Using Cookies in PHP

[Vswe]

Cookies is small text files saved locally on the user's computer by the website, when the website later on wants the information it just reads the cookie on the user's computer. An example on what you can use cookies for is to see if the user has visited the site before, if it has then a cookie you saved the last time lies on the computer so therefor you can only check if it does.



Creating a Cookie


When creating a cookie you have to do it before sending anything to the page, so you can't have a html tag before it. To create a cookie you do like this:

setcookie(name, value, expire, path, domain); 

1. Name - The name of the cookie, you use this to receive the cookie later.
2. Value - The value that you'll store in the cookie.
3. Expire - When the cookie will expire.
4. Path - The path on the server where the cookie is available on, leaving this empty will allow whole domain to access it.
5. Domain - The domain which can access the cookie, leaving this empty will allow all your domains to access it.

Here's an example on how to create a cookie:

$expire=time()+60*60*24*3;
setcookie("Cookie_Name", "Cookie_Value", $expire); 

The above example will create a cookie called "Cookie_Name" with the value "Test_Value" which will expire after 3 days.







Reading Cookies

To read a cookie you use:

$_COOKIE["<Name of cookie>"]; 

and replace <Name of cookie> with the name of the cookie you want to read.


So if we want to read the cookie we created above we should do like this:

$_COOKIE["Cookie_Name"]; 

Here comes a simple example on reading a cookie:

if (isset($_COOKIE["Cookie_Name"]))
{
$Value = $_COOKIE["Cookie_Name"];
$expire=time()+60*60*24*3;
setcookie("Cookie_Name", $Value, $expire);
$Value = "The Value of Cookie_Name is " . $Value;
}
else
{
$Value = "Cookie not set";
}

echo $Value; 

So first of all we check if the cookie exists, if it do we reads it. Then recreate the cookie with an expire time of 3 days, this is so each time the user visit the site we will update the expire date, then we set the value to be a message telling what the value is, and if the cookie didn't existed we stored "Cookie not set" in the variable called Value. At the the end we just echo the result.


That was everything about how you're using cookies with PHP. I hope you found this tutorial useful.

[Jordan]

Nicely done, +rep!

[WingedPanther]

Nice +rep

[Hilary]

Nicely done. Thank you; you make it look so simple

[technica]

The only use of cookies I know is for "Remember Me On this computer" check-box that we can see on some of websites.

Good article with good explanation.

[James.H]

Good guide, +rep!

[Orjan]

The only use of cookies I know is for "Remember Me On this computer" check-box that we can see on some of websites.

Good article with good explanation.

There is another, even bigger use for cookies, and that is to keep sessions live. one alternative is via url, but many uses a cookie for this information. Such cookies usually is just an 32 digit long hexstring as string name and another 32 digit long hexstring as value...

[PGP_Protector]

The only use of cookies I know is for "Remember Me On this computer" check-box that we can see on some of websites.

Good article with good explanation.

I've got a PHP Sig Image on another site I visit that uses cookies.
It keeps track of how many times you've viewed the Image, and allows it to pull the relevant data from the database based on the number of views.

[nemoku]

is that possible, maybe you can even not only use it but you can edit it?

[PGP_Protector]

is that possible, maybe you can even not only use it but you can edit it?

??
If you asking if the site that saves the cookie can edit it, yes.
Or you can edit the cookie file yourself.

Example.


Will create a cookie if you allow it to, then display verse 1.
The next time it is called, it attempts to read the cookie stored on your computer
Increments a counter, displays the next verse, and then saves the new verse location overwriting the old cookie (editing the file)

If 3rd party cookies are blocked by your browser (My cookie would be a 3rd party cookie as CodeCall isn't giving it to you) it wouldn't be able to read the cookie, and then just give you a random verse.