digitalevidencetoolkit / clj-exif

Read and write image EXIF data with Clojure

clj-exif

A Clojure library intended to provide an easier interface to reading and writing metadata associated with image files. Really just wraps a small part of org.apache.commons/commons-imaging to achieve this. NOTE: commons-imaging is not fully developed and is not producing official releases yet, so tread carefully when using this library.

Current state is far from thorough, code has only been evaluated with a small number of JPEG files.

Usage

See src/clj-exif/examples.clj for code examples. In brief:

Read metadata:

(require '[clj-exif.core :as exif])
(let [input-file (java.io.File. "/path/to/file.jpg")
      metadata (exif/get-metadata input-file)]
  (println (exif/read metadata)))

{Root {ExifOffset 194, XResolution 72, ....

Write metadata:

Currently in-place modification is not supported. However, it is possible to copy an image with an updated metadata set to a new file.

(require '[clj-exif.core :as exif])
(import
    '[org.apache.commons.imaging.formats.tiff.constants
       TiffDirectoryConstants
       TiffTagConstants])
(let [input-file (java.io.File. "/path/to/file.jpg")
      output-file (java.io.File. "/tmp/output.jpg")
      metadata (exif/get-metadata input-file)
      ;; output-set is a writeable copy of the data retrieve from input-file.
      output-set (exif/get-output-set metadata)]
  (exif/update-value output-set
                     TiffDirectoryConstants/DIRECTORY_TYPE_ROOT
                     TiffTagConstants/TIFF_TAG_MAKE
                     ["this is a new value"])
  (exif/copy-file-with-new-metadata input-file output-file output-set))

TODO

• Don't rely on a snapshot release of commons-imaging.
• Evaluate different input formats and file types.

License

Copyright © 2014 Oliver McCormack

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.