Initial

css2xpath.py

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+#!/usr/bin/env python3
+
+from io import StringIO
+import re
+import sys
+
+
+def tok2nodetest(tok, write):
+    m = re.match('\\w+', tok)
+    if m is None:
+        write('*')
+        return tok
+    write(m.group())
+    return tok[len(m.group()):]
+
+
+def tok2predicate(tok, write):
+    predicates = (
+        (r'\.([\-\w_]+)', "[contains(@class, '{}')]"),
+        (r'#([\-\w_]+)', "[@id='{}']"),
+        (r':nth-child\((\d+)\)', '[{}]'),
+        (r'():first', '{}[1]')
+    )
+    for regexp, fmt in predicates:
+        m = re.match(regexp, tok)
+        if m:
+            write(fmt.format(m.group(1)))
+            return tok[len(m.group()):]
+    raise Exception('Unknown predicate token: {}'.format(tok))
+
+
+def transform(sel):
+    'Transform a css selector to xpath query string'
+    buf = StringIO()
+    tokens = sel.split()
+    if not tokens:
+        return ''
+    direct = False
+    for token in tokens:
+        if token == '>':
+            direct = True
+        else:
+            axis, direct = '/' if direct else '//', False
+            buf.write(axis)
+            token = tok2nodetest(token, buf.write)
+            while token:
+                token = tok2predicate(token, buf.write)
+    return buf.getvalue()
+
+
+def main():
+    if len(sys.argv) > 1:
+        for sel in sys.argv[1:]:
+            print(transform(sel))
+    else:
+        while 1:
+            try:
+                sel = input()
+            except EOFError:
+                break
+            else:
+                print(transform(sel))
+
+
+if __name__ == '__main__':
+    main()

test.py

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+#!/usr/bin/env python3
+
+import io
+import unittest
+import css2xpath
+
+
+class Css2XpathTest(unittest.TestCase):
+
+    def runfunc(self, func, expwrite, expreturn, *args):
+        f = io.StringIO()
+        actreturn = func(*(args + (f.write,)))
+        actwrited = f.getvalue()
+        msg = lambda e, a: 'Tested: {}{},\n : Expected={}, Actual={}'.format(
+            func.__name__, args, e, a)
+        self.assertEqual(expwrite, actwrited, msg(expwrite, actwrited))
+        self.assertEqual(expreturn, actreturn, msg(expreturn, actreturn))
+
+    def batch(self, func, expwrite, expreturn, args):
+        for w, r, a in zip(expwrite, expreturn, args):
+            self.runfunc(func, w, r, a)
+
+    def test_node_star(self):
+        i = ['#egg', '.egg', '.spam:nth-child(1)',]
+        w = ['*', '*', '*']
+        r = i.copy()
+        self.batch(css2xpath.tok2nodetest, w, r, i)
+
+    def test_node_el(self):
+        i = ['h1#egg', 'h2.egg', 'h3.spam:nth-child(1)',]
+        w = ['h1', 'h2', 'h3']
+        r = ['#egg', '.egg', '.spam:nth-child(1)']
+        self.batch(css2xpath.tok2nodetest, w, r, i)
+
+    def test_predicate(self):
+        i = ['.eggs', '#egg', '.eggs:nth-child(1)', ':nth-child(1)']
+        w = ["[contains(@class, 'eggs')]", "[@id='egg']",
+             "[contains(@class, 'eggs')]", '[1]']
+        r = ['', '', ':nth-child(1)', '']
+        self.batch(css2xpath.tok2predicate, w, r, i)
+
+    def test_transform(self):
+        inp = '.spam > p.and-eggs:nth-child(3) a.something.otherthing'
+        exp = "//*[contains(@class, 'spam')]"\
+              "/p[contains(@class, 'and-eggs')][3]"\
+              "//a[contains(@class, 'something')]"\
+              "[contains(@class, 'otherthing')]"
+        self.assertEqual(exp, css2xpath.transform(inp))
+
+
+if __name__ == '__main__':
+    unittest.main()