I'm trying to use Go to log into a website and store the cookies for later use.
Could you give example code for posting a form, storing the cookies, and accessing another page using the cookies?
I think I might need to make a Client to store the cookies, by studying http://gotour.golang.org/src/pkg/net/http/client.go
package main
import ("net/http"
"log"
"net/url"
)
func Login(user, password string) string {
postUrl := "http://www.pge.com/eum/login"
// Set up Login
values := make(url.Values)
values.Set("user", user)
values.Set("password", password)
// Submit form
resp, err := http.PostForm(postUrl, values)
if err != nil {
log.Fatal(err)
}
defer resp.Body.Close()
// How do I store cookies?
return "Hello"
}
func ViewBill(url string, cookies) string {
//What do I put here?
}
Go 1.1 introduced a cookie jar implementation net/http/cookiejar
.
import (
"net/http"
"net/http/cookiejar"
)
cookieJar, _ := cookiejar.New(nil)
client := &http.Client{
Jar: cookieJar,
}
First you'll need to implement the http.CookieJar
interface. You can then pass this into the client you create and it will be used for requests made with the client. As a basic example:
package main
import (
"fmt"
"net/http"
"net/url"
"io/ioutil"
"sync"
)
type Jar struct {
lk sync.Mutex
cookies map[string][]*http.Cookie
}
func NewJar() *Jar {
jar := new(Jar)
jar.cookies = make(map[string][]*http.Cookie)
return jar
}
// SetCookies handles the receipt of the cookies in a reply for the
// given URL. It may or may not choose to save the cookies, depending
// on the jar's policy and implementation.
func (jar *Jar) SetCookies(u *url.URL, cookies []*http.Cookie) {
jar.lk.Lock()
jar.cookies[u.Host] = cookies
jar.lk.Unlock()
}
// Cookies returns the cookies to send in a request for the given URL.
// It is up to the implementation to honor the standard cookie use
// restrictions such as in RFC 6265.
func (jar *Jar) Cookies(u *url.URL) []*http.Cookie {
return jar.cookies[u.Host]
}
func main() {
jar := NewJar()
client := http.Client{nil, nil, jar}
resp, _ := client.PostForm("http://www.somesite.com/login", url.Values{
"email": {"myemail"},
"password": {"mypass"},
})
resp.Body.Close()
resp, _ = client.Get("http://www.somesite.com/protected")
b, _ := ioutil.ReadAll(resp.Body)
resp.Body.Close()
fmt.Println(string(b))
}
At the version 1.5 of Go, we can use http.NewRequest to make a post request with cookie.
package main
import "fmt"
import "net/http"
import "io/ioutil"
import "strings"
func main() {
// Declare http client
client := &http.Client{}
// Declare post data
PostData := strings.NewReader("useId=5&age=12")
// Declare HTTP Method and Url
req, err := http.NewRequest("POST", "http://localhost/", PostData)
// Set cookie
req.Header.Set("Cookie", "name=xxxx; count=x")
resp, err := client.Do(req)
// Read response
data, err := ioutil.ReadAll(resp.Body)
// error handle
if err != nil {
fmt.Printf("error = %s \n", err);
}
// Print response
fmt.Printf("Response = %s", string(data));
}
Another way of doing it. Works in Go 1.8.
expiration := time.Now().Add(5 * time.Minute)
cookie := http.Cookie{Name: "myCookie", Value: "Hello World", Expires: expiration}
http.SetCookie(w, &cookie)