Export multiple json files - php

Question

I'm using wordpress with nextgen gallery, and i would like to get the images from a specific gallery id in a seperate JSON file. So far i have this code, but that just exports the images from the given ID (in this case; 7). I know there must be some kind of foreach function, but my javascript knowledge won't go that far.
Could someone help me with this one? The code i have so far:
mysql_connect("localhost","DB-NAME","DB-PASSWORD");
mysql_select_db("DB-NAME");
$result=mysql_query("SELECT filename FROM zs_ngg_pictures WHERE galleryid = '7' ORDER BY sortorder LIMIT 3");
while($row=mysql_fetch_assoc($result)){
$output[]=$row;
}
$fp = fopen('result.json', 'w');
fwrite($fp, json_encode($output));
fclose($fp);
echo json_encode($output);

Answer 1

If I correctly understand what you're trying to achieve you can simply get all the pictures, put them in a multidimensional array:
$result=mysql_query("SELECT filename, galleryid FROM zs_ngg_pictures ORDER BY sortorder");
while($row=mysql_fetch_assoc($result)){
$output[$row['galleryid']][] = $row['filename'];
}
and you have a PHP array like this (if you got two galleries with id 7 and 23):
array(
7 => array('file7-1.jpg','file7-2.jpg','file7-3.jpg'),
23 => array('file23-1.jpg','file23-2.jpg'),
);
so the result.json file will be like:
{ "7" : ["file7-1.jpg", "file7-2.jpg", "file7-3.jpg"],
"23" : ["file23-1.jpg", "file23-2.jpg"] }
If you want separate files for each galleryid you can then loop and save files with different names:
foreach($output as $gall_id => $gallery) {
file_put_contents('result-'.$gall_id.'.json', json_encode($gallery));
}
and you'll have two files named result-7.json and result-23.json

Answer 2

Instead of doing complicated fopen() stuff and echo:
$fp = fopen('result.json', 'w');
fwrite($fp, json_encode($output));
fclose($fp);
echo json_encode($output);
you can simply call:
file_put_contents('result.json', json_encode($output));
readfile('result.json');
or you skip the file and simple output the JSON:
echo json_encode($output));