Golang : Storing cookies in http.CookieJar example

Cookie can be useful for storing data and to be retrieved later on to fill in form values such as username, address or other hidden parameters that a server might need. For this tutorial, we will explore how to store values into a cookies jar and when the client(usually a browser) encounter the URL the cookies are associated with, the values will be utilized back.

The code below simulate an event where the user visited back youtube.com and the cookies values are reused back.

 package main

 import (
 "fmt"
 "io/ioutil"
 "net/http"
 "net/http/cookiejar"
 "net/url"
 "strings"
 )

 func main() {
 jar, _ := cookiejar.New(nil)

 var cookies []*http.Cookie

 firstCookie := &http.Cookie{
 Name: "PREF",
 Value:  "f1=50000000&f5=30",
 Path: "/",
 Domain: ".youtube.com",
 }

 cookies = append(cookies, firstCookie)

 secondCookie := &http.Cookie{
 Name: "VISITOR_INFO1_LIVE",
 Value:  "Luy_gz784rQ",
 Path: "/",
 Domain: ".youtube.com",
 }

 cookies = append(cookies, secondCookie)

 thirdCookie := &http.Cookie{
 Name: "YSC",
 Value:  "9jGyTn_JiBk",
 Path: "/",
 Domain: ".youtube.com",
 }

 cookies = append(cookies, thirdCookie)

 fourthCookie := &http.Cookie{
 Name: "dkv",
 Value:  "19a17a80fd703efd450d5ef9dadc32cee3QEAAAAdGxpcGn9mTBVMA==",
 Path: "/",
 Domain: ".youtube.com",
 }

 cookies = append(cookies, fourthCookie)

 // URL for cookies to remember. i.e reply when encounter this URL
 cookieURL, _ := url.Parse("https://www.youtube.com/results?search_query=")

 jar.SetCookies(cookieURL, cookies)

 // sanity check
 fmt.Println(jar.Cookies(cookieURL))

 //setup our client based on the cookies data
 client := &http.Client{
 Jar: jar,
 }

 urlData := url.Values{}
 urlData.Set("search_query", "macross")

 req, _ := http.NewRequest("POST", "https://www.youtube.com/results?search_query=", strings.NewReader(urlData.Encode()))

 req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
 resp, err := client.Do(req)
 if err != nil {
 panic(nil)
 }

 body, _ := ioutil.ReadAll(resp.Body)
 resp.Body.Close()

 // display content to screen ... save this to a HTML file and view the file with browser ;-)
 fmt.Println(string(body))
 }

NOTE : If you are using Google Chrome browser, go to Views->Developer->Developer Tools and under the Resources tab, you should see Cookies->www.youtube.com. The cookies values use in the example above are taken from there.

Reference :

http://golang.org/pkg/net/http/#CookieJar