Set the crate root directory without loading

[multimeric]

Let's say you have a directory with data files in it that you want to document, but it's not the current working directory. You also don't have an ro-crate-metadata.json yet.

/path/to/crate/
    some_file.txt

If you crate = ROCrate("/path/to/crate"), you will get ValueError: Not a valid RO-Crate: missing ro-crate-metadata.json.

If you use:

crate = ROCrate()
crate.add_file("some_file.txt")
crate.write("/path/to/crate")

You get FileNotFoundError: [Errno 2] No such file or directory: 'some_file.txt'

Even if you try to hack it:

crate = ROCrate()
crate.source = "/path/to/crate"
crate.add_file("some_file.txt")
crate.write("/path/to/crate")

This fails with FileNotFoundError: [Errno 2] No such file or directory: 'some_file.txt', because it uses self.source as the file path which isn't resolved relative to `crate.source.

I could write out the absolute path of each entity, but it's a bit verbose.

[simleo]

Try this:

>>> from rocrate.rocrate import ROCrate
>>> crate = ROCrate("/path/to/crate", init=True)
>>> crate.source
'/path/to/crate'
>>> f = crate.get("some_file.txt")
>>> f["encodingFormat"] = "audio/mpeg"
>>> crate.write(crate.source)

ROCrate("/path/to/crate", init=True) means you don't want to read a crate at that path, but initialize one based on the directory tree rooted at that path (the tree is walked recursively, adding files as File and directories as Dataset)