Use linkedin api to fetch contact information in php ..

First Register your domain for linkedin api .

Then get your API_KEY, API_SECRET REDIRECT_URI , SCOPE ...

Run the script .. Njoy :)
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<?php

// Change these
define('API_KEY',      ' '          );  /*put API_KEY between '  ' */
define('API_SECRET',   ' '      ); /*put between API_SECRET '  '*/
define('REDIRECT_URI', ' '); /*put REDIRECT_URI between '  '*/
define('SCOPE',        ' '     ); /*put Scope between '  '*/


session_name('linkedin');
session_start();
$_SESSION['state']="India" // Name the country you live in
;
// OAuth 2 Control Flow
if (isset($_GET['error'])) {
    // LinkedIn returned an error
    print $_GET['error'] . ': ' . $_GET['error_description'];
    exit;
} elseif (isset($_GET['code'])) {
    // User authorized your application
    if ($_SESSION['state'] == "India") {
        // Get token so you can make API calls
        getAccessToken();
    } else {
        // CSRF attack? Or did you mix up your states?
        exit;
    }
} else {
    if ((empty($_SESSION['expires_at'])) || (time() > $_SESSION['expires_at'])) {
        // Token has expired, clear the state
        $_SESSION = array();
    }
    if (empty($_SESSION['access_token'])) {
        // Start authorization process
        getAuthorizationCode();
    }
}

// Congratulations! You have a valid token. Now fetch your profile by defining field you wanted

$user = fetch('GET', '/v1/people/~:(id,firstName,lastName,skills,location,industry,network)');
echo "<pre>";
print_r($user);
echo "<pre>";
exit;

function getAuthorizationCode() {
    $params = array('response_type' => 'code',
                    'client_id' => API_KEY,
                    'scope' => SCOPE,
                    'state' => uniqid('', true), // unique long string
                    'redirect_uri' => REDIRECT_URI,
              );

    // Authentication request
    $url = 'https://www.linkedin.com/uas/oauth2/authorization?' . http_build_query($params);
   
    // Needed to identify request when it returns to us
    $_SESSION['state'] = $params['state'];

    // Redirect user to authenticate
    header("Location: $url");
    exit;
}
   
function getAccessToken() {
    $params = array('grant_type' => 'authorization_code',
                    'client_id' => API_KEY,
                    'client_secret' => API_SECRET,
                    'code' => $_GET['code'],
                    'redirect_uri' => REDIRECT_URI,
              );
   
    // Access Token request
    $url = 'https://www.linkedin.com/uas/oauth2/accessToken?' . http_build_query($params);
   
    // Tell streams to make a POST request
    $context = stream_context_create(
                    array('http' =>
                        array('method' => 'POST',
                        )
                    )
                );

    // Retrieve access token information
    $response = file_get_contents($url, false, $context);

    // Native PHP object, please
    $token = json_decode($response);

    // Store access token and expiration time
    $_SESSION['access_token'] = $token->access_token; // guard this!
    $_SESSION['expires_in']   = $token->expires_in; // relative time (in seconds)
    $_SESSION['expires_at']   = time() + $_SESSION['expires_in']; // absolute time
   
    return true;
}

function fetch($method, $resource, $body = '') {
    $params = array('oauth2_access_token' => $_SESSION['access_token'],
                    'format' => 'json',
              );
   
    // Need to use HTTPS
    $url = 'https://api.linkedin.com' . $resource . '?' . http_build_query($params);
    // Tell streams to make a (GET, POST, PUT, or DELETE) request
    $context = stream_context_create(
                    array('http' =>
                        array('method' => $method,
                        )
                    )
                );


    // Hocus Pocus
    $response = file_get_contents($url, false, $context);

    // Native PHP object, please
    return json_decode($response);
}