Upfront

Upfront is a very small library for adding type signatures to your HTTP handlers using generics.

Useage

For requests where you don't care about the request body:

func handleGet() upfront.Handler[ResponseType, ErrorType] {
	return func(in upfront.Request) upfront.Result[ResponseType, ErrorType] {
		// `in` will contain your normall *http.Request

		// Use `upfront.OKResult` or `upfront.ErrResult` to return a status code
		// along with either the left or right type paramters
		return upfront.OKResult[ResponseType, ErrorType](
			val,
			http.StatusOK,
		)
	}
}

For requests where you want the request body, upfront will try to decode it for you and pass it along:

func handlePost() upfront.BodyHandler[Body, ResponseType, ErrorType] {
	return func(in upfront.BodyRequest[Record]) upfront.Result[Record, APIError] {
		// `in` not only has your `*http.Request`, but also has your `Body` type
		// in there as well

		// Do something with `in.Body`...

		// Maybe something has gone wrong
		return upfront.Err[Body, ResponseType, ErrorType](
			ErrorType{
				Err: err,
			},
			http.StatusInternalServerError,
		)
	}
}

Example server

There's an example server and in-memory database to see how someone might use the package. Run make example to start the server at :4444.

Contributing

This is a small library, so I don't imagine there will be too much to add to it, but you're more than welcome to open a PR or open an issue! If you're looking to get into the source code, you'll just need Go, and make sure it's at least version 1.18 to use generics. You can run make test at the root of the repo to easily run tests.