Cookie setting and acquisition using web.py cookie

The previous article talked about the first page of web.py, hello word. Let’s continue to delve into web.py programming and talk about the cookie settings of web.py.

I believe that people who have learned web programming are familiar with cookies. It plays a very important role in web programming. User login, verification code, session (based on cookies), language selector, identity recognition, etc. all have cookies. So how to set cookies in web.py?

In fact, setting cookies in web.py is very simple. web.py has already thought of this for us and provided a very simple and useful function:

setcookie(name, value, expires="", domain=None, secure=False)

Parameter details:

name (string) - The name of the cookie, saved by the browser and sent to the server.

value (string) -The value of the cookie, corresponding to the name of the cookie.

expires (int) - Cookie expiration time. This is an optional parameter. It determines how long the cookie is valid. In seconds. It must be an integer and never a string. Optional parameter. If this parameter is not written, it will be permanently valid by default.

domain (string) - The valid domain of the cookie - the cookie is valid within this domain. In general, to be available within a certain site, the parameter value should be written as the domain of the site (such as .webpy.org), not the host name of the site owner (such as wiki.webpy.org). The optional parameter

secure (bool) - If True, this cookie is required to be transmitted only over HTTPS. Optional parameters

For example:

#设置website的值为www.pythontab.com，有效期60秒
web.setcookie("website", "www.pythontab.com", 60)

Example

Use web.setcookie() to set cookies, as follows:

class CookieSet:
    def GET(self):
        i = web.input(age='25')
        web.setcookie('age', i.age, 3600)
        return "Age set in your cookie"

Call the above using GET method The class will set a cookie named age with a default value of 25 (actually, the default value 25 is assigned to i.age in web.input, thereby indirectly assigning the cookie, rather than directly assigning it to the cookie in the setcookie function) . This cookie will expire in one hour (i.e. 3600 seconds).

The third parameter of web.setcookie() - "expires" is an optional parameter, which is used to set the cookie expiration time. If it is a negative number, the cookie will expire immediately. If it is a positive number, it indicates how long the cookie is valid, in seconds. If this parameter is empty, the cookie will never expire.

Getting Cookies

Overview

There are many ways to get the value of Cookie. The difference lies in how to deal with it when the cookie cannot be found.

Method 1 (If the cookie is not found, return None):

Get

#通过设置的cookie的名字获取cookie，例如website
#web.cookies().get("website") 
web.cookies().get(cookieName)

through the get method

Method 2 (If the cookie is not found, throw an AttributeError exception ):

#先把cookie对象赋值给一个变量，然后通过cookie的名字获得
#例如：foo.website
foo = web.cookies()
foo.cookieName

Method 3 (if the cookie cannot be found, you can set a default value to avoid throwing an exception):

#该方法最大的特点就是可以设置cookie的默认值
foo = web.cookies(cookieName=defaultValue)
#如果不存在该cookieName，就会返回设置的默认cookie
foo.cookieName

If you want to confirm whether the cookie value exists,

You can do this:

class CookieGet:
    def GET(self):
        try:
             return "Your website name is: " + web.cookies().website
        except:
             #抛出异常处理
             return "Cookie 不存在."

or

class CookieGet:
    def GET(self):
        #先进行赋值
        website = web.cookies().get('website')
        if age:
            return "Your website name is: %s" % website
        else:
            return "Cookie 不存在."