handle JWT error

app/controllers/errors_controller.rb

@@ -17,4 +17,10 @@ def internal_server_error
   def incorrect_passcode
     render status: 401
   end
+
+  def login_error
+    # a status in the 500 range will automatically bypass this and
+    # render internal_server_error
+    render status: 200
+  end
 end

app/controllers/omniauth_callbacks_controller.rb

@@ -7,11 +7,20 @@ class OmniauthCallbacksController < Devise::OmniauthCallbacksController
   def mediawiki
     @user = UserImporter.from_omniauth(request.env['omniauth.auth'])
 
+    return handle_jwt_error if request.env['JWT_ERROR']
+
     if @user.persisted?
       remember_me @user
       sign_in_and_redirect @user
     else
       redirect_to root_url
     end
   end
+
+  protected
+
+  def handle_jwt_error
+    Raven.capture_message "\nJWT Decoding failed: #{request.env['JWT_DATA'].body}\n"
+    return redirect_to errors_login_error_path
+  end
 end

app/views/errors/login_error.html.erb

@@ -0,0 +1,12 @@
+<header class="main-page">
+  <h1><%= Figaro.env.dashboard_title %></h1>
+</header>
+
+<section id="courses">
+  <div class="container narrow">
+    <div class="section-header">
+      <h3><%= t("login_error.header") %></h3>
+      <p><%= t("login_error.explanation") %></p>
+    </div>
+  </div>
+</section>

config/initializers/devise.rb

@@ -1,3 +1,5 @@
+require_relative '../../lib/custom_strategy'
+
 # Use this hook to configure devise mailer, warden hooks and so forth.
 # Many of these configuration options can be set straight in your model.
 Devise.setup do |config|
@@ -240,6 +242,7 @@
   config.omniauth :mediawiki,
                   Figaro.env.wikipedia_token,
                   Figaro.env.wikipedia_secret,
+                  strategy_class: CustomStrategy,
                   client_options: {
                     site: "https://#{Figaro.env.wiki_language}.wikipedia.org"
                   }
@@ -249,7 +252,7 @@
                   Figaro.env.wikipedia_token,
                   Figaro.env.wikipedia_secret,
                   name: 'mediawiki_signup',
-                  strategy_class: OmniAuth::Strategies::Mediawiki,
+                  strategy_class: CustomStrategy,
                   client_options: {
                     site: "https://#{Figaro.env.wiki_language}.wikipedia.org",
                     signup: true

config/locales/en.yml

@@ -326,6 +326,11 @@ en:
       Something went wrong. Please contact the maintainers of this dashboard
       to let them know about the problem.
 
+  login_error:
+    header: "Login Error"
+    explanation: >
+      It looks like there was an problem with the sign in process. (Sorry about that! It happens occasionally.) Please try logging in or enrolling again.
+
   # This is a maintenance script message.
   timeout: "A request to the %{api} API has timed out and will retried %{tries} times."
 

config/routes.rb

@@ -3,6 +3,7 @@
 Rails.application.routes.draw do
   get 'errors/file_not_found'
   get 'errors/unprocessable'
+  get 'errors/login_error'
   get 'errors/internal_server_error'
   get 'errors/incorrect_passcode'
 
@@ -160,5 +161,6 @@
   # Errors
   match '/404', to: 'errors#file_not_found', via: :all
   match '/422', to: 'errors#unprocessable', via: :all
+  match '/599', to: 'errors#login_error', via: :all
   match '/500', to: 'errors#internal_server_error', via: :all
 end

lib/custom_strategy.rb

@@ -0,0 +1,12 @@
+class LoginError < StandardError; end
+
+class CustomStrategy < OmniAuth::Strategies::Mediawiki
+  def parse_info(jwt_data)
+    begin
+      super
+    rescue JWT::DecodeError
+      request.env['JWT_ERROR'] = true
+      request.env['JWT_DATA'] = jwt_data
+    end
+  end
+end

lib/wiki.rb

@@ -21,6 +21,7 @@ def self.get_user_id(username, language=nil)
     user_query = { list: 'users',
                    ususers: username }
     user_data = wikipedia('query', user_query, language: language)
+    return unless user_data.data['users'].any?
     user_id = user_data.data['users'][0]['userid']
     user_id
   end