dotfoles/scripts/xpath

#!/usr/bin/env python
#
# Copy me if you can.
# by 20h
#

import os
import sys
import getopt
from lxml import etree

def getxpath(fd, xpath, attribute=None, encoding=None):
	try:
		parser = etree.HTMLParser(encoding=encoding)
		xml = etree.parse(fd, parser)
		sels = xml.xpath(xpath)
	except AssertionError:
		return None

	if attribute != None:
		return "\n".join(["".join(i.attrib[attribute]) for i in sels \
			if attribute in i.attrib])

	try:
		return "\n".join([("".join(i.itertext())).strip() for i in sels])
	except AttributeError:
		return "\n".join(sels)

def usage(app):
	app = os.path.basename(app)
	sys.stderr.write("usage: %s [-h] [-e encoding] "\
			"[-a attribute] xpath\n" % (app))
	sys.exit(1)

def main(args):
	try:
		opts, largs = getopt.getopt(args[1:], "he:a:")
	except getopt.GetoptError as err:
		print(str(err))
		usage(args[0])

	encoding = None 
	attribute = None
	for o, a in opts:
		if o == "-h":
			usage(args[0])
		elif o == "-e":
			encoding = a
		elif o == "-a":
			attribute = a
		else:
			assert False, "unhandled option"
	
	if len(largs) < 1:
		usage(args[0])

	rpath = getxpath(sys.stdin, largs[0], attribute, encoding)
	if rpath == None:
		return 1

	print(rpath)

	return 0

if __name__ == "__main__":
	sys.exit(main(sys.argv))