RLHTTPClient.go

package main

import (
	"context"
	"net/http"

	"golang.org/x/time/rate"
)

// Credit to Melchi Salins for the original code
//https://medium.com/mflow/rate-limiting-in-golang-http-client-a22fba15861a

// RLHTTPClient Rate Limited HTTP Client
type RLHTTPClient struct {
	client      *http.Client
	Ratelimiter *rate.Limiter
}

// Do dispatches the HTTP request to the network
func (c *RLHTTPClient) Do(req *http.Request) (*http.Response, error) {
	// Comment out the below 5 lines to turn off ratelimiting
	ctx := context.Background()
	err := c.Ratelimiter.Wait(ctx) // This is a blocking call. Honors the rate limit
	if err != nil {
		return nil, err
	}
	resp, err := c.client.Do(req)
	if err != nil {
		return nil, err
	}
	return resp, nil
}