IMPLEMENTATION.md

HTTP Server Improvements Checklist

🔴 Critical Issues (Fix Immediately)

Security & Correctness

• Add request size limits to prevent memory exhaustion attacks

  • Set MAX_REQUEST_SIZE constant (e.g., 1MB)
  • Track totalBytes in data handler
  • Respond with 413 Payload Too Large when exceeded
  • Close connection after limit breach

• Fix Content-Length based parsing to prevent request smuggling

  • Parse Content-Length header from request
  • Only consider request complete when: headerEndIndex + 4 + contentLength bytes received
  • Don't rely solely on \r\n\r\n detection
  • Handle missing Content-Length for GET/HEAD requests

• Fix headersSent bug in response.ts

  • Line: this.headersSent = false; should be this.headersSent = true;
  • After sending headers, set flag to true, not false

HTTP Compliance

• Support all HTTP methods in request parsing

  • Change regex from (GET|POST) to ([A-Z]+)
  • Support: PUT, DELETE, PATCH, OPTIONS, HEAD, CONNECT, TRACE

• Validate Host header (required in HTTP/1.1)

  • Check if Host header exists in request
  • Respond with 400 Bad Request if missing
  • Per RFC 7230 section 5.4

🟡 Important Issues (Fix Soon)

Connection Management

• Fix timeout handling in httpServer.ts

  • Clear timeout when request completes successfully
  • Reset timeout for persistent connections between requests
  • Prevent timeout from killing connection prematurely

• Remove redundant connection.end() in close handler

  • Connection is already closed when 'close' event fires
  • This call does nothing and can be removed

Data Handling

• Make query parameter handling consistent

  • parseQuery returns undefined or object
  • Constructor defaults to {}
  • Pick one: always return object or always allow undefined

• Decide on stream vs property for request body

  • Current _read() implementation pushes entire body at once
  • Either: implement proper streaming (chunk by chunk)
  • Or: remove Readable inheritance and use body as plain property

Response Improvements

• Expand status code map in response.ts
  • Add: 100 Continue, 206 Partial Content
  • Add: 307 Temporary Redirect, 308 Permanent Redirect
  • Add: 410 Gone, 429 Too Many Requests
  • Add: 501 Not Implemented, 504 Gateway Timeout

🟢 Feature Additions (Future Enhancements)

Essential HTTP/1.1 Features

• Implement chunked transfer encoding support

  • Parse Transfer-Encoding: chunked header
  • Handle chunk size lines (hex format)
  • Reassemble chunks into complete body
  • Handle trailing headers

• Add Expect: 100-continue support

  • Detect Expect: 100-continue header
  • Send HTTP/1.1 100 Continue before reading body
  • Allow server to reject before client sends large body

• Implement HTTP pipelining

  • Handle multiple requests on single connection
  • Queue responses in correct order
  • Maintain request-response ordering

Content Handling

• Add multipart/form-data parsing

  • Parse boundary from Content-Type header
  • Handle file uploads
  • Parse mixed text and binary data
  • Support multiple files in single request

• Implement compression support

  • Parse Accept-Encoding header
  • Support gzip compression
  • Support deflate compression
  • Add Content-Encoding to response

• Add Range request support (HTTP 206)

  • Parse Range header
  • Support byte ranges (e.g., bytes=0-1023)
  • Respond with 206 Partial Content
  • Send Content-Range header

Developer Experience

• Add request/response logging

  • Log method, path, status code
  • Include timestamp
  • Optional verbose mode for headers/body

• Implement better error handling

  • Catch parsing errors gracefully
  • Send proper 400 Bad Request responses
  • Don't crash server on malformed requests
  • Add error event emitter with context

• Add request timeout configuration

  • Make timeout configurable per-server
  • Add per-request timeout option
  • Emit timeout events

📚 Learning Additions

• Add HTTPS support

  • Use tls.createServer() instead of net.createServer()
  • Handle SSL/TLS certificates
  • Support both HTTP and HTTPS

• Implement HTTP/2 support

  • Use http2 module
  • Handle binary framing
  • Support multiplexing

• Add WebSocket upgrade support

  • Detect Upgrade header
  • Perform WebSocket handshake
  • Switch protocols from HTTP to WebSocket

Testing Checklist

• Test with large request bodies (>1MB)
• Test with malformed HTTP requests
• Test concurrent connections
• Test persistent connections (keep-alive)
• Test connection timeout behavior
• Test with missing required headers
• Test all HTTP methods
• Test query parameter edge cases (arrays, duplicates)
• Test different Content-Types
• Load test with tools like wrk or autocannon

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