SagaSaga
Rata
Rata
Guide

Getting started

A how-to for making HTTP requests from Saga code with Rata. The intended consumer is an application or library author who wants a typed HTTP client on the BEAM. Rata handles outbound HTTP transport.

For language syntax see llms-full.txt.

Quick start

module Main

import Rata.Fetch
import Rata.Fetch.Httpc

main () = {
  case Fetch.get "https://example.com" {
    Ok response -> {
      dbg response.status
      dbg (Fetch.body_text response)
    }
    Err error -> dbg error
  }
} with Httpc.httpc

The Httpc.httpc handler satisfies the Fetch effect by calling Erlang/OTP inets:httpc. Code that calls Fetch.get, Fetch.post, or Fetch.send can stay backend-neutral and choose a real or mock handler at the boundary.

Scope

Rata handles:

  • building outbound fetch descriptions,
  • running them through a backend handler,
  • returning response status, headers, and raw body bytes,
  • mapping transport/backend failures into FetchError,
  • testing needs {Fetch} code without network access.

Response bodies are BitString values; pass them to your JSON library or application decoder for structured data.

Install

For local development, use a path dependency:

[deps]
rata = { path = "/home/dylan/projects/rata" }

The public library modules are:

Rata.Fetch
Rata.Fetch.Httpc
Rata.Fetch.Mock
Requests →