EventBufferEvent::connectHost

    (PECL event >= 1.2.6-beta)

    EventBufferEvent::connectHost — Connects to a hostname with optionally asyncronous DNS resolving

    说明

    public EventBufferEvent::connectHost(
         EventDnsBase $dns_base ,
         string $hostname ,
         int $port ,
         int $family = EventUtil::AF_UNSPEC
    ): bool

    Resolves the DNS name hostname, looking for addresses of type family ( EventUtil::AF_* constants). If the name resolution fails, it invokes the event callback with an error event. If it succeeds, it launches a connection attempt just as EventBufferEvent::connect() would.

    dns_base is optional. May be null, or an object created with EventDnsBase::__construct() . For asyncronous hostname resolving pass a valid event dns base resource. Otherwise the hostname resolving will block.

    注意:

    EventDnsBase is available only if Event configured --with-event-extra ( event_extra library, libevent protocol-specific functionality support including HTTP, DNS, and RPC ).

    注意:

    EventBufferEvent::connectHost() requires libevent-2.0.3-alpha or greater.

    参数

    dns_base

    Object of EventDnsBase in case if DNS is to be resolved asyncronously. Otherwise null.

    hostname

    Hostname to connect to. Recognized formats are: 

    www.example.com (hostname)
 1.2.3.4 (ipv4address)
 ::1 (ipv6address)
[::1] ([ipv6address])

    port

    Port number

    family

    Address family. EventUtil::AF_UNSPEC , EventUtil::AF_INET , or EventUtil::AF_INET6 . See EventUtil constants .

    返回值

    成功时返回 true， 或者在失败时返回 false。

    示例

    示例 #1 EventBufferEvent::connectHost() example

    <?php
    /* Read callback */
    function readcb($bev, $base) {
    //$input = $bev->input; //$bev->getInput();

    //$pos = $input->search("TTP");
    $pos = $bev->input->search("TTP");

    while ((    $n = $bev->input->remove($buf, 1024)) > 0) {
    echo     $buf;
    }
    }

    /* Event callback */
    function eventcb($bev, $events, $base) {
    if (    $events & EventBufferEvent::CONNECTED) {
    echo     "Connected.\n";
    } elseif (    $events & (EventBufferEvent::ERROR | EventBufferEvent::EOF)) {
    if (    $events & EventBufferEvent::ERROR) {
    echo     "DNS error: ", $bev->getDnsErrorString(), PHP_EOL;
    }

    echo     "Closing\n";
    $base->exit();
    exit(    "Done\n");
    }
    }

    $base = new EventBase();

    $dns_base = new EventDnsBase($base, TRUE); // We'll use async DNS resolving
    if (!$dns_base) {
    exit(    "Failed to init DNS Base\n");
    }

    $bev = new EventBufferEvent($base, /* use internal socket */ NULL,
    EventBufferEvent::OPT_CLOSE_ON_FREE | EventBufferEvent::OPT_DEFER_CALLBACKS,
    "readcb", /* writecb */ NULL, "eventcb", $base
    );
    if (!    $bev) {
    exit(    "Failed creating bufferevent socket\n");
    }

    //$bev->setCallbacks("readcb", /* writecb */ NULL, "eventcb", $base);
    $bev->enable(Event::READ | Event::WRITE);

    $output = $bev->output; //$bev->getOutput();
    if (!$output->add(
    "GET {$argv[2]} HTTP/1.0\r\n".
    "Host: {$argv[1]}\r\n".
    "Connection: Close\r\n\r\n"
    )) {
    exit(    "Failed adding request to output buffer\n");
    }

    if (!    $bev->connectHost($dns_base, $argv[1], 80, EventUtil::AF_UNSPEC)) {
    exit(    "Can't connect to host {$argv[1]}\n");
    }

    $base->dispatch();
    ?>

    以上示例的输出类似于：

    Connected.
HTTP/1.0 301 Moved Permanently
Location: http://www.google.co.uk/
Content-Type: text/html; charset=UTF-8
Date: Sat, 09 Mar 2013 12:21:19 GMT
Expires: Mon, 08 Apr 2013 12:21:19 GMT
Cache-Control: public, max-age=2592000
Server: gws
Content-Length: 221
X-XSS-Protection: 1; mode=block
X-Frame-Options: SAMEORIGIN

<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<TITLE>301 Moved</TITLE></HEAD><BODY>
<H1>301 Moved</H1>
The document has moved
<A HREF="http://www.google.co.uk/">here</A>.
</BODY></HTML>
Closing
Done

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