Commit b765922b0d6914131132584121b79bd0477186a6 - dmesktop

Add basic dmesktop script Getty Ritter 5 years ago

1 changed file(s) with 154 addition(s) and 0 deletion(s). Collapse all Expand all

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dmesktop.py less more

	1	#!/usr/bin/env python3
	2
	3	import os
	4	import re
	5	import subprocess
	6	import sys
	7	from typing import List, Mapping, NamedTuple, Union
	8
	9	# compiled regexes for faux-parsing INI files
	10	KV = re.compile('([A-Za-z0-9-](\[[A-Za-z@_]\])?)=(.*)')
	11	SECTION = re.compile('\[([A-Za-z -]*)\]')
	12	METAVAR = re.compile('%.')
	13	# default argv for running dmenu
	14	DMENU_CMD = ['dmenu', '-i', '-l', '10']
	15
	16	# this is probably not right, in the long term!
	17	XDG_APP_DIRS = [
	18	'/usr/share/applications',
	19	os.path.join(os.getenv('HOME'), '/.local/share/applications'),
	20	]
	21
	22	class DesktopEntry(NamedTuple):
	23	'''This is our wrapper struct for .desktop files. Right now, we only
	24	bother caring about the name, the command to execute, the type,
	25	and the other associated actions. Eventually this could be expanded?
	26	'''
	27	name: str
	28	exec: str
	29	type: str
	30	actions: Mapping[str, 'DesktopEntry']
	31
	32	@classmethod
	33	def from_map(cls, m: Mapping[str, Union[str, Mapping[str, str]]]) -> 'DesktopEntry':
	34	'''Constructor function to take the key-value map we create in reading
	35	the file and turn it into a DesktopEntry.
	36	'''
	37	actions = dict(((e['Name'], cls.from_map(e))
	38	for e in m.get('ACTIONS', {}).values()))
	39	return cls(
	40	m['Name'],
	41	m['Exec'],
	42	m.get('Type', None),
	43	actions,
	44	)
	45
	46	def command(self) -> str:
	47	'''Clean out the metavariables we don't care about in
	48	the provided Exec field
	49	'''
	50	return METAVAR.sub('', self.exec)
	51
	52	def main():
	53	ensure_dmenu()
	54	desktop_entries = get_all_entries()
	55
	56	# let's only ask about Applications for now, at least
	57	all_choices = sorted([key for (key, e)
	58	in desktop_entries.items()
	59	if e.type == 'Application'])
	60	choice = dmenu_choose(all_choices)
	61	if choice in desktop_entries:
	62	try:
	63	entry = desktop_entries[choice]
	64	if not entry.actions:
	65	os.execvp('/bin/sh', ['sh', '-c', entry.command()])
	66	else:
	67	choice = dmenu_choose(entry.actions.keys())
	68	if choice in entry.actions:
	69	entry = entry.actions[choice]
	70	os.execvp('/bin/sh', ['sh', '-c', entry.command()])
	71	except Exception as e:
	72	# this should be more granular eventually!
	73	pass
	74
	75	def dmenu_choose(stuff: List[str]) -> str:
	76	'''Given a list of strings, we provide them to dmenu and
	77	return back which one the user chose (or an empty string,
	78	if the user chose nothing)
	79	'''
	80	choices = '\n'.join(stuff).encode('utf-8')
	81	dmenu = subprocess.Popen(
	82	DMENU_CMD,
	83	stdin=subprocess.PIPE,
	84	stdout=subprocess.PIPE)
	85	# we probably shouldn't ignore stderr, but whatevs
	86	choice, _ = dmenu.communicate(choices)
	87	return choice.decode('utf-8').strip()
	88
	89	def get_all_entries() -> Mapping[str, DesktopEntry]:
	90	'''Walk the relevant XDG dirs and parse all the Desktop files we can
	91	find, returning them as a map from the Name of the desktop file to
	92	the actual contents
	93	'''
	94	desktop_entries = {}
	95
	96	# walk all the app dirs
	97	for dir in XDG_APP_DIRS:
	98	for root, dirs, files in os.walk(dir):
	99	# for whatever .desktop files we find
	100	for f in files:
	101	if f.endswith('.desktop'):
	102	# add 'em to our Name-indexed map of files
	103	entry = parse_entry(os.path.join(root, f))
	104	desktop_entries[entry.name] = entry
	105
	106	return desktop_entries
	107
	108	def parse_entry(path: str) -> DesktopEntry:
	109	'''Read and parse the .desktop file at the provided path
	110	'''
	111	# the `entry` is the basic key-value bag for the whole file
	112	entry = {}
	113	# but `current_bag` points to the current section being parsed,
	114	# which may or may not be the current overall file
	115	current_bag = entry
	116	with open(path) as f:
	117	for line in f:
	118	# this will be non-None if it's of the form `Key=Value`
	119	match = KV.match(line)
	120	# this will be non-None if it's of the form `[Name]`
	121	sect = SECTION.match(line)
	122	if match:
	123	# if it's a key-value pair, add it to the current bag
	124	current_bag[match.group(1)] = match.group(3)
	125	elif sect and sect.group(1) != 'Desktop Entry':
	126	# if it's a section header, then we ask: is it the
	127	# Desktop Entry section, which is the main obligatory
	128	# chunk of a desktop file? If so, then we ignore this
	129	# chunk entirely. Otherwise: make sure we have an
	130	# ACTIONS field
	131	actions = entry.get('ACTIONS', {})
	132	# create a new key/value map for this new sub-entry
	133	current_bag = {}
	134	# add the new key/value map to the actions map
	135	actions[sect.group(1)] = current_bag
	136	# and make sure the ACTIONS key points to that map
	137	entry['ACTIONS'] = actions
	138
	139	# wrap it in in our nice wrapper type, too!
	140	return DesktopEntry.from_map(entry)
	141
	142	def ensure_dmenu():
	143	'''Shells out to `which` to find out whether dmenu is installed. We
	144	won't do anything useful if it's not, after all!
	145	'''
	146	try:
	147	subprocess.check_output(['which', 'dmenu'])
	148	except subprocess.CalledProcessError:
	149	sys.stderr.write("Error: could not find `dmenu'\n")
	150	sys.exit(99)
	151
	152
	153	if __name__ == '__main__':
	154	main()