Convert a ROOT File to a JSON

[hep_physics]

I have read that I can convert the ROOT file into a JSON using TBufferJSON. Is there a simple example do start with ?

[Danilo]

Hi,

you cannot convert files but rather single objects which are not TTrees.
The operation is very easy: https://root.cern.ch/doc/master/classTBufferJSON.html#a2dd3ce085948fcee17114cdaf3325575

Cheers,
D

[linev]

Hi,

In ROO5 docu there is simple example:

https://root.cern/root/html534/TBufferJSON.html

If you want to save result into text file, you can directly use method TBufferJSON::ExportToFile

https://root.cern.ch/doc/master/classTBufferJSON.html#a99af349993de8ed1a8736aba15faf4f1

This method used, when you call obj->SaveAs(“file.json”);

Regards,
Sergey

[hep_physics]

Great, exactly what I was looking for !

I am on ROOT v6.04, and couldn’t find TBufferJSON.h header file in the $ROOTSYS/include directory. Is it included by default during installation?

[linev]

Hi,

For ROOT 6.04 you should enable compilation of http server.
With cmake:

cmake -Dhttp=ON

Regards,
Sergey

[hep_physics]

I have recompiled ROOT for JSON. Noticed that in my ROOT version, the ExportToFile is not available, checked the include file, didn’t find such a method obviously. Is it possible to write to a JSON file or I have to just write to a file manually ?

[linev]

Hi,

If your ROOT version does not have TBufferJSON::ExportToFile function,
you need to create text file yourself.

Sorry, I somehow miss notification for this topic.

Regards,
Sergey