Fix #460 - missing parse_rule method

This method was removed from the public API in werkzeug 2.2.0. Copying it into this project because the method is self-contained.

Author: plowman

flask_restx/swagger.py

@@ -53,6 +53,21 @@
     r"^:raises\s+(?P<name>[\w\d_]+)\s*:\s*(?P<description>.*)$", re.MULTILINE
 )
 
+RE_PARSE_RULE = re.compile(
+    r"""
+    (?P<static>[^<]*)                           # static rule data
+    <
+    (?:
+        (?P<converter>[a-zA-Z_][a-zA-Z0-9_]*)   # converter name
+        (?:\((?P<args>.*?)\))?                  # converter arguments
+        \:                                      # variable delimiter
+    )?
+    (?P<variable>[a-zA-Z_][a-zA-Z0-9_]*)        # variable name
+    >
+    """,
+    re.VERBOSE,
+)
+
 
 def ref(model):
     """Return a reference to model in definitions"""
@@ -72,22 +87,6 @@ def extract_path(path):
     return RE_URL.sub(r"{\1}", path)
 
 
-RE_PARSE_RULE = re.compile(
-    r"""
-    (?P<static>[^<]*)                           # static rule data
-    <
-    (?:
-        (?P<converter>[a-zA-Z_][a-zA-Z0-9_]*)   # converter name
-        (?:\((?P<args>.*?)\))?                  # converter arguments
-        \:                                      # variable delimiter
-    )?
-    (?P<variable>[a-zA-Z_][a-zA-Z0-9_]*)        # variable name
-    >
-    """,
-    re.VERBOSE,
-)
-
-
 def parse_rule(rule):
     """
     This originally lived in werkzeug.routing.parse_rule until it was removed in werkzeug 2.2.0. Copying it here to