一直以来,PHP很少用于socket编程,毕竟是一门脚本语言,效率会成为很大的瓶颈,但是不能说PHP就无法用于socket编程,也不能说PHP的socket编程性能就有多么的低,例如知名的一款PHP socket框架 workerman 就是用纯PHP开发,并且号称拥有优秀的性能,所以在某些环境下,PHP socket编程或许也可一展身手。
PHP提供了一系列类似C语言socket库中的方法供我们调用:
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- socket_accept — Accepts a connection on a socket
- socket_bind — 给套接字绑定名字
- socket_clear_error — 清除套接字或者最后的错误代码上的错误
- socket_close — 关闭套接字资源
- socket_cmsg_space — Calculate message buffer size
- socket_connect — 开启一个套接字连接
- socket_create_listen — Opens a socket on port to accept connections
- socket_create_pair — Creates a pair of indistinguishable sockets and stores them in an array
- socket_create — 创建一个套接字(通讯节点)
- socket_get_option — Gets socket options for the socket
- socket_getopt — 别名 socket_get_option
- socket_getpeername — Queries the remote side of the given socket which may either result in host/port or in a Unix filesystem path, dependent on its type
- socket_getsockname — Queries the local side of the given socket which may either result in host/port or in a Unix filesystem path, dependent on its type
- socket_import_stream — Import a stream
- socket_last_error — Returns the last error on the socket
- socket_listen — Listens for a connection on a socket
- socket_read — Reads a maximum of length bytes from a socket
- socket_recv — 从已连接的socket接收数据
- socket_recvfrom — Receives data from a socket whether or not it is connection-oriented
- socket_recvmsg — Read a message
- socket_select — Runs the select() system call on the given arrays of sockets with a specified timeout
- socket_send — Sends data to a connected socket
- socket_sendmsg — Send a message
- socket_sendto — Sends a message to a socket, whether it is connected or not
- socket_set_block — Sets blocking mode on a socket resource
- socket_set_nonblock — Sets nonblocking mode for file descriptor fd
- socket_set_option — Sets socket options for the socket
- socket_setopt — 别名 socket_set_option
- socket_shutdown — Shuts down a socket for receiving, sending, or both
- socket_strerror — Return a string describing a socket error
- socket_write — Write to a socket
更多细节请查看PHP关于socket的官方手册:http://php.net/manual/zh/book.sockets.php
一个简单的TCP服务器示例 phptcpserver.php :
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- <?php
- $servsock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP); // 创建一个socket
- if (FALSE === $servsock)
- {
- $errcode = socket_last_error();
- fwrite(STDERR, "socket create fail: " . socket_strerror($errcode));
- exit(-1);
- }
- if (!socket_bind($servsock, ‘127.0.0.1‘, 8888)) // 绑定ip地址及端口
- {
- $errcode = socket_last_error();
- fwrite(STDERR, "socket bind fail: " . socket_strerror($errcode));
- exit(-1);
- }
- if (!socket_listen($servsock, 128)) // 允许多少个客户端来排队连接
- {
- $errcode = socket_last_error();
- fwrite(STDERR, "socket listen fail: " . socket_strerror($errcode));
- exit(-1);
- }
- while (1)
- {
- $connsock = socket_accept($servsock); //响应客户端连接
- if ($connsock)
- {
- socket_getpeername($connsock, $addr, $port); //获取连接过来的客户端ip地址和端口
- echo "client connect server: ip = $addr, port = $port" . PHP_EOL;
- while (1)
- {
- $data = socket_read($connsock, 1024); //从客户端读取数据
- if ($data === ‘‘)
- {
- //客户端关闭
- socket_close($connsock);
- echo "client close" . PHP_EOL;
- break;
- }
- else
- {
- echo ‘read from client:‘ . $data;
- $data = strtoupper($data); //小写转大写
- socket_write($connsock, $data); //回写给客户端
- }
- }
- }
- }
- socket_close($servsock);
启动这个服务器:
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- [[email protected] php]# php phptcpserver.php
之后这个服务器就一直阻塞在那里,等待客户端连接,我们可以用telnet命令来连接这个服务器:
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- [[email protected] ~]# telnet 127.0.0.1 8888
- Trying 127.0.0.1...
- Connected to 127.0.0.1.
- Escape character is ‘^]‘.
- ajdjajksdjkaasda
- AJDJAJKSDJKAASDA
- 小明哈哈哈哈笑
- 小明哈哈哈哈笑
- 小明efsfsdfsdf了哈哈哈
- 小明EFSFSDFSDF了哈哈哈
服务器端输出:
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- [[email protected] php]# php phptcpserver.php
- client connect server: ip = 127.0.0.1, port = 50398
- read from client:ajdjajksdjkaasda
- read from client:小明哈哈哈哈笑
- read from client:小明efsfsdfsdf了哈哈哈
但其实这个TCP服务器是有问题的,它一次只能处理一个客户端的连接和数据传输,这是因为一个客户端连接过来后,进程就去负责读写客户端数据,当客户端没有传输数据时,tcp服务器处于阻塞读状态,无法再去处理其他客户端的连接请求了。
解决这个问题的一种办法就是采用多进程服务器,每当一个客户端连接过来,服务器开一个子进程专门负责和该客户端的数据传输,而父进程仍然监听客户端的连接,但是起进程的代价是昂贵的,这种多进程的机制显然支撑不了高并发。
另一个解决办法是使用IO多路复用机制,使用php为我们提供的socket_select方法,它可以监听多个socket,如果其中某个socket状态发生了改变,比如从不可写变为可写,从不可读变为可读,这个方法就会返回,从而我们就可以去处理这个socket,处理客户端的连接,读写操作等等。来看php文档中对该socket_select的介绍
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- socket_select — Runs the select() system call on the given arrays of sockets with a specified timeout
- 说明
- int socket_select ( array &$read , array &$write , array &$except , int $tv_sec [, int $tv_usec = 0 ] )
- socket_select() accepts arrays of sockets and waits for them to change status.
- Those coming with BSD sockets background will recognize that those socket resource arrays are in fact the so-called file descriptor sets.
- Three independent arrays of socket resources are watched.
- You do not need to pass every array to socket_select(). You can leave it out and use an empty array or NULL instead.
- Also do not forget that those arrays are passed by reference and will be modified after socket_select() returns.
- 返回值
- On success socket_select() returns the number of socket resources contained in the modified arrays,
- which may be zero if the timeout expires before anything interesting happens.
- On error FALSE is returned. The error code can be retrieved with socket_last_error().
大致翻译下:
socket_select --- 在给定的几组sockets数组上执行 select() 系统调用,用一个特定的超时时间。
socket_select() 接受几组sockets数组作为参数,并监听它们改变状态
这些基于BSD scokets 能够识别这些socket资源数组实际上就是文件描述符集合。
三个不同的socket资源数组会被同时监听。
这三个资源数组不是必传的, 你可以用一个空数组或者NULL作为参数,不要忘记这三个数组是以引用的方式传递的,在函数返回后,这些数组的值会被改变。
socket_select() 调用成功返回这三个数组中状态改变的socket总数,如果设置了timeout,并且在timeout之内都没有状态改变,这个函数将返回0,出错时返回FALSE,可以用socket_last_error() 获取错误码。
使用 socket_select() 优化之前 phptcpserver.php 代码:
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- <?php
- $servsock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP); // 创建一个socket
- if (FALSE === $servsock)
- {
- $errcode = socket_last_error();
- fwrite(STDERR, "socket create fail: " . socket_strerror($errcode));
- exit(-1);
- }
- if (!socket_bind($servsock, ‘127.0.0.1‘, 8888)) // 绑定ip地址及端口
- {
- $errcode = socket_last_error();
- fwrite(STDERR, "socket bind fail: " . socket_strerror($errcode));
- exit(-1);
- }
- if (!socket_listen($servsock, 128)) // 允许多少个客户端来排队连接
- {
- $errcode = socket_last_error();
- fwrite(STDERR, "socket listen fail: " . socket_strerror($errcode));
- exit(-1);
- }
- /* 要监听的三个sockets数组 */
- $read_socks = array();
- $write_socks = array();
- $except_socks = NULL; // 注意 php 不支持直接将NULL作为引用传参,所以这里定义一个变量
- $read_socks[] = $servsock;
- while (1)
- {
- /* 这两个数组会被改变,所以用两个临时变量 */
- $tmp_reads = $read_socks;
- $tmp_writes = $write_socks;
- // int socket_select ( array &$read , array &$write , array &$except , int $tv_sec [, int $tv_usec = 0 ] )
- $count = socket_select($tmp_reads, $tmp_writes, $except_socks, NULL); // timeout 传 NULL 会一直阻塞直到有结果返回
- foreach ($tmp_reads as $read)
- {
- if ($read == $servsock)
- {
- /* 有新的客户端连接请求 */
- $connsock = socket_accept($servsock); //响应客户端连接, 此时不会造成阻塞
- if ($connsock)
- {
- socket_getpeername($connsock, $addr, $port); //获取远程客户端ip地址和端口
- echo "client connect server: ip = $addr, port = $port" . PHP_EOL;
- // 把新的连接sokcet加入监听
- $read_socks[] = $connsock;
- $write_socks[] = $connsock;
- }
- }
- else
- {
- /* 客户端传输数据 */
- $data = socket_read($read, 1024); //从客户端读取数据, 此时一定会读到数组而不会产生阻塞
- if ($data === ‘‘)
- {
- //移除对该 socket 监听
- foreach ($read_socks as $key => $val)
- {
- if ($val == $read) unset($read_socks[$key]);
- }
- foreach ($write_socks as $key => $val)
- {
- if ($val == $read) unset($write_socks[$key]);
- }
- socket_close($read);
- echo "client close" . PHP_EOL;
- }
- else
- {
- socket_getpeername($read, $addr, $port); //获取远程客户端ip地址和端口
- echo "read from client # $addr:$port # " . $data;
- $data = strtoupper($data); //小写转大写
- if (in_array($read, $tmp_writes))
- {
- //如果该客户端可写 把数据回写给客户端
- socket_write($read, $data);
- }
- }
- }
- }
- }
- socket_close($servsock);
现在,这个TCP服务器就可以支持多个客户端同时连接了,测试下:
服务器端:
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- [[email protected] php]# php phptcpserver.php
- client connect server: ip = 127.0.0.1, port = 50404
- read from client # 127.0.0.1:50404 # hello world
- client connect server: ip = 127.0.0.1, port = 50406
- read from client # 127.0.0.1:50406 # hello PHP
- read from client # 127.0.0.1:50404 # 少小离家老大回
- read from client # 127.0.0.1:50404 # 乡音无改鬓毛衰
- read from client # 127.0.0.1:50406 # 老当益壮,
- read from client # 127.0.0.1:50406 # 宁移白首之心
- client close
- client connect server: ip = 127.0.0.1, port = 50408
稍微修改上面的服务器返回,返回一个HTTP响应头和一个简单的HTTP响应体,这样就摇身一变成了一个最简单的HTTP服务器:
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- ....
- socket_getpeername($read, $addr, $port); //获取远程客户端ip地址和端口
- echo "read from client # $addr:$port # " . $data;
- $response = "HTTP/1.1 200 OK\r\n";
- $response .= "Server: phphttpserver\r\n";
- $response .= "Content-Type: text/html\r\n";
- $response .= "Content-Length: 3\r\n\r\n";
- $response .= "ok\n";
- if (in_array($read, $tmp_writes))
- {
- //如果该客户端可写 把数据回写给客户端
- socket_write($read, $response);
- socket_close($read); // 主动关闭客户端连接
- //移除对该 socket 监听
- foreach ($read_socks as $key => $val)
- {
- if ($val == $read) unset($read_socks[$key]);
- }
- foreach ($write_socks as $key => $val)
- {
- if ($val == $read) unset($write_socks[$key]);
- }
- }
- .....
重新启动该服务器,用curl模拟请求该http服务器:
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- [[email protected] ~]# curl ‘127.0.0.1:8888‘
- ok
- [[email protected] ~]# curl ‘127.0.0.1:8888‘
- ok
- [[email protected] ~]# curl ‘127.0.0.1:8888‘
- ok
- [[email protected] ~]# curl ‘127.0.0.1:8888‘
- ok
- [[email protected] ~]# curl ‘127.0.0.1:8888‘
- ok
- [[email protected] ~]#
服务器端输出:
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- client connect server: ip = 127.0.0.1, port = 50450
- read from client # 127.0.0.1:50450 # GET / HTTP/1.1
- User-Agent: curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.27.1 zlib/1.2.3 libidn/1.18 libssh2/1.4.2
- Host: 127.0.0.1:8888
- Accept: */*
- client close
- client connect server: ip = 127.0.0.1, port = 50452
- read from client # 127.0.0.1:50452 # GET / HTTP/1.1
- User-Agent: curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.27.1 zlib/1.2.3 libidn/1.18 libssh2/1.4.2
- Host: 127.0.0.1:8888
- Accept: */*
- client close
- client connect server: ip = 127.0.0.1, port = 50454
- read from client # 127.0.0.1:50454 # GET / HTTP/1.1
- User-Agent: curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.27.1 zlib/1.2.3 libidn/1.18 libssh2/1.4.2
- Host: 127.0.0.1:8888
- Accept: */*
- client close
- client connect server: ip = 127.0.0.1, port = 50456
- read from client # 127.0.0.1:50456 # GET / HTTP/1.1
- User-Agent: curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.27.1 zlib/1.2.3 libidn/1.18 libssh2/1.4.2
- Host: 127.0.0.1:8888
- Accept: */*
- client close
这样一个高并发的HTTP服务器就开发好了,用压测软件测试下并发能力:
看到高达5000多的QPS,有没有小激动呢^^。
PHP是世界上最好的语言 that‘s all !
原文地址:https://www.cnblogs.com/wanglijun/p/8732790.html