LinkedIn API client in PHP

A PHP library to handle authentication and communication with LinkedIn API. The library/SDK helps you to get an access token and when authenticated it helps you to send API requests. You will not get everything for free though... You have to read the LinkedIn documentation to understand how you should query the API.

To get an overview what this library actually is doing for you. Take a look at the authentication page from the API docs.

Features

Here is a list of features that might convince you to choose this LinkedIn client over some of our competitors'.

• Flexible and easy to extend
• Developed with modern PHP standards
• Not developed for a specific framework.
• Handles the authentication process
• Respects the CSRF protection

Installation

TL;DR

composer require php-http/curl-client guzzlehttp/psr7 php-http/message happyr/linkedin-api-client

This library does not have a dependency on Guzzle or any other library that sends HTTP requests. We use the awesome HTTPlug to achieve the decoupling. We want you to choose what library to use for sending HTTP requests. Consult this list of packages that support php-http/client-implementation find clients to use. For more information about virtual packages please refer to HTTPlug. Example:

composer require php-http/guzzle6-adapter

You do also need to install a PSR-7 implementation and a factory to create PSR-7 messages (PSR-17 whenever that is released). You could use Guzzles PSR-7 implementation and factories from php-http:

composer require guzzlehttp/psr7 php-http/message 

Now you may install the library by running the following:

composer require happyr/linkedin-api-client

If you are updating form a previous version make sure to read the upgrade documentation.

Finding the HTTP client (optional)

The LinkedIn client need to know what library you are using to send HTTP messages. You could provide an instance of HttpClient and MessageFactory or you could fallback on auto discovery. Below is an example on where you provide a Guzzle6 instance.

$linkedIn=new Happyr\LinkedIn\LinkedIn('app_id', 'app_secret');
$linkedIn->setHttpClient(new \Http\Adapter\Guzzle6\Client());
$linkedIn->setHttpMessageFactory(new Http\Message\MessageFactory\GuzzleMessageFactory());

Usage

In order to use this API client (or any other LinkedIn clients) you have to register your application with LinkedIn to receive an API key. Once you've registered your LinkedIn app, you will be provided with an API Key and Secret Key.

LinkedIn login

This example below is showing how to login with LinkedIn.

<?php

/**
 * This demonstrates how to authenticate with LinkedIn and send api requests
 */

/*
 * First you need to make sure you've used composers auto load. You have is probably 
 * already done this before. You usually don't bother..
 */
//require_once "vendor/autoload.php";

$linkedIn=new Happyr\LinkedIn\LinkedIn('client_id', 'client_secret');

if ($linkedIn->isAuthenticated()) {
    //we know that the user is authenticated now. Start query the API
    $user=$linkedIn->get('v1/people/~:(firstName,lastName)');
    echo "Welcome ".$user['firstName'];

    exit();
} elseif ($linkedIn->hasError()) {
    echo "User canceled the login.";
    exit();
}

//if not authenticated
$url = $linkedIn->getLoginUrl();
echo "<a href='$url'>Login with LinkedIn</a>";

How to post on LinkedIn wall

The example below shows how you can post on a users wall. The access token is fetched from the database.

$linkedIn=new Happyr\LinkedIn\LinkedIn('app_id', 'app_secret');
$linkedIn->setAccessToken('access_token_from_db');

$options = array('json'=>
    array(
        'comment' => 'Im testing Happyr LinkedIn client! https://github.com/Happyr/LinkedIn-API-client',
        'visibility' => array(
            'code' => 'anyone'
        )
    )
);

$result = $linkedIn->post('v1/people/~/shares', $options);

var_dump($result);

// Prints: 
// array (size=2)
//   'updateKey' => string 'UPDATE-01234567-0123456789012345678' (length=35)
//   'updateUrl' => string 'https://www.linkedin.com/updates?discuss=&scope=01234567&stype=M&topic=0123456789012345678&type=U&a=mVKU' (length=104)

You may of course do the same in xml. Use the following options array.

$options = array(
'format' => 'xml',
'body' => '<share>
 <comment>Im testing Happyr LinkedIn client! https://github.com/Happyr/LinkedIn-API-client</comment>
 <visibility>
   <code>anyone</code>
 </visibility>
</share>');

Configuration

The api options

The third parameter of LinkedIn::api is an array with options. Below is a table of array keys that you may use.

Option name	Description
body	The body of a HTTP request. Put your xml string here.
format	Set this to 'json', 'xml' or 'simple_xml' to override the default value.
headers	This is HTTP headers to the request
json	This is an array with json data that will be encoded to a json string. Using this option you do need to specify a format.
response_data_type	To override the response format for one request
query	This is an array with query parameters

Changing request format

The default format when communicating with LinkedIn API is json. You can let the API do json_encode for you. The following code shows you how.

$body = array(
    'comment' => 'Im testing Happyr LinkedIn client! https://github.com/Happyr/LinkedIn-API-client',
    'visibility' => array('code' => 'anyone')
);

$linkedIn->post('v1/people/~/shares', array('json'=>$body));
$linkedIn->post('v1/people/~/shares', array('body'=>json_encode($body)));

When using array('json'=>$body) as option the format will always be json. You can change the request format in three ways.

// By constructor argument
$linkedIn=new Happyr\LinkedIn\LinkedIn('app_id', 'app_secret', 'xml');

// By setter
$linkedIn->setFormat('xml');

// Set format for just one request
$linkedIn->post('v1/people/~/shares', array('format'=>'xml', 'body'=>$body));

Understanding response data type

The data type returned from LinkedIn::api can be configured. You may use the forth construtor argument, the LinkedIn::setResponseDataType or as an option for LinkedIn::api

// By constructor argument
$linkedIn=new Happyr\LinkedIn\LinkedIn('app_id', 'app_secret', 'json', 'array');

// By setter
$linkedIn->setResponseDataType('simple_xml');

// Set format for just one request
$linkedIn->get('v1/people/~:(firstName,lastName)', array('response_data_type'=>'psr7'));

Below is a table that specifies what the possible return data types are when you call LinkedIn::api.

Type	Description
array	An assosiative array. This can only be used with the json format.
simple_xml	A SimpleXMLElement. See PHP manual. This can only be used with the xml format.
psr7	A PSR7 response.
stream	A file stream.
string	A plain old string.

Use different Session classes

You might want to use an other storage than the default SessionStorage. If you are using Laravel you are more likely to inject the IlluminateSessionStorage.

$linkedIn=new Happyr\LinkedIn\LinkedIn('app_id', 'app_secret');
$linkedIn->setStorage(new IlluminateSessionStorage());

You can inject any class implementing DataStorageInterface. You can also inject different UrlGenerator classes.

Using different scopes

If you want to define special scopes when you authenticate the user you should specify them when you are generating the login url. If you don't specify scopes LinkedIn will use the default scopes that you have configured for the app.

$scope = 'r_fullprofile,r_emailaddress,w_share';
//or 
$scope = array('rw_groups', 'r_contactinfo', 'r_fullprofile', 'w_messages');

$url = $linkedIn->getLoginUrl(array('scope'=>$scope));
echo "<a href='$url'>Login with LinkedIn</a>";

Framework integration

If you want an easier integration with a framwork you may want to check out these repositories:

• HappyrLinkedInBundle for Symfony
• Laravel-Linkedin by mauri870 for Laravel 5