Detailed explanation of cookies in php-PHP Tutorial-php.cn

Detailed explanation of cookies in php

怪我咯

Release： 2023-03-13 10:38:02

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To establish a commercial website or a personal website with relatively complete functions, it is often necessary to record visitor information. PHP provides two convenient means: session and cookie function. In order to permanently maintain user information , then cookies are the most convenient way. Here I will explain the functions and usage of cookies in detail.

1: Setting cookies
You must set cookies before using cookies .
FunctionPrototype: int setcookie(string name,string value,int expire,string path,string domain,int secure)
Among them, except name, all parameters are optional Yes, you can use an empty string to indicate that it is not set.
Attributevalue: used to specify the value.
Attribute path: used to specify the cookie to be sent to the server Which directory path.
Attribute domain: can limit the sending of cookies on the browser side.
expire parameter: used to specify the validity time of the cookie, which is a standard Unix time mark.
It can be obtained using the time() or mktime() function, in seconds.
secure parameter: Indicates whether this cookie is transmitted over the network through the encrypted HTTPS protocol.

2: Set cookie Notes
Setting cookies on the same page is actually done in order from back to front. If you want to delete a cookie first and then write a cookie, You must first write the write statement, and then write the delete statement. Otherwise, an error will occur.

三: setcookie example
Simple: setcookie("mycookie","value_of_mycookie") ;
With expiration time: setcookie("withExpire","Expire_in_1_hour",time()+3600);
Everything: setcookie("FullCookie","Full_cookie_value",time+3600,"/ forum","www.123.com",1);

Four: Some characteristics of cookies
Cookies are path-oriented. When the default path attribute is used, the WEB server page The current path will be automatically passed to the browser. Specifying the path will force the server to use the set path.
Cookies set in one directory page cannot be seen in another directory page.

五: Receiving and processing cookies
PHP's processing of cookies is fully automatic, and the principle of processing FORM variables is the same. Of course, you can also use PHP global variables, $HTTP_COOKIE_VARSarray.
Example: echo $mycookie;
echo $cookie Array[0];
echo count($cookie Array);
echo $HTTP_COOKIE_VARS["mycookie"];

6: Delete cookie
(1) Call setcookie() with only name parameter;
(2) Make the expiration time be time() or time-1;

Seven: Restrictions on the use of cookies
(1) Must be set before the content of the HTML file is output;
(2) Different browsers handle cookies inconsistently, so you must consider it when using it;
(3) Client restrictions, such as user settings prohibiting cookies, the cookie cannot be created;

8: A specific example, I hope everyone has a deeper understanding of cookies

The code is as follows:

<? 
//cookie.php 
if(!isset($flag)) 
{ 
setcookie("mycookie","this my cookie!"); 
header("location:cookie.php?flag=1"); 
exit; 
} 
?> 
<html> 
<body> 
<? 
echo "cookie中有:".$mycookie; 
?> 
</body> 
</html>

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