README

This simple library makes it easy to read EXIF data from JPEG and TIFF files. It handles NUL-bytes correctly and automatically converts GPS coordinates to floating point numbers.

Installation

composer require 1tomany/exif-tools

Usage

Using the library is simple:

require_once __DIR__.'/vendor/autoload.php';

use OneToMany\Reader\ExifTagReader;

// $exifTags is an ExifMap object
$exifTags = new ExifTagReader()->read('/path/to/photo.jpeg');

var_dump($exifTags->has('FileName')); // bool(true)
var_dump($exifTags->get('FileName')->value()); // string(10) "photo.jpeg"

// Iterate over the tags
foreach ($exifTags as $tag => $value) {
    printf("%s: %s\n", $tag, $value);
}

Behind the scenes, each EXIF tag value is an object of type ExifValue. The ExifValue object can represent an integer, a string, an ExifList, or an ExifMap. Each element of an ExifList and ExifMap object is also an ExifValue object.

Timestamps

ExifMap objects have a method named capturedAt() that attempts to create a \DateTimeImmutable object that best represents when the photo was taken. In order, it analyzes the following tags: DateTimeOriginal, DateTimeDigitized, and DateTime. The first tag that creates a valid \DateTimeImmutable object is returned as the captured date.

Additionally, ExifMap objects have a method named getTimestamp(string $tag) that will attempt to convert any tag to a \DateTimeImmutable object. Only integer and string ExifValue objects are considered - lists and maps will always return null.

GPS Coordinates

ExifMap objects have a method named gps() that will attempt to read the GPSLatitude, GPSLatitudeRef, GPSLongitude, GPSLongitudeRef, GPSAltitude, and GPSAltitudeRef tags and convert them to their floating point equivalents. The gps() method returns an object of type GpsValue. The GpsValue object has three properties:

• ?float $latitude
• ?float $longitude
• ?float $altitude

These properties will be a non-null floating point number if the value was found in the EXIF tag. A positive $altitude represents the altitude in meters above sealevel, and a negative $altitude represents the same below sealevel.

Binary Conversion

Some EXIF tags store data encoded as binary bytes. For example, the tag ComponentsConfiguration stores a list of numbers as a NUL-terminated string. This library will unpack any control characters and convert them to their integer or list equivalents so the data can be safely encoded as JSON and stored in a database as text.

Credits

• Vic Cherubini, 1:N Labs, LLC

License

The MIT License