githubAuthCallback.pl

get '/auth/github/callback' => sub {
	#github sends us a code to authenticate. Here we need to retrieve it
        my $code = params->{'code'};
        #create a new instance of LWP:UserAgent
	my $browser = LWP::UserAgent->new;
	#send a post request for an access token
	my $resp  = $browser->post('https://github.com/login/oauth/access_token',
		[
		#these two are global variables in our dancer app
 		 client_id     => $client_id,
 		 client_secret => $client_secret, 
 		 #this is the code we received from github
 		 code          => $code,
 		 #this is some random state we passed during the login
 		 #ideally it should be a unguessable string
 		 state         => 'x12'
		]);
	#check if everything went well	
	die "error while fetching: ", $resp->status_line
	    unless $resp->is_success;
	#parse the query string, we get a access token from github...    
	my %querystr = parse_query_str($resp->decoded_content);
	#grab the access token
	my $acc = $querystr{access_token};
	#make another GET request to github with our access token to get the logged user info
	my $jresp  = $browser->get("https://api.github.com/user?access_token=$acc");
	#decode the JSON gives us
	my $json = json_to_perl($jresp->decoded_content);
	#set our session variables to the stuff we got from github
	session 'username' => $json->{login};
	session 'avatar' => $json->{avatar_url};
	session 'logged_in' => true;
	#redict to home page
	redirect "/";
};