Helping kevinburke

concurrency.go

package main

import (
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"net"
	"net/http"
)

func getjson(loc string, dst interface{}) error {
	req, err := http.NewRequest("GET", loc, nil)
	req.Header.Set("Accept", "application/json")
	if err != nil {
		return err
	}

	resp, err := http.Get(loc)
	if err != nil {
		return err
	}
	defer func() {
		if _, ce := io.Copy(ioutil.Discard, resp.Body); ce != nil {
			log.Print("Error discarding response body for ", loc, ": ", ce)
		}
		if ce := resp.Body.Close(); ce != nil {
			log.Print("Unable to close response for ", loc, ": ", ce)
		}
	}()

	return json.NewDecoder(resp.Body).Decode(dst)
}

type jsonIP struct {
	IP  net.IP
	loc string
	err error
}

func main() {
	ipch := make(chan jsonIP, 1)
	getip := func(loc string) {
		ip := jsonIP{loc: loc}
		ip.err = getjson(loc, &ip)
		ipch <- ip
	}

	go getip("http://ipinfo.io/json")
	go getip("http://jsonip.com")

	lhs := <-ipch
	if lhs.err != nil {
		log.Print("Error requesting IP from ", lhs.loc, ":", lhs.err)
	}

	rhs := <-ipch
	if rhs.err != nil {
		log.Print("Error requesting IP from ", rhs.loc, ":", rhs.err)
	}

	fmt.Print(rhs.loc, " IP result: ", rhs.IP, "\n")
	fmt.Print(lhs.loc, " IP result: ", lhs.IP, "\n")
}