Everything in CAP / Java
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Java: Answers in Java
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DebuggingSAP and community
Surviving and Thriving with the SAP Cloud Application Programming Model: Local development hurdlesSurviving and Thriving with the SAP Cloud Application Programming Model: Local development hurdlesThree hurdles in running a CAP application locally: services mocked with cds run --with-mocks return no data across OData associations until the ON clause is hand-written into the imported CDS, an on-premise API reached through the SAP Cloud Connector times out because its proxy is part of destinations and connectivity and reachable only from inside SAP BTP, and a Fiori frontend served from the HTML5 Application Repository needs the HTML5 Repo Mock to reach a local backend at all. It closes with the launch configurations the author uses for debugging cds watch locally and attaching to a running Cloud Foundry instance.maxstreifeneder, published 2023-02-02
Editor supportSAP and community
Develop CAP Project with Lazyvim in DockerDevelop CAP Project with Lazyvim in DockerA Docker image running Lazyvim with language server support for CDS, TypeScript and JSON, so a CAP project can be developed with an editing experience comparable to VS Code without leaving the keyboard. Narrow by intent, and the useful general point underneath it is that CAP's editor support reaches anything that speaks LSP.published 2024-03-28
Making CAP Application Development Easier and Faster with the Help of Storyboard in SAP Business Application StudioMaking CAP Application Development Easier and Faster with the Help of Storyboard in SAP Business Application StudioThe Storyboard from the other side — someone who came across it while learning the high-productivity tools, rather than someone who shipped it. It follows the whole arc a CAP project takes through the tool: entities, relationships, services, sample data, a UI, roles, and external resources, each as a thing the diagram can add rather than a file you open.Aryan_Raj_Sinha, published 2023-09-20
SAP CAP: Best VSCode extensions for TypeScript development (UI5 & NodeJS)SAP CAP: Best VSCode extensions for TypeScript development (UI5 & NodeJS)A working editor setup for CAP with TypeScript, listed extension by extension across the Node.js and UI5 halves. The kind of post that ages by attrition rather than by being wrong — the reasoning about what an editor needs to know about a CDS project outlives any particular extension in the list.published 2024-04-29
SAP CAP: Best VSCode extensions for TypeScript development (UI5 & NodeJS)
Editor support changed in @sap/cds-dk 8.8.0, 2025-03-04. Affects Runnable code.
Local developmentSAP only
Avoid design time CAP server restarts when maintaining local data filesAvoid design time CAP server restarts when maintaining local data filescds watch restarting on every file change is the feature; this is the case where it is not. Editing a CSV seed file mid-edit restarts the server against half-finished data, and the post is about suppressing that without giving up the watch loop. A small friction most people work around silently rather than fix.published 2024-04-26
Avoid design time CAP server restarts when maintaining local data files
Local development changed in @sap/cds-dk 7.9.1, 2024-05-02. Affects Runnable code.
CAP for nodejs安全的暴露接口练习CAP for nodejs安全的暴露接口练习Starting from the risk-management sample, the walkthrough adds an open ExternalAPI service beside the existing RiskService, then moves every security annotation into a separate service-auth.cds file: @requires: authenticated-user on one entity, role-scoped @restrict grants for RiskViewer and RiskManager on another. It tests the unprotected action locally with cds watch, calling it from Postman with the session cookie read out of SAP Business Application Studio's preview tab. It then deploys to BTP and reads Risks with a client-credentials OAuth token fetched from a service key of the cpapp-auth instance, after changing that entity's READ grant from RiskViewer to authenticated-user, which the post, citing capire's CDS-based Authorization page, describes as a grant for a technical user integrating systems rather than for access from a front end.ArthurYang, published 2024-12-10
CAP PostgreSql setup local debugging using Docker - Part 2CAP PostgreSql setup local debugging using Docker - Part 2PostgreSQL in a container so the local loop matches the deployed one — the thing SQLite quietly stops you doing. Short, and it assumes the project from part one already runs.ramonlee5, published 2023-11-22
CAP PostgreSql setup local debugging using Docker - Part 2
Database connectors has changed twice since this was published, most recently in @sap/cds 10.1.0, 2026-09-07. Affects A recipe.
CAP Typescript + Fiori Typescript + live reload Initial app setupCAP Typescript + Fiori Typescript + live reload Initial app setupA full-stack TypeScript starting point recorded as it was arrived at — the terminal commands and the configuration files, in order, for the CAP side, the conversion to TypeScript, and then the Fiori side. The author is explicit that it takes a while to go through, which is the honest framing for a setup that has this many steps.Christophe_SW, published 2023-06-18
CAP Typescript + Fiori Typescript + live reload Initial app setup
TypeScript patterns changed in @cap-js/cds-typer 0.5.0, 2023-07-25. Affects Runnable code.
cds-launchpad-plugin supercharged & ready for the future - CAP Plugin, UI5 Tooling support & Async Launchpadcds-launchpad-plugin supercharged & ready for the future - CAP Plugin, UI5 Tooling support & Async LaunchpadThe maintainer on a set of changes rather than on the plugin's original purpose, which is indexing every SAPUI5 project in a workspace into one sandbox launchpad so all of them can be tested together. What moved: it became a CAP plugin, gained UI5 Tooling support, and moved to the async launchpad — each framed as keeping pace with where SAPUI5 itself is going rather than as a feature.published 2023-12-11
Develop CAP Project with Lazyvim in DockerDevelop CAP Project with Lazyvim in DockerA Docker image running Lazyvim with language server support for CDS, TypeScript and JSON, so a CAP project can be developed with an editing experience comparable to VS Code without leaving the keyboard. Narrow by intent, and the useful general point underneath it is that CAP's editor support reaches anything that speaks LSP.published 2024-03-28
SAP Tech Bytes: Using the SAP Approuter at dev time - a full-stack journey with UI5 and CAPSAP Tech Bytes: Using the SAP Approuter at dev time - a full-stack journey with UI5 and CAPGetting UI5 Tooling and the CAP server onto one port under one command, using cds-plugin-ui5 — which the post presents as the thing that removes the proxy and destination configuration a full-stack dev setup otherwise needs. Part one of a journey that goes on to put the approuter in front at development time.published 2023-10-13
SAP Tech Bytes: Using the SAP Approuter at dev time - a full-stack journey with UI5 and CAP
cds-plugin-ui5 has been through 11 major lines since this was published, most recently 0.15 (2025-11), 0.16 (2025-12), 0.17 (2026-03). Affects Runnable code.
Surviving and Thriving with the SAP Cloud Application Programming Model: Local development hurdlesSurviving and Thriving with the SAP Cloud Application Programming Model: Local development hurdlesThree hurdles in running a CAP application locally: services mocked with cds run --with-mocks return no data across OData associations until the ON clause is hand-written into the imported CDS, an on-premise API reached through the SAP Cloud Connector times out because its proxy is part of destinations and connectivity and reachable only from inside SAP BTP, and a Fiori frontend served from the HTML5 Application Repository needs the HTML5 Repo Mock to reach a local backend at all. It closes with the launch configurations the author uses for debugging cds watch locally and attaching to a running Cloud Foundry instance.maxstreifeneder, published 2023-02-02
XSUAA Local TestingXSUAA Local TestingAdding XSUAA to a CAP project two ways, and then the part that is usually missing: getting the authorisation to behave on a laptop rather than only after deployment. The default authentication mechanism is the easy half; testing it without a landscape is the reason this exists.ManasaManu, published 2024-10-17
XSUAA Local Testing
Authorization has changed twice since this was published, most recently in CAP Java 3.7.1, 2025-01-30. Affects A recipe, Runnable code.
Plugin authoringSAP only
BTP CAP : Custom plugin to separate generic change log capture logicBTP CAP : Custom plugin to separate generic change log capture logicWalks through building a custom [CAP](ecosystem:cap) plugin that centralises change-log capture: on cds.once('served') it collects entities annotated @audit, then hooks srv.before('UPDATE') to read the existing record, diff it field by field against the incoming payload, and record old/new values with the user and timestamp. It also documents a cds build failure packaging the plugin's own directory into gen/srv for MTA deployment, fixed by adding it as a copyfiles build-parameter step in mta.yaml.sreehari_vpillai, published 2023-05-10
Create your first CAP pluginCreate your first CAP pluginA step-by-step guide to the cds-plugin.js extension point: scaffold a package, add an index.cds for shared model artifacts, and test it locally against a throwaway CAP project before publishing to npm, with a separate section on building the same plugin in TypeScript and compiling it with tsc. Points to the author's own cds-plugin-handlers and ui5-cap-serverside-rendering-plugin as worked examples.published 2024-12-09
How to build reusable plugin components for CAP Java applicationsHow to build reusable plugin components for CAP Java applicationsA companion to Daniel Schlachter's Reusable components for CAP with cds-plugin, showing the same mechanism on CAP Java: a plugin ships as its own Maven artifact with an event handler and a CdsRuntimeConfiguration implementation, registered through the JDK's ServiceLoader rather than any CAP-specific wiring. The walkthrough builds a cds-emoji-plugin-java jar that decorates @emoji-annotated fields on read, installs it to the local Maven repository, and adds it as a runtime dependency to a cds init --add java bookshop application. It argues the plugin mechanism was not new to CAP Java, just previously undocumented.robinjayasinghe, published 2023-05-16
Reusable components for CAP with cds-pluginReusable components for CAP with cds-pluginThe post that taught the mechanism, and it teaches it by picking a requirement small enough to be absurd: every string a service returns should end in a random emoji. Working through that on the bookshop example leaves nothing to argue about except the plumbing, which is the point — what a cds-plugin is, where it hooks in, and why packaging it beats copying it into the next project. Vinícius Barrionuevo credits this post as the thing that gave him the idea for sap-cap-sdm-plugin, and it is hard to read the plugin ecosystem in this graph without it.published 2023-04-30
SAP AI Services - DOX - Gen AI with SAP CAP Plugin - Part 3SAP AI Services - DOX - Gen AI with SAP CAP Plugin - Part 3Building on Reusable components for CAP with cds-plugin by Daniel Schlachter, this part walks through a custom CAP plugin — a cds-plugin.js plus a lib_cap_dox.js helper — that authenticates against SAP's Document Information Extraction (DOX) service and calls its schema and job-status APIs to fill an entity from extracted document fields. It covers reading the service key from Cloud Foundry (cf service-key) for the OAuth token endpoint, and dynamically mapping DOX's header and line-item output onto CAP entity properties.sabarna17, published 2024-06-11
Seed dataCommunity only
Avoid design time CAP server restarts when maintaining local data filesAvoid design time CAP server restarts when maintaining local data filescds watch restarting on every file change is the feature; this is the case where it is not. Editing a CSV seed file mid-edit restarts the server against half-finished data, and the post is about suppressing that without giving up the watch loop. A small friction most people work around silently rather than fix.published 2024-04-26
Avoid design time CAP server restarts when maintaining local data files
Local development changed in @sap/cds-dk 7.9.1, 2024-05-02. Affects Runnable code.
ISO content for common CAP typesISO content for common CAP typesThe npm package that supplies ISO-standard content — countries, languages, currencies, timezones — for CAP's common types, and how it works underneath. The author flags the length and the reason for it up front, having followed the mechanism further than the question required, which is what makes it worth reading rather than a package announcement.published 2024-03-14
ISO content for common CAP types
Seed data changed in @sap/cds-dk 7.9.1, 2024-05-02. Affects Runnable code.
TestingSAP and community
CAP full-stack testing with BDD flavourCAP full-stack testing with BDD flavourIntroduces Behavior-Driven Development for CAP applications: specifications written in Gherkin against a running app, validated by Cucumber, using cds-cucumber's ready-made step definitions for SAP Fiori elements and OData screens. The library handles service lifecycle — starting the app, assigning a port, driving the browser and authenticating a named user — and its OData steps know the service's entities and fields from the CDS model itself, so a scenario can open a list report, search it and assert row counts without hand-written glue code.published 2023-10-10
TypeScript patternsDoes not apply
CAP Typescript + Fiori Typescript + live reload Initial app setupCAP Typescript + Fiori Typescript + live reload Initial app setupA full-stack TypeScript starting point recorded as it was arrived at — the terminal commands and the configuration files, in order, for the CAP side, the conversion to TypeScript, and then the Fiori side. The author is explicit that it takes a while to go through, which is the honest framing for a setup that has this many steps.Christophe_SW, published 2023-06-18
CAP Typescript + Fiori Typescript + live reload Initial app setup
TypeScript patterns changed in @cap-js/cds-typer 0.5.0, 2023-07-25. Affects Runnable code.
CDS-TS-Dispatcher: Simplifying SAP CAP TypeScript DevelopmentCDS-TS-Dispatcher: Simplifying SAP CAP TypeScript DevelopmentThe first of a pair introducing the author's own libraries, and it states what it is reacting to: CAP derives OData services from a CDS model, but the communication between business logic, service and persistence layers is left to you, and the earlier attempt at the service-layer half, cds-routing-handler, appeared unmaintained against newer CAP. The dispatcher is the answer offered for that layer.published 2023-11-13
CDS-TS-Dispatcher: Simplifying SAP CAP TypeScript Development
@dxfrontier/cds-ts-dispatcher has been through 6 major lines since this was published, most recently 4 (2025-01), 5 (2025-07), 6 (2026-07). Affects Runnable code.
CDS-TS-Repository: Simplify SAP CAP Entity persistance with BaseRepositoryCDS-TS-Repository: Simplify SAP CAP Entity persistance with BaseRepositoryThe persistence half of the same pair, three days later: a BaseRepository putting entity access behind a typed repository rather than CQN written inline in a handler. Shares its opening argument with the dispatcher post — the layer between business logic and persistence is the part CAP leaves open — and the two are designed to be used together.published 2023-11-16
CDS-TS-Repository: Simplify SAP CAP Entity persistance with BaseRepository
@dxfrontier/cds-ts-repository has been through 9 major lines since this was published, most recently 5 (2024-12), 6 (2025-07), 7 (2026-07). Affects Runnable code.
How we could potentially have nestjs as runtime for SAP CAPHow we could potentially have nestjs as runtime for SAP CAPA proof-of-concept that swaps @sap/cds's ApplicationService and ODataAdapter dispatch for NestJS controllers, providers and interceptors, built by the author to learn NestJS rather than to ship a runtime. It works through CAP's run-dispatch-handle loop and AsyncLocalStorage-based transaction boundaries in detail before mapping them onto NestJS dependency injection and interceptors — one community answer to the controller-service-repository layering question core TypeScript support leaves open. The author's own conclusion is that the result reimplements CAP Java in Node.js, and they do not plan to take it further.alex_myakinkii, published 2024-09-19
SAP CAP: Controller - Service - Repository architectureSAP CAP: Controller - Service - Repository architectureThe pattern the author's two libraries exist to support, set out as a whole rather than one package at a time: a controller layer receiving the request, a service layer holding business logic, and a repository layer owning persistence — the separation CAP leaves to the developer once a model has produced an OData service. Read after the dispatcher and repository posts, or before them as the argument for both.published 2024-04-22
SAP CAP: Controller - Service - Repository architecture
@dxfrontier/cds-ts-dispatcher has been through 4 major lines since this was published, most recently 4 (2025-01), 5 (2025-07), 6 (2026-07). Affects Runnable code.
Use TypeScript with the SAP Cloud Application Programming ModelUse TypeScript with the SAP Cloud Application Programming ModelWritten from the position of someone who avoided JavaScript for years and then had to cover CAP, which gives it a useful angle: what TypeScript buys a person arriving from a typed language, and where to start rather than how to finish. Ends on a worked example rather than a survey.KevinR, published 2024-06-24
TypingSAP only
Exploring the TypeScript Ecosystem with @cap-js/cds-typer, cds-ts, and node-tsExploring the TypeScript Ecosystem with @cap-js/cds-typer, cds-ts, and node-tsPart one of two: a bookshop project built in TypeScript from cds init, with cds-typer added as a development dependency and the surrounding tools — cds-ts and node-ts — put in place so the project runs locally. A setup walkthrough rather than an argument about typing, and it stops at the point where the application works on a laptop; deployment is part two.satya-dev, published 2024-07-08
Exploring the TypeScript Ecosystem with @cap-js/cds-typer, cds-ts, and node-ts
@cap-js/cds-typer has been through 18 major lines since this was published, most recently 0.39 (2026-05), 0.40 (2026-06), 0.41 (2026-08). Affects A recipe, Runnable code.
Exploring the TypeScript Ecosystem with @cap-js/cds-typer, cds-ts, and node-ts Part - 2Exploring the TypeScript Ecosystem with @cap-js/cds-typer, cds-ts, and node-ts Part - 2Part two takes the TypeScript project from part one to Cloud Foundry: cds add mta, then the parts of the generated descriptor the author singles out as needing attention for a TypeScript build rather than a JavaScript one. The pair together is the whole path — typed model locally, then deployed — which is where a typing walkthrough usually stops short.satya-dev, published 2024-07-19
Exploring the TypeScript Ecosystem with @cap-js/cds-typer, cds-ts, and node-ts Part - 2
@cap-js/cds-typer has been through 17 major lines since this was published, most recently 0.39 (2026-05), 0.40 (2026-06), 0.41 (2026-08). Affects Runnable code.
TypeScript Sheriff: How can I use TypeScript in the SAP ecosystem? (Part 2 of 3)TypeScript Sheriff: How can I use TypeScript in the SAP ecosystem? (Part 2 of 3)The middle part of three, and the one about SAP: where TypeScript is supported across a side-by-side extension on BTP, as of July 2023. It says the SAP Cloud SDK already generates OData clients as .ts files and UI5 ships types for its controls and modules, the ground of TypeScript support in UI5, while CAP offers standard types and the new @cap-js/cds-typer generates types for a service, which is typing, with the caveat that running cds-ts commands could overwrite what cds-typer generated.MikeDoyle, published 2023-07-05