create-a-basic-http-server

description: Use Http.server.serve with a platform-specific layer to run an HTTP application. globs: "**/*.ts" alwaysApply: true

Create a Basic HTTP Server

Rule: Use Http.server.serve with a platform-specific layer to run an HTTP application.

Example

This example creates a minimal server that responds to all requests with "Hello, World!". The application logic is a simple Effect that returns an Http.response. We use NodeRuntime.runMain to execute the server effect, which is the standard way to launch a long-running application.

import { Effect, Duration } from "effect";
import * as http from "http";

// Create HTTP server service
class HttpServer extends Effect.Service<HttpServer>()("HttpServer", {
  sync: () => ({
    start: () =>
      Effect.gen(function* () {
        const server = http.createServer(
          (req: http.IncomingMessage, res: http.ServerResponse) => {
            res.writeHead(200, { "Content-Type": "text/plain" });
            res.end("Hello, World!");
          }
        );

        // Add cleanup finalizer
        yield* Effect.addFinalizer(() =>
          Effect.gen(function* () {
            yield* Effect.sync(() => server.close());
            yield* Effect.logInfo("Server shut down");
          })
        );

        // Start server with timeout
        yield* Effect.async<void, Error>((resume) => {
          server.on("error", (error) => resume(Effect.fail(error)));
          server.listen(3456, "localhost", () => {
            resume(Effect.succeed(void 0));
          });
        }).pipe(
          Effect.timeout(Duration.seconds(5)),
          Effect.catchAll((error) =>
            Effect.gen(function* () {
              yield* Effect.logError(`Failed to start server: ${error}`);
              return yield* Effect.fail(error);
            })
          )
        );

        yield* Effect.logInfo("Server running at http://localhost:3456/");

        // Run for a short duration to demonstrate the server is working
        yield* Effect.sleep(Duration.seconds(3));
        yield* Effect.logInfo("Server demonstration complete");
      }),
  }),
}) {}

// Create program with proper error handling
const program = Effect.gen(function* () {
  const server = yield* HttpServer;

  yield* Effect.logInfo("Starting HTTP server...");

  yield* server.start();
}).pipe(
  Effect.scoped // Ensure server is cleaned up properly
);

// Run the server with proper error handling
const programWithErrorHandling = Effect.provide(
  program,
  HttpServer.Default
).pipe(
  Effect.catchAll((error) =>
    Effect.gen(function* () {
      yield* Effect.logError(`Program failed: ${error}`);
      return yield* Effect.fail(error);
    })
  )
);

Effect.runPromise(programWithErrorHandling).catch(() => {
  process.exit(1);
});

/*
To test:
1. Server will timeout after 5 seconds if it can't start
2. Server runs on port 3456 to avoid conflicts
3. Proper cleanup on shutdown
4. Demonstrates server lifecycle: start -> run -> shutdown
*/