exif_imagetype - PHP code example

How to Use the PHP Function Exif_ImageType

If you want to work with Exif data in PHP (Metadata of image files) you may need the php function exif_imagetype. But when you try to use it you get the error: call to undefined function exif_imagetype(). So what's the solution?

This article will show you how to solve the issue.

The php function exif_imagetype reads the first bytes of an image file and checks its signature. When a correct signature is found a constant value will be returned, else FALSE. The constants are: 1 = IMAGETYPE_GIF, 2 = IMAGETYPE_JPG, 3 = IMAGETYPE_PNG, 4 = IMAGETYPE_SWF, 5 = IMAGETYPE_PSD, 6 = IMAGETYPE_BMP, 7 = IMAGETYPE_TIFF_II (intel byte order), 8 = IMAGETYPE_TIFF_MM (motorola byte order) and 9 = IMAGETYPE_JPC.

It can be used to avoid calls to other exif functions with unsupported file teypes or in conjunction with $_SERVER['HTTP_ACCEPT'] to check whether an image is allowed in the web browser.

exif_imagetype example

function wp_get_image_mime( $file ) {
    /* * Use exif_imagetype() to check the mimetype if available or fall back to * getimagesize() if exif isn't available. If either function throws an Exception * we assume the file could not be validated. */
    try {
        if ( is_callable( 'exif_imagetype' ) ) {
            $imagetype = exif_imagetype( $file );
            $mime      = ( $imagetype ) ? image_type_to_mime_type( $imagetype ) : false;
        } elseif ( function_exists( 'getimagesize' ) ) {
            // Don't silence errors when in debug mode, unless running unit tests.             if ( defined( 'WP_DEBUG' ) && WP_DEBUG
                && ! defined( 'WP_RUN_CORE_TESTS' )
            ) {
                // Not using wp_getimagesize() here to avoid an infinite loop.                 $imagesize = getimagesize( $file );
            } else {
                // phpcs:ignore WordPress.PHP.NoSilencedErrors                 $imagesize = @getimagesize( $file );
            }