Add Request properties for HTTP method info (#2516)

sanic/constants.py

@@ -34,6 +34,15 @@ class LocalCertCreator(str, Enum):
 
 
 HTTP_METHODS = tuple(HTTPMethod.__members__.values())
+SAFE_HTTP_METHODS = (HTTPMethod.GET, HTTPMethod.HEAD, HTTPMethod.OPTIONS)
+IDEMPOTENT_HTTP_METHODS = (
+    HTTPMethod.GET,
+    HTTPMethod.HEAD,
+    HTTPMethod.PUT,
+    HTTPMethod.DELETE,
+    HTTPMethod.OPTIONS,
+)
+CACHEABLE_HTTP_METHODS = (HTTPMethod.GET, HTTPMethod.HEAD)
 DEFAULT_HTTP_CONTENT_TYPE = "application/octet-stream"
 DEFAULT_LOCAL_TLS_KEY = "key.pem"
 DEFAULT_LOCAL_TLS_CERT = "cert.pem"

sanic/request.py

@@ -38,7 +38,12 @@ from httptools import parse_url
 from httptools.parser.errors import HttpParserInvalidURLError
 
 from sanic.compat import CancelledErrors, Header
-from sanic.constants import DEFAULT_HTTP_CONTENT_TYPE
+from sanic.constants import (
+    CACHEABLE_HTTP_METHODS,
+    DEFAULT_HTTP_CONTENT_TYPE,
+    IDEMPOTENT_HTTP_METHODS,
+    SAFE_HTTP_METHODS,
+)
 from sanic.exceptions import BadRequest, BadURL, ServerError
 from sanic.headers import (
     AcceptContainer,
@@ -975,6 +980,33 @@ class Request:
 
         return self.transport.scope
 
+    @property
+    def is_safe(self) -> bool:
+        """
+        :return: Whether the HTTP method is safe.
+            See https://datatracker.ietf.org/doc/html/rfc7231#section-4.2.1
+        :rtype: bool
+        """
+        return self.method in SAFE_HTTP_METHODS
+
+    @property
+    def is_idempotent(self) -> bool:
+        """
+        :return: Whether the HTTP method is iempotent.
+            See https://datatracker.ietf.org/doc/html/rfc7231#section-4.2.2
+        :rtype: bool
+        """
+        return self.method in IDEMPOTENT_HTTP_METHODS
+
+    @property
+    def is_cacheable(self) -> bool:
+        """
+        :return: Whether the HTTP method is cacheable.
+            See https://datatracker.ietf.org/doc/html/rfc7231#section-4.2.3
+        :rtype: bool
+        """
+        return self.method in CACHEABLE_HTTP_METHODS
+
 
 class File(NamedTuple):
     """