Why is a called 'string' invisible to an array? - php

Question

The file below, can be setup using any JPG file from PhotoShop that has XMP data. In the 'pattern', replace 'eat:' with 'dc:' or any namespace returned from the '$string'.
Calling $string (1) using following array setup it produces a print_r array that looks like: (2)
If you uncomment the line ubove (1a), it will print to the browse, copy & paste into the line below (1a). this should produce an array that looks like: (3)
Why the difference print_r readings, when it's the same string?
How do I get it to behave like (3); ... better yet how do I make it end up like the(4)?
<?php
header("Content-Type: text/html; charset=utf-8");
$filename = "2012-04-24_WestCoast_2.jpg";
echo '<img src="'. $filename . '" alt="'. $filename . '" title="' . $filename . '" width="350" /><p />';
$source = file_get_contents($filename);
$xmpdata_start = strpos($source,'<x:xmpmeta');
$xmpdata_end = strpos($source,"</rdf:Description>");
$xmplenght = $xmpdata_end-$xmpdata_start;
$xmpdata = substr($source,$xmpdata_start,$xmplenght+18);
$string = htmlentities($xmpdata); //(1)
//if (is_string($string)) {
// echo "is a string\n"; //TRUE
//} else {
// echo "is not a string\n";
//}
//$string = print_r("'".$string."';");
// (1a)=====================================
//$string = '<x:xmpmeta xmlns: === Truncated for simplicity ===x="adobe:ns:meta/" x:xmptk="Adobe XMP Core 5.3-c011 66.145661, 2012/02/06-14:56:27 "> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"></rdf:Description>';
$pattern = '/eat:(.*?)="(.*?)"/is';
preg_match_all($pattern, $string, $matches);
$group = array($matches[1], $matches[2]);
// foreach($group as &$match);
echo '<pre>';
// print_r ($match);
print_r ($group);
echo '</pre>';
?>
(2)=====================================
// If i just call the '$string', this is what i get:
Array
(
[0] => Array
(
)
[1] => Array
(
)
)
(3)=====================================
// If I uncomment (1), the '$string' that I pasted inside the file, i get this:
Array
(
[0] => Array
(
[0] => Biography
[1] => Title
[2] => object_description
[3] => Medium
[4] => in_height
[5] => in_width
[6] => in_depth
[7] => Dated
[8] => Photograph
)
[1] => Array
(
[0] => American B1942 Castine, Maine
[1] => Reunion Dinner Party at the Slanted Door
[2] => Nancy Freeman, Tim Patterson The Slanted Door San Francisco Calf.
[3] => photography
[4] => 2736
[5] => 3648
[6] => # 240 dpi
[7] => April 24, 2012
[8] => PrimaryImage
)
)
(4)=====================================
// This is what i'm trying to get too:
Biography: American B1942 Castine, Maine
Title: Reunion Dinner Party at the Slanted Door
object_description: Reunion Dinner Party at the Slanted Door
Nancy Freeman, Tim Patterson The Slanted Door San Francisco Calf.
Medium: photography
in_height: 2736
in_width: 3648
in_depth: # 240 dpi
Dated: April 24, 2012
Photograph: PrimaryImage

Answer 1

I'm not clear on what the issue is with the string being set inside or outside of file. It is unclear what you are trying to explain.
The output of the array(3) is caused by the brackets in the Regular Expression. I don't know the exact reason for this, but to get the results you want(4) you could use a loop to join the two arrays in a new array.
Note: What your doing with $group is making an array of arrays. You are not merging the two arrays into one. To merge the arrays you need to iterate through both arrays and merging each element as new element of new array.
example:
for($i=0; $i<match[0].length; $i++){
$result[i] = $match[0][i]. ": " .$match[1][i];
}
Im rusty on my php, but that is the idea for merging the arrays.
--EDIT--
Now that I understand what you are trying to do I see two possible places where problems may occur. First is: are you 100% sure the image you are using contains any meta data in the fields you want? Im not sure of the exact nature of meta data, but I do know there will be the required data set by the computer(what you filtered out with the start and end points), and the custom data. If blank it might not even be included.
Second possible issue is how you are chunking up the meta data. Maybe try writing to Regular Expressions to strip the start and end from the string. Replace everything in front of a set of characters with "" and do a similar expression for the back.
Also the variable you set for $group is the exact same thing that $match was. You took the two arrays that where contained in the array %match and assigned them to an array called $group. Just a FYI. Use the sudo code I posted earlier to design the loop that will actually combine the two arrays into one.
Good Luck. Maybe when I get php set up on testing computer I will play with the code to see what exactly is happening.

Answer 2

Well it looks like i get to answer my own question of "Why it is a called 'string' invisible to an array?".
The answer is: When it's preceded by a call to 'htmlentities()'.
Now I'm not really sure why it happens but it does happen and the instant I went back and checked all my assumptions ... that 'htmlentities()' would clean up the raw string. Commenting out 'htmlentities()' made everything work.
Is this a bug? I personally don't know, and i don't have the necessary experience using PHP to even hazard a guess. What i do know is it drove me up the wall for a week.