Move command should support copying files without modifying database

[fortes]

Currently the copy flag on the move command will copy files and change their paths in the database. It would be useful to have a version of this that copies without modifying the library.

[sampsyo]

Good idea. Maybe the flag should be called -e for --external or --export?

[fortes]

Export makes sense. Could also be a separate command instead of just a flag. I think either will work.

[ghost]

Hey guys! we would like to tackle this issue, if anyone is going to work on this soon let me know so we can look at other issues! We're planning to start working on this on Monday February 1st. Thanks! -Jake

[SpirosChadoulos]

Greetings..I was thinking about tackling this issue but it is really old. Is it worth tackling it or not? Thanks a lot.

[sampsyo]

Absolutely, if you're interested!

[SpirosChadoulos]

Nice, could you explain me what you want me to do exactly?

[sampsyo]

The idea would be to add a flag to the move command, with one of the names above, that works like the current -c (copy) option but slightly different. Where the current option does two things—it copies the files and also updates the library database—the new -e option would instead copy the file but leave the database unchanged. I think that will involve a call along the lines of util.copy(item.path, item.destination(basedir=...)).

[SpirosChadoulos]

Should I do that in the commnad.py file or somewhere else?

[sampsyo]

Right in commands.py is the right place.

[SpirosChadoulos]

Could you explain to me briefly how the move_items function works in commands.py(line1453)?
Thanks a lot.

[sampsyo]

I'd be happy to explain more, but can I please ask you to be specific with your question? The comments we've put there are already my best effort at explaining what's going on. What part specifically are you wondering about?

[SpirosChadoulos]

I see that the move_items function is where the move command is executed but I can't distinguish where the database interaction is happening.

[sampsyo]

Aha! Good question. That's the obj.remove call, which invokes either Item.remove or Album.remove, which are defined in library.py.

[SpirosChadoulos]

In line 1491 in command.py obj.move is called. obj.remove is called at line 1217. I am kind of confused with the code that is executed when the user uses the move command.

[sampsyo]

Oops! I'm so sorry; I lost track of what we were talking about and looked at the wrong function (delete_items). Anyway, you're right—the call to obj.move is the one you're looking for. That both moves the file and updates the stored path to reflect the new location.

[SpirosChadoulos]

So should I make changes to the move_items function in commands.py or in the move function in the Item class in library.py?

[sampsyo]

Good question! Just in the move_items function there. Let's leave the core library functionality unchanged—we can just change the way we invoke it.

[SpirosChadoulos]

I think that the move command is specifically happening at line 1491:obj.move(copy, basedir=dest). If this is true how am I supposed to make it so that the database path doesn't change?

[sampsyo]

There's no current way to make item.move not update the database—updating the database is its purpose in life—but I suggested an alternative solution above in #435 (comment). Alternatively, if you think it would be easier to just add a simple change to library.py, we can of course discuss that too.

[SpirosChadoulos]

What do you mean by adding a flag to the move command?

[sampsyo]

I just mean adding one more command-line option, like these ones:
https://github.com/beetbox/beets/blob/master/beets/ui/commands.py#L1506-L1524

[SpirosChadoulos]

Something like: move_cmd.parser.add_option( u'-e', u'--export', default=False, action='store_true', help=u'...' ) ?? And then where do I write the main code of the feature??

[sampsyo]

Yep, like that! Then, you'll notice that the options get exposed in the opts argument to the command function, and then those values get passed to the move_items function. That last function is where the actual work will go.

[SpirosChadoulos]

What do you mean by exposed?

[sampsyo]

The values are available—for example, as opts.pretend and opts.force here: https://github.com/beetbox/beets/blob/master/beets/ui/commands.py#L1562

[SpirosChadoulos]

So the work that will happen in the move_items function should be in an if statement like if export ??

[sampsyo]

Yep, exactly!

[SpirosChadoulos]

Okay I will start the work and stay in touch for any further explanation. Thanks a lot!