user-agent-parser

A lightweight HTTP server that parses User-Agent strings and returns structured JSON responses.

Installation

Install dependencies and start the server:

npm install
npm start

By default, the server listens on port 3000. You can set PORT to change it.

Usage

Health-check endpoint:

curl http://localhost:3000/
# → {"status":"ok"}

Parse User-Agent strings:

curl http://localhost:3000/parse \
  -H "User-Agent: YourUserAgentString"

Note: If no CACHE_CONTROL environment variable is provided, the server responds with a default Cache-Control: public, max-age=0 header.

You’ll receive a JSON payload with ua, browser, engine, os, device, cpu, plus Cache-Control and ETag headers for client caching.

Custom Cache-Control

Start the server with a custom header:

CACHE_CONTROL="private, max-age=3600" npm start

Then request the parse endpoint:

curl -I http://localhost:3000/parse \
  -H "User-Agent: TestAgent/1.0"
# → Cache-Control: private, max-age=3600

Changelog

See the full release notes in CHANGELOG.md.

Testing

Run the full test suite:

npm test

Generate a coverage report:

npm run coverage

Conditional-GET example

curl -i \
  -H "If-None-Match: <etag>" \
  http://localhost:3000/your-endpoint

If the resource has not changed, the server responds with:

HTTP/1.1 304 Not Modified
Cache-Control: public, max-age=0
ETag: