ratalada

A DSL for running Rack servers as easily as you can in JavaScript.

require "ratalada/puma"

Server.run do |request|
  case request
  in ["GET", "/"] then "hello\n"
  end
end

That's a whole app. Run the file, and it's listening on http://127.0.0.1:9292.

Installation

gem install ratalada

Ratalada has no runtime dependencies of its own — install whichever server you want to run on (puma, falcon, or sinatra for that flavour of DSL).

Usage

Requiring a backend picks the server and defines the top-level Server constant:

require "ratalada/puma"    # or
require "ratalada/falcon"

The Server.run block is a router: it receives each request and returns a handler for it. A request pattern-matches as [verb, path] (or by keys: in {verb:, path:, query:}), and a handler can be:

• a String — sent as a 200 text/plain response
• a callable — called with the request, its result handled the same way
• a [status, headers, body] triplet — used as-is
• nothing (nil or a fall-through case ... in) — a 404

require "ratalada/falcon"

Server.run do |request|
  case request
  in ["GET", "/"]      then "hello\n"
  in ["GET", "/up"]    then "ok\n"
  in ["POST", "/echo"] then ->(req) { [200, { "content-type" => "text/plain" }, req.body] }
  end
end

Prefer Sinatra's routing? Swap the frontend and keep whichever backend you required:

require "ratalada/falcon"
require "ratalada/sinatra"

Server.run do
  get "/" do
    "hello\n"
  end
end

The host and port default to 127.0.0.1:9292, configurable via the HOST and PORT environment variables or explicitly:

Server.run(host: "0.0.0.0", port: 3000) do |request|
  # ...
end

Like node, one process is one event loop: plenty for IO-bound work, but only one core of Ruby. To use more cores, count: (or the COUNT environment variable) runs that many forked workers accepting from a shared socket — the equivalent of node's cluster module, and with the same contract: each worker has its own state, so anything shared between requests (sessions, caches) needs an external store or count: 1 (the default).

Server.run(count: 4) do |request|
  # ...
end

Currently only the falcon backend forks workers; the puma backend warns and ignores count:.

See examples/ for complete runnable servers.

Development

bin/setup     # install dependencies
bin/test      # run the tests
bin/console   # interactive prompt

License

MIT