Go で Cookie を使用して HTTP POST リクエストを処理する方法

package main

import (
    "fmt"
    "net/http"
    "net/http/cookiejar"
    "net/url"
)

func main() {
    // Create a new cookie jar.
    jar, err := cookiejar.New(nil)
    if err != nil {
        panic(err)
    }

    // Create an HTTP client that uses the cookie jar.
    client := &http.Client{
        Jar: jar,
    }

    // Login to the website.
    loginPostUrl := "http://www.example.com/login"
    values := url.Values{}
    values.Set("username", "my_username")
    values.Set("password", "my_password")
    resp, err := client.PostForm(loginPostUrl, values)
    if err != nil {
        panic(err)
    }
    defer resp.Body.Close()

    // View the user's bill.
    viewBillUrl := "http://www.example.com/my/bill"
    resp, err = client.Get(viewBillUrl)
    if err != nil {
        panic(err)
    }
    defer resp.Body.Close()

    // Read the bill's contents.
    billContents, err := resp.Body.ReadString('\n')
    if err != nil {
        panic(err)
    }

    fmt.Println(billContents)
}