LTI-255: allows the overriding of params based on custom params (#150)

* LTI-255: allows the overriding of params based on custom params

* LTI-255: cleaned rubocops

* reverted doorkeeper to 5.4

Gemfile

@@ -41,7 +41,7 @@ gem 'redis', '~> 4.2'
 gem 'jwt', '~> 2.2.2'
 gem 'oauth', '~> 0.5.1'
 
-gem 'doorkeeper', '~> 5.5.0'
+gem 'doorkeeper', '~> 5.4.0'
 gem 'repost', '~> 0.3.8'
 
 gem 'lodash-rails'

Gemfile.lock

@@ -136,7 +136,7 @@ GEM
     docile (1.4.0)
     domain_name (0.5.20190701)
       unf (>= 0.0.5, < 1.0.0)
-    doorkeeper (5.5.4)
+    doorkeeper (5.4.0)
       railties (>= 5)
     dotenv (2.8.1)
     dotenv-rails (2.8.1)
@@ -426,7 +426,7 @@ DEPENDENCIES
   byebug
   coffee-rails (~> 5.0, >= 5.0.0)
   coveralls
-  doorkeeper (~> 5.5.0)
+  doorkeeper (~> 5.4.0)
   dotenv-rails
   faraday
   font-awesome-sass (~> 5.9.0)

lib/bbb_lti_broker/helpers.rb

@@ -67,7 +67,7 @@ def standarized_message(message_json)
         message['resource_link_description'] = message['unknown_params']['https://purl.imsglobal.org/spec/lti/claim/resource_link']['description']
         message['launch_presentation_locale'] = message['unknown_params']['https://purl.imsglobal.org/spec/lti/claim/launch_presentation']['locale']
       end
-      message.to_json
+      custom_overrides(message).to_json
     end
 
     def user_params(tc_instance_guid, params)
@@ -86,5 +86,26 @@ def user_params(tc_instance_guid, params)
         last_accessed_at: Time.current,
       }
     end
+
+    ##
+    # Overrides core parameters with custom parameters when following certain pattern.
+    #
+    # Core parameters may have to be overriden in order to make the applications behave differently
+    # for that, the LTI link in the tool consumer would need to include a custom parameter in the form:
+    #
+    # custom_resource_link_id=static:"some value" -> resource_link_id="some value"
+    # custom_resource_link_id=param:contenxt_id   -> resource_link_id=<value obtained from context_id>
+    # custom_resource_link_id="another value"     -> resource_link_id=<no overriding is made>
+    #
+    def custom_overrides(message)
+      custom_params = message['custom_params'].to_h
+      custom_params.each do |key, value|
+        custom_param = key.delete_prefix('custom_')
+        pattern = value.split(':')
+        message[custom_param] = pattern[1] if pattern[0] == 'static'
+        message[custom_param] = message[pattern[1]] if pattern[0] == 'param'
+      end
+      message
+    end
   end
 end

lib/tasks/db_registration.rake

@@ -63,7 +63,7 @@ namespace :db do
       )
 
       puts(jwk) if args[:type] == 'jwk'
-      puts(public_key.to_s) if args[:type] == 'key'
+      puts(public_key) if args[:type] == 'key'
     rescue StandardError => e
       puts(e.backtrace)
       exit(1)
@@ -139,7 +139,7 @@ namespace :db do
       registration.update(tool_settings: tool_settings.to_json, shared_secret: client_id)
 
       puts(jwk) if args[:type] == 'jwk'
-      puts(public_key.to_s) if args[:type] == 'key'
+      puts(public_key) if args[:type] == 'key'
     end
 
     desc 'Lists the Registration Configuration URLs need to register an app'

spec/rails_helper.rb

@@ -55,7 +55,7 @@
 end
 RSpec.configure do |config|
   # Remove this line if you're not using ActiveRecord or ActiveRecord fixtures
-  config.fixture_path = "#{::Rails.root}/spec/fixtures"
+  config.fixture_path = Rails.root.join('spec/fixtures')
 
   # If you're not using ActiveRecord, or you'd prefer not to run each of your
   # examples within a transaction, remove the following line or assign false