Connect LinkedIn Account into your Rails Application with Authlogic and OAuth

LinkedIn launched its new API in November 2009, allowing any developer brave enough to implement OAuth to integrate with one of the largest social networks around. Seeking an opportunity to really understand OAuth more fully and play around with the LinkedIn API at the same time, I created the LinkedIn connect sample code.

This is a sample Ruby on Rails tutorial to demonstrate how you can use the LinkedIn API to authenticate users and pull their profile data into your own website.

GETTING STARTED

Before you can use the LinkedIn API, you'll need to set up your API keys.

Getting Started with the LinkedIn API


1. Where do I begin? Start by navigating to http://developer.linkedin.com. This is Linkedin developer portal where you can read API documentation, collaborate with other developers, and keep abreast of changes to the LinkedIn API. From here, click on “LinkedIn APIs.”

2. Now click on “Request an API Key”

3. After logging in, you’re now presented with an opportunity. You can create as many API keys as you like, one for each application that you create. Let’s get started.

4. This isn’t as complicated as it looks. Let’s look closely.
Application Developers: This is a list of your LinkedIn Connections that will receive network updates published by your application and is used only while it is in development mode. You need to be connected to any LinkedIn member that you want to put on this whitelist. Interface Language: Your application is provided in one or more languages to end users. Let us know what those languages are so we can better support you in the future. Programming Tools: Knowing what kind of programming languages and tools you use to develop your application lets us know what languages and environments are most important for us to support. Just a few more fields to go over!

5. Ready to get your API keys? When you’re done, click “Add Application”
Contact Info: Tell us how to get in contact with you should we have a question about or there is a problem with your application.
OAuth Redirect URL: If you have a static location that should always be used for your OAuth callbacks, you can specify it here. It is recommended that you use the oauth_callback parameter in the appropriate requests instead.
Agreement Language: If you’d like to force the login screen to appear in one of the languages LinkedIn supports, you can set that here. It is recommended to leave the setting at “Browser Locale Setting.”
Terms of Service/CAPTCHA: Please do read our API Terms of Use. You cannot create an API key without agreeing to our terms. You’ve likely seen a CAPTCHA before, and it needs little explanation.

6. You’ve got your API keys. What’s next?
The LinkedIn Developer Network is where you’ll find guidelines, documentation, and growing community of developers.

RUBY GEM INSTALLATION

First you need to upgrade your Rails VERSION to 2.3.x, and install the required Ruby Gems below：

1. Setup and use Authlogic

$ sudo gem install authlogic

2. Install OAuth and Authlogic_Oauth

$ sudo gem install oauth

$ sudo gem install authlogic-oauth

3. Install other required Ruby gems

$ sudo gem install json

$ sudo gem install crack

Or for older version of Rails, you can install it as a plugin:

$ script/plugin install git://github.com/binarylogic/authlogic.git

$ script/plugin install git://github.com/jrallison/authlogic_oauth.git

* Authlogic at Github：http://github.com/binarylogic/authlogic

* Authlogic Example: http://github.com/binarylogic/authlogic_example

SETUP API KEY IN YOUR APP

Create load_linkedin_config.rb in #{RAILS_ROOT}/config/initializers directory

Create linkedin_config.yml in #{RAILS_ROOT}/config directory

DATABASE MIGRATION

1. Make some changes to user table in your database:

$ script/generate migration AddLinkedinConnectToUsers

2. Create Position，Education and Connection model：

$ script/generate model position

$ script/generate model education

$ script/generate model connection


3. Modify the User model, add the content below to the #{RAILS_ROOT}/app/models/user.rb：

The private method "populate_oauth_user", which is called before user record created, and is used to fetch profile info (name, headline, industry, profile pic, public url, summary, specialties, web urls) in LinkedIn.com, and save these info to your user record. The other private method "populate_child_models", which is called after user record created, and which will save past position info (companies, job titles, durations, descriptions), education info (schools, degrees, field of study, dates, etc) and connections info (names, industries, headlines, profile pics) for user.

4. Modify the Connection model, add the contents below to the #{RAILS_ROOT}/app/models/connection.rb：

5. Modify the Education model, add the content below to the #{RAILS_ROOT}/app/models/education.rb：

6. Modify the Position model, add the content below to the #{RAILS_ROOT}/app/models/position.rb：

7. Create UserSession model, and define the oauth_consumer class method on your UserSession model：

CONTROLLER METHOD

You only need to save your objects this way if you want the user to authenticate with their OAuth provider.

That being said, you probably want to do this in your controllers. You should do this for BOTH your User objects and UserSession objects (assuming you are authenticating users). It should look something like this:

You should save your @user objects this way as well, because you also want the user to authenticate with OAuth.

In my case, I have to integrating the LinkedIn OAuth Sign in feature to my current Rails project, so I changed the "Create" method in my UsersController like this way：

When the user click on the LinkedIn Login button and we can't find the oauth_token and oauth_secret in the database, the user will be redirect to signup page with "linkedin_user" parameter. After fill in the fields, they will be redirect to LinkedIn authentication page, then user record will be created. If we can find the oauth_token and oauth_secret in the database, the user will be login to the site.

ADD REGISTER BUTTON

You can simply use the "oauth_register_button" helper method to add LinkedIn register buttons to your views, like this：

Now add some style in your CSS file for LinkedIn button：

NEXT STEPS

Now we have user's LinkedIn data saved in the database, so you can write some codes to show the user's LinkedIn profile data (such as Username, Headline, Location, Education, Position, Websites, Skills, Experience, Connections) in the website.

You may want to add methods to update profile info on each login or update request. Or pull status updates, specialties, and current position for connection.

If you're interested in learning more about LinkedIn and OAuth, I encourage you to checkout Taylor Singletary's presentation LinkedIn OAuth: Zero to Hero.