How to create an adb shell am like argument parser in python?

Question

The adb shell am command (activity manager) has parameters like this:

 [--eia <EXTRA_KEY> <EXTRA_INT_VALUE>[,<EXTRA_INT_VALUE...]]

To my knowledge argparse is the python way to parse arguments. I'd need an action that should:

• consists of 2 or more arguments (eg. --eia key1 1 2 3) (see last point)
• is optional
• edit it can occour multiple times, eg. --eia key1 1,2 --eia key2 2,1 is valid
• the type of the first argument may differ from the type of the rest
• other optional arguments like this can exist
• the example has the delimiter of a , but I'd like to allow delimiting with spaces, because my actual argument values may be strings and I'd like to leave parsing them to the shell (if a string should start with -, quotation marks help: "-asdf")

An other question has an answer that can do this with positional arguments:

parser = argparse.ArgumentParser(usage='%(prog)s [-h] file file [file ...]')
parser.add_argument('file1', nargs=1, metavar='file')
parser.add_argument('file2', nargs='+', metavar='file', help=argparse.SUPPRESS)
namespace = parser.parse_args()
namespace.file = namespace.file1 + namespace.file2

But I cannot see if these works for optional arguments too?

With my requirements is it a good idea to start with argparse at all? Are there other options?

Answer 1

- consists of 2 or more arguments (eg. --eia key1 1 2 3) (see last point)

There is a proposed patch that would allow nargs like 2 or more, modeled on the re {n,m} notation. But for now I think nargs='+' is your best bet. The important thing is that it grabs the necessary arguments. You can check for '2 or more' after parse_args (a custom type could also check that).

- is optional

Use of the --eia flag takes care of that

- edit it can occour multiple times, eg. --eia key1 1,2 --eia key2 2,1 is valid

With the --eia flag that is allowed, but only the last entry is preserved. But action='append' will save each entry set as a list (or tuple?); so the namespace will have args.eia = [['key1','1','2'],['key2',...],...]. Play with with action type and verify this.

- the type of the first argument may differ from the type of the rest

Leaving the values as strings, and doing your own transformation after is simplest. You could write a custom type (or action) to check the values. But the code would be similar to what you'd used after argparse.

- other optional arguments like this can exist

That's going to depend on how you write the added code.

- the example has the delimiter of a , but I'd like to allow delimiting with spaces, because my actual argument values may be strings and I'd like to leave parsing them to the shell (if a string should start with -, quotation marks help: "-asdf")

The primary shell, the one the calls your script, is the one that splits the command line into strings, primarily on spaces. argparse uses sys.argv, that list of strings. If that list is not what you want, you'll have to fiddle with it before passing it to argparse.parse_args(argv).

A common way to test argparse is:

parser.parse_args('--eia key1 1,2 --eia key2 2,1'.split())

The replicates the main splitting on spaces, but does not deal with quoting and escape characters as the shell would. There is a way of replicating the shell action, but I'd have to dig around to find it.