acumen/nonce

Nonce fetching for ACME replay protection.

ACME uses nonces to prevent replay attacks. Every request to the ACME server must include a fresh nonce, and every response includes a new nonce for the next request.

Usage

You need to fetch an initial nonce before making your first ACME request:

import acumen
import acumen/nonce
import gleam/httpc

// After fetching the directory...
let assert Ok(nonce_req) = nonce.build(directory)
let assert Ok(resp) = httpc.send(nonce_req)
let assert Ok(initial_nonce) = nonce.response(resp)

let ctx = acumen.Context(directory:, nonce: initial_nonce)

After the initial nonce, subsequent nonces are handled automatically by acumen.execute, which extracts nonces from response headers and updates the context.

Extracting Nonces from Any Response

The response function can extract a nonce from any ACME response, not just dedicated nonce responses. This is useful if you need to manually manage nonces outside of the execute flow.

pub fn build(
  directory: acumen.Directory,
) -> request.Request(String)

pub fn response(
  resp: response.Response(a),
) -> Result(String, acumen.AcmeError)