bring back exiv2json (or remove the remnants from the repo)

[jpicht]

Is your feature request related to a problem?

The exiv2json sample has been removed by #2183, but is still referenced in the docs, vs2019 project, doxygen, and tests/suite.conf. As I'm using it (indirectly) in some scripts I'd like for it to come back.

It has been part of the exiv2 binary package for my linux distribution for quite a long time, so I never realized it wasn't in fact supported, but just a sample.

Describe the solution you would like

I'd like the merge be reverted and the problem with the aging JSON library be solved by porting to a newer json-library like (for example) nlohmann/json. As I'm familiar with that library, I would volunteer to do the work, if the MIT license is acceptable for you to include that as a dependency.

Describe alternatives you have considered

Providing a compatible tool, probably based on the last version, as a third-party package.

[MuhammadSYahyaS]

I found a simple workaround for this using Boost.PropertyTree v1.74.0 or later. Check https://github.com/MuhammadSYahyaS/exiv2json for the code.

[piponazo]

Hi @jpicht , thanks for your message.

We would be happy to accept any examples that would be beneficial for Exiv2 users. Although I am not an expert in terms of licensing, I think the MIT one would conflict with the GPLv2 license of Exiv2.

If you would propose an addition which does not conflict with the GPLv2, we would be happy to incorporate it to the project.

[jpicht]

Hi @piponazo,

I'm not a legal expert by far, but as far as I can tell, the MIT license is one of the most compatible licenses out there. In my opinion: it would not clash with GPLv2, the authors of the wikipedia page for that license seem to agree.

Edit: gnu.org also agrees, though they call the license "expat license".