php array values to regex pattern

Question

So I have an array with values, this case file extentions but i'm using preg_match to filter out file extentions that are not allowed.

Is there an easy way to translate an array to an regex pattern?

Source array

(
  [1] => 'file-to-path/thumbs/allowedfile.pdf',
  [2] => 'file-to-path/thumbs/notallowedfile.psd',
  [3] => 'file-to-path/project/test/notallowedfile.txt',
)

Allowed extentions array

( 
    [0] => bmp
    [1] => jpg
    [2] => jpeg
    [3] => gif
    ...
)

The code that im using right now.

foreach($array as $key => $val){

     if( !preg_match('/^.*\.(jpg|png|jpeg|bmp|gif|pdf)$/i', $val ) ){

           // this part needs to be an array
           '/^.*\.(jpg|png|jpeg|bmp|gif|pdf)$/i' -> [array with the values]

      }

}

Answer 1

I would avoid regex for this, and use pathinfo($value, PATHINFO_EXTENSION) and in_array()

For example, which populates an $error array and filters your array.

<?php
$allowed_ext = array ( 
    'bmp',
    'jpg',
    'jpeg',
    'gif',
    'pdf'
);

$files = array(
  1 => 'file-to-path/thumbs/allowedfile.pdf',
  2 => 'file-to-path/thumbs/notallowedfile.psd',
  3 => 'file-to-path/project/test/notallowedfile.txt'
);

$errors = [];

foreach ($files as $key => $value) {
    if (!in_array(pathinfo($value, PATHINFO_EXTENSION), $allowed_ext)) {
        $errors[] = basename($value).' is not allowed.';
        unset($arr[$key]);
    }
}

print_r($errors);
print_r($files);

https://3v4l.org/oSOJT

Result:

Array
(
    [0] => notallowedfile.psd is not allowed.
    [1] => notallowedfile.txt is not allowed.
)
Array
(
    [1] => file-to-path/thumbs/allowedfile.pdf
)

---

If you just want to filter the array, then you can use array_filter()

$files = array_filter($files, function ($file) use ($allowed_ext) {
   return in_array(pathinfo($file, PATHINFO_EXTENSION), $allowed_ext);
});

Answer 2

You can use array_filter function then check the extension of a single file in the list of available extensions, and return true if it's valid extension otherwise returns false and it's exclude.

$validFiles = array_filter($files, function ($file) use ($key, $value, arrOfValidExtensions) {
   $fileExtenstion = getFileExtension($value); //Implement this function to return the file extension
   return in_array($fileExtension, $arrOfValidExtensions);
});

Answer 3

all not allowed files you can quick ignore them with minimum cpu use

function check(){
    $who = array(
        1 => 'file-to-path/thumbs/allowedfile.pdf',
        2 => 'file-to-path/thumbs/notallowedfile.psd',
        3 => 'file-to-path/project/test/notallowedfile.txt'
    );
    return preg_grep('/^.*\.(jpg|png|jpeg|bmp|gif|pdf)$/i', $who );
}

print_r(check());

In my browser, I got this push Run Code Snippet:

Array
(
    [1] => file-to-path/thumbs/allowedfile.pdf
)

or

function check($who){
    return preg_grep('/^.*\.(jpg|png|jpeg|bmp|gif|pdf)$/i', $who );
}

print_r(check(array(
  1 => 'file-to-path/thumbs/allowedfile.pdf',
  2 => 'file-to-path/thumbs/notallowedfile.psd',
  3 => 'file-to-path/project/test/notallowedfile.txt'
)));