I recently got tasked with posting offline messages to twitter, i.e when a user completes an action on my application, there would be a message posted to linkedin.
I looked at the many oauth libraries about on the web for php and codeigniter and couldn’t find one that worked perfectly for my situation so i mashed a few together and ended up with this- and i learnt a few lessons on the way.
Where I got the php libraries that where built around the linkedin api, nothing was clean and coherent.. and simple so I found a twitter library and modified it to my needs- both linkedin and twitter are built around OAUTH (so is facebook) and this made it super easy to change a few urls and directories and have a working library.
The source for my derived work came from this library listed here - https://www.packtpub.com/article/user-authentication-with-codeigniter-1.7-using-twitter-oauth if you check my code you will see i edited slightly to change it for use with linkedin. If your using this library you will also need the PHP oauth Library which is listed here- http://oauth.googlecode.com/svn/code/php/
The library- save this as linked.php in your application/libraries folder- also save your “OAuth.php” in there as well
The llibrary
<?php
require_once("OAuth.php");
class linkedin
{
var $consumer;
var $token;
var $method;
var $http_status;
var $last_api_call;
var $callback;
function linkedin($data)
{
$this->method = new OAuthSignatureMethod_HMAC_SHA1();
$this->consumer = new OAuthConsumer($data['consumer_key'], $data['consumer_secret']);
$this->callback = $data['callback_url'];
//print_r($data);
if(!empty($data['oauth_token']) && !empty($data['oauth_token_secret']) && !empty($data['callback_url']))
{
$this->token = new OAuthConsumer($data['oauth_token'],$data['oauth_token_secret']);
}
else
{
$this->token = NULL;
}
}
function debug_info()
{
echo("Last API Call: ".$this->last_api_call."<br />\n");
echo("Response Code: ".$this->http_status."<br />\n");
}
function get_request_token()
{
$args = array();
$request = OAuthRequest::from_consumer_and_token($this->consumer,
$this->token, 'GET',
"https://api.linkedin.com/uas/oauth/requestToken", $args);
$request->set_parameter("oauth_callback", $this->callback);
$request->sign_request($this->method, $this->consumer,$this->token);
$request = $this->http($request->to_url());
parse_str($request,$token);
$this->token = new OAuthConsumer($token['oauth_token'],$token['oauth_token_secret'],$this->callback);
return $token;
}
function get_access_token($oauth_verifier)
{
$args = array();
$request = OAuthRequest::from_consumer_and_token($this->consumer, $this->token, 'GET', "https://api.linkedin.com/uas/oauth/accessToken",$args);
$request->set_parameter("oauth_verifier", $oauth_verifier);
$request->sign_request($this->method, $this->consumer,$this->token);
$request = $this->http($request->to_url());
echo $request ;
parse_str($request,$token);
//echo $oauth_verifier;
$this->token = new OAuthConsumer($token['oauth_token'],
$token['oauth_token_secret'],1);
return $token;
}
function parse_request($string)
{
$args = explode("&", $string);
$args[] = explode("=", $args['0']);
$args[] = explode("=", $args['1']);
$token[$args['2']['0']] = $args['2']['1'];
$token[$args['3']['0']] = $args['3']['1'];
return $token;
}
function parse_access($string)
{
$r = array();
foreach(explode('&', $string) as $param)
{
$pair = explode('=', $param, 2);
if(count($pair) != 2) continue;
$r[urldecode($pair[0])] = urldecode($pair[1]);
}
return $r;
}
function get_authorize_URL($token)
{
if(is_array($token)) $token = $token['oauth_token'];
return "https://api.linkedin.com/uas/oauth/authorize?oauth_token=" .
$token;
}
function http($url, $post_data = null)
{
$ch = curl_init();
if(defined("CURL_CA_BUNDLE_PATH"))
curl_setopt($ch, CURLOPT_CAINFO, CURL_CA_BUNDLE_PATH);
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 30);
curl_setopt($ch, CURLOPT_TIMEOUT, 30);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
if(isset($post_data))
{
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_data);
}
$response = curl_exec($ch);
$this->http_status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
$this->last_api_call = $url;
curl_close($ch);
return $response;
}
function share($comment, $title, $url, $imageUrl,$access_token) {
$shareUrl = "http://api.linkedin.com/v1/people/~/shares";
$xml = "<share>
<comment>$comment</comment>
<content>
<title>$title</title>
<submitted-url>$url</submitted-url>
<submitted-image-url>$imageUrl</submitted-image-url>
</content>
<visibility>
anyone
</visibility>
</share>";
//echo $this->consumer;
//echo "<br>at : ".$this->access_token."<br>";
//echo "<b>".$access_token."</b>";
$request = OAuthRequest::from_consumer_and_token($this->consumer, $access_token, "POST", $shareUrl);
$request->sign_request($this->method, $this->consumer, $access_token);
$auth_header = $request->to_header("https://api.linkedin.com");
/*
echo $xml . "\n";
echo $auth_header . "\n";
*/
//$auth_header = preg_replace("/Authorization\: OAuth\,/", "Authorization: OAuth ", $auth_header);
//$auth_header = preg_replace('/\"\,/', '", ', $auth_header);
$response = $this->httpRequest($shareUrl, $auth_header, "POST", $xml);
echo $response;
return $response;
}
function httpRequest($url, $auth_header, $method, $body = NULL) {
if (!$method) {
$method = "GET";
};
//echo $url. " " .$method. " " .$body;
//echo $auth_header;
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_HEADER, 0);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_HTTPHEADER, array($auth_header)); // Set the headers.
//echo $auth_header;
if ($body) {
curl_setopt($curl, CURLOPT_POST, 1);
curl_setopt($curl, CURLOPT_POSTFIELDS, $body);
curl_setopt($curl, CURLOPT_CUSTOMREQUEST, $method);
curl_setopt($curl, CURLOPT_HTTPHEADER, array($auth_header, "Content-Type: text/xml;charset=utf-8"));
}
$data = curl_exec($curl);
echo curl_getinfo($curl, CURLINFO_HTTP_CODE);
//if ($this->debug) {
//echo "bla";
echo $data . "\n";
//}
curl_close($curl);
return $data;
}
}
?>I have commented the code more so than giving a run through of how it works.
The codeigniter stuff 
<?php session_start(); class User extends controller { var $data; function user(){ parent::Controller(); parse_str(substr(strrchr($_SERVER['REQUEST_URI'], "?"), 1), $_GET); $this->load->helper('url'); $this->load->library('session'); $this->data['consumer_key'] = ""; $this->data['consumer_secret'] = ""; $this->data['callback_url'] = "yourcallback"; } function index(){ } function linkedin(){ $this->load->library('linkedin', $this->data); $token = $this->linkedin->get_request_token(); $_SESSION['oauth_request_token'] = $token['oauth_token']; $_SESSION['oauth_request_token_secret'] = $token['oauth_token_secret']; $request_link = $this->linkedin->get_authorize_URL($token); $data['link'] = $request_link; header("Location: " . $request_link); } function linkedin_submit(){ $this->data['oauth_token'] = $_SESSION['oauth_request_token']; $this->data['oauth_token_secret'] = $_SESSION['oauth_request_token_secret']; // //laod the library with the variables defined in the constructor // $this->load->library('linkedin', $this->data); //echo $_REQUEST['oauth_verifier']; $_SESSION['oauth_verifier'] = $_REQUEST['oauth_verifier']; /* Request access tokens from linkedin */ $tokens = $this->linkedin->get_access_token($_SESSION['oauth_verifier']); /*Save the access tokens.*/ /*Normally these would be saved in a database for future use. */ $_SESSION['oauth_access_token'] = $tokens['oauth_token']; $_SESSION['oauth_access_token_secret'] = $tokens['oauth_token_secret']; //store your user info //if your going to store the tokens you will need to serialise in and out of the db // // you will need to write your own models- simple storage- serialization done here in the controller $this->load->model('muser'); $data_id = array('linked_in' => serialize($this->linkedin->token),'id' => $user_id,'oauth_secret' => $_REQUEST['oauth_verifier']); //i used this to store the link_in tokens in the db if(!$this->muser->store_id($data_id)){ //error } } function linkedin_post(){ $id = $this->input->get('id'); // //this is the get from db // //you will have to make your own models // $row = $this->muser->get_by_id($id); $linked_in = $row['linked_in']; // //setup the post info // $comment = "message"; $title = "story title"; $targetUrl = "http://link"; $imgUrl = "image title"; // // //load the library for linkedin with the variables defined in the constructor // $this->load->library('linkedin', $this->data); $apiCallStatus = $this->linkedin->share($comment, $title, $targetUrl, $imgUrl,unserialize($linked_in)); } ?>
