(PECL event >= 1.2.6-beta)
EventBufferEvent::connectHost — Connects to a hostname with optionally asyncronous DNS resolving
$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.
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
      .
     
   Returns TRUE on success. Otherwise FALSE.
  
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