add support for redirectmatch rules

Signed-off-by: Doug Hellmann <doug@doughellmann.com>

whereto/rules.py

@@ -15,6 +15,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import re
+
 
 class Rule(object):
     "Base class for rules."
@@ -53,3 +55,18 @@ class Redirect(Rule):
         if path == self.pattern:
             return (self.code, self.target)
         return None
+
+
+class RedirectMatch(Rule):
+    "A RedirectMatch rule with a regular expression."
+
+    def __init__(self, linenum, *params):
+        super(RedirectMatch, self).__init__(linenum, *params)
+        self.regex = re.compile(self.pattern)
+        self.target_repl = self.target.replace('$', '\\')
+
+    def match(self, path):
+        m = self.regex.search(path)
+        if m:
+            return (self.code, self.regex.sub(self.target_repl, path))
+        return None

whereto/tests/test_rules.py

@@ -65,4 +65,70 @@ class TestRedirect(base.TestCase):
             rules.Redirect,
             (1, 'redirect', '301', '/the/path', '/new/path', 'extra-value'),
         )
+
+
+class TestRedirectMatch(base.TestCase):
+
+    def test_match(self):
+        rule = rules.RedirectMatch(
+            1,
+            'redirectmatch', '301', '^/user/.*$', '/pike/user/',
+        )
+        self.assertEqual(
+            ('301', '/pike/user/'),
+            rule.match('/user/'),
+        )
+
+    def test_match_with_group(self):
+        rule = rules.RedirectMatch(
+            1,
+            'redirectmatch', '301', '^/user/(.*)$', '/pike/user/$1',
+        )
+        self.assertEqual(
+            ('301', '/pike/user/foo'),
+            rule.match('/user/foo'),
+        )
+
+    def test_no_match(self):
+        rule = rules.RedirectMatch(
+            1,
+            'redirectmatch', '301', '^/user/.*$', '/pike/user/',
+        )
+        self.assertIsNone(
+            rule.match('/different/path'),
+        )
+
+    def test_implied_code(self):
+        rule = rules.RedirectMatch(
+            1,
+            'redirectmatch', '^/user/.*$', '/pike/user/',
+        )
+        self.assertEqual(
+            '301',
+            rule.code,
+        )
+
+    def test_str(self):
+        rule = rules.RedirectMatch(
+            1,
+            'redirectmatch', '301', '^/user/.*$', '/pike/user/',
+        )
+        self.assertEqual(
+            '[1] redirectmatch 301 ^/user/.*$ /pike/user/',
+            str(rule),
+        )
+
+    def test_too_few_args(self):
+        self.assertRaises(
+            ValueError,
+            rules.RedirectMatch,
+            (1, 'redirectmatch', '/the/path'),
+        )
+
+    def test_too_many_args(self):
+        self.assertRaises(
+            ValueError,
+            rules.RedirectMatch,
+            (1, 'redirectmatch', '301', '/the/path', '/new/path',
+             'extra-value'),
         )