Develop Reference

how to use $_POST to change some contents forever [duplicate]

This question already has an answer here:
Once I refresh the page that is getting data through a form , every thing will be gone
(1 answer)
Closed 10 months ago.
I am trying to populate data from a website to another wensite:
a.html:
<form action="b.php" method="post">
<textarea id="myProjects" name="mp"></textarea>
<input id="submit" type="submit" value="Submit" />
</form>
in b.php:
<?php $content=$_POST['mp'];
echo "you entered ".$content;
?>
This works in a very strange way, when I click submit button, I am directed to the b.php page, and I can see what I entered. But if I reload this page, not refresh, my contents disappear, and throwWarning: Undefined array key "mp" It looks like data received from $_POST is "temporarily" stored. I am new to PHP, so I am not sure how can I figure it out.

You can use the PHP SESSION feature to keep the data persistent:
in b.php:
<?php
// Start the session
session_start();
// save the input var as a SESSION property
if (isset($_POST['mp'])) {
$_SESSION['content'] = $_POST['mp'];
}
// display the property
echo "you entered " . $_SESSION['content'];

Generally speaking, what you want to do is to store the value of $_POST['mp'] into the $_SESSION variable so that it persists from one page request to the next.
However doing it by manipulating these variables directly is generally bad practice. Unless you sanitize the user input you are open to a myriad of scripting attacks. Although there is some learning involved, you are much better off using an established PHP framework (for example Laravel), which has a full set of validation functions, and manages the process of starting the session for you. A good framework will also help you in many other ways.

Get cookie of parent page (iframe) using JS

I need to get a cookie created in parent page.
I need get a spesific cookie (example) who was cread on modiface--locatelcolomia.myvtex.com and used this on my child page modiface.locatelcolobmia.com (this one is called by vtex iframe)

You cannot directly get cookies from other pages.
You can send a request to that page to send the cookies.
getCookies.php (put on parent page)
window.onload = function(){document.getElementById('submitpost').submit();}
<?php if(!isset($_COOKIE['COOKIE_NAME_HERE']) {die('set cookie');} ?>
<h3>Please wait</h3>
<form id="submitpost" action="PUT_PREVIOUS_PAGE_URL_HERE" method="post">
<input type="hidden" name="cookie" value="<?php echo $_COOKIE['COOKIE_NAME_HERE']; ?>">
</form>
Then set the cookie to that.
Redirect users without the set cookie to the getCookies.php page.
This form can be intercepted and changed, but cookies can as well. Never put account details in cookies.
This answer requires a web server with PHP, chances are that your host does support PHP.

Thanks for the help, this is the answer: I got the cookie by Jquery and save on a input type hidden at the end send to my iframe calling a php page and send this value by URL (GET).
jQUERY
let cartId = $('#idCartInput').val();
IFRAME
("#idCartBtn").html("<iframe src='http://localhost:81/projectExample/modiface/index.php?cartId="+cartId+"' class='frameModiface' id='pruebasId' allow='camera' name='iframe_a'></iframe>");

How to Redirect to a URL in PHP from with Post Data as URL String

I have searched a lot but did not find any answer...
My Question is, let's say I have a random page and user click on the download button to download a file, and the html in the button is:
<form action="http://seconddomain.com/thanks-for-downloading/" target="_blank" method="post">
<input type="hidden" name="FileID" value="dYnte-m9bZ4">
<div align="center">
<input alt="Download Movie" src="image url here" type="image">
</div>
</form>
This data is submitted to the next page with post method using in the form, as you can note the value is defined as "dYnte-m9bZ4"
In this case, this value is the file download link, eg: downlaodfile.com/dYnte-m9bZ4
I want that when this data is submitted with post method on the next page there should be some PHP code that will automatically attach the defined value to the server URL/link as downlaodfile.com/dYnte-m9bZ4 and the user will be automatically redirected to the download page.
If this is not possible with post form method, then please suggest any other method...
Please tell me how can I do it.
Thanks...

Add this line,from where you want to redirect in your post handler php file.
$var = $_POST["FileID"];
// do input validation ,type-check etc on $var.
header("Location: http://downlaodfile.com/".$var);
I have done same thing of redirecting after form submission
you can check my code # Bitbucket line no 459 of link

Never use user input directly. Never.
Sanitize and validate before using user input.
Escape data when necessary (when data switches execution contexts).
Note: This does not include error handling. This is just a skeleton.
$filteredPost = filter_input_array(INPUT_POST, $filterRulesArray); //Sanitize
$validatedPost = filter_var_array($filterdPost, $validationRulesArray) //Validate
$fileId = urlencode($validatedPost['FileID']); //Potentially, an important step in this case.
header("Location: http://downloadfile.com/{$fileId}");
PHP Manual: filter_input_array()
PHP Manual: filter_var_array()
PHP Manual: urlencode()

global variable not displayed in div

I declare a variable at the beginning of my .js file:
var option="blabla";
On page 1.html I click on a link to page 2.html where I have
<script>document.write(option);</script>
No text is displayed on 2.html. When I refresh the browser while I am on 2.html I get undefined as an output.
What do I have to do to have the text displayed straight after I click the link?
Alternatively, how can I get the following code work to output strUrl on 2.html:
on 1.html I have a link:
<a href="2.html" onclick="function1("item")">
on 2.html I have a div:
<div id="display">document.write(strUrl);</div>
then I have in my .js file:
function1(searchitem)
{
strUrl = 'http://blabla.com/'
+ '?key=' + searchitem;
}

You try to create a Javascript variable on a page and then use it on another page. This is a more-or-less broad problem, since you want to maintain values across pages. First of all, you need to decide where is this value going to be defined and where is it going to be used. If this is more like a server-side variable, then you need to define it on server-side and then generate it into your Javascript code. If you are using PHP, then you can do it like this:
<script type="text/javascript>
var foo = '<?php echo $bar; ?>';
</script>
Naturally, you need to initialize $bar to be able to do that. If the variable should be a client-side variable, then you need to use localStorage, like this on 1.html:
localStorage.setItem("option", "blablabla");
and then load it on 2.html:
localStorage.getItem("option");
Or, if you need to use it both on server-side and client-side, then you can use a cookie for this purpose. Using cookies i slightly more complex, but my answer to another question should get you going.
Let's focus on the cause this did not work for you. A Javascript variable will cease to exist when the page is unloaded, so you will not be able to use its value after that. So, you need to persist it somehow, storing it either on the server or the computer where the browser is being run.
As a side-note, I should mention that you can use Javascript variables accross pages if you load some pages inside iframes of a page, but that is a different scenario.

This is what FORMS and AJAX were invented for. If your server has a PHP processor (virtually ALL of them do), then you can rename your .html files to .php and use a bit of PHP to accomplish your goal.
A web page ending with .PHP works exactly the same as one ending in .html, except that you can now add snippets of PHP code where desired. It is not necessary to have any PHP code, but if you have some it can do stuff.
Method One: FORMs
If you want to switch to page2.html and see a value sent from page1.html, you can use a FORM construct and post the data from page1 to page2:
page1.php
<form action="2.html" method="post">
<input name="option" type="text" />
<input type="submit" name="sub" value="Go" />
</form>
page2.php
<?php
$p1 = $_POST['option'];
?>
<div>On page1 of this website, you typed: <?php echo $p1; ?>. That's what you did.</div>
Note how a <form> uses the name= attribute for the name of the variable that is sent to the other side.
Example Two: The AJAX method
HTML:
<div id=nonForm">
<input id="option" type="text" />
<input type="button" id="myButt" value="Go" />
</div>
<div id="results"></div>
jQuery:
$('#myButt').click(function(){
var opt = $('#option').val();
$.ajax({
type: 'post',
url: 'page2.php',
data: 'option='+opt,
success: function(john){
if (d.length) alert(john); //display result from Page2 in a pop-up box
$('#results').html(john); //Or, display it right on the page
}
});
});
PAGE2.PHP -- The AJAX processor file
<?php
$opt = $_POST['option'];
//Now, you can do something with the data in $opt, and then send back a result
$rtn = 'Hey, you sent: ' .$opt;
echo $rtn;
The primary (and most important) difference between the two methods is that the FORM will change pages on you. The user will be sent from Page1 to Page2, and the screen will flash as this happens.
What's exciting about AJAX is it sends data to Page2, where Page2 can do something with it (for example, a database lookup), and then Page2 sends different data back to Page1. This new data can then be displayed on the page WITHOUT the page refreshing.
Here are a couple of very basic AJAX examples, to get you going:
AJAX request callback using jQuery

Jquery and AJAX script to run a PHP script in the background to avoid any refreshing

I have built a follow/unfollow Twitter like system using PHP. Now I would like to run the follow-unfollow PHP script in the background using AJAX/JQUERY to avoid refreshing the page when you follow/unfollow a user. To make things simpler, I will be here just using the example of “unfollow”. As you notice, I am running an iteration to output all the members in the database. I am outputting here (as well for simplicity) just the member’s name and an unfollow button to each one.
This is the code using php.
members.php
<?php foreach($members as $member){ ?>
<p class="member_name"><?php echo $member->name; ?></p>
<p class="follow_button">Unfollow</p>
<?php } ?>
unfollow.php
<?php
if($_GET['unfollow_id']){
$unfollow_id=$_GET['unfollow_id'];
$unfollow=Following::unfollow($id, $unfollow_id); //Function that will make the changes in the database.
// $id argument will be gotten from a $_SESSION.
}
I am trying to achieve the same result running unfollow.php in the background to avoid any refreshing. This is what I have come up with, as you might imagine it is not working properly. I am including the Jquery script inside the iteration which I think is the only way of obtaining the $member->id property to then assign it to the Jquery variable.
members.php THE NEW ONE THAT TRYS TO RUN THE SCRIPT WITH AJAX JQUERY
<?php foreach($members as $member){ ?>
<p class="member_name"><?php echo $member_name; ?></p>
<button type="button" class="unfollow_button" id="unfollow">Unfollow</button>
<script type="text/javascript">
$(document).ready(function(){
$("#unfollow").click(function(){
// Get value from input element on the page
var memberId = "<?php $member->id ?>";
// Send the input data to the server using get
$.get("unfollow.php", {unfollow_id: memberId} , function(data){
// Success
});
});
});
</script>
<?php } ?>
Can you provide me any help for this to work?
Thanks in advance.

Remember, in HTML, id attributes have to be unique.
Because you're rendering multiple members on a single page, you should not use an id selector in jQuery, but a class selector (e.g. button.unfollow). If you use #unfollow, you'll run into ID conflicts between each of the members' buttons.
First, render all of your members with unfollow buttons without ids. I'm adding the member_id in the markup using a data attribute called data-member_id.
<?php foreach($members as $member) { ?>
<p class="member_name"><?=$member_name?></p>
<button type="button" class="unfollow_button" data-member_id="<?=$member->id?>">Unfollow</button>
<?php } ?>
Then add a single click handler for all button.follow buttons, which extracts the member_id from the clicked button's data-member_id attribute and sends it to the server.
<script type="text/javascript">
$(document).ready(function() {
$("button.unfollow_button").on('click', function() {
// Get value from input element on the page
var memberId = $(this).attr('data-member_id');
// Send the input data to the server using get
$.get("unfollow.php", {unfollow_id: memberId} , function(data) {
// Success
});
});
});
</script>
On a side-note, you should probably look into building a RESTful service for this, to which you can post proper HTTP requests using http://api.jquery.com/jquery.ajax/.
See here for an intro on REST in PHP I wrote a while back:
Create a RESTful API in PHP?