Python Learning---io async [custom Asynchronous IO]

Custom IO Async Basics:

--all requests are based on the socket implementation, and a request is a socket

Socket.setblocking (False) does not need to block, a request is over send another, will error, need to solve

--io multiplexing [is a synchronous request]

IO multiplexing has epoll, poll, select, knowing that epoll performance is better than others [Epoll find the house number first and look for someone].

Io multiplexing is essentially a way to perform multiple IO operations in the same thread or process by toggling the switch. Note that virtually every IO operation is performed independently. Just from the original one-to-one turn into many-to-many.

R,w,e = Select.select ([],[],[], Time-out) # The socket has a request/response to the previous r,w,e will receive the

io Async principle:

io Async implementation: essentially "non-blocking socket" + "IO multiplexing"

io Async implementation: essentially "non-blocking socket" + "IO multiplexing"

Import Selectimport socketimport timeclass asynctimeoutexception (timeouterror): "" "Request time-out exception class" "Def __init__ (s Elf, msg): Self.msg = Msg Super (asynctimeoutexception, self). __init__ (msg) # encapsulates the object class Httpcon for sockets and buffer        Text (object): "" "encapsulates the request and the corresponding basic data" "" Def __init__ (self, sock, host, port, method, URL, data, callback, timeout=5): "" "" Sock: Client socket object requested host: requested hostname port: Ports requested: Port method: Request Method URL        : Requested URL data: Callback in Request body: callback function after request completed timeout: timeout for request "" "Self.sock = Sock Self.callback = Callback Self.host = Host Self.port = Port Self.method = Method Self.url = URL Self.data = Data Self.timeout = Timeout Self.__start_time = time.time () Self.__buffer = [] def is_timeout (self): "" "whether the current request has timed out" "" Current_time = Time.time () if (Self.__start_time + self. Timeout) < Current_tiMe:return True def Fileno (self): "" "Request Sockect object's file descriptor for select Listener" "" Return Self.sock.fileno ()        Def write (self, data): "" In buffer Write response content "" "Self.__buffer.append (data) def finish (self, exc=none): "" "writes the response content in buffer complete, and executes the requested callback function" "If not Exc:response = B '. Join (Self.__buffer) self.cal Lback (self, Response, exc) else:self.callback (self, None, exc) def send_request_data (self): C        ontent = "" "%s%s Http/1.0\r\nhost:%s\r\n\r\n%s" ""% (Self.method.upper (), Self.url, Self.host, Self.data,)        Return Content.encode (encoding= ' UTF8 ') class Asyncrequest (object): Def __init__ (self): Self.fds = []        Self.connections = [] def add_request (self, host, port, method, URL, data, callback, timeout): "" Create a Request "" "  Client = Socket.socket () client.setblocking (False) # does not block the request, does not wait for the response Try:client.connect (host, Port)) except BlOckingioerror as E:pass # print (' request to send connection remotely ') req = HttpContext (client, host, port, method , URL, data, callback, timeout) self.connections.append (req) # Package HttpContext object Self.fds.append (req) def Check_conn_timeout (self): "" "checks for all requests, whether there is a connection timeout, if any, terminates" "" timeout_list = [] for the context in Self.connec             Tions:if context.is_timeout (): timeout_list.append (context) for the context in Timeout_list: Context.finish (asynctimeoutexception (' Request timed out ')) Self.fds.remove (context) self.connections.  Remove (context) def running (self): "" "Event loop to detect if the requested socket is ready to perform the relevant operation" "" while True:r, W, E            = Select.select (Self.fds, Self.connections, Self.fds, 0.05) if not Self.fds:return                        For-context in R:sock = Context.sock while true:try: data = SOCK.RECV (80) If not data:self.fds.remove (context) con                     Text.finish () break else:context.write (data)                         Except Blockingioerror as E:break except Timeouterror as E:                        Self.fds.remove (context) self.connections.remove (context)                 Context.finish (e) Break for context in W: # already connected to a successful remote server, start sending request data to remote If context in Self.fds:data = Context.send_request_data () context.s Ock.sendall (data) self.connections.remove (context) Self.check_conn_timeout () if __name__ = = '        __main__ ': Def callback_func (context, Response, ex): "" ":p Aram Context:httpcontext object, internally encapsulating request-related information :p Aram Response: Request Response Content        :p Aram ex: If an exception occurs (the value is the exception object if there is an exception; otherwise the value is None): return: "" Print (context, response, ex) obj = A Syncrequest () # based TCP constructs HTTP url_list = [{' Host ': ' www.google.com ', ' Port ': ', ' method ': ' GET ', ' url ': '/', ' Data ': ', ' timeout ': 5, ' callback ': Callback_func}, {' Host ': ' www.baidu.com ', ' Port ': ' method ': ' GET ' , ' url ': '/', ' data ': ', ' timeout ': 5, ' callback ': Callback_func}, {' Host ': ' www.bing.com ', ' Port ': ' Method ':        ' GET ', ' url ': '/', ' data ': ', ' timeout ': 5, ' callback ': Callback_func},] for item in Url_list:print (item) Obj.add_request (**item) obj.running ()

Python Learning---io async [custom Asynchronous IO]