Solved

Question on $_POST , does it persist?

Posted on 2015-01-27
5
157 Views
Last Modified: 2015-01-27
hi,

I am a little confused on $_POST.

I basically have a form that submits a $_POST value , and calling another php page.
Later, in a completely different php page, i'd like to reuse the $_POST that was submitted earlier, and I find that it isnt available to me.

The php.net states that its a superglobal. But it looks to me like it disappears as soon as I navigate away from the page, unlike $_SESSION. Is this true?
0
Comment
5 Comments
 
LVL 12

Assisted Solution

by:Phil Phillips
Phil Phillips earned 125 total points
Comment Utility
The $_POST variable gets whatever data is in the POST request submitted by using the form.  That data is only available to the page that receives the POST request.

You can copy the $_POST data to the session to save that information for future requests.
0
 
LVL 74

Accepted Solution

by:
käµfm³d   👽 earned 250 total points
Comment Utility
You need to get a basic understanding of how HTTP works, then you'll understand why you are seeing this behavior. Ray Paseur has an introductory article on the topic:

http://www.experts-exchange.com/Web_Development/Web_Languages-Standards/A_11271-Understanding-Client-Server-Protocols-and-Web-Applications.html

The short of it is that you post to the server only exists on the server for that one request. Once the request is processed, there is no reason to keep that information. If you need to persist that information, then you move to session state--or for the hardcore, a database.

Session is used to persist information across requests.

His session article may be useful also:

http://www.experts-exchange.com/Programming/Languages/Scripting/PHP/A_11909-PHP-Sessions-Simpler-Than-You-May-Think.html
0
 
LVL 34

Assisted Solution

by:gr8gonzo
gr8gonzo earned 125 total points
Comment Utility
A superglobal is just a variable that can be accessed from within the scope of a function without having to explicitly bring it in. For example:

$not_a_superglobal = "foo";
$_POST["something"] = "bar";

function show_scope()
{
  echo $_POST["something"]; // shows "bar"
  echo $not_a_superglobal; // Undefined variable

  global $not_a_superglobal; // Brings it into the scope
  echo $not_a_superglobal; // "foo"  
}

In short, $_POST does not persist across pages. Only $_SESSION persists.
0
 
LVL 74

Assisted Solution

by:käµfm³d 👽
käµfm³d   👽 earned 250 total points
Comment Utility
The term superglobals just means that those particular variables can be accessed from within anywhere inside of your application. It does not imply that they persist data  in any such way.
0
 

Author Closing Comment

by:NeverEndingFlashStories
Comment Utility
Whoa, I blinked, and 4 comments popped up :). Thanks everyone, it confirmed what i expected - i was wondering if i had an error in my syntax.
0

Featured Post

How your wiki can always stay up-to-date

Quip doubles as a “living” wiki and a project management tool that evolves with your organization. As you finish projects in Quip, the work remains, easily accessible to all team members, new and old.
- Increase transparency
- Onboard new hires faster
- Access from mobile/offline

Join & Write a Comment

Foreword (July, 2015) Since I first wrote this article, years ago, a great many more people have begun using the internet.  They are coming online from every part of the globe, learning, reading, shopping and spending money at an ever-increasing ra…
These days socially coordinated efforts have turned into a critical requirement for enterprises.
The viewer will learn how to dynamically set the form action using jQuery.
The viewer will learn how to look for a specific file type in a local or remote server directory using PHP.

772 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

10 Experts available now in Live!

Get 1:1 Help Now