Path parser refactor

Author: p1c2u

openapi_core/templating/paths/parsers.py

@@ -1,33 +1,73 @@
-from typing import Any
+# Allow writing union types as X | Y in Python 3.9
+from __future__ import annotations
 
-from parse import Parser
+import re
+from dataclasses import dataclass
 
 
-class PathParameter:
-    name = "PathParameter"
-    pattern = r"[^\/]*"
+@dataclass(frozen=True)
+class PathMatchResult:
+    """Result of path parsing."""
 
-    def __call__(self, text: str) -> str:
-        return text
+    named: dict[str, str]
 
 
-class PathParser(Parser):  # type: ignore
+class PathParser:
+    """Parses path patterns with parameters into regex and matches against URLs."""
 
-    parse_path_parameter = PathParameter()
+    _PARAM_PATTERN = r"[^/]*"
 
     def __init__(
         self, pattern: str, pre_expression: str = "", post_expression: str = ""
     ) -> None:
-        extra_types = {
-            self.parse_path_parameter.name: self.parse_path_parameter
-        }
-        super().__init__(pattern, extra_types)
-        self._expression: str = (
-            pre_expression + self._expression + post_expression
-        )
+        self.pattern = pattern
+        self._group_to_name: dict[str, str] = {}
+
+        regex_body = self._compile_template_to_regex(pattern)
+        self._expression = f"{pre_expression}{regex_body}{post_expression}"
+        self._compiled = re.compile(self._expression)
+
+    def search(self, text: str) -> PathMatchResult | None:
+        """Searches for a match in the given text."""
+        match = self._compiled.search(text)
+        return self._to_result(match)
+
+    def parse(self, text: str) -> PathMatchResult | None:
+        """Parses the entire text for a match."""
+        match = self._compiled.fullmatch(text)
+        return self._to_result(match)
 
-    def _handle_field(self, field: str) -> Any:
-        # handle as path parameter field
-        field = field[1:-1]
-        path_parameter_field = "{%s:PathParameter}" % field
-        return super()._handle_field(path_parameter_field)
+    def _compile_template_to_regex(self, template: str) -> str:
+        parts: list[str] = []
+        i = 0
+        group_index = 0
+        while i < len(template):
+            start = template.find("{", i)
+            if start == -1:
+                parts.append(re.escape(template[i:]))
+                break
+            end = template.find("}", start + 1)
+            if end == -1:
+                raise ValueError(f"Unmatched '{{' in template: {template!r}")
+
+            parts.append(re.escape(template[i:start]))
+            param_name = template[start + 1 : end]
+            group_name = f"g{group_index}"
+            group_index += 1
+            self._group_to_name[group_name] = param_name
+            parts.append(f"(?P<{group_name}>{self._PARAM_PATTERN})")
+            i = end + 1
+
+        return "".join(parts)
+
+    def _to_result(
+        self, match: re.Match[str] | None
+    ) -> PathMatchResult | None:
+        if match is None:
+            return None
+        return PathMatchResult(
+            named={
+                param_name: match.group(group_name)
+                for group_name, param_name in self._group_to_name.items()
+            },
+        )

poetry.lock

@@ -21,7 +21,6 @@ module = [
     "isodate.*",
     "jsonschema.*",
     "more_itertools.*",
-    "parse.*",
     "requests.*",
     "werkzeug.*",
 ]
@@ -69,7 +68,6 @@ aiohttp = {version = ">=3.0", optional = true}
 starlette = {version = ">=0.26.1,<0.50.0", optional = true}
 isodate = "*"
 more-itertools = "*"
-parse = "*"
 openapi-schema-validator = "^0.6.0"
 openapi-spec-validator = "^0.7.1"
 requests = {version = "*", optional = true}

pyproject.toml

@@ -42,13 +42,6 @@ def test_chars_valid(self, path_pattern, expected):
 
         assert result.named == expected
 
-    @pytest.mark.xfail(
-        reason=(
-            "Special characters of regex not supported. "
-            "See https://github.com/python-openapi/openapi-core/issues/672"
-        ),
-        strict=True,
-    )
     @pytest.mark.parametrize(
         "path_pattern,expected",
         [