wp_get_image_mime( string $file ): string|false

Description

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$filestring

Full path to the file.

Return value

string|false

The actual mime type or false if the type cannot be determined.

Performance profile

How much work a call to wp_get_image_mime() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Heavy

Reads or writes the filesystem via file_get_contents().

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

16–101

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 131.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

5

5 places in core call this, so the cost is paid more often than your own code shows.

What it touches

• filesystemfilesystem accessfile_get_contents()called directly

What one call costs · 27 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_get_image_mime() can have, taken from its control-flow graph on PHP 8.5.

Uses · 4

• bin2hex()
• str_starts_with()Polyfill for `str_starts_with()` function added in PHP 8.0.
• hex2bin()
• wp_is_heic_image_mime_type()Checks if a mime type is for a HEIC/HEIF image.

Used by · 5

• WP_Image_Editor_GD::load()Loads image from $this->file into new GD Resource.
• wp_check_filetype_and_ext()Attempts to determine the real file type of a file.
• wp_get_avif_info()Extracts meta information about an AVIF file: width, height, bit depth, and number of channels.
• wp_get_webp_info()Extracts meta information about a WebP file: width, height, and type.
• wp_getimagesize()Allows PHP's getimagesize() to be debuggable when necessary.

Source code

View on Trac ↗View on GitHub ↗

3330function wp_get_image_mime( $file ) {3331	/*3332	 * Use exif_imagetype() to check the mimetype if available or fall back to3333	 * getimagesize() if exif isn't available. If either function throws an Exception3334	 * we assume the file could not be validated.3335	 */3336	try {3337		if ( is_callable( 'exif_imagetype' ) ) {3338			$imagetype = exif_imagetype( $file );3339			$mime      = ( $imagetype ) ? image_type_to_mime_type( $imagetype ) : false;3340		} elseif ( function_exists( 'getimagesize' ) ) {3341			// Don't silence errors when in debug mode, unless running unit tests.3342			if ( defined( 'WP_DEBUG' ) && WP_DEBUG && ! defined( 'WP_RUN_CORE_TESTS' ) ) {3343				// Not using wp_getimagesize() here to avoid an infinite loop.3344				$imagesize = getimagesize( $file );3345			} else {3346				$imagesize = @getimagesize( $file );3347			}3348 3349			$mime = ( isset( $imagesize['mime'] ) ) ? $imagesize['mime'] : false;3350		} else {3351			$mime = false;3352		}3353 3354		if ( false !== $mime ) {3355			return $mime;3356		}3357 3358		$magic = file_get_contents( $file, false, null, 0, 12 );3359 3360		if ( false === $magic ) {3361			return false;3362		}3363 3364		/*3365		 * Add WebP fallback detection when image library doesn't support WebP.3366		 * Note: detection values come from LibWebP, see3367		 * https://github.com/webmproject/libwebp/blob/master/imageio/image_dec.c#L303368		 */3369		$magic = bin2hex( $magic );3370		if (3371			// RIFF.3372			( str_starts_with( $magic, '52494646' ) ) &&3373			// WEBP.3374			( 16 === strpos( $magic, '57454250' ) )3375		) {3376			$mime = 'image/webp';3377		}3378 3379		/**3380		 * Add AVIF fallback detection when image library doesn't support AVIF.3381		 *3382		 * Detection based on section 4.3.1 File-type box definition of the ISO/IEC 14496-123383		 * specification and the AV1-AVIF spec, see https://aomediacodec.github.io/av1-avif/v1.1.0.html#brands.3384		 */3385 3386		// Divide the header string into 4 byte groups.3387		$magic = str_split( $magic, 8 );3388 3389		if ( isset( $magic[1] ) && isset( $magic[2] ) && 'ftyp' === hex2bin( $magic[1] ) ) {3390			if ( 'avif' === hex2bin( $magic[2] ) || 'avis' === hex2bin( $magic[2] ) ) {3391				$mime = 'image/avif';3392			} elseif ( 'heic' === hex2bin( $magic[2] ) ) {3393				$mime = 'image/heic';3394			} elseif ( 'heif' === hex2bin( $magic[2] ) ) {3395				$mime = 'image/heif';3396			} else {3397				/*3398				 * HEIC/HEIF images and image sequences/animations may have other strings here3399				 * like mif1, msf1, etc. For now fall back to using finfo_file() to detect these.3400				 */3401				if ( extension_loaded( 'fileinfo' ) ) {3402					$fileinfo  = finfo_open( FILEINFO_MIME_TYPE );3403					$mime_type = finfo_file( $fileinfo, $file );3404					finfo_close( $fileinfo );3405 3406					if ( wp_is_heic_image_mime_type( $mime_type ) ) {3407						$mime = $mime_type;3408					}3409				}

Changelog

Introduced in 4.7.1. Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 6.8.8 tag, from src/wp-includes/functions.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

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