add-timeouts-to-http-requests

description: Always set timeouts on HTTP requests to ensure your application doesn't hang. globs: "**/*.ts" alwaysApply: true

Add Timeouts to HTTP Requests

Rule: Always set timeouts on HTTP requests to ensure your application doesn't hang.

Example

import { Effect, Duration, Data } from "effect"
import { HttpClient, HttpClientRequest, HttpClientResponse } from "@effect/platform"

// ============================================
// 1. Basic request timeout
// ============================================

const fetchWithTimeout = (url: string, timeout: Duration.DurationInput) =>
  Effect.gen(function* () {
    const client = yield* HttpClient.HttpClient

    return yield* client.get(url).pipe(
      Effect.flatMap((r) => HttpClientResponse.json(r)),
      Effect.timeout(timeout)
    )
    // Returns Option<A> - None if timed out
  })

// ============================================
// 2. Timeout with custom error
// ============================================

class RequestTimeoutError extends Data.TaggedError("RequestTimeoutError")<{
  readonly url: string
  readonly timeout: Duration.Duration
}> {}

const fetchWithTimeoutError = (url: string, timeout: Duration.DurationInput) =>
  Effect.gen(function* () {
    const client = yield* HttpClient.HttpClient

    return yield* client.get(url).pipe(
      Effect.flatMap((r) => HttpClientResponse.json(r)),
      Effect.timeoutFail({
        duration: timeout,
        onTimeout: () => new RequestTimeoutError({
          url,
          timeout: Duration.decode(timeout),
        }),
      })
    )
  })

// ============================================
// 3. Different timeouts for different phases
// ============================================

const fetchWithPhasedTimeouts = (url: string) =>
  Effect.gen(function* () {
    const client = yield* HttpClient.HttpClient

    // Connection timeout (initial)
    const response = yield* client.get(url).pipe(
      Effect.timeout("5 seconds"),
      Effect.flatten,
      Effect.mapError(() => new Error("Connection timeout"))
    )

    // Read timeout (body)
    const body = yield* HttpClientResponse.text(response).pipe(
      Effect.timeout("30 seconds"),
      Effect.flatten,
      Effect.mapError(() => new Error("Read timeout"))
    )

    return body
  })

// ============================================
// 4. Timeout with fallback
// ============================================

interface ApiResponse {
  data: unknown
  cached: boolean
}

const fetchWithFallback = (url: string): Effect.Effect<ApiResponse> =>
  Effect.gen(function* () {
    const client = yield* HttpClient.HttpClient

    return yield* client.get(url).pipe(
      Effect.flatMap((r) => HttpClientResponse.json(r)),
      Effect.map((data) => ({ data, cached: false })),
      Effect.timeout("5 seconds"),
      Effect.flatMap((result) =>
        result._tag === "Some"
          ? Effect.succeed(result.value)
          : Effect.succeed({ data: null, cached: true })  // Fallback
      )
    )
  })

// ============================================
// 5. Timeout with interrupt
// ============================================

const fetchWithInterrupt = (url: string) =>
  Effect.gen(function* () {
    const client = yield* HttpClient.HttpClient

    return yield* client.get(url).pipe(
      Effect.flatMap((r) => HttpClientResponse.json(r)),
      Effect.interruptible,
      Effect.timeout("10 seconds")
    )
    // Fiber is interrupted if timeout, freeing resources
  })

// ============================================
// 6. Configurable timeout wrapper
// ============================================

interface TimeoutConfig {
  readonly connect: Duration.DurationInput
  readonly read: Duration.DurationInput
  readonly total: Duration.DurationInput
}

const defaultTimeouts: TimeoutConfig = {
  connect: "5 seconds",
  read: "30 seconds",
  total: "60 seconds",
}

const createHttpClient = (config: TimeoutConfig = defaultTimeouts) =>
  Effect.gen(function* () {
    const baseClient = yield* HttpClient.HttpClient

    return {
      get: (url: string) =>
        baseClient.get(url).pipe(
          Effect.timeout(config.connect),
          Effect.flatten,
          Effect.flatMap((r) =>
            HttpClientResponse.json(r).pipe(
              Effect.timeout(config.read),
              Effect.flatten
            )
          ),
          Effect.timeout(config.total),
          Effect.flatten
        ),
    }
  })

// ============================================
// 7. Usage
// ============================================

const program = Effect.gen(function* () {
  yield* Effect.log("Fetching with timeout...")

  const result = yield* fetchWithTimeoutError(
    "https://api.example.com/slow",
    "5 seconds"
  ).pipe(
    Effect.catchTag("RequestTimeoutError", (error) =>
      Effect.gen(function* () {
        yield* Effect.log(`Request to ${error.url} timed out`)
        return { error: "timeout" }
      })
    )
  )

  yield* Effect.log(`Result: ${JSON.stringify(result)}`)
})