PHP - cURL - Optimise Speed Reusing SSL Connections 1:28 PM

Below is an example of using cURL to fetch multiple URLs that are using SSL and then reuse those connections to retrieve more data. This example fetches 2 URLs simultaneously which both open an SSL connection, then the next lot of 2 URLs reuse those connections to retrieve data thereby bypassing the SSL handshake.

<?php
//Number of SSL connections to use
$connections = 2;

//Array of URLs to retrieve using https
$urls = array();
$urls[] = 'https://www.googleapis.com/plus/v1/people/105381197794279347286?fields=displayName%2Cgender%2CobjectType&key=AIzaSyCFj15TpkchL4OUhLD1Q2zgxQnMb7v3XaM';
$urls[] = 'https://www.googleapis.com/plus/v1/people/105381197794279347286?fields=displayName%2Cgender%2CobjectType&key=AIzaSyCFj15TpkchL4OUhLD1Q2zgxQnMb7v3XaM';
$urls[] = 'https://www.googleapis.com/plus/v1/people/105381197794279347286?fields=displayName%2Cgender%2CobjectType&key=AIzaSyCFj15TpkchL4OUhLD1Q2zgxQnMb7v3XaM';
$urls[] = 'https://www.googleapis.com/plus/v1/people/105381197794279347286?fields=displayName%2Cgender%2CobjectType&key=AIzaSyCFj15TpkchL4OUhLD1Q2zgxQnMb7v3XaM';
$urls[] = 'https://www.googleapis.com/plus/v1/people/105381197794279347286?fields=displayName%2Cgender%2CobjectType&key=AIzaSyCFj15TpkchL4OUhLD1Q2zgxQnMb7v3XaM';
$urls[] = 'https://www.googleapis.com/plus/v1/people/105381197794279347286?fields=displayName%2Cgender%2CobjectType&key=AIzaSyCFj15TpkchL4OUhLD1Q2zgxQnMb7v3XaM';

//Number of times to reuse each SSL connection (6/2 = 3)
$reuse = count($urls) / $connections;

//Array used to store multiple cURL handles for each SSL connection
$handle = array();

//Array used to store all returned page data
$result = array();

//Log file used to see that only 2 SSL conections are being used
//$logfh = fopen("curl.log", 'a+');

//Loop for each SSL connection
for($r=0;$r<$reuse;$r++) {
  //Loop for each reuse of the SSL connection
  for($c=0;$c<$connections;$c++) {
    //Initialise a cURL session using the urls
    $handle[$c] = curl_init($urls[($r*$connections)+$c]);

    //Set any options you want here
    curl_setopt($handle[$c], CURLOPT_HTTPHEADER, array('x-origin: https://developers.google.com'));
    curl_setopt($handle[$c], CURLOPT_RETURNTRANSFER, true);
    //Turns on detailed info for the log
    //curl_setopt($handle[$c], CURLOPT_VERBOSE, true);
    //Send the output to the log file
    //curl_setopt($handle[$c], CURLOPT_STDERR, $logfh);

    static $multi = NULL;
    if (empty($multi)) {
      //Initialise a multi cURL session if one does not already exist
      $multi = curl_multi_init();
    }

    //Add the single cURL handle to the mutli cURL handle
    curl_multi_add_handle($multi, $handle[$c]);
  }

  $running = NULL;
  do {
    //Execute all handles in $multi until all are completed
    curl_multi_exec($multi, $running);
  } while($running > 0);

  for($i=0;$i<$connections;$i++) {
    //Do something with each result
    $result[] = curl_multi_getcontent($handle[$i]);
    //Remove the single cURL handle from the multi cURL handle
    curl_multi_remove_handle($multi, $handle[$i]);
  }
}
//Dump the result which will show my public profile info 6 times
var_dump($result);
?>

Output: This will output 6 arrays, one for each of the pages we retrieved. It will contain some public information from my Google+ profile.

Note: If you use the curl.log you must ensure you have the correct permissions on the file.