Php – How to keep already-set GET parameter values on form submission

formsgetparameter-passingPHP

I have a URL : foo.php?name=adam&lName=scott, and in foo.php I have a form which gives me values of rectangleLength & rectangleBreadth with a submit button.

When I click this submit button with form action as $_SERVER['REQUEST_URI'], I get this result URL: foo.php?rectangleLength=10&rectangleBreadth=5 (these values have been filled in by the user).

Notice that I am losing my previous values name & lName from the URL.

How can I keep them?

Also, keep in mind that I have to come back to foo.php and if the user wants to submit the form again then the length and breadth values should change.

Best Answer

You can add two hidden fields in the form on the first target site, blabla.php in your case:

<form ...>
  <input type="hidden" name="name" value="<?php echo htmlspecialchars($_GET['name']);?>">
  <input type="hidden" name="lName" value="<?php echo htmlspecialchars($_GET['lName']);?>">

  <!-- rest of the form here -->
</form>

For a dynamic solution, use a foreach loop:

<?php
foreach($_GET as $name => $value) {
  $name = htmlspecialchars($name);
  $value = htmlspecialchars($value);
  echo '<input type="hidden" name="'. $name .'" value="'. $value .'">';
}
?>

You may consider locking the dynamic approach down to a list of known possible keys:

<?php
$keys = array('name', 'lName', ...);
foreach($keys as $name) {
  if(!isset($_GET[$name])) {
    continue;
  }
  $value = htmlspecialchars($_GET[$name]);
  $name = htmlspecialchars($name);
  echo '<input type="hidden" name="'. $name .'" value="'. $value .'">';
}
?>
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