CAP Service SDK for Node.js

Reference Documentation

Introduction

As an application developer you’d primarily use the Node.js APIs documented herein to implement domain-specific custom logic along these lines:

1. Define services in CDS → see Cookbook > Providing & Consuming Services
2. Add service implementations → cds.Service > Implementations
3. Register custom event handlers in which → srv.on/before/after
4. Read/write data from other services in which → srv.run + cds.ql
5. …, i.e. from your primary database → cds.DatabaseService
6. …, i.e. from other connected services → cds.RemoteService
7. Emit and handle asynchronous events → cds.MessagingService

All the rest is largely handled by the CAP runtime framework behind the scenes. This especially applies to bootstrapping the cds.server and the generic features provided through cds.ApplicationService.

Content

• The cds Facade Object
• cds.server — bootstrapping
• cds.serve… ⇢ service(s)
• cds.connect ⇢ service
• cds.ql → queries
  
  
• cds.Service
• cds.Event/Request
• cds.ApplicationService
• cds.DatabaseService
• cds.RemoteService
• cds.MessagingService
• cds.ProtocolAdapter
  
  
• cds.log → logging
• cds.env → config
• Authentication
• Best Practices

Conventions

We use the following notations in method signatures:

Read them as follows:

• param? — appended question marks denote optional parameters
• → result — solid line arrows: returns the given result
• ⇢ result — dashed arrows: returns a [Promise] resolving to the given result
• ... — denotes a fluent API, eventually returning/resolving to given result
• ↳ — denotes subsequent methods to add options in a fluent API