Passing arrays as url parameter

Question

There is a very simple solution: http_build_query(). It takes your query parameters as an associative array:

$data = array(
    1,
    4,
    'a' => 'b',
    'c' => 'd'
);
$query = http_build_query(array('aParam' => $data));

will return

string(63) "aParam%5B0%5D=1&aParam%5B1%5D=4&aParam%5Ba%5D=b&aParam%5Bc%5D=d"

http_build_query() handles all the necessary escaping for you (%5B => [ and %5D => ]), so this string is equal to aParam[0]=1&aParam[1]=4&aParam[a]=b&aParam[c]=d.

Edit: Don't miss Stefan's solution above, which uses the very handy http_build_query() function: https://stackoverflow.com/a/1764199/179125

knittl is right on about escaping. However, there's a simpler way to do this:

$url = 'http://example.com/index.php?';
$url .= 'aValues[]=' . implode('&aValues[]=', array_map('urlencode', $aValues));

If you want to do this with an associative array, try this instead:

PHP 5.3+ (lambda function)

$url = 'http://example.com/index.php?';
$url .= implode('&', array_map(function($key, $val) {
    return 'aValues[' . urlencode($key) . ']=' . urlencode($val);
  },
  array_keys($aValues), $aValues)
);

PHP <5.3 (callback)

function urlify($key, $val) {
  return 'aValues[' . urlencode($key) . ']=' . urlencode($val);
}

$url = 'http://example.com/index.php?';
$url .= implode('&', array_map('urlify', array_keys($aValues), $aValues));

Easiest way would be to use the serialize function.

It serializes any variable for storage or transfer. You can read about it in the php manual - serialize

The variable can be restored by using unserialize

So in the passing to the URL you use:

$url = urlencode(serialize($array))

and to restore the variable you use

$var = unserialize(urldecode($_GET['array']))

Be careful here though. The maximum size of a GET request is limited to 4k, which you can easily exceed by passing arrays in a URL.

Also, its really not quite the safest way to pass data! You should probably look into using sessions instead.

please escape your variables when outputting (urlencode).

and you can’t just print an array, you have to build your url using a loop in some way

$url = 'http://example.com/index.php?'
$first = true;
foreach($aValues as $key => $value) {
  if(!$first) $url .= '&amp';
  else $first = false;
  $url .= 'aValues['.urlencode($key).']='.urlencode($value);
}

 <?php
$array["a"] = "Thusitha";
$array["b"] = "Sumanadasa";
$array["c"] = "Lakmal";
$array["d"] = "Nanayakkara";

$str = serialize($array);
$strenc = urlencode($str);
print $str . "\n";
print $strenc . "\n";
?> 

print $str . "\n"; gives a:4:{s:1:"a";s:8:"Thusitha";s:1:"b";s:10:"Sumanadasa";s:1:"c";s:6:"Lakmal";s:1:"d";s:11:"Nanayakkara";} and

print $strenc . "\n"; gives

a%3A4%3A%7Bs%3A1%3A%22a%22%3Bs%3A8%3A%22Thusitha%22%3Bs%3A1%3A%22b%22%3Bs%3A10%3A%22Sumanadasa%22%3Bs%3A1%3A%22c%22%3Bs%3A6%3A%22Lakmal%22%3Bs%3A1%3A%22d%22%3Bs%3A11%3A%22Nanayakkara%22%3B%7D

So if you want to pass this $array through URL to page_no_2.php,

ex:-

$url ='http://page_no_2.php?data=".$strenc."';

To return back to the original array, it needs to be urldecode(), then unserialize(), like this in page_no_2.php:

    <?php
    $strenc2= $_GET['data'];
    $arr = unserialize(urldecode($strenc2));
    var_dump($arr);
    ?>

gives

 array(4) {
  ["a"]=>
  string(8) "Thusitha"
  ["b"]=>
  string(10) "Sumanadasa"
  ["c"]=>
  string(6) "Lakmal"
  ["d"]=>
  string(11) "Nanayakkara"
}

again :D

I do this with serialized data base64 encoded. Best and smallest way, i guess. urlencode is to much wasting space and you have only 4k.

• why: http://mizine.de/html/array-ueber-get-url-parameter-uebergeben/
• how: https://gist.github.com/vdite/79919fa33a3e4fbf505c

This isn't a direct answer as this has already been answered, but everyone was talking about sending the data, but nobody really said what you do when it gets there, and it took me a good half an hour to work it out. So I thought I would help out here.

I will repeat this bit

$data = array(
'cat' => 'moggy',
'dog' => 'mutt'
);
$query = http_build_query(array('mydata' => $data));
$query=urlencode($query);

Obviously you would format it better than this www.someurl.com?x=$query

And to get the data back

parse_str($_GET['x']);
echo $mydata['dog'];
echo $mydata['cat'];