Usage of cookies in PHP

What is the usage of cookies in PHP? What do I need to note about using cookies in PHP? A cookie is a mechanism for storing data on a remote browser to track and identify users.
PHP sends a cookie in the header of the HTTP protocol, so the Setcookie () function must be called before other information is exported to the browser, similar to the limit on the header () function.

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Http://blog.chinaunix.net/u/27731/showart_259031.html

1.1 Setting Cookies:
You can use the Setcookie () or Setrawcookie () function to set the cookie. It can also be set by sending HTTP headers directly to the client.
1.1.1 Use the Setcookie () function to set the cookie:
BOOL Setcookie (string name [, string value [, int expire [, String path [, string domain [, bool secure [, BOOL HttpOnly ]]]]]] )
Name:cookie variable Name
The value of the Value:cookie variable
Expire: The time at which the validity period ends,
Path: Valid directory,
Domain: Valid domain name, top-level domain unique
Secure: If the value is 1, the cookie is valid only on HTTPS connections, and HTTP and HTTPS are available if the default value is 0.
Example:
<?php
$value = ' something from somewhere ';

Setcookie ("TestCookie", $value); /* Simple cookie settings */
Setcookie ("TestCookie", $value, Time () +3600); /* Valid for 1 hours * *
Setcookie ("TestCookie", $value, Time () +3600, "/~rasmus/", ". example.com", 1); /* Valid directory/~rasmus, valid domain name example.com and all sub-domains */
?>

Set multiple cookie variables: Setcookie (' var[a] ', ' value '), use an array to represent the variable, but his subscript is not quoted. This allows you to read the cookie variable with $_cookie[' var ' [' a '].

1.1.2. Setting a cookie using the header ();
Header ("Set-cookie:name= $value [;p ath= $path [;d omain=xxx.com[; ...]];
The following parameters are the same as those listed above for the Setcookie function.
Like what:

$value = ' something from somewhere ';
Header ("Set-cookie:name= $value");

1.2 Cookie read:

The browser-side cookie can be read directly with PHP's built-in Super global variable $_cookie.
The above example sets the cookie "TestCookie" and now we are reading:

Print $_cookie[' TestCookie '];

Is the cookie being exported?!

1.3 Deleting cookies
Just set the valid time to less than the current time, and leave the value blank. For example:
Setcookie ("name", "", Time ()-1);
Similar to the header ().

1.4 Frequently Asked questions resolved:

1) There is an error when using Setcookie (), possibly because there is an output or a space in front of the call to Setcookie (). It is also possible that your document will be converted from another character set, with a BOM signature behind the document (that is, adding some hidden BOM characters to the file contents). The solution is to keep your documents from happening. There is also a point that can be handled by using the Ob_start () function.
2) $_cookie affected by MAGIC_QUOTES_GPC, may be automatically escaped
3) When using, it is necessary to test whether the user supports cookies


1.5 Cookie working mechanism:

Some learners are more impulsive and have no mind to study the principle, so I put it back.
A) The server sets a cookie (more than one cookie) in the client computer by sending an HTTP Set-cookie header in response.
b) The client automatically sends an HTTP cookie header to the server and the server receives the read.

http/1.x OK
x-powered-by:php/5.2.1
Set-cookie:testcookie=something from somewhere; path=/
Expires:thu, 18:52:00 GMT
Cache-control:no-store, No-cache, Must-revalidate, post-check=0, pre-check=0
Pragma:no-cache
Content-type:text/html

This line implements the cookie function, after receiving this row
Set-cookie:testcookie=something from somewhere; path=/
The browser creates a cookie file on the client's disk and writes it inside:

Testcookie=something from somewhere;

This line is the result of our use of Setcookie (' TestCookie ', ' Something from somewhere ', '/'); that is, with the header (' Set-cookie:testcookie=something from somewhere; path=/'); the result.

Usage of cookies in PHP