How do I make an asynchronous GET request in PHP?

Question

I wish to make a simple GET request to another script on a different server. How do I do this?

In one case, I just need to request an external script without the need for any output.

make_request('http://www.externalsite.com/script1.php?variable=45'); //example usage

In the second case, I need to get the text output.

$output = make_request('http://www.externalsite.com/script2.php?variable=45');
echo $output; //string output

To be honest, I do not want to mess around with CURL as this isn't really the job of CURL. I also do not want to make use of http_get as I do not have the PECL extensions.

Would fsockopen work? If so, how do I do this without reading in the contents of the file? Is there no other way?

Thanks all

Update

I should of added, in the first case, I do not want to wait for the script to return anything. As I understand file_get_contents() will wait for the page to load fully etc?

Answer 1

I found this interesting link to do asynchronous processing(get request).

askapache

Furthermore you could do asynchronous processing by using a message queue like for instance beanstalkd.

Answer 2

function make_request($url, $waitResult=true){
    $cmi = curl_multi_init();

    $curl = curl_init();
    curl_setopt($curl, CURLOPT_URL, $url);
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);

    curl_multi_add_handle($cmi, $curl);

    $running = null;
    do {
        curl_multi_exec($cmi, $running);
        sleep(.1);
        if(!$waitResult)
        break;
    } while ($running > 0);
    curl_multi_remove_handle($cmi, $curl);
    if($waitResult){
        $curlInfos = curl_getinfo($curl);
        if((int) $curlInfos['http_code'] == 200){
            curl_multi_close($cmi);
            return curl_multi_getcontent($curl);
        }
    }
    curl_multi_close($cmi);
}

Answer 3

Here's an adaptation of the accepted answer for performing a simple GET request.

One thing to note if the server does any url rewriting, this will not work. You'll need to use a more full featured http client.

  /**
   * Performs an async get request (doesn't wait for response)
   * Note: One limitation of this approach is it will not work if server does any URL rewriting
   */
  function async_get($url)
  {
      $parts=parse_url($url);

      $fp = fsockopen($parts['host'],
          isset($parts['port'])?$parts['port']:80,
          $errno, $errstr, 30);

      $out = "GET ".$parts['path']." HTTP/1.1\r\n";
      $out.= "Host: ".$parts['host']."\r\n";
      $out.= "Connection: Close\r\n\r\n";
      fwrite($fp, $out);
      fclose($fp);
  }

Answer 4

let me show you my way :)

needs nodejs installed on the server

(my server sends 1000 https get request takes only 2 seconds)

url.php :

<?
$urls = array_fill(0, 100, 'http://google.com/blank.html');

function execinbackground($cmd) { 
    if (substr(php_uname(), 0, 7) == "Windows"){ 
        pclose(popen("start /B ". $cmd, "r"));  
    } 
    else { 
        exec($cmd . " > /dev/null &");   
    } 
} 
fwite(fopen("urls.txt","w"),implode("\n",$urls);
execinbackground("nodejs urlscript.js urls.txt");
// { do your work while get requests being executed.. }
?>

urlscript.js >

var https = require('https');
var url = require('url');
var http = require('http');
var fs = require('fs');
var dosya = process.argv[2];
var logdosya = 'log.txt';
var count=0;
http.globalAgent.maxSockets = 300;
https.globalAgent.maxSockets = 300;

setTimeout(timeout,100000); // maximum execution time (in ms)

function trim(string) {
    return string.replace(/^\s*|\s*$/g, '')
}

fs.readFile(process.argv[2], 'utf8', function (err, data) {
    if (err) {
        throw err;
    }
    parcala(data);
});

function parcala(data) {
    var data = data.split("\n");
    count=''+data.length+'-'+data[1];
    data.forEach(function (d) {
        req(trim(d));
    });
    /*
    fs.unlink(dosya, function d() {
        console.log('<%s> file deleted', dosya);
    });
    */
}


function req(link) {
    var linkinfo = url.parse(link);
    if (linkinfo.protocol == 'https:') {
        var options = {
        host: linkinfo.host,
        port: 443,
        path: linkinfo.path,
        method: 'GET'
    };
https.get(options, function(res) {res.on('data', function(d) {});}).on('error', function(e) {console.error(e);});
    } else {
    var options = {
        host: linkinfo.host,
        port: 80,
        path: linkinfo.path,
        method: 'GET'
    };        
http.get(options, function(res) {res.on('data', function(d) {});}).on('error', function(e) {console.error(e);});
    }
}


process.on('exit', onExit);

function onExit() {
    log();
}

function timeout()
{
console.log("i am too far gone");process.exit();
}

function log() 
{
    var fd = fs.openSync(logdosya, 'a+');
    fs.writeSync(fd, dosya + '-'+count+'\n');
    fs.closeSync(fd);
}

Answer 5

For me the question about asynchronous GET request is appeared because of I met with situation when I need to do hundreds of requests, get and deal with result data on every request and every request takes significant milliseconds of executing that leads to minutes(!) of total executing with simple file_get_contents.

In this case it was very helpful comment of w_haigh at php.net on function http://php.net/manual/en/function.curl-multi-init.php

So, here is my upgraded and cleaned version of making lot of requests simultaneously. For my case it's equivalent to "asynchronous" way. May be it helps for someone!

// Build the multi-curl handle, adding both $ch
$mh = curl_multi_init();

// Build the individual requests, but do not execute them
$chs = [];
$chs['ID0001'] = curl_init('http://webservice.example.com/?method=say&word=Hello');
$chs['ID0002'] = curl_init('http://webservice.example.com/?method=say&word=World');
// $chs[] = ...
foreach ($chs as $ch) {
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,  // Return requested content as string
        CURLOPT_HEADER => false,         // Don't save returned headers to result
        CURLOPT_CONNECTTIMEOUT => 10,    // Max seconds wait for connect
        CURLOPT_TIMEOUT => 20,           // Max seconds on all of request
        CURLOPT_USERAGENT => 'Robot YetAnotherRobo 1.0',
    ]);

    // Well, with a little more of code you can use POST queries too
    // Also, useful options above can be  CURLOPT_SSL_VERIFYHOST => 0  
    // and  CURLOPT_SSL_VERIFYPEER => false ...

    // Add every $ch to the multi-curl handle
    curl_multi_add_handle($mh, $ch);
}

// Execute all of queries simultaneously, and continue when ALL OF THEM are complete
$running = null;
do {
    curl_multi_exec($mh, $running);
} while ($running);

// Close the handles
foreach ($chs as $ch) {
    curl_multi_remove_handle($mh, $ch);
}
curl_multi_close($mh);

// All of our requests are done, we can now access the results
// With a help of ids we can understand what response was given
// on every concrete our request
$responses = [];
foreach ($chs as $id => $ch) {
    $responses[$id] = curl_multi_getcontent($ch);
    curl_close($ch);
}
unset($chs); // Finita, no more need any curls :-)

print_r($responses); // output results

It's easy to rewrite this to handle POST or other types of HTTP(S) requests or any combinations of them. And Cookie support, redirects, http-auth, etc.

Answer 6

This is how to make Marquis' answer work with both POST and GET requests:

  // $type must equal 'GET' or 'POST'
  function curl_request_async($url, $params, $type='POST')
  {
      foreach ($params as $key => &$val) {
        if (is_array($val)) $val = implode(',', $val);
        $post_params[] = $key.'='.urlencode($val);
      }
      $post_string = implode('&', $post_params);

      $parts=parse_url($url);

      $fp = fsockopen($parts['host'],
          isset($parts['port'])?$parts['port']:80,
          $errno, $errstr, 30);

      // Data goes in the path for a GET request
      if('GET' == $type) $parts['path'] .= '?'.$post_string;

      $out = "$type ".$parts['path']." HTTP/1.1\r\n";
      $out.= "Host: ".$parts['host']."\r\n";
      $out.= "Content-Type: application/x-www-form-urlencoded\r\n";
      $out.= "Content-Length: ".strlen($post_string)."\r\n";
      $out.= "Connection: Close\r\n\r\n";
      // Data goes in the request body for a POST request
      if ('POST' == $type && isset($post_string)) $out.= $post_string;

      fwrite($fp, $out);
      fclose($fp);
  }