make-an-outgoing-http-client-request

description: Use the Http.client module to make outgoing requests to keep the entire operation within the Effect ecosystem. globs: "**/*.ts" alwaysApply: true

Make an Outgoing HTTP Client Request

Rule: Use the Http.client module to make outgoing requests to keep the entire operation within the Effect ecosystem.

Example

This example creates a proxy endpoint. A request to /proxy/posts/1 on our server will trigger an outgoing request to the JSONPlaceholder API. The response is then parsed and relayed back to the original client.

import { NodeHttpServer, NodeRuntime } from "@effect/platform-node";
import * as HttpRouter from "@effect/platform/HttpRouter";
import * as HttpServer from "@effect/platform/HttpServer";
import * as HttpResponse from "@effect/platform/HttpServerResponse";
import { Console, Data, Duration, Effect, Fiber, Layer } from "effect";

class UserNotFoundError extends Data.TaggedError("UserNotFoundError")<{
  id: string;
}> {}

export class Database extends Effect.Service<Database>()("Database", {
  sync: () => ({
    getUser: (id: string) =>
      id === "123"
        ? Effect.succeed({ name: "Paul" })
        : Effect.fail(new UserNotFoundError({ id })),
  }),
}) {}

const userHandler = Effect.flatMap(HttpRouter.params, (p) =>
  Effect.flatMap(Database, (db) => db.getUser(p["userId"] ?? "")).pipe(
    Effect.flatMap(HttpResponse.json)
  )
);

const app = HttpRouter.empty.pipe(
  HttpRouter.get("/users/:userId", userHandler)
);

const server = NodeHttpServer.layer(() => require("node:http").createServer(), {
  port: 3457,
});

const serverLayer = HttpServer.serve(app);

const mainLayer = Layer.merge(Database.Default, server);

const program = Effect.gen(function* () {
  yield* Effect.log("Server started on http://localhost:3457");
  const layer = Layer.provide(serverLayer, mainLayer);

  // Launch server and run for a short duration to demonstrate
  const serverFiber = yield* Layer.launch(layer).pipe(Effect.fork);

  // Wait a moment for server to start
  yield* Effect.sleep(Duration.seconds(1));

  // Simulate some server activity
  yield* Effect.log("Server is running and ready to handle requests");
  yield* Effect.sleep(Duration.seconds(2));

  // Shutdown gracefully
  yield* Fiber.interrupt(serverFiber);
  yield* Effect.log("Server shutdown complete");
});

NodeRuntime.runMain(
  Effect.provide(
    program,
    Layer.provide(serverLayer, Layer.merge(Database.Default, server))
  ) as Effect.Effect<void, unknown, never>
);