PHP SOCKET Programming

You're not a stranger to TCP/IP, UDP, socket programming. With the development of network technology, these words are filled with our ears. Then I would like to ask:

1. What is TCP/IP, UDP?
2. Where's the socket?
3. What is a socket?
4. Will you use them?

What is TCP/IP, UDP?

TCP/IP (transmission Control protocol/internet Protocol) is a protocol/inter-network protocol, an industry-standard set of protocols designed for wide area networks (WANs).

UDP (User data Protocol, Subscriber Datagram Protocol) is the protocol that corresponds to TCP. It is a part of the TCP/IP protocol family.

Here is a diagram showing the relationship of these protocols.

The TCP/IP protocol family includes transport layer, network layer, and link layer. Now you know the relationship between TCP/IP and UDP.

Where's the socket?

In Figure 1, we don't see the socket shadow, so where is it? Or use a diagram to speak, at a glance.

The original socket is here.

What is a socket?

A socket is an intermediate software abstraction layer that the application layer communicates with the TCP/IP protocol family, which is a set of interfaces. In design mode, the socket is actually a façade mode, it is the complex TCP/IP protocol family hidden behind the socket interface, for the user, a set of simple interface is all, let the socket to organize data to meet the specified protocol.

Will you use them?

Predecessors have done a lot of things to us, the communication between the network is a lot simpler, but after all, there is still a lot of work to do. Previously heard socket programming, think it is more advanced programming knowledge, but as long as understand how the socket programming principle, the mysterious veil also opened.

A scene in the life. You have to call a friend, dial first, a friend hears a phone call, and then you and your friend establish a connection, you can talk. When the communication is over, hang up the phone and end the conversation. The scene in life explains this work principle, perhaps the TCP/IP protocol family is born in the life, this is not necessarily.

Start with the server side. The server-side initializes the socket, then binds to the port (BIND), listens to the port (listen), calls the Accept block, waits for the client to connect. At this point if a client initializes a socket and then connects to the server (connect), the client-server connection is established if the connection is successful. The client sends the data request, the server receives the request and processes the request, then sends the response data to the client, the client reads the data, closes the connection, and ends the interaction at the end.

Socket correlation function:

Socket_accept () accepts a socket connection
Socket_bind () binds the socket to an IP address and port
Socket_clear_error () Clears the socket error or the last error code
Socket_close () Close a socket resource
Socket_connect () Start a socket connection
Socket_create_listen () Open a socket listener on the specified port
Socket_create_pair () produces a pair of indistinguishable sockets into an array
Socket_create () produces a socket equivalent to a data structure that produces a socket
Socket_get_option () Get socket options
Socket_getpeername () Gets the IP address of a remote similar host
Socket_getsockname () Gets the IP address of the local socket
Socket_iovec_add () Add a new vector to a scatter/aggregate array
Socket_iovec_alloc () This function creates a IOVEC data structure that can send the received read and write
Socket_iovec_delete () Delete an already assigned Iovec
Socket_iovec_fetch () returns the data for the specified Iovec resource
Socket_iovec_free () releasing a Iovec resource
Socket_iovec_set () Sets the new data value of the Iovec
Socket_last_error () Gets the last error code for the current socket
Socket_listen () listens for all connections by the specified socket
Socket_read () reads the specified length of data
SOCKET_READV () reads data from a scatter/aggregate array
SOCKET_RECV () end data from socket to cache
Socket_recvfrom () accepts data from the specified socket, if not specified, the default current socket
Socket_recvmsg () receive messages from Iovec
Socket_select () multi-channel selection
Socket_send () This function sends the data to the connected socket
SOCKET_SENDMSG () Send message to socket
Socket_sendto () sends a message to the socket at the specified address
Socket_set_block () set as block mode in socket
Socket_set_nonblock () set to non-block mode in socket
Socket_set_option () Set socket options
Socket_shutdown () This function allows you to close a read, write, or specified socket
Socket_strerror () returns a detailed error for the specified error number
Socket_write () write data to the socket cache
Socket_writev () write data to a scatter/aggregate array

[PHP manual] http://php.net/manual/en/book.sockets.php

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PHP SOCKET Programming