eCAP EXIF metadata filter

eCAP adapter for stripping EXIF and other metadata from files, primarly JPEG.

Installation

libecap and several other dependencies are required to build and use the adapter. libecap is available at http://e-cap.org/.

Dependencies:

• exiv2
• taglib
• libzip
• podofo

The adapter can be built and installed from sources, usually by running:

$ ./bootstrap.sh
$ ./configure
$ make
$ make install

Note: See README for more details.

Configuration

• tmp_filename_format Set the format of temporary files that will be processed by the adapter.
• memory_filesize_limit Files with size greater than limit will be stored in temporary disk storage, otherwise processing will be done in RAM.
• exclude_types List of semicolon seprated MIME types which shouldn't be handled by adapter.

Supported MIME types

• image/jpeg
• image/x-exv
• image/x-canon-cr2
• image/x-canon-crw
• image/tiff
• image/x-nikon-nef
• image/x-pentax-pef
• image/x-samsung-srw
• image/x-olympus-orf
• image/png
• image/pgf
• application/rdf+xml
• image/x-photoshop
• image/jp2
• audio/3gpp
• audio/3gpp2
• video/3gpp
• video/3gpp2
• audio/mp4
• audio/mp4a-latm
• audio/x-m4a
• video/mp4
• video/quicktime
• audio/mpeg
• audio/ogg
• application/pdf
• application/vnd.oasis.opendocument.text
• application/vnd.oasis.opendocument.presentation
• application/vnd.oasis.opendocument.spreadsheet
• application/vnd.oasis.opendocument.graphics
• application/vnd.openxmlformats-officedocument.wordprocessingml.document
• application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
• application/vnd.openxmlformats-officedocument.presentationml.presentation

Adapter is capable of processing messages with MIME type multipart/form-data by parsing the message and applying corresponding filter for every part of the message.

Messages with MIME type application/octet-stream are handled in a special way by checking actual type of the message content and applying corresonding filter (if any).

Squid configuration

Example configuration for stripping metadata from outgoing requests.

ecap_enable on
loadable_modules /usr/local/lib/ecap_adapter_exif.so
ecap_service eReqmod reqmod_precache bypass=off ecap://www.thecacheworks.com/exif-filter

adaptation_service_set reqFilter eReqmod
adaptation_access reqFilter allow all

To log debug messages use:

debug_options ALL,1 93,9