maloja/doreah/settings.py

import os
import shutil

# set configuration
# defaultextension	unused
# files				list of all files that will be used for configuration. high indicies overwrite low indicies
# comment			symbols that indicate comments. careful!
# category			symbols that indicate start and end of category name. only works at start of line
# onlytext			interpret everything as a string. if False, strings can be put into quotes to avoid confusion
def config(defaultextension=".ini",files=["settings.ini","settings.conf","configuration.ini","configuration.conf"],
			comment=["#","//"],category=("[","]"),onlytext=False):
	global _defaultextension, _files, _comment, _category, _onlytext
	_defaultextension = defaultextension
	_files = files
	_comment = comment
	_category = category
	_onlytext = onlytext


	global Settings, get_settings, update_settings, update


	# manager object so we can read settings once and retain them
	class Settings:
		def __init__(self,**kwargs):
			self.settings = get_settings(**kwargs)

		def get(self,*keys):
			result = (self.settings.get(k) for k in keys)
			if len(result) == 1: result = result[0]
			return result




	def _interpret(text):
		if _onlytext: return text

		if text.lower() in ["true","yes"]: return True
		if text.lower() in ["false","no"]: return False
		if text.lower() in ["none","nan","n/a",""]: return None
		if text.startswith("'") and text.endswith("'"): return text[1:-1]
		if text.startswith('"') and text.endswith('"'): return text[1:-1]
		try:
			return int(text)
		except:
			pass
		try:
			return float(text)
		except:
			pass
		return text


	# get settings
	# keys			list of requested keys. if present, will return list of according values, if not, will return dict of key-value pairs
	# files			which files to parse. later files (higher indicies) will overload earlier ones
	# prefix		only request keys with a certain prefix. key filter will still be applied if present
	# cut_prefix	return keys without the prefix
	# category		return only keys of specific category
	# raw			do not interpret data type, only return strings
	def get_settings(*keys,files=_files,prefix="",cut_prefix=False,category=None,raw=False):

		allsettings = {}

		for f in files:
			if not os.path.exists(f): continue

			# if category is specified, ignore all entries by default and switch when we encounter the right heading
			ignore = False if category is None else True

			with open(f) as file:
				lines = file.readlines()


			for l in lines:
				# clean up line
				l = l.replace("\n","")
				for symbol in _comment:
					l = l.split(symbol)[0]
				l = l.strip()

				# check if valid settings entry
				if l == "": continue
				if l.startswith(_category[0]):
					# ignore category headers if we don't care
					if category is None: continue
					# otherwise, find out if this is the category we want
					else:
						if l.endswith(_category[1]):
							cat = l[len(_category[0]):-len(_category[1])]
							ignore = not (cat == category) #if this is the right heading, set ignore to false
						continue

				if ignore: continue

				if "=" not in l: continue

				# read
				(key,val) = l.split("=")
				key = key.strip()
				val = val.strip() if raw else _interpret(val.strip())

				if key.startswith(prefix):
					# return keys without the common prefix
					if cut_prefix:
						allsettings[key[len(prefix):]] = val

					# return full keys
					else:
						allsettings[key] = val

		# no arguments means all settings
		if len(keys) == 0:
			return allsettings

		# specific keys requested
		else:
			if len(keys) == 1: return allsettings.get(keys[0])
			else: return [allsettings.get(k) for k in keys]


	def update_settings(file,settings,create_new=False):

		if not os.path.exists(file): open(file,"w").close()

		with open(file,"r") as origfile:
			lines = origfile.readlines()

		newlines = []

		for origline in lines:
			l = origline
			# clean up line
			l = l.replace("\n","")
			for symbol in _comment:
				l = l.split(symbol)[0]
			l = l.strip()

			# check if valid settings entry
			if l == "":
				newlines.append(origline)
				continue
			if l.startswith(_category[0]):
				newlines.append(origline)
				continue
			if "=" not in l:
				newlines.append(origline)
				continue

			# read
			(key,val) = l.split("=")
			key = key.strip()
			val = val.strip()


			if key not in settings:
				newlines.append(origline)
				continue

			else:
				#print("Found key")
				newline = origline.split("=",1)
				#print({"linepart":newline[1],"keytoreplace":val,"new":settings[key]})
				newline[1] = newline[1].replace(val,str(settings[key]),1)
				newline = "=".join(newline)
				newlines.append(newline)

				del settings[key]

		if create_new:
			# settings that were not present in the file
			for key in settings:
				newlines.append(key + " = " + settings[key] + "\n")

		with open(file,"w") as newfile:
			newfile.write("".join(newlines))




	# updates a user settings file to a newer format from a default file without overwriting user's settings
	def update(source="default_settings.ini",target="settings.ini"):

		if not os.path.exists(target):
			shutil.copyfile(source,target)
		else:
			usersettings = get_settings(files=[target],raw=True)
			shutil.copyfile(source,target)
			update_settings(target,usersettings)


# initial config on import, set everything to default
config()