Sharp: How to decode metadata EXIF buffer?

[rayshan]

Hi, I tried to console.log(metadata.exif.toString()) and it returns semi-scrambled text like below:

ExifMnv(;   ~�� ��i��%nHHRay ShanRay Shan�0230�����P�0100��P2015:08:21 23:11:23ASCIIMETAR MMMX 220347Z 07003KT 8SM OVC080 16/12 A3036 NOSIG RMK 8/07/ HZY SCR980100N�W���dc   ad
                          $�G

[lovell]

Hello, the functional tests use the exif-reader module for this purpose - see https://github.com/lovell/sharp/blob/master/test/unit/metadata.js#L46-L49

[rayshan]

Ahh, I should always check the tests first. Thanks!

[ickata]

Hi @lovell ,

Even with the exif-reader module I get the following exif properties as buffers:

• 'ExifVersion'
• 'ComponentsConfiguration'
• 'MakerNote'
• 'FlashpixVersion'
• 'SceneType'

But when I try to stringify them like exifdata.MakerNote.toString( 'utf8' ) I get this:

Apple iOS\u0000\u0000\u0001MM\u0000\u000b\u0000\u0001\u0000\t\u0000\u0000\u0000\u0001

Any advice?

[lovell]

@ickata These properties are all Buffers rather than strings - you'll need something to decode the raw proprietary data they contain.

[ickata]

Thanks for the clarification, @lovell . And also many thanks for this great module!

[papandreou]

@ickata If you're going to read the exif data of images from untrusted sources, I recommend using the https://npmjs.org/package/exif-reader-paras20xx fork, which has been hardened with a bunch of range checks (https://github.com/devongovett/exif-reader/pull/5). The original module doesn't validate the offsets in the exif blob and will loop for a long time or run out of memory with certain kinds of corrupted or malicious exif data.

[jsdevtom]

exif-reader now validates the offsets in the exif blob

[lovell]

I recently became a maintainer of the https://github.com/devongovett/exif-reader repo so was able to merge @papandreou's fixes and publish them in a new version of the original https://www.npmjs.com/package/exif-reader module.