Exercise 4: Multiple Services Configuration

4.1 Understanding the Real Services Architecture

In this exercise, you'll configure multiple OData services based on the actual CAP services running on http://localhost:4004 . We have two services available:

• BookshopService : /bookshop - Main service with Books, Chapters, and Reviews entities
• ReviewsService : /reviews - Service for review management

This represents a microservices setup where different domains are handled by separate services.

4.2 Setup Multiple Services Configuration

1. Create directory structure for the reviews service:

mkdir -p webapp/localService/reviewService
mkdir -p webapp/localService/reviewService/data

2. Copy the actual reviews service metadata:

Since we're using a real CAP service, we can copy the metadata directly from the running service:

Create webapp/localService/reviewService/metadata.xml by copying the metadata from http://localhost:4004/reviews/$metadata .

3. Create review data ( webapp/localService/reviewService/data/Reviews.json ):

[
  {
    "ID": "23a6dd83-a75d-41c5-ad57-2314bc67ed2b",
    "reviewer": "John Doe",
    "rating": 5,
    "comment": "A timeless classic that never gets old!",
    "book_ID": "3afb35fa-e2c9-40d0-8e22-90e96ead9944",
    "createdAt": "2024-01-15T10:30:00Z",
    "IsActiveEntity": true,
    "HasActiveEntity": false,
    "HasDraftEntity": false
  },
  {
    "ID": "34b7ee94-f86c-52e6-be58-3425cd78fe3c",
    "reviewer": "Jane Smith",
    "rating": 4,
    "comment": "Great character development and storytelling.",
    "book_ID": "7c8f2a1b-d4e5-4c6a-9b7e-1f3a5c8d2e4b",
    "createdAt": "2024-01-20T14:45:00Z",
    "IsActiveEntity": true,
    "HasActiveEntity": false,
    "HasDraftEntity": false
  },
  {
    "ID": "45c8ff05-097d-63f7-cf69-4536de89df5d",
    "reviewer": "Book Lover",
    "rating": 3,
    "comment": "Decent read, but could be better paced.",
    "book_ID": "3afb35fa-e2c9-40d0-8e22-90e96ead9944",
    "createdAt": "2024-02-01T09:15:00Z",
    "IsActiveEntity": true,
    "HasActiveEntity": false,
    "HasDraftEntity": false
  }
]

4. Create Books reference data ( webapp/localService/reviewService/data/Books.json ):

[
  {
    "ID": "3afb35fa-e2c9-40d0-8e22-90e96ead9944",
    "title": "The Great Gatsby",
    "author": "F. Scott Fitzgerald",
    "IsActiveEntity": true,
    "HasActiveEntity": false,
    "HasDraftEntity": false
  },
  {
    "ID": "7c8f2a1b-d4e5-4c6a-9b7e-1f3a5c8d2e4b",
    "title": "To Kill a Mockingbird",
    "author": "Harper Lee",
    "IsActiveEntity": true,
    "HasActiveEntity": false,
    "HasDraftEntity": false
  }
]

5. Update ui5-mock.yaml to include both services:

server:
  customMiddleware:
    - name: sap-fe-mockserver
      beforeMiddleware: csp
      configuration:
        mountPath: /
        debug: true
        watch: true
        services:
          # Main bookshop service
          - urlPath: /bookshop
            alias: bookshop
            metadataPath: ./webapp/localService/mainService/metadata.xml
            mockdataPath: ./webapp/localService/mainService/data
            generateMockData: false
          # Reviews service
          - urlPath: /reviews
            alias: reviews
            metadataPath: ./webapp/localService/reviewService/metadata.xml
            mockdataPath: ./webapp/localService/reviewService/data
            generateMockData: false
        annotations: []

4.3 Start the Application

# from folder ex4
npm run start-mock
# or from root folder
npm run start:ex4

Now you should see in the List Report the Books from the mainService defined in the /webapp/localService/mainService/data folder.

To see the data from the reviewService you can request the data by simply opening the URLs:

• http://localhost:8084/reviews/Reviews
• http://localhost:8084/reviews/Books

Now you could include the reviews in the app in any way you want.

Next Steps

Exercise 5 will show how to implement cross-service communication where operations in one service trigger actions in another service, simulating real microservices integration patterns.