gistfile1.go

package main

import (
	"fmt"
	"net/http"
	"time"
)

func main() {
	t0 := time.Now()
	url := "http://www.npr.org/robots.txt"
	asyncHttpGets(url)
	t1 := time.Now()
	fmt.Printf("Total call took %v to run.\n", t1.Sub(t0))
}

type HttpResponse struct {
	url      string
	response *http.Response
	err      error
}

func send(url string, ch chan *HttpResponse) {
	t0 := time.Now()
	resp, err := http.Get(url)
	t1 := time.Now()
	fmt.Printf("single request took %v to run.\n", t1.Sub(t0))
	ch <- &HttpResponse{url, resp, err}
}


func asyncHttpGets(url string) []*HttpResponse {
	total := 100
	ch := make(chan *HttpResponse)
	responses := []*HttpResponse{}


	for i := 0; i< total; i++ {
		go send(url, ch)
	}

	for {
		select {
		case r := <-ch:
			responses = append(responses, r)
			if len(responses) == total {
				return responses
			}
		}
	}
	return responses
}