https://github.com/anuragsoni/postgres-protocol

IO independent postgres protocol implementation
https://github.com/anuragsoni/postgres-protocol

ocaml postgres postgresql

Last synced: 9 days ago
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IO independent postgres protocol implementation

• Host: GitHub
• URL: https://github.com/anuragsoni/postgres-protocol
• Owner: anuragsoni
• License: mpl-2.0
• Created: 2020-09-21T03:47:25.000Z (about 4 years ago)
• Default Branch: main
• Last Pushed: 2023-05-29T02:22:46.000Z (over 1 year ago)
• Last Synced: 2024-08-04T01:28:39.848Z (3 months ago)
• Topics: ocaml, postgres, postgresql
• Language: OCaml
• Homepage:
• Size: 156 KB
• Stars: 19
• Watchers: 7
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Postgres-ocaml

Work-in-progress OCaml implementation of the Postgres frontend/backend protocol. This library implements the wire protocol in OCaml, instead of using C ffi with `libpq`.

Only postgresql [extended query](https://www.postgresql.org/docs/15/protocol-flow.html) workflow is supported. The library contains the following components:

## [postgres](./postgres/)

This is the core library that defines all backend/frontend types. This library performs no I/O and is intended as a building block for I/O wrappers using lwt, async, etc. The library also includes a bare bones implementation of [RFC 5802](https://datatracker.ietf.org/doc/html/rfc5802) that covers just enough of the spec to address the needs for using `scram-sha-256` auth mechanism with postgresql.

## [postgres_eio](./postgres_eio/)

[Eio](https://github.com/ocaml-multicore/eio) driver for postgresql.

### Example

```ocaml

open Core

open Eio.Std

open Or_error.Let_syntax

let make_parameters ids =

  Sequence.of_list ids

  |> Sequence.map ~f:(fun id ->

       let b = Bytes.create 4 in

       Caml.Bytes.set_int32_be b 0 id;

       Postgres.Param.create

         ~parameter:(Bytes.to_string b)

         Postgres.Format_code.binary)

  |> Sequence.to_array

;;

let run ~sw ~net ~addr ~user ~password ~database =

  let%bind conn = Postgres_eio.connect ~sw ~net ~user ~password ~database addr in

  traceln "Logged in to postgres";

  let%bind () =

    Postgres_eio.prepare conn "SELECT id, email from users where id IN ($1, $2, $3)"

  in

  let%bind () = Postgres_eio.execute ~on_data_row:ignore conn in

  let parameters = make_parameters [ 1l; 2l; 3l ] in

  Postgres_eio.execute conn ~parameters ~on_data_row:(fun data_row ->

    match data_row with

    | [| Some id; Some name |] -> traceln "Id: %s and email: %s" id name

    | _ -> assert false)

;;

let main ~env ~user ~password ~database =

  let addr = `Tcp (Eio.Net.Ipaddr.V4.loopback, 5432) in

  Mirage_crypto_rng_eio.run

    (module Mirage_crypto_rng.Fortuna)

    env

    (fun () ->

      Switch.run (fun sw ->

        Or_error.ok_exn

          (run ~user ~password ~addr ~database ~sw ~net:(Eio.Stdenv.net env))))

;;

```

## TODO

* add wrapper to handle parameters in an easier manner

* Support transactions

* Support postgres notify/listen channels

* documentation

* support TLS encrypted connections

* TEST!!