
WordPress高级自定义字段教程
wp_get_image_mime ( $file )
wp_get_image_mime: 该函数用于根据文件扩展名确定图像文件的MIME类型。它接受一个文件路径作为其唯一的参数,并返回图像的MIME类型。
返回一个图像文件的真实mime类型。
这取决于 exif_imagetype() 或 getimagesize() 来确定真正的 mime 类型。
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 ); } $mime = ( isset( $imagesize['mime'] ) ) ? $imagesize['mime'] : false; } else { $mime = false; } if ( false !== $mime ) { return $mime; } $magic = file_get_contents( $file, false, null, 0, 12 ); if ( false === $magic ) { return false; } /* * Add WebP fallback detection when image library doesn't support WebP. * Note: detection values come from LibWebP, see * https://github.com/webmproject/libwebp/blob/master/imageio/image_dec.c#L30 */ $magic = bin2hex( $magic ); if ( // RIFF. ( 0 === strpos( $magic, '52494646' ) ) && // WEBP. ( 16 === strpos( $magic, '57454250' ) ) ) { $mime = 'image/webp'; } } catch ( Exception $e ) { $mime = false; } return $mime; }