A portable pure OCaml CA Store, with no dependencies, inspired by Elixir's :castore.

First, install castore in your switch:

# latest published version
opam install castore

# latest development version
opam pin castore git+https://github.com/leostera/castore

Now we can add it to your dune project dependencies:

(package
 ;...
 (depends
   (castore (>= "0.0.0"))
   ;...)
 ;...)

And to your dune stanzas:

(executable
  (name my_app)
  (libraries castore))

And finally we can use it by decoding the certificates, and building a chain of trust we can build our Tls config with.

Here's an example of how to do it:

let decode_pem ca =
  let ca = Cstruct.of_string ca in
  let cert = X509.Certificate.decode_pem ca in
  Result.get_ok cert
in
let cas = List.map decode_pem Ca_store.certificates in
let authenticator = X509.Authenticator.chain_of_trust ~time cas in
(* ... *)

This project would not be possible without ocaml-tls and ca-certs, in fact, we use ca-certs to generate the Ca_store.cas with code taken from the implementation of ca-certs.