is this $_POST considered empty

Posted on 2011-09-14
Medium Priority
Last Modified: 2012-05-12
I am trying to code a error callback using php and ajax.

What I cannot get past is, I am assinging a variable to a $_POST in PHP to check for an empty value. If empty, then trigger error message.

However, jquery is passing the post to php as carton%5B0%5D:carton%5B1%5D if no data is entered.

Would php see this as an empty post? What are these numbers etc after carton? carton is actually an array. thanks

Also, why is the error triggered when the statement becomes, !empty rather than empty?. This is the code that jquery uses to create an input from a slider change event.

for(var i = 0;i < $(this).val();i++) {
        $("#carton").append('<div data-role="fieldcontain"><label for="carton" class="ui-input-text">Enter box ' + (i + 1) + ' number:</label><input type="text" name="carton['+i+']" id="carton['+i+']" class="carton ui-input-text ui-body-null ui-corner-all ui-shadow-inset ui-body-c" /></div>')

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sample php

$carton = $_POST['carton'];

elseif(empty($carton)) {

    //set the response
    $response_array['status'] = 'error';
    $response_array['message'] = 'You must enter a carton for retrieveal';

//if no errors

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Question by:peter_coop
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LVL 82

Expert Comment

ID: 36539503
%5B is urlencoded hex value of [
%5D is urlencoded hex value of ]

So what you are sending is:

PHP turns that to:
$_POST['carton']=array('0'=>'', '1'=>'')

So $_POST['carton'] is NOT empty. It contains an array of TWO elements. Each of the elements in THAT array are actually empty, but not $_POST['carton'].

On another note, on your post you have:

Is it really sending a colon? The correct url should look more like:

IF you really want to verify that the server does get a value for carton, do:

at the beginning of your script. Does it  show carton? If yes, exactly what are its reported values?

>>$carton = $_POST['carton'];
>>elseif(empty($carton)) {

You cannot have an elseif without an if. So that should be:

$carton = $_POST['carton'];
if(empty($carton)) {

Author Comment

ID: 36539555
This is the result of the var_dump with no data input. The elseif is correct because it is in the middle of other elseif statements. So on the basis that a user sends the form with empty inputs, how would I code a condition to check for to trigger the error message. Thanks

array(2) {
  string(0) ""
  string(0) ""
LVL 82

Expert Comment

ID: 36539604
OK, based on that, carton is NOT empty. It contains TWO elements. What you can do is "implode/join" the values. If you end up with a zero-length string, then all of them were left empty:

elseif( '' == trim(implode('',$_POST['carton']) ) )
  echo 'You must fill in at least one item';
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Author Comment

ID: 36542130
halfway there. This only checks the first input. Based on what a user selects, there could be 10 inputs created by the slider. So if for example a user selects 2 inputs using the slider, then 2 inputs are genegrated, but using your code, it only checks the first input. So if a user filled the first input but ignored the second it is acting like it completed successfully when in fact it did not becuase 1 of the inputs was blank. Thanks
LVL 111

Expert Comment

by:Ray Paseur
ID: 36542236
Suggest you create a test case at a public-facing URL so we can see the whole problem instead of incremental fragments.  When you have done that, you are ready to ask a question at EE.  Just post the link to the URL, post the code, and then we can show you how to diagnose and debug anything that might be going awry.
LVL 82

Accepted Solution

hielo earned 1000 total points
ID: 36542916
In that case you need to iterate through the array checking each element. So, forget about the elseif. Instead use:

//initialize an array to contain the indices of the missing items
foreach($_POST['carton'] as $i=>$v){
    if( ''==trim(strval($v)) )

//here, if missing is NOT empty then at least one item was not filled in:
  echo 'You did not fill the following items: ' . implode(', ', $missing) ;

Author Closing Comment

ID: 36543551
perfect. thanks very much

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