jQuery serialized string to PHP array

[kongondo]

Hi,

This is not PW-specific so not sure if I am posting in the right board.

I have a PW page with a jQuery ajax  call that serializes some values and sends them by POST like so:

list[7]=root&list[2]=root&list[5]=2&list[4]=root&list[3]=4&list[6]=root&list[8]=6&list[1]=8 

These are sent to another PW page for processing.

I have the following code. It works fine but I get an "Invalid argument supplied for foreach() in..." error (in the example I haven't sanitized anything; will do so in final version ).

$i = 0;
foreach ($input->post ['list']as $key => $value) {//values to be sanitized; this is a basic example 
	$x = $key;
	$y = $value;
	$z = $i;
	$i++;
	if ($y == "foo") {
	$y = "bar";
	}
	//do other stuff with $x, $y and $z
} 

Although the code works, I'd like to get rid of the warning. I know foreach expects an array in this case so ideally, I would want to convert the serialized string to an array first. That's where I am getting stuck (searched StackOverflow, etc ). I also know I could use jQuery toArray but that sends some other value pairs that I don't need. I think "serialize" is simpler to use.  Maybe explode the string? Overkill for this? Thanks for any pointers!

Cheers

/k

Edit: Just to clarify. The warning would occur even outside PW. It had nothing to do with PW methods. 

Edited May 22, 2013 by kongondo

[adrian]

Does parse_str do what you need?

http://www.php.net/manual/en/function.parse-str.php

[diogo]

Shouldn't it be simply 

foreach ($input->post as $key => $value)

?

[Soma]

Just use

isset($input->post->list)

[kongondo]

Does parse_str do what you need?

http://www.php.net/manual/en/function.parse-str.php

Think I tried this earlier but can't remember the outcome; tried so many things! Thx.

Shouldn't it be simply 

foreach ($input->post as $key => $value)

?

This takes away the Warning but the code doesn't work; cannot save to DB

Just use

isset($input->post->list)

Works like a charm, thanks!

For fellow-newbies, I used this like so

if (isset($input->post->list){//access as object property
$i = 0;
foreach($input->post->list as $key => $value){
blah blah...
}
//this also works
//if (isset($input->post['list']))//access as array index
}

<cliche>I owe you one Soma!</cliche>

ps: If you have a minute, please explain why this works....and I thought I knew what isset does 

[Wanze]

I think that Pw returns null if a POST variable isn't set.

So this should also work:

if (!is_null($input->post->list)) {}
if ($input->post->list !== null) {}

// Simplest but be careful when list contains the value '0' - this is casted to false  
if ($input->post->list) {}

You get the warning from PHP if your array is empty and you want to iterate over it - that's why you always should first check if the variable is set / contains values.

Quote from the docs:

$input returns NULL if you access a variable that doesn't exist (no need to use isset() like with PHP's superglobals)

http://processwire.com/api/variables/input/

[kongondo]

Thanks Wanze for the additions. 

In my case, I am sure that the array was not empty so the warning was due to foreach not liking the serialized string...

Edit: Just to clarify. The warning would occur even outside PW. It had nothing to do with PW methods. 

Edited May 22, 2013 by kongondo

[kongondo]

Btw, how can I easily sanitize the $key=> $value pairs? The $key is straightforward  because it will always be an integer. So I can do this?

$x = (int) $key; 

or should I sanitize earlier at the $input->post->list?

The $value is tricky because it could be an integer or it could be the string "root". Maybe use an if on this one?

Thanks.

[ryan]

or should I sanitize earlier at the $input->post->list?

I think it's probably just whatever you find most useful in your situation. But my preference is usually to sanitize on first access, unless I potentially need an unsanitized version to determine how it should be sanitized (which might be the case here).

The $value is tricky because it could be an integer or it could be the string "root". Maybe use an if on this one?

You could sanitize first with pageName (which sanitizes to [-_.a-z0-9], and then use ctype_digit to determine if it's an integer or string:

$value = $sanitizer->pageName($input->post->something); 
if(ctype_digit("$value")) {
  // it's an integer
  $value = (int) $value; 
} else {
  // it's a string
}

[kongondo]

Thanks Ryan.