How to set cookies in golang

Golang is a popular programming language that has become the language of choice for many web developers. An important concept involved is cookies, which can help us track user information. In this article, we will detail how to set cookies in Go.

What are cookies?

A cookie is a simple text file that is stored on a user's computer when they visit a website. When the user visits the same website again, the cookie will be sent to the server so that the server can recognize the user and provide personalized services.

Generally speaking, a cookie consists of a name, a value and a set of optional attributes. Attributes may include information such as expiration time, domain name, and path.

How to set cookies in Go?

The following are the general steps for setting cookies in Go:

1. Import the "net/http" package.

import (
    "net/http"
)

2. Create a variable named "cookie".

cookie := &http.Cookie{
    Name:  "my_cookie",
    Value: "my_value",
}

3. Add cookies to response headers.

http.SetCookie(w, cookie)

Full code example:

package main

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

func main() {
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        cookie := &http.Cookie{
            Name:  "my_cookie",
            Value: "my_value",
        }

        http.SetCookie(w, cookie)

        fmt.Fprintln(w, "Cookie set!")
    })

    log.Fatal(http.ListenAndServe(":8080", nil))
}

In the above example, we created a cookie named "my_cookie" and added it to the response header. When a user visits this page, a cookie will be set and sent to the user's computer. You can view the cookie value in your browser's developer tools.

How to set the properties of Cookie?

As mentioned earlier, cookies have a set of optional attributes. Setting properties such as cookie expiration time, domain name and path is very simple in Go.

1. Set expiration time

You can set the expiration time by setting the "Expires" field of the cookie. This field should contain a timestamp or a value of type time.Time. Here is an example:

expiration := time.Now().Add(24 * time.Hour)

cookie := &http.Cookie{
    Name:    "my_cookie",
    Value:   "my_value",
    Expires: expiration,
}

http.SetCookie(w, cookie)

The above code sets the cookie expiration time to 24 hours later.

2. Set the domain name and path

You can set the domain name and path of the cookie by setting the "Domain" and "Path" fields of the cookie. Here is an example:

cookie := &http.Cookie{
    Name:   "my_cookie",
    Value:  "my_value",
    Domain: "example.com",
    Path:   "/",
}

http.SetCookie(w, cookie)

The above code sets the cookie's domain name to "example.com" and the path to "/".

Summary

Setting cookies in Go is very simple, just create a Cookie object and add it to the response header. You can set a cookie with your own name and value, and set optional attributes (such as expiration time, domain name, path, etc.). By understanding how to set cookies with Go, you can better track users and provide personalized services.

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