ReScript AWS SDK v3 bindings

A set of bindings for the AWS JavaScript SDK v3 for use with ReScript.

These are an unofficial set of ReScript bindings - they are not officially provided by or endorsed by AWS.

The bindings are still a bit experimental as they haven't been validated extensively and some SDKs are missing due to generation issues that need to be resolved (see the TODO for more details).

Installation

npm i rescript-aws-sdk-v3

and add to your bsconfig.json dependencies list:

  ...
  "bs-dependencies": ["rescript-aws-sdk-v3"]

Usage

1. For each AWS SDK you wish to use, install the corresponding client packages e.g. for S3:

npm i @aws-sdk/client-s3

2. Create a client for the corresponding API:

open AwsSdkV3;
let client = S3.createClient();

3. Identify the API you wish to call (e.g. GetObject). You can then construct the command by passing the request type to make() (in some instances make() won't be present - use new() instead)

// make() is used to construct the equivalent of GetObjectCommand - note that () is always needed to indicate the end of parameters
let command = S3.GetObject.make(~bucket="my-bucket", ~key="path/to/key.json", ());

(in the cases that make() has no arguments, e.g. S3.ListBuckets, use let command = S3.ListBuckets.make();)

4. Dispatch the command with send():

S3.GetObject.send(client, command)
  ->Promise.then(result => {
      Js.log2("Object body: ", )
      Promise.resolve()
  })

Error Handling

The AWS SDK throws ordinary JavaScript exceptions. The rescript-promise library wraps these as ReScript errors, so to filter them in your catch handler, you will need code like the following:

  ->
  ->catch(error => {
    switch error {
    | JsError(error) =>
      switch AwsSdkV3.Exn.asAwsError(error) {
      | Some(awsError) =>
        // The `name` property is set to the AWS API error code (e.g. AccessDenied, NoSuchKey, etc.)
        switch awsError.name {
        | "NoSuchBucket" => Js.log("The specified bucket does not exist")
        | _ => Js.log2("An AWS Error occurred", awsError.name)
        }
      | None => Js.log2("An unknown JS error occurred", error)
      }
      | _ => Js.log2("An unknown ReScript error occurred", error)
    }
    Promise.resolve()
  })

Copyright (C) 2021 Chris Armstrong - see LICENSE for more details on licensing