNORE_ERRORS_ON_CLOSE: if __debug__: self.err_log.debug('Ignorable socket Error received...' 'closing connection.') return False else: self.status = "999 Utter Server Failure" tb_fmt = traceback.format_exception(typ, val, tb) self.err_log.error('Unhandled Error when serving ' 'connection:\n' + '\n'.join(tb_fmt)) return False self.closeConnection = True tb_fmt = traceback.format_exception(typ, val, tb) self.err_log.error('\n'.join(tb_fmt)) self.send_response('500 Server Error') return False def run(self): if __debug__: self.err_log.debug('Entering main loop.') # Enter thread main loop while True: conn = self.active_queue.get() if not conn: # A non-client is a signal to die if __debug__: self.err_log.debug('Received a death threat.') return conn if isinstance(conn, tuple): conn = Connection(*conn) self.conn = conn if conn.ssl != conn.secure: self.err_log.info('Received HTTP connection on HTTPS port.') self.send_response('400 Bad Request') self.closeConnection = True conn.close() continue else: if __debug__: self.err_log.debug('Received a connection.') self.closeConnection = False # Enter connection serve loop while True: if __debug__: self.err_log.debug('Serving a request') try: self.run_app(conn) except: exc = sys.exc_info() handled = self._handleError(*exc) if handled: break finally: if self.request_line: log_info = dict(client_ip=conn.client_addr, time=datetime.now().strftime('%c'), status=self.status.split(' ')[0], size=self.size, request_line=self.request_line) self.req_log.info(LOG_LINE % log_info) if self.closeConnection: try: conn.close() except: self.err_log.error(str(traceback.format_exc())) break def run_app(self, conn): # Must be overridden with a method reads the request from the socket # and sends a response. self.closeConnection = True raise NotImplementedError('Overload this method!') def send_response(self, status): stat_msg = status.split(' ', 1)[1] msg = RESPONSE % (self.protocol, status, len(stat_msg), 'text/plain', stat_msg) try: self.conn.sendall(b(msg)) except socket.timeout: self.closeConnection = True msg = 'Tried to send "%s" to client but received timeout error' self.err_log.error(msg % status) except socket.error: self.closeConnection = True msg = 'Tried to send "%s" to client but received socket error' self.err_log.error(msg % status) def read_request_line(self, sock_file): self.request_line = '' try: # Grab the request line d = sock_file.readline() if PY3K: d = d.decode('ISO-8859-1') if d == '\r\n': # Allow an extra NEWLINE at the beginning per HTTP 1.1 spec if __debug__: self.err_log.debug('Client sent newline') d = sock_file.readline() if PY3K: d = d.decode('ISO-8859-1') except socket.timeout: raise SocketTimeout('Socket timed out before request.') except TypeError: raise SocketClosed( 'SSL bug caused closure of socket. See ' '"https://groups.google.com/d/topic/web2py/P_Gw0JxWzCs".') d = d.strip() if not d: if __debug__: self.err_log.debug( 'Client did not send a recognizable request.') raise SocketClosed('Client closed socket.') self.request_line = d # NOTE: I've replaced the traditional method of procedurally breaking # apart the request line with a (rather unsightly) regular expression. # However, Java's regexp support sucks so bad that it actually takes # longer in Jython to process the regexp than procedurally. So I've # left the old code here for Jython's sake...for now. if IS_JYTHON: return self._read_request_line_jython(d) match = re_REQUEST_LINE.match(d) if not match: self.send_response('400 Bad Request') raise BadRequest req = match.groupdict() for k, v in req.iteritems(): if not v: req[k] = "" if k == 'path': req['path'] = r'%2F'.join( [unquote(x) for x in re_SLASH.split(v)]) self.protocol = req['protocol'] return req def _read_request_line_jython(self, d): d = d.strip() try: method, uri, proto = d.split(' ') if not proto.startswith('HTTP') or \ proto[-3:] not in ('1.0', '1.1') or \ method not in HTTP_METHODS: self.send_response('400 Bad Request') raise BadRequest except ValueError: self.send_response('400 Bad Request') raise BadRequest req = dict(method=method, protocol=proto) scheme = '' host = '' if uri == '*' or uri.startswith('/'): path = uri elif '://' in uri: scheme, rest = uri.split('://') host, path = rest.split('/', 1) path = '/' + path else: self.send_response('400 Bad Request') raise BadRequest query_string = '' if '?' in path: path, query_string = path.split('?', 1) path = r'%2F'.join([unquote(x) for x in re_SLASH.split(path)]) req.update(path=path, query_string=query_string, scheme=scheme.lower(), host=host) return req def read_headers(self, sock_file): try: headers = dict() lname = None lval = None while True: l = sock_file.readline() if PY3K: try: l = str(l, 'ISO-8859-1') except UnicodeDecodeError: self.err_log.warning( 'Client sent invalid header: ' + repr(l)) if l.strip().replace('\0', '') == '': break if l[0] in ' \t' and lname: # Some headers take more than one line lval += ' ' + l.strip() else: # HTTP header values are latin-1 encoded l = l.split(':', 1) # HTTP header names are us-ascii encoded lname = l[0].strip().upper().replace('-', '_') lval = l[-1].strip() headers[str(lname)] = str(lval) except socket.timeout: raise SocketTimeout("Socket timed out before request.") return headers
Worker继承自Thread，线程启动会执行run方法，在这个方法中做了以下的事情：
1、从连接队列中取得con对象
2、执行方法run_app(con),这个方法由子类实现
Rocket中Worker子类是：
class WSGIWorker(Worker): def __init__(self, *args, **kwargs): """Builds some instance variables that will last the life of the thread.""" Worker.__init__(self, *args, **kwargs) if isinstance(self.app_info, dict): multithreaded = self.app_info.get('max_threads') != 1 else: multithreaded = False self.base_environ = dict( {'SERVER_SOFTWARE': self.app_info['server_software'], 'wsgi.multithread': multithreaded, }) self.base_environ.update(BASE_ENV) # Grab our application self.app = self.app_info.get('wsgi_app') if not hasattr(self.app, "__call__"): raise TypeError("The wsgi_app specified (%s) is not a valid WSGI application." % repr(self.app)) # Enable futures if has_futures and self.app_info.get('futures'): executor = self.app_info['executor'] self.base_environ.update({"wsgiorg.executor": executor, "wsgiorg.futures": executor.futures}) def build_environ(self, sock_file, conn): """ Build the execution environment. """ # Grab the request line request = self.read_request_line(sock_file) # Copy the Base Environment environ = self.base_environ.copy() # Grab the headers for k, v in self.read_headers(sock_file).iteritems(): environ[str('HTTP_' + k)] = v # Add CGI Variables environ['REQUEST_METHOD'] = request['method'] environ['PATH_INFO'] = request['path'] environ['SERVER_PROTOCOL'] = request['protocol'] environ['SERVER_PORT'] = str(conn.server_port) environ['REMOTE_PORT'] = str(conn.client_port) environ['REMOTE_ADDR'] = str(conn.client_addr) environ['QUERY_STRING'] = request['query_string'] if 'HTTP_CONTENT_LENGTH' in environ: environ['CONTENT_LENGTH'] = environ['HTTP_CONTENT_LENGTH'] if 'HTTP_CONTENT_TYPE' in environ: environ['CONTENT_TYPE'] = environ['HTTP_CONTENT_TYPE'] # Save the request method for later self.request_method = environ['REQUEST_METHOD'] # Add Dynamic WSGI Variables if conn.ssl: environ['wsgi.url_scheme'] = 'https' environ['HTTPS'] = 'on' try: peercert = conn.socket.getpeercert(binary_form=True) environ['SSL_CLIENT_RAW_CERT'] = \ peercert and ssl.DER_cert_to_PEM_cert(peercert) except Exception: print sys.exc_info()[1] else: environ['wsgi.url_scheme'] = 'http' if environ.get('HTTP_TRANSFER_ENCODING', '') == 'chunked': environ['wsgi.input'] = ChunkedReader(sock_file) else: environ['wsgi.input'] = sock_file return environ def send_headers(self, data, sections): h_set = self.header_set # Does the app want us to send output chunked? self.chunked = h_set.get('Transfer-Encoding', '').lower() == 'chunked' # Add a Date header if it's not there already if not 'Date' in h_set: h_set['Date'] = formatdate(usegmt=True) # Add a Server header if it's not there already if not 'Server' in h_set: h_set['Server'] = HTTP_SERVER_SOFTWARE if 'Content-Length' in h_set: self.size = int(h_set['Content-Length']) else: s = int(self.status.split(' ')[0]) if (s < 200 or s not in (204, 205, 304)) and not self.chunked: if sections == 1 or self.protocol != 'HTTP/1.1': # Add a Content-Length header because it's not there self.size = len(data) h_set['Content-Length'] = str(self.size) else: # If they sent us more than one section, we blow chunks h_set['Transfer-Encoding'] = 'Chunked' self.chunked = True if __debug__: self.err_log.debug('Adding header...' 'Transfer-Encoding: Chunked') if 'Connection' not in h_set: # If the application did not provide a connection header, # fill it in client_conn = self.environ.get('HTTP_CONNECTION', '').lower() if self.environ['SERVER_PROTOCOL'] == 'HTTP/1.1': # HTTP = 1.1 defaults to keep-alive connections if client_conn: h_set['Connection'] = client_conn else: h_set['Connection'] = 'keep-alive' else: # HTTP < 1.1 supports keep-alive but it's quirky # so we don't support it h_set['Connection'] = 'close' # Close our connection if we need to. self.closeConnection = h_set.get('Connection', '').lower() == 'close' # Build our output headers header_data = HEADER_RESPONSE % (self.status, str(h_set)) # Send the headers if __debug__: self.err_log.debug('Sending Headers: %s' % repr(header_data)) self.conn.sendall(b(header_data)) self.headers_sent = True def write_warning(self, data, sections=None): self.err_log.warning('WSGI app called write method directly. This is ' 'deprecated behavior. Please update your app.') return self.write(data, sections) def write(self, data, sections=None): """ Write the data to the output socket. """ if self.error[0]: self.status = self.error[0] data = b(self.error[1]) if not self.headers_sent: self.send_headers(data, sections) if self.request_method != 'HEAD': try: if self.chunked: self.conn.sendall(b('%x\r\n%s\r\n' % (len(data), data))) else: self.conn.sendall(data) except socket.timeout: self.closeConnection = True except socket.error: # But some clients will close the connection before that # resulting in a socket error. self.closeConnection = True def start_response(self, status, response_headers, exc_info=None): """ Store the HTTP status and headers to be sent when self.write is called. """ if exc_info: try: if self.headers_sent: # Re-raise original exception if headers sent # because this violates WSGI specification. raise finally: exc_info = None elif self.header_set: raise AssertionError("Headers already set!") if PY3K and not isinstance(status, str): self.status = str(status, 'ISO-8859-1') else: self.status = status # Make sure headers are bytes objects try: self.header_set = Headers(response_headers) except UnicodeDecodeError: self.error = ('500 Internal Server Error', 'HTTP Headers should be bytes') self.err_log.error('Received HTTP Headers from client that contain' ' invalid characters for Latin-1 encoding.') return self.write_warning def run_app(self, conn): self.size = 0 self.header_set = Headers([]) self.headers_sent = False self.error = (None, None) self.chunked = False sections = None output = None if __debug__: self.err_log.debug('Getting sock_file') # Build our file-like object if PY3K: sock_file = conn.makefile(mode='rb', buffering=BUF_SIZE) else: sock_file = conn.makefile(BUF_SIZE) try: # Read the headers and build our WSGI environment self.environ = environ = self.build_environ(sock_file, conn) # Handle 100 Continue if environ.get('HTTP_EXPECT', '') == '100-continue': res = environ['SERVER_PROTOCOL'] + ' 100 Continue\r\n\r\n' conn.sendall(b(res)) # Send it to our WSGI application output = self.app(environ, self.start_response) if not hasattr(output, '__len__') and not hasattr(output, '__iter__'): self.error = ('500 Internal Server Error', 'WSGI applications must return a list or ' 'generator type.') if hasattr(output, '__len__'): sections = len(output) for data in output: # Don't send headers until body appears if data: self.write(data, sections) if not self.headers_sent: # Send headers if the body was empty self.send_headers('', sections) if self.chunked and self.request_method != 'HEAD': # If chunked, send our final chunk length self.conn.sendall(b('0\r\n\r\n')) # Don't capture exceptions here. The Worker class handles # them appropriately. finally: if __debug__: self.err_log.debug('Finally closing output and sock_file') if hasattr(output, 'close'): output.close() sock_file.close() # Monolithic build...end of module: rocket/methods/wsgi.py
在runapp中主要执行了下面的代码：
self.environ = environ = self.build_environ(sock_file, conn)
output = self.app(environ, self.start_response)
第一行是读取客户端的请求，并取得所有的请求头。
第二行是调用请求对应的方法，并取得输出。
app是worker初始化的时候传入的。