Delay route compilation to allow late register_type calls

src/microdot/__init__.py

@@ -1,2 +1,2 @@
 from microdot.microdot import Microdot, Request, Response, abort, redirect, \
-    send_file  # noqa: F401
+    send_file, URLPattern  # noqa: F401

src/microdot/microdot.py

@@ -819,8 +819,10 @@ class URLPattern():
         self.url_pattern = url_pattern
         self.segments = []
         self.regex = None
+
+    def compile(self):
         pattern = ''
-        for segment in url_pattern.lstrip('/').split('/'):
+        for segment in self.url_pattern.lstrip('/').split('/'):
             if segment and segment[0] == '<':
                 if segment[-1] != '>':
                     raise ValueError('invalid URL pattern')
@@ -844,6 +846,7 @@ class URLPattern():
                 pattern += '/' + segment
                 self.segments.append({'parser': None})
         self.regex = re.compile('^' + pattern + '$')
+        return self.regex
 
     @classmethod
     def register_type(cls, type_name, pattern='[^/]+', parser=None):
@@ -852,7 +855,7 @@ class URLPattern():
 
     def match(self, path):
         args = {}
-        g = self.regex.match(path)
+        g = (self.regex or self.compile()).match(path)
         if not g:
             return
         i = 1

tests/test_url_pattern.py

@@ -119,8 +119,10 @@ class TestURLPattern(unittest.TestCase):
         self.assertIsNone(p.match('/foo/abc/def/123/test'))
 
     def test_invalid_url_patterns(self):
-        self.assertRaises(ValueError, URLPattern, '/users/<foo/bar')
-        self.assertRaises(ValueError, URLPattern, '/users/<badtype:id>')
+        p = URLPattern('/users/<foo/bar')
+        self.assertRaises(ValueError, p.compile)
+        p = URLPattern('/users/<badtype:id>')
+        self.assertRaises(ValueError, p.compile)
 
     def test_custom_url_pattern(self):
         URLPattern.register_type('hex', '[0-9a-f]+')