Python Simple Web server

The process of establishing a TCP connection for a server is divided into 4 steps:

1. Set up the socket object: here, as with the client, remains:

S=socket.socket (Socket.af_inet,socket. SOCK_STREAM)

2. Setting and getting socket options

Python defines setsockopt () and getsockopt (), one is the setup option and the other is set. Here the main use of setsockopt (), the specific structure is as follows:

SetSockOpt (Level,optname,value)

Level defines which option will be used. Usually it is sol_socket, which means the SOCKET option is being used. It can also set protocol options by setting a special protocol number, but for a given operating system, most protocol options are clear, so for simplicity, they are rarely used for applications designed for mobile devices.

The optname parameter provides special options for use. The settings for the available options vary slightly depending on the operating system. If level Sol_socket is selected, some common options are shown in the following table:

Options	Significance	Expectations
So_bindtodevice	You can make the socket valid only on a particular network interface (NIC). Maybe not a mobile portable device.	A string gives the name of the device or an empty string to return the default value
So_broadcast	Allow broadcast addresses to send and receive packets. Valid only for UDP. How to send and receive broadcast packets	Boolean integer
So_dontroute	Sending packets out through routers and gateways is prohibited. This is primarily a way to use UDP traffic on Ethernet for security purposes. Prevents data from leaving the local network, regardless of the IP address used for the destination address	Boolean integer
So_keepalive	You can keep packets of TCP traffic contiguous. These packets can make sure that the connection is maintained when no information is transmitted.	Boolean integer
So_oobinline	The abnormal data received can be considered as normal data, which means that the data will be received through a standard call to recv ().	Boolean integer
So_reuseaddr	When the socket is closed, the port number that the local side uses for the socket can be reused immediately. In general, it can be reused only after the system has been defined for a period of time.	Boolean integer

In this section, we use the SO_REUSEADDR option when studying, specifically:

S.setsockopt (socket. Sol_socket,socket. so_reuseaddr,1) Here value is set to 1, which means that the SO_REUSEADDR is marked as true, and the operating system releases the port of the server immediately after the server socket is closed or the server process terminates, otherwise the operating system retains the port for a few minutes.

3. Bind socket

Binding requires a port number for the server.

S.bind ((Host,port)), where host is the server IP, usually empty, or can be bound to a specific IP address. Port is the port number.

4. Listen for connections.

Use the Listen () function to listen for connections. The function has only one parameter, which indicates how many pending (waiting) connections are allowed to wait in the queue when the server actually processes the connection. As a convention, many people are set to 5. Example: S.listen (5)

[Python]View Plaincopyprint?

2. Import socket
6. Host = ' '
8. Port =
12. Print "Create socket"
14. s = socket.socket (socket.af_inet, socket. SOCK_STREAM)
16. Print "Done"
20. Print "Set the socket Options"
22. S.setsockopt (socket. Sol_socket, SOCKET. SO_REUSEADDR, 1)
24. Print "Done"
28. Print "Build to Port and interface"
30. S.bind ((host, Port))
32. Print "Done"
36. Print "Listen for Connection"
38. S.listen (5)
42. Print "Connect from", S.getsockname ()

Python Simple Web server