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This question is commonly asked for Software Engineer candidates at Rippling during technical interviews.

Implement a minimal local HTTP server | Rippling Interview Question

Quick Overview

This question evaluates proficiency in network programming, HTTP/1.1 protocol parsing, concurrent server design, request routing and security (including path traversal protection), observability, testing, and graceful shutdown using only the language standard library.

Build a Minimal Local HTTP/1.1 Server (No Frameworks)

Context

You are asked to implement a minimal HTTP/1.1 server from scratch using only the standard library (no web frameworks). The server should run locally, be configurable, and handle concurrency and shutdown cleanly. Include unit tests and clear run instructions.

Requirements

Configuration
- Listen on a configurable host and port.
- Serve static files from a configurable root directory.
Protocol and Methods
- Parse HTTP/1.1 requests: request line, headers, and optional body.
- Support methods: GET and POST.
- Return appropriate errors: 400 (Bad Request), 404 (Not Found), 405 (Method Not Allowed).
Routing
- GET /health → returns 200 OK with body "OK".
- POST /echo → returns the request body verbatim, with Content-Type preserved if present.
- Static files: for any other GET path, serve files from the configured root directory.
  - Use correct Content-Type for common file extensions.
  - Protect against path traversal attacks (e.g., ".." segments).
Concurrency and Reliability
- Handle multiple concurrent connections.
- Per-connection request timeout.
- Graceful shutdown (e.g., on SIGINT/SIGTERM): stop accepting new connections and allow in-flight requests to finish.
Observability
- Structured per-request logging (e.g., JSON lines) including: timestamp, remote address, method, path, status, duration, bytes in/out, and user agent.
Testing and Docs
- Include unit tests that verify the core behaviors.
- Provide clear run instructions for local development.

Constraints

Use only the language standard library. No web frameworks (e.g., Flask, Express, Spring), no third-party libraries.
Keep the implementation minimal but robust enough for the above requirements.

Quick Overview

Requirements

Configuration

Listen on a configurable host and port.
Serve static files from a configurable root directory.

Protocol and Methods

Parse HTTP/1.1 requests: request line, headers, and optional body.
Support methods: GET and POST.
Return appropriate errors: 400 (Bad Request), 404 (Not Found), 405 (Method Not Allowed).

Routing

GET /health → returns 200 OK with body "OK".
POST /echo → returns the request body verbatim, with Content-Type preserved if present.
Static files: for any other GET path, serve files from the configured root directory.
- Use correct Content-Type for common file extensions.
- Protect against path traversal attacks (e.g., ".." segments).

Concurrency and Reliability

Handle multiple concurrent connections.
Per-connection request timeout.
Graceful shutdown (e.g., on SIGINT/SIGTERM): stop accepting new connections and allow in-flight requests to finish.

Observability

Structured per-request logging (e.g., JSON lines) including: timestamp, remote address, method, path, status, duration, bytes in/out, and user agent.

Testing and Docs

Include unit tests that verify the core behaviors.
Provide clear run instructions for local development.

Implement a minimal local HTTP server

Quick Overview

Build a Minimal Local HTTP/1.1 Server (No Frameworks)

Context

Requirements

Constraints

Solution

Submit Your Answer to Earn 20XP

Implement a minimal local HTTP server

Quick Overview

Build a Minimal Local HTTP/1.1 Server (No Frameworks)

Context

Requirements

Constraints

Solution

Submit Your Answer to Earn 20XP