Use JSON to support control characters

[rathgar]

When exiftool returns tag fields on the command line it converts control characters into .

You'll be familiar with this if you try to import images that have CR (char(13)) in the Caption-Abstract.

This commit optionally supports the miniexif -j option via use_json: true. It will then use JSON to allow control characters in field values.

I'm happy to be told this isn't the way to do it - I just needed a solution to process text fields correctly - I can't be the only one.

[janfri]

Exiftool supports the -j option since version 7.65. So not to use JSON by default is a historic relict. I think it would be a better solution to check if exiftool is to old (< 7.65) and only in this the case use the "old" parse_line. A patch is very wellcome. :-)

[rathgar]

I've set it to use JSON by default now so long as exiftool is recent enough.

apologies
Unfortunately, this has revealed that the tests fail as a result of not letting exiftool mangle the output. I am working to get it to pass the tests now. Hopefully, I can do this without too much input but I may need to ask you the odd question so that I don't do things that conflict with your general intention or other users' expected behaviour.

[janfri]

I'm not yet happy. The exiftool version is a very global thing. So I would prefer to use a class variable (@@use_json) for the flag and set it in the setup class method (analog to @@Separator or @@sep_op).

[janfri]

So I've looked at your idea but the actual implementation dosn't pass all tests! Specially a defect encoding conversion is critical. I don't have much time at the moment and no idea how to fix it. :-(

[janfri]

I have mini_exiftool 2.0.0 released. It uses JSON to parse the exiftool output (need exiftool version 7.65 or higher) and drop Ruby 1.8 compatibility. So I hope that helps. :-)

[rathgar]

That's fantastic! Thanks.

I only wish I was able to contribute - I'll look out for other places I can help out.

[janfri]

@rathgar Make all tests pass on windows. ;-)

[rathgar]

ROFL! If I had a windows machine, I might give it a go :-P