PHP 警告 : socket_read(): unable to read from socket [104]: Connection reset by peer

Question

我用 socket_create()创建套接字资源，然后绑定(bind) IP通过 socket_bind() 向它发送地址，它的工作正常；

但过了一会儿(超过 30 分钟)在行 socket_read($sock, 2048)抛出此错误:
"PHP Warning: socket_read(): unable to read from socket [104]: Connection reset by peer in test.php on line 198" .

这是我的简化代码:

$this->sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);

// check if tcp socket ceated or not
if ($this->sock === false) {
    $errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
     die("Couldn't create socket: [$errorcode] $errormsg");
}

// Bind the source address
socket_bind($this->sock, $this->ip);
// Connect to destination address
socket_connect($this->sock, $this->mxHost, $this->port);
$buf = socket_read($this->sock, 2048);

这段代码与另一端的 MX 主机建立了 SMTP(端口 25)连接。
也许这是您连接另一端的故障，但是我如何检测到另一端现在还没有准备好连接。换句话说，我怎样才能发现“对等连接重置”发生了？

Answer 1

您应该检查 socket_connect()在读取它之前是成功的。

所以你可以像这样重写你的代码:

-- 更新 --

$this->sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
// Bind the source address
socket_bind($this->sock, $this->ip);
// Connect to destination address
if (socket_connect($this->sock, $this->mxHost, $this->port)) {
    // suppress the warning for now since we have error checking below
    $buf = @socket_read($this->sock, 2048);

    // socket_read() returns a zero length string ("") when there is no more data to read.
    // This indicates that the socket is closed on the other side. 
    if ($buf === '') 
    { 
        throw new \Exception('Connection reset by peer'); 
    } 
} else {
    // Connection was not successful. Get the last error and throw an exception
    $errorMessage = socket_strerror(socket_last_error());
    throw new \Exception($errorMessage);
}