Drupal 7 - LinkedIn login module
If you are looking for a way to add Linkedin login/signup buttons to your Drupal 7 website then you came to the right place. Only module that seems to provide Linkedin integration is LinkedIn module but unfortunately its only available in dev version and quickly after enabling it I figured out its not working well to be used on production sites.
Module shows Linkedin login button on user login form but by default, this module sends the user twice to the linkedin website. Ideal scenario would be to visits linkedin login screen only once in following workflow:
Anonymous user clicks on linkedin button -> authenticates at linkedin.com -> automatically user gets created and logs him in.
Registered user clicks on linkedin button -> authenticates at linkedin.com -> the current drupal account gets connected with linkedin. Next time on-wards, he can login via linkedin.
Looking through the issue queue I found what seemed to be patch that would do the job: http://drupal.org/node/1542130
But this patch had couple of bugs/flaws. First it failed to retrieve email address from linkedin account instead using a hardcoded address 'email@example.com', secondly it left username empty resulting in mysql 'Duplicate entry' error.
After looking through Linkedin API I figured out that we need additional permission to retrieve email address from Linkedin user.
You can find my patch at http://drupal.org/node/1542130 and for those who don't want to bother with patching the module here I attached working version of Drupal 7 Linkedin authentication module.