exif_read_data
(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
exif_read_data — Reads the EXIF headers from an image file
Description
resource|string
$file
,?string
$required_sections
= null
,bool
$as_arrays
= false
,bool
$read_thumbnail
= false
): array|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 (» http://exif.org/Exif2-2.PDF, page 20).
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
, andCOMMENT
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.
Return Values
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
.
Errors/Exceptions
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.
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:
|
Examples
Example #1 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.
The above example will output something similar to:
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
Example #2 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);
}
?>
The above example will output something similar to:
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
Notes
Note:
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().
Note:
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.
See Also
- exif_thumbnail() - Retrieve the embedded thumbnail of an image
- getimagesize() - Get the size of an image
- Supported Protocols and Wrappers