EventBufferEvent
PHP Manual

EventBufferEvent::connectHost

Connects to a hostname with optionally asyncronous DNS resolving

Description

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

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.

Note:

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

Note:

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

Parameters

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 .

Return Values

Returns true on success or false on failure.

Examples

Example #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();
?>

The above example will output something similar to:

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

See Also

  • EventBufferEvent::connect