The examples in this article describe the socket communication mechanism and usage in php. Share it with everyone for your reference. The specific analysis is as follows:
1. What is socket
What is a socket? The so-called socket is usually also called "socket", which is used to describe the IP address and port. It is the handle of a communication chain. Applications usually make requests to the network or respond to network requests through "sockets". To put it bluntly, it is a communication mechanism. It is similar to the telephone customer service departments of banks, telecommunications and other departments. When you call, a person will be assigned to answer your questions. The customer service department is equivalent to the server side of the socket, and your side is equivalent to the client. Before the call ends with you, if someone is on It is impossible to talk to the person you are talking to because you are communicating with him. Of course, the telephone switchboard of the customer service department will not be duplicated.
I will give an example below to explain how socket works. If you are developing based on the application layer, you do not necessarily need to understand the principle, but it is better to know. There are php apis about sockets on the Internet. Just put it down and use it.
2. socket server server.php
The code is as follows:
$tcp = getprotobyname("tcp");
$socket = socket_create(af_inet, sock_stream, $tcp);
socket_bind($socket, '127.0.0.1', 10008); //Bind the port to be monitored
socket_listen($socket); //Listening port
//Initialize a data and communicate with the client
$buffer = "connect";
while (true) {
//Accept a socket connection
$connection = socket_accept($socket);
if(!$connection){
echo "connect fail";
}else{
echo "socket connected ";
// Pass an information data to the client
if ($buffer != "") {
echo "send data to client ";
socket_write($connection, $buffer . " ");
echo "wrote to socket ";
} else {
echo "no data in the buffer " ;
}
// Get information from the client
while ($data = @socket_read($connection, 1024, php_normal_read)) {
printf("buffer: " . $data . " ");
//Get information and give feedback to the client
socket_write($connection, "information received ");
}
}
socket_close($connection);
//Close socket
printf("closed the socket ");
}
?>
3. socket client client.php
The code is as follows:
$socket = socket_create(af_inet, sock_stream, sol_tcp);
$connection = socket_connect($socket, '127.0.0.1', 10008); //Connect to the server-side socket
while ($buffer = @socket_read($socket, 1024, php_normal_read)) {
//The server tells the client its status
if (preg_match("/not connect/",$buffer)) {
echo "don`t connect ";
break;
} else {
//Message sent from server
echo "buffer data: " . $buffer . " ";
echo "writing to socket ";
//Write the customer's information into the channel and pass it to the server
if (!socket_write($socket, "some data ")) {
echo "write failed ";
}
//After the server receives the information, it will give the response information
while ($buffer = socket_read($socket, 1024, php_normal_read)) {
echo "sent to server: some data response from server was:" . $buffer . " ";
}
}
}
?>
4. A picture of the communication mechanism (automatically closing the socket regardless of the waiting time)
A brief explanation. Before I explain, I want to say why you need to use php commands to execute the server and client. For the client, you use fsockopen, so that you can access it on the browser, and at least the connection will time out. Why is this? Because when you create a socket, it will constantly monitor whether the client wants to connect.
The establishment of socket communication requires two socket channels, one created by the server and one created by the client.
Line 1, the server creates a socket channel, puts the information in the cache, and waits for the client to connect
Line 2, the client creates a socket channel and connects to the server, obtains the server-side information for communication, and sends the information to be transmitted into the channel
Line 3, the server gets the information from the client and tells the client that I have received the information. Send the information to be transmitted into the channel
Line 4, the client obtains confirmation information from the server
At this point, a communication is completely established. After the data transmission is completed, the server will disconnect the socket communication. The specific operations are as follows.
1 Run the socket server
The code is as follows:
interactive mode enabled
What kind of work have been done on this point?
a listened to a 10008 port
The code is as follows:
tcp 0 0 127.0.0.1:10008 0.0.0.0:* listen
[zhangy@blackghost ~]$
b Send the information to the cache
The code is as follows:
2 Run socket client
The code is as follows:
interactive mode enabled
buffer data: connect
writing to socket
sent to server: some data
response from server was:information received
3 Return to the server
The code is as follows:
interactive mode enabled
socket connected
send data to client
wrote to socket
buffer: some data
closed the socket
I hope this article will be helpful to everyone’s PHP programming design.