PHP implementation code for getting the binary file header to quickly determine the file type

The following code identifies the actual type of a file by reading the file header information. If you need a friend, you can refer to it. generally, we judge the file type based on the file extension, but this is very unreliable and can be easily avoided by modifying the extension, it is generally necessary to read the file information for identification. PHP extensions provide functions such as exif_imagetype to read Image file types. However, in many cases, extensions are not necessarily installed, sometimes you need to identify the file type on your own.

The following code identifies the actual type of a file by reading the file header information.
The code is as follows:
$ Files = array (
'C: \ 1.jpg ',
'C: \ 1.png ',
'C: \ 1.gif ',
'C: \ 1.rar ',
'C: \ 1.zip ',
'C: \ 1.exe ',
);
Foreach ($ files AS $ file ){
$ Fp = fopen ($ file, "rb ");
$ Bin = fread ($ fp, 2); // read-only 2 bytes
Fclose ($ fp );
$ Str_info = @ unpack ("C2chars", $ bin );
$ Type_code = intval ($ str_info ['chars1']. $ str_info ['chars2']);
$ File_type = '';
Switch ($ type_code ){
Case 7790:
$ File_type = 'exe ';
Break;
Case 7784:
$ File_type = 'midi ';
Break;
Case 8075:
$ File_type = 'Zip ';
Break;
Case 8297:
$ File_type = 'rar ';
Break;
Case 255216:
$ File_type = 'jpg ';
Break;
Case 7173:
$ File_type = 'GIF ';
Break;
Case 6677:
$ File_type = 'bmp ';
Break;
Case 13780:
$ File_type = 'PNG ';
Break;
Default:
$ File_type = 'unknown ';
Break;
}

Echo $ file, 'type: ', $ File_type ,'Code: ', $ Type_code ,'
';

}

Output result in this example
C: \ 1.jpg type: jpg code: 255216
C: \ 1.png type: png code: 13780
C: \ 1.gif type: gif code: 7173
C: \ 1.rar type: rar code: 8297
C: \ 1.zip type: zip code: 8075
C: \ 1.exe type: exe code: 7790