Cookies

Cookie is a small piece of data sent from a website server and stored in the user's web browser while browsing. Every time the user loads the website, the browser sends the cookies back to the server to notify the server of user's latest activity. Cookies were designed to be a reliable mechanism for websites to remember stateful information (e.g. items added to the shopping cart in an online store) or to record the user's browsing activity (such as clicking particular buttons, logging in, or user previously visited pages of the website). Cookies can also store form content a user has previously entered, such as username, gender, age, address, etc.

Cookie Attributes

Attribute	Optional
Name	No
Value	No
Path	Yes
Domain	Yes
Expires	Yes
Secure	Yes
HttpOnly	Yes

Echo uses go standard http.Cookie object to add/retrieve cookies from the context received in the handler function.

Create a Cookie

func writeCookie(c echo.Context) error {
	cookie := new(http.Cookie)
	cookie.Name = "username"
	cookie.Value = "jon"
	cookie.Expires = time.Now().Add(24 * time.Hour)
	c.SetCookie(cookie)
	return c.String(http.StatusOK, "write a cookie")
}

• Cookie is created using new(http.Cookie).
• Attributes for the cookie are set assigning to the http.Cookie instance public attributes.
• Finally c.SetCookie(cookie) adds a Set-Cookie header in HTTP response.

Read a Cookie

func readCookie(c echo.Context) error {
	cookie, err := c.Cookie("username")
	if err != nil {
		return err
	}
	fmt.Println(cookie.Name)
	fmt.Println(cookie.Value)
	return c.String(http.StatusOK, "read a cookie")
}

• Cookie is read by name using c.Cookie("username") from the HTTP request.
• Cookie attributes are accessed using Getter function.

Read all the Cookies

func readAllCookies(c echo.Context) error {
	for _, cookie := range c.Cookies() {
		fmt.Println(cookie.Name)
		fmt.Println(cookie.Value)
	}
	return c.String(http.StatusOK, "read all the cookies")
}