REST Demo Using Ruby

Author: Scott Hurrey
Categories: []
Tags: [‘rest’, ‘blackboard learn’, ‘example’, ‘sample code’, ‘saas’, ‘developer’]


The rest demo script demonstrates authenticating a REST application, management and use of the authorization token, and creating, updating, discovering, and deleting supported Learn objects.

Prerequisites

This Ruby command line Application allows you to:

  • Authenticate
  • Create, Read, and Update a Data Source
  • Create, Read, and Update a Term
  • Create, Read, and Update a Course
  • Create, Read, and Update a User
  • Create, Read, and Update a Membership
  • Delete created objects in reverse order of create - membership, user, course, term, datasource.

All generated output is sent to the terminal.

This is not meant to be a Ruby tutorial. It will not teach you to write code in Ruby. It will, however, give a Developer familiar with Ruby the knowledge necessary to build a Web Services integration.

Assumptions

This help topic assumes the Developer:

  • is familiar with Ruby
  • has installed Ruby and the Ruby rest-client gem.
  • has obtained a copy of the source code and built it in conjunction with the project README.md file.
  • has a REST-enabled Blackboard Learn instance.

Code Walkthrough

To build an integration with the Blackboard REST Web Services, regardless of the programming language of choice, can really be summed up in two steps:

  1. Use the Application Key and Secret to obtain an OAuth 2.0 access token, as described in the Basic Authentication document.
  2. Call the appropriate REST endpoint with the appropriate data to perform the appropriate action.

Authorization and Authentication

The REST Services rely on OAuth 2.0 Bearer Tokens for authentication. A request is made to the token endpoint with a Basic Authorization header containing the base64-encoded key:secret string as its key. The token service returns a JSON object containing the Access Token, the Token Type, and the number of seconds until the token expires. The token is set to expire after one hour, and subsequent calls to retrieve the token will return the same token with an updated expiry time until such time that the token has expired. There is no refresh token and currently no revoke token method.

The Ruby code handles this with the following code:

    bb_rest = RestClient::Resource.new $AUTH_PATH, $KEY, $SECRET
    bb_rest.post('grant_type=client_credentials', :accept => :json){ |response, request, result, &block|
              case response.code
                   when 200
                        p "It worked !"
                        token = JSON.parse(response)
                        $access_token = token['access_token']
                        $auth = "Bearer " + $access_token
                        p 'Access_Token: ' + $access_token 
                   else
                        p response.to_s
                        response.return!(request, result, &block)
                   end
      }

The JSON response is serialized into the Token object, and you may then retrieve those values from that object.

Calling Services

The individual service calls are handled in succession in the restdemo.rb file. Each operation and object combination creates the JSON body by instantiating the appropriate JSON object in the form of a String (required if you need to control the content-type, which you do) when necessary, and then generating the appropriate HTTP Request, shipping it to Learn, and serializing the JSON response back into the appropriate object.

End points are generally defined as /learn/api/public/v1/<object type>/<objectId>. Object ID can be either the pk1, like _1_1, or as the batchuid. This value should be prepended by externalId:, like externalId:test101.

For example, to retrieve a course by the pk1 _1_1, you would call GET /learn/api/public/v1/courses/_1_1. To retrieve by the batchuid test101, you would call GET /learn/api/public/v1/courses/externalId:test101.

Create is sent to Learn as a HTTP POST message with a JSON body that defines the object. The endpoint should omit the objectId, as this will be generated on creation.

Read is sent to Learn as a HTTP GET message with an empty body. The endpoint should include the objectId being retrieved.

Update is sent to Learn as a HTTP PATCH message with a JSON body that defines the object. The endpoint should include the objectId being updated.

Delete is sent to Learn as a HTTP DELETE message with empty body. The endpoint should include the objectId being deleted.


Datasources

Create

    payload = "{ \"externalId\":\"BBDN-DSK-RUBY\", \"description\": \"Demo Data Source used for REST Ruby Demo\" }"
    RestClient.post($DSK_PATH, payload, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
           case response.code
                  when 201
                    p "It worked !"
                    datasource = JSON.parse(response)
                    $dsk_id = datasource['id']
                    p 'Create Datasource: dsk_id=' + $dsk_id
             else
                    p response.to_s
                    response.return!(request, result, &block)
             end
    }

Read

    RestClient.get($DSK_PATH + $dsk_id, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
               case response.code
                 when 200
                   p "Got Datasource !" + response.to_s
                 else
                   p response.to_s
                   response.return!(request, result, &block)
                 end
               }

Update

    payload = "{ \"externalId\":\"BBDN-DSK-RUBY\", \"description\": \"Demo Data Source used for REST Ruby Demo - Updated\" }"
      
        RestClient.patch($DSK_PATH + $dsk_id, payload, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
        case response.code
          when 200
            p 'Updated Datasource: ' + response.to_s
          else
            p response.to_s
            response.return!(request, result, &block)
          end
        }

Delete

    RestClient.delete($DSK_PATH + $dsk_id, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
              case response.code
                when 204
                  p "Datasource Deleted !"
                else
                  p response.to_s
                  response.return!(request, result, &block)
                end
              }

Terms

Create

    payload = "{ \"externalId\":\"BBDN-TERM-RUBY\", \"dataSourceId\":\"" + $dsk_id + "\", \"name\" : \"REST Demo Term - Ruby\", \"description\": \"Term Used For REST Demo - Ruby\", \"availability\" : { \"available\" : \"Yes\" } }"
    RestClient.post($TERM_PATH, payload, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
         case response.code
               when 201
                      p "It worked !"
                      term = JSON.parse(response)
                      $term_id = term['id']
                      p 'Create Term: term_id=' + $term_id
               else
                      p response.to_s
                      response.return!(request, result, &block)
               end
    }

Read

    RestClient.get($TERM_PATH + $term_id, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
              case response.code
                when 200
                  p "Got Term !" + response.to_s
                else
                  p response.to_s
                  response.return!(request, result, &block)
                end
              }

Update

    payload = "{ \"externalId\":\"BBDN-TERM-RUBY\", \"dataSourceId\":\"" + $dsk_id + "\", \"name\" : \"REST Demo Term - Ruby\", \"description\": \"Updated Term Used For REST Demo - Ruby\", \"availability\" : { \"available\" : \"Yes\" } }"
        RestClient.patch($TERM_PATH + $term_id, payload, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
        case response.code
          when 200
            p 'Updated Term: ' + response.to_s
          else
            p response.to_s
            response.return!(request, result, &block)
          end
        }

Delete

    RestClient.delete($TERM_PATH + $term_id, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
              case response.code
                when 204
                  p "Term Deleted !"
                else
                  p response.to_s
                  response.return!(request, result, &block)
                end
              }

Course

Create

    payload = "{ \"externalId\" : \"BBDN-Java-Ruby-Demo\", \"courseId\" : \"BBDN-Java-Ruby-Demo\", \"name\" : \"Course Used For REST Demo - Ruby\", \"description\" : \"Course Used For REST Demo - Ruby\", \"allowGuests\" : \"true\", \"readOnly\" : \"false\", \"termId\" : \"" + $term_id + "\", \"dataSourceId\" : \"" + $dsk_id + "\", \"availability\" : { \"available\" : \"Yes\" } }"
        RestClient.post($COURSE_PATH, payload, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
        case response.code
          when 201
            p "It worked !"
            course = JSON.parse(response)
            $course_id = course['id']
            p 'Create Course: course_id=' + $course_id
          else
            p response.to_s
            response.return!(request, result, &block)
          end
        }

Read

    RestClient.get($COURSE_PATH + $course_id, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
              case response.code
                when 200
                  p "Got Course !" + response.to_s
                else
                  p response.to_s
                  response.return!(request, result, &block)
                end
              }

Update

    payload = "{ \"externalId\" : \"BBDN-Java-Ruby-Demo\", \"courseId\" : \"BBDN-Java-Ruby-Demo\", \"name\" : \"Course Used For REST Demo - Ruby\", \"description\" : \"Updated Course Used For REST Demo - Ruby\", \"allowGuests\" : \"true\", \"readOnly\" : \"false\", \"termId\" : \"" + $term_id + "\", \"dataSourceId\" : \"" + $dsk_id + "\", \"availability\" : { \"available\" : \"Yes\" } }"
        RestClient.patch($COURSE_PATH + $course_id, payload, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
        case response.code
          when 200
          p 'Updated Course: ' + response.to_s
          else
            p response.to_s
            response.return!(request, result, &block)
          end
        }

Delete

    RestClient.delete($COURSE_PATH + $course_id, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
              case response.code
                when 204
                  p "Course Deleted !"
                else
                  p response.to_s
                  response.return!(request, result, &block)
                end
              }

Users

Create

    payload = "{ \"externalId\" : \"bbdnrestdemorubyuser\", \"userName\" : \"restrubyuser\", \"password\" : \"Bl@ckb0ard!\", \"studentId\" : \"restrubyuser\", \"dataSourceId\" : \"" + $dsk_id + "\", \"name\" : { \"given\" : \"Ruby\", \"family\" : \"Rest Demo\" }, \"contact\" : { \"email\" : \"developers@blackboard.com\" }, \"availability\" : { \"available\" : \"Yes\" } }"
      
          RestClient.post($USER_PATH, payload, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
          case response.code
            when 201
              p "It worked !"
              user = JSON.parse(response)
              $user_id = user['id']
              p 'Create User: user_id=' + $user_id
            else
              p response.to_s
              response.return!(request, result, &block)
            end
          }

Read

    RestClient.get($USER_PATH + $user_id, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
                case response.code
                  when 200
                    p "Got User !" + response.to_s
                  else
                    p response.to_s
                    response.return!(request, result, &block)
                  end
                } 

Update

    payload = "{ \"externalId\" : \"bbdnrestdemorubyuser\", \"userName\" : \"restrubyuser\", \"password\" : \"Bl@ckb0ard!\", \"studentId\" : \"restrubyuser\", \"dataSourceId\" : \"" + $dsk_id + "\", \"name\" : { \"given\" : \"Ruby\", \"family\" : \"Rest Demo\", \"middle\" : \"updated\" }, \"contact\" : { \"email\" : \"developers@blackboard.com\" }, \"availability\" : { \"available\" : \"Yes\" } }"
      
          RestClient.patch($USER_PATH + $user_id, payload, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
          case response.code
            when 200
            p 'Updated User: ' + response.to_s
            else
              p response.to_s
              response.return!(request, result, &block)
            end
          }

Delete

    RestClient.delete($USER_PATH + $user_id, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
              case response.code
                when 204
                  p "User Deleted !"
                else
                  p response.to_s
                  response.return!(request, result, &block)
                end
              }

Memberships

Create

    payload = "{ \"userId\" : \"" + $user_id + "\", \"courseId\" : \"" + $course_id + "\", \"courseRoleId\" : \"Student\", \"dataSourceId\" : \"" + $dsk_id + "\", \"availability\" : { \"available\" : \"Yes\" } }"
      
          RestClient.put($COURSE_PATH + $course_id + '/users/' + $user_id, payload, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
          case response.code
            when 201
              p "It worked !"
              membership = JSON.parse(response)
              $created = membership['created']
              p 'Create Membership: ' + $created
            else
              p response.to_s
              response.return!(request, result, &block)
            end
          }

Read

    RestClient.get($COURSE_PATH + $course_id + '/users/' + $user_id, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
              case response.code
                when 200
                  p "Got Membership !" + response.to_s
                else
                  p response.to_s
                  response.return!(request, result, &block)
                end
              }

Update

    payload = "{ \"userId\" : \"" + $user_id + "\", \"courseId\" : \"" + $course_id + "\", \"courseRoleId\" : \"Instructor\", \"dataSourceId\" : \"" + $dsk_id + "\", \"availability\" : { \"available\" : \"Yes\" } }"
      
          RestClient.patch($COURSE_PATH + $course_id + '/users/' + $user_id, payload, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
          case response.code
            when 200
            p 'Updated Membership: ' + response.to_s
            else
              p response.to_s
              response.return!(request, result, &block)
            end
          }

Delete

    RestClient.delete($COURSE_PATH + $course_id + '/users/' + $user_id, :content_type => :json, :accept => :json, :Authorization => $auth){ |response, request, result, &block|
            case response.code
              when 204
                p "Membership Deleted !"
              else
                p response.to_s
                response.return!(request, result, &block)
              end
            }

Conclusion

All of the code snippets included in this document at included in a sample REST Demo Ruby application available on GitHub. There is a README.html included that talks more specifically about building and running the code. Feel free to review the code and run it against a test or development Learn instance to see how it works.