How to check the mime_type of a file after extracting with Ziparchive?

Question

With Ziparchive how can I check the mime_type of the files being unzipped?

Example, taking the elements of a compressed file https://php.net/manual/en/ziparchive.extractto.php

$path = 'zipfile.zip'

$zip = new ZipArchive;
if ($zip->open($path) === true) {

for($i = 0; $i < $zip->numFiles; $i++) {

    $zip->extractTo('path/to/extraction/', array($zip->getNameIndex($i)));


}

$zip->close();

}

Answer 1

From php5.3+ you can use finfo, in older versions use mime_content_type (although it is rare to use older than PHP5.3), a retrocompatible function would be so:

function mimeType($file)
{
    $mimetype = false;

    if (class_exists('finfo')) {//PHP5.3+
        $finfo = finfo_open(FILEINFO_MIME_TYPE);
        $mimetype = finfo_file($finfo, $file);
        finfo_close($finfo);
    } else if (function_exists('mime_content_type')) {//php5.3 ou inferiror
        $mimetype = mime_content_type($file);
    }

    return $mimetype;
}

---

Check mime-type after ripping

$path = 'zipfile.zip';
$extrairPara = 'path/to/extraction/';

$zip = new ZipArchive;

if ($zip->open($path) === true) {

    for($i = 0; $i < $zip->numFiles; $i++) {
        $nome = $zip->getNameIndex($i);
        $zip->extractTo($extrairPara, array( $nome ));

        $mime = mimeType($extrairPara . $nome); //Verifica o mime depois de extrair

        var_dump(array( $nome => $mime )); //Exibe o MIME
    }

    $zip->close();

}

---

Check mime-type before extracting

To check before extracting it will be necessary to use the ZipArchive::getStream, with this you can read only part of a specific file and use combined with finfo_buffer (only php5.3+), the function could be so:

function mimeTypeByResource($handle)
{
    $data = fread($handle, 5000); //Lê somente parte do handle

    $finfo = finfo_open(FILEINFO_MIME_TYPE);
    $mimetype = finfo_buffer($finfo, $data);
    finfo_close($finfo);

    $handle = $data = null;

    return $mimetype;
}

So suppose you want to filter which types are allowed

$path = 'zipfile.zip';
$extrairPara = 'path/to/extraction/';

$zip = new ZipArchive;

if ($zip->open($path) === true) {

    for($i = 0; $i < $zip->numFiles; $i++) {
        $nome = $zip->getNameIndex($i);

        $mime = mimeTypeByResource($zip->getStream($nome)); //Verifica o mime depois de extrair

        //Extrai somente JPEG
        if ($mime === 'image/jpeg') {
             $zip->extractTo($extrairPara, array( $nome ));
        }
    }

    $zip->close();

}

You can then adapt to use with in_array, add before the for this:

//Tipos permitidos
$permitidos = array( 'image/jpeg', 'image/png', 'application/pdf' );

And then change inside the for for:

$mime = mimeTypeByResource($zip->getStream($nome)); //Verifica o mime depois de extrair

//Extrai somente os tipos permitos
if (in_array($mime, $permitidos)) {
     $zip->extractTo($extrairPara, array( $nome ));
}

---

Enabling fileinfo/finfo in php.ini

If finfo is not enabled you will get the following error message:

Call to Undefined Function finfo_open()

Then to enable the functions finfo_* it is necessary to edit the php.ini from your server, if it’s Windows Server (or Windows if it’s local) search on php.ini the following line:

 ;extension=php_fileinfo.dll

If it’s Linux or Mac look like this:

 ;extension=fileinfo.so

If PHP7.2 (in 7.1 and 7.0 is not so) is Linux, Mac or Windows:

 ;extension=fileinfo

then remove the ; from the front, save the edit and reboot your HTTP server such as Apache, Nginx or IIS