ui5-middleware-cap

3.3.4 verified Sat Apr 25 auth: no javascript

UI5 CLI middleware that embeds the CDS server middleware from SAP Cloud Application Programming Model (CAP) into the UI5 development server. Version 3.3.4 requires @ui5/cli >=3 and @sap/cds >=6.8.1. It improves local development by integrating CAP services (including mock data and in-memory database) directly into the UI5 dev server lifecycle. Community-maintained, with active monitoring and contributions.

Common errors

error Error: Cannot find module '@sap/cds' ↓

cause @sap/cds not installed or version too low

fix

Run npm install @sap/cds@>=6.8.1 -D and ensure it's in package.json

error Invalid configuration: specVersion must be '3.0' ↓

cause ui5.yaml uses old specVersion incompatible with middleware

fix

Update ui5.yaml specVersion: '3.0'

error TypeError: cds.server is not a function ↓

cause Incompatible @sap/cds version (<6.8.1)

fix

Upgrade @sap/cds to >=6.8.1

Warnings

breaking Major version 3 requires @ui5/cli >=3 (specVersion 3.0). Older UI5 CLI versions are not compatible. ↓

fix Upgrade @ui5/cli to latest major version 3+ and ensure ui5.yaml uses specVersion: '3.0'.

deprecated The 'in-memory' option has been renamed to 'in-memory?' with optional question mark syntax. Old usage may break. ↓

fix Use 'in-memory?' instead of 'in-memory' in ui5.yaml options.

gotcha CDS server is only attached if '@sap/cds' is listed as a dependency or devDependency, not just transitive. ↓

fix Add '@sap/cds' to your package.json dependencies or devDependencies.

Install

npm install ui5-middleware-cap

yarn add ui5-middleware-cap

pnpm add ui5-middleware-cap

Imports

ui5-middleware-cap

wrong

import ui5MiddlewareCap from 'ui5-middleware-cap'

correct

// No JavaScript import; configured via ui5.yaml
server:
  customMiddleware:
  - name: ui5-middleware-cap
    afterMiddleware: compression
    mountPath: '/cap'

This is a UI5 CLI middleware, not a JavaScript module. It is configured declaratively in ui5.yaml.

cds
wrong
```
import { cds } from '@sap/cds'
```
correct
```
const cds = require('@sap/cds')
```
@sap/cds is CommonJS-only; use require() in Node.js. ESM import may fail.
express
wrong
```
const express = require('express')
```
correct
```
import express from 'express'
```
Modern versions of express support ESM import in Node >=14 via 'import'.

Quickstart

Shows minimal setup: install deps, configure ui5.yaml, verify CDS version, start UI5 server.

// Step 1: Install dependencies
npm add ui5-middleware-cap @sap/cds -D

// Step 2: Create ui5.yaml in project root with:
// specVersion: '3.0'
// metadata:
//   name: my-app
// server:
//   customMiddleware:
//   - name: ui5-middleware-cap
//     afterMiddleware: compression
//     mountPath: '/cap'

// Step 3: Ensure @sap/cds version >=6.8.1 in package.json

// Step 4: Run UI5 dev server
// ui5 serve --port 8080 --open /cap