reazen / relude-fetch Goto Github PK

I'm struggling to understand the decoding example in the tests

    let decode: Js.Json.t => Belt.Result.t(t, string) =
      json => {
        make
        <$> JD.intFor("userId", json)
        <*> JD.intFor("id", json)
        <*> JD.stringFor("title", json)
        <*> JD.boolFor("completed", json)
        |> Relude.Result.fromValidation
        |> Relude.Result.mapError(_ => "Decode failed");
      };

Would this be equal to the following?

let decode: Js.Json.t => Belt.Result.t(t, string) =
      json => {
        make
        |> map(JD.intFor("userId", json))
        |> ap(JD.intFor("id", json))
        |> ap(JD.stringFor("title", json))
        |> ap(JD.boolFor("completed", json))
        |> Relude.Result.fromValidation
        |> Relude.Result.mapError(_ => "Decode failed");
      };

With some direction, I'd be glad to open a PR adding examples sans infix operators. It would be nice to able to see the two versions side by side for mere mortals like I.

Instead of taking in a string as the url for fetching, should this lib instead take in the url type from https://github.com/reazen/relude-url ?

Currently, we're assuming (really, bs-fetch is assuming) that the fetch global exists. This is true for browsers, but for other environments like Node or React Native, this requires a polyfill like isomorphic-fetch or cross-fetch. Importing one of those libraries purely for the side-effect of attaching junk to the global object is really gross (and worse, it's easy to forget to do, which could cause things to break at runtime).

I'm definitely open to ideas, but it seems like the safest thing to do would be to expect ReludeFetch to be constructed with a Fetch object (module?) that provides the actual fetch implementation. In a more perfect world, maybe we'd have a trifunctor IO like ZIO where the Fetch interface could just be part of the environment.

Hi guys, thanks for the awesome libraries!

I tried to do this using ReludeFetch but the code couldn't comple since the output of ReludeFetch.post is not compatible with the input of ReludeFetch.Response.StatusCode.ensure2xx.

module IO = Relude.IO;
module Error = ReludeFetch.Error;

module IOE = IO.WithError({
  type t = Error.t(Decco.decodeError)
})

[@decco encode]
type request = {
  username: string,
  password: string,
};

[@decco decode]
  type response = {
  token: string,
};

let login = (~username, ~password) => {
    ReludeFetch.post(
      ~headers=Headers.acceptJson,
      ~body=
        ReludeFetch.Body.Content.Json(
          request_encode({
            username,
            password,
          }),
        ),
       "/some/login",
    )
    >>= ReludeFetch.Response.StatusCode.ensure2xx;
  };
};

When I look at the this it has Relude.IO.t(Fetch.response, Error.t('decodeError)) but it should be Fetch.Response.t. Am I compose the wrong function here?

I've been trying to use this library, but hit a wall when trying to work with the response. I'm not sure if this is an error on my side (understanding) or issue with the library as I'm getting the following error with the demo example too:

open Relude;

// Defines our API error type
module Error = {
  type t = ReludeFetch.Error.t(string);
  let show = error => ReludeFetch.Error.show(a => a, error);
  module Type = {
    type nonrec t = t;
  };
};

// Open the IO infix operators
module IOE = IO.WithError(Error.Type);
open IOE.Infix;

let textResponse = ReludeFetch.fetch("some_url") >>= ReludeFetch.Response.text;

Last line errors with:

Error: This expression has type
         Fetch.Response.t => Relude.IO.t(string, ReludeFetch_Error.t('a))
       but an expression was expected of type
         Fetch.response => IOE.Monad.t('b)
       Type Fetch.Response.t is not compatible with type Fetch.response

Link to relude's IO documentation for info on IO.

Provide an example of using the IO-based fetch - e.g. in a ReasonReact app?