PHP removing querystring variable from a string

Question

This is $postfields value:

image=%40E%3A%5Cdev%5Cphoto.jpg&oauth_timestamp=1291739697&oauth_token=123456&tile=true

I need to take out any the image=xxxxx part of that value so i only have this at the end:

oauth_timestamp=1291739697&oauth_token=123456&tile=true

I tried explode() and parse_str() approaches with no success. The best solution would be to find any image=xxxxx inside the long string, then convert it to an array like this:

$array['image'] = '%40E%3A%5Cdev%5Cphoto.jpg';
$array['oauth_timestamp'] = '1291739697';
$array['oauth_token'] = '123456';
$array['tile'] = 'true';

That way is really easy to just unset($array['image']) and then implode() everything back. Any ideas on how to do that? Thanks!

Answer 1

Use parse_str() to take it apart, and http_build_query() to put it back together again.

• Andres SK: i tried that approach also. the problem is that sometimes there are more or less variables in the querystring... and because of that http_build_query becomes really cumbersome.
• Ignacio Vazquez-Abrams: ... How so? Take the array returned, remove the key, pass it back in.
• Andres SK: but parse_str doesn't return any arrays. It only creates new variables based on the key and value of the long string php.net/parse_str
• Andres SK: it would be great if parse_str would return the variable names as key names in an array.
• Ignacio Vazquez-Abrams: ... I don't think we were reading the same documentation then... "arr If the second parameter arr is present, variables are stored in this variable as array elements instead. "

Answer 2

use strpos of &oauth and then use substring

$rest = substr($post_data, strpos($post_data, '&oauth'));

• Brad Christie: @thedom, hey, thanks! Sometimes simpler is better. Though I believe @Ignacio's solution is better-served and more robust.
• Andres SK: this works only if image goes first and before &oauth... what if image goes in the middle of the querystring between yet unknown variables? (i cannot control that :s)
• Brad Christie: I'm aware of the limitations, which is why I pointed out the other solution is inevitably a better-fit, but was just posting a lightweight solution. That's the joy of SO, you get many ways to skin a cat. ;-)
• Andres SK: hehe, i'll stay with the parse_str() approach. Thanks for your support!

Answer 3

This should do the trick:

function removeVarFromQueryString($varToRemove, $originalQs=null) {
 if (!$originalQs) {
 $originalQs = $_SERVER['QUERY_STRING'];
 }
 $params = [];
 parse_str($originalQs, $params);
 unset($params[$varToRemove]);
 return http_build_query($params);
}

Then for your example:

$qs = "image=%40E%3A%5Cdev%5Cphoto.jpg&oauth_timestamp=1291739697&oauth_token=123456&tile=true";
echo removeVarFromQueryString("image", $qs); // => oauth_timestamp=1291739697&oauth_token=123456&tile=true