title: getting parameter from a response curl php
body: <p>I'm really newbie with php. I'm trying to develop a simple php app. 
  I have a button in my app and I want when I click on it to open some webpage, allow an user to connect using his credential. When the user is connected he can grant me a privilege to access to his information by clicking in some button "Allow". After clicking in that button, he is redirected to an url that contain a parameter named "code". My goal is to use this code parameter in my php script. 
  I found some information about curl and I guess I need it to do that but how ?
  I can open google webpage by doing this :</p>
  
  <pre><code>&lt;?php
  $curl = curl_init();
  curl_setopt($curl, CURLOPT_URL, "http://www.google.com");
  curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
  $result = curl_exec($curl);
  curl_close($curl);
  print $result;
  ?&gt;
  </code></pre>
  
  <p>To resume I would like to know :
  1) After redirecting the user to a website, after his logging and allowing me to access to his data, how can I get a parameter that is include to the url he is redirected after allowing me the access. 
  Thank you in advance for your help.</p>