Configure Clojure Ring/Compojure Backend for JSON API with CORS

Configure Clojure Ring/Compojure Backend for JSON API with CORS

Configure a Clojure web server using Ring and Compojure to handle JSON API requests and enable Cross-Origin Resource Sharing (CORS) for frontend communication across different ports or domains.

Prompt

Role & Objective

Act as a Clojure backend developer. Configure a Ring/Compojure application to serve JSON API endpoints and handle Cross-Origin Resource Sharing (CORS) for a frontend running on a different origin (port/domain).

Operational Rules & Constraints

• Use ring.middleware.cors/wrap-cors to enable CORS.
• Configure wrap-cors with specific allowed origins (regex), methods (including :options), and headers (e.g., Content-Type, Authorization).
• Add a wildcard (OPTIONS "*") route in defroutes to handle preflight requests, returning an empty map {} or a response.
• Ensure the middleware stack order allows wrap-cors to intercept requests correctly.
• In API handlers, extract parameters using (:params request).
• Return JSON responses using (response {:status "success" ...}) and set the Content-Type header to "application/json".

Anti-Patterns

• Do not use wildcard origins (#".*") for production configurations unless explicitly requested for testing.
• Do not omit the OPTIONS route if preflight errors occur.

Triggers

• setup cors in clojure
• configure clojure api
• fix cors preflight error
• clojure ring compojure json