exif_read_data

Reads the EXIF headers from an image file

&reftitle.description; ``array``false```exif_read_data` ``resource``string```file` ``string``null```required_sections`&null; `bool` `as_arrays`&false; `bool` `read_thumbnail`&false;

`exif_read_data` reads the EXIF headers from an image file. This way you can read meta data generated by digital cameras.

EXIF headers tend to be present in JPEG/TIFF images generated by digital cameras, but unfortunately each digital camera maker has a different idea of how to actually tag their images, so you can't always rely on a specific Exif header being present.

`Height` and `Width` are computed the same way `getimagesize` does so their values must not be part of any header returned. Also, `html` is a height/width text string to be used inside normal HTML.

When an Exif header contains a Copyright note, this itself can contain two values. As the solution is inconsistent in the Exif 2.10 standard, the `COMPUTED` section will return both entries `Copyright.Photographer` and `Copyright.Editor` while the `IFD0` sections contains the byte array with the NULL character that splits both entries. Or just the first entry if the datatype was wrong (normal behaviour of Exif). The `COMPUTED` will also contain the entry `Copyright` which is either the original copyright string, or a comma separated list of the photo and editor copyright.

The tag `UserComment` has the same problem as the Copyright tag. It can store two values. First the encoding used, and second the value itself. If so the `IFD` section only contains the encoding or a byte array. The `COMPUTED` section will store both in the entries `UserCommentEncoding` and `UserComment`. The entry `UserComment` is available in both cases so it should be used in preference to the value in `IFD0` section.

`exif_read_data` also validates EXIF data tags according to the EXIF specification (&url.exifspec;, page 20).

&reftitle.parameters;

`file`

- The location of the image file. This can either be a path to the file (stream wrappers are also supported as usual) or a stream `resource`.

`required_sections`

- Is a comma separated list of sections that need to be present in file to produce a result `array`. If none of the requested sections could be found the return value is &false;.

  FILE | FileName, FileSize, FileDateTime, SectionsFound
  COMPUTED | html, Width, Height, IsColor, and more if available. Height and Width are computed the same way `getimagesize` does so their values must not be part of any header returned. Also, `html` is a height/width text string to be used inside normal HTML.
  ANY_TAG | Any information that has a Tag e.g. `IFD0`, `EXIF`, ...
  IFD0 | All tagged data of IFD0. In normal imagefiles this contains image size and so forth.
  THUMBNAIL | A file is supposed to contain a thumbnail if it has a second `IFD`. All tagged information about the embedded thumbnail is stored in this section.
  COMMENT | Comment headers of JPEG images.
  EXIF | The EXIF section is a sub section of `IFD0`. It contains more detailed information about an image. Most of these entries are digital camera related.

`as_arrays`

- Specifies whether or not each section becomes an array. The `required_sections` `COMPUTED`, `THUMBNAIL`, and `COMMENT` always become arrays as they may contain values whose names conflict with other sections.

`read_thumbnail`

- When set to &true; the thumbnail itself is read. Otherwise, only the tagged data is read.

&reftitle.returnvalues;

It returns an associative `array` where the array indexes are the header names and the array values are the values associated with those headers. If no data can be returned, `exif_read_data` will return &false;.

&reftitle.errors;

Errors of level `E_WARNING` and/or `E_NOTICE` may be raised for unsupported tags or other potential error conditions, but the function still tries to read all comprehensible information.

&reftitle.changelog;

&Version; | &Description;
8.0.0 | `required_sections` is nullable now.
7.2.0 | The `file` parameter now supports both local files and stream resources.
7.2.0 | Support for the following EXIF formats were added: Samsung DJI Panasonic Sony Pentax Minolta Sigma/Foveon AGFA Kyocera Ricoh Epson

&reftitle.examples;

### `exif_read_data` example

    <?php
    echo "test1.jpg:<br />\n";
    $exif = exif_read_data('tests/test1.jpg', 'IFD0');
    echo $exif===false ? "No header data found.<br />\n" : "Image contains headers<br />\n";

    $exif = exif_read_data('tests/test2.jpg', 0, true);
    echo "test2.jpg:<br />\n";
    foreach ($exif as $key => $section) {
        foreach ($section as $name => $val) {
            echo "$key.$name: $val<br />\n";
        }
    }
    ?>

The first call fails because the image has no header information.

&example.outputs.similar;

    test1.jpg:
    No header data found.
    test2.jpg:
    FILE.FileName: test2.jpg
    FILE.FileDateTime: 1017666176
    FILE.FileSize: 1240
    FILE.FileType: 2
    FILE.SectionsFound: ANY_TAG, IFD0, THUMBNAIL, COMMENT
    COMPUTED.html: width="1" height="1"
    COMPUTED.Height: 1
    COMPUTED.Width: 1
    COMPUTED.IsColor: 1
    COMPUTED.ByteOrderMotorola: 1
    COMPUTED.UserComment: Exif test image.
    COMPUTED.UserCommentEncoding: ASCII
    COMPUTED.Copyright: Photo (c) M.Boerger, Edited by M.Boerger.
    COMPUTED.Copyright.Photographer: Photo (c) M.Boerger
    COMPUTED.Copyright.Editor: Edited by M.Boerger.
    IFD0.Copyright: Photo (c) M.Boerger
    IFD0.UserComment: ASCII
    THUMBNAIL.JPEGInterchangeFormat: 134
    THUMBNAIL.JPEGInterchangeFormatLength: 523
    COMMENT.0: Comment #1.
    COMMENT.1: Comment #2.
    COMMENT.2: Comment #3end
    THUMBNAIL.JPEGInterchangeFormat: 134
    THUMBNAIL.Thumbnail.Height: 1
    THUMBNAIL.Thumbnail.Height: 1

### `exif_read_data` with streams available as of PHP 7.2.0

    <?php
    // Open a the file, this should be in binary mode
    $fp = fopen('/path/to/image.jpg', 'rb');

    if (!$fp) {
        echo 'Error: Unable to open image for reading';
        exit;
    }

    // Attempt to read the exif headers
    $headers = exif_read_data($fp);

    if (!$headers) {
        echo 'Error: Unable to read exif headers';
        exit;
    }

    // Print the 'COMPUTED' headers
    echo 'EXIF Headers:' . PHP_EOL;

    foreach ($headers['COMPUTED'] as $header => $value) {
        printf(' %s => %s%s', $header, $value, PHP_EOL);
    }
    ?>

&example.outputs.similar;

    EXIF Headers:
     Height => 576
     Width => 1024
     IsColor => 1
     ByteOrderMotorola => 0
     ApertureFNumber => f/5.6
     UserComment =>
     UserCommentEncoding => UNDEFINED
     Copyright => Denis
     Thumbnail.FileType => 2
     Thumbnail.MimeType => image/jpeg

&reftitle.notes;

If mbstring is enabled, exif will attempt to process the unicode and pick a charset as specified by exif.decode_unicode_motorola and exif.decode_unicode_intel. The exif extension will not attempt to figure out the encoding on its own, and it is up to the user to properly specify the encoding for which to use for decoding by setting one of these two ini directives prior to calling `exif_read_data`.

If the `file` is used to pass a stream to this function, then the stream must be seekable. Note that the file pointer position is not changed after this function returns.

&reftitle.seealso;

- `exif_thumbnail`
- `getimagesize`
- wrappers