Golang Fasthttp Middleware

#go #middlewarer #fasthttp #http

I am using FastHttp to implemente Http in go. Most people are using Gorilla Mux, but I decided to try a different http implementation.

There are scenarios where a request should chained, I mean, we must execute previous actions before handling the request resolver itself. The most common case is evaluating Authorization before executing the business.

Having said that, lets imagine a scenario where we must have an endpoint that must be protected by an Auth middleware, check for token and if its valid you can execute the business otherwise you get a 401 http status.

First set up the router

router := fasthttprouter.New()
router.GET("/", GetProducts)
fasthttp.ListenAndServe(":5002", router.Handler)

The GetProducts is a function that simply respond with a product object. For example:

func GetProducts(ctx *fasthttp.RequestCtx) {

    product := &productModel.Product{}
    product.Id = "123890"
    product.Name = "Shoes"
    product.Price = 100.30

    json.NewEncoder(ctx).Encode(response)
}

Now we are going to create our Auth Middleware

func Auth(requestHandler fasthttp.RequestHandler) fasthttp.RequestHandler {
    return func(ctx *fasthttp.RequestCtx) {
        token := string(ctx.Request.Header.Peek("Authorization"))

        if token == "" {
            return 
        } else {
               requestHandler(ctx)
                }
    }
}

And now... we are going to wrap the GetProducts on router.Get method wit