em-http-requestvsmechanize
em-http-request is a Ruby gem for making asynchronous HTTP requests using EventMachine. It allows you to perform multiple requests simultaneously and handle the responses as they come in, rather than waiting for each request to complete before making the next one.
In short it supports: - Asynchronous HTTP API for single & parallel request execution - Keep-Alive and HTTP pipelining support - Auto-follow 3xx redirects with max depth - Automatic gzip & deflate decoding - Streaming response processing - Streaming file uploads - HTTP proxy and SOCKS5 support - Basic Auth & OAuth - Connection-level & global middleware support - HTTP parser via http_parser.rb - Works wherever EventMachine runs: Rubinius, JRuby, MRI
Mechanize is a Ruby library for automating interaction with websites. It automatically stores and sends cookies, follows redirects, and can submit forms — making it behave like a web browser without needing an actual browser engine.
Key features include:
- Automatic cookie management Stores cookies received from servers and sends them back on subsequent requests, maintaining session state across multiple pages.
- Form handling Can find, fill in, and submit HTML forms programmatically. Supports text inputs, selects, checkboxes, radio buttons, and file uploads.
- Link following Navigate through pages by clicking links using their text content, CSS selectors, or href patterns.
- History and back/forward Maintains a browsing history, allowing you to go back and forward through visited pages.
- HTTP authentication Supports basic and digest HTTP authentication.
- Proxy support Can route requests through HTTP proxies.
- Redirect handling Automatically follows HTTP redirects (configurable).
Mechanize is one of the oldest and most established web interaction libraries in Ruby. It is best suited for scraping traditional server-rendered websites with forms and multi-page workflows. For JavaScript-heavy sites, a browser automation tool like Selenium or Playwright is recommended instead.