LibWeb: Add definitions from '2.2.1. Methods' in the Fetch spec

Userland/Libraries/LibWeb/Fetch/Infrastructure/HTTP/Methods.cpp

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2022, Linus Groh <linusg@serenityos.org>
+ * Copyright (c) 2022, Kenneth Myhra <kennethmyhra@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/ByteBuffer.h>
+#include <AK/StringView.h>
+#include <LibRegex/Regex.h>
+#include <LibWeb/Fetch/Infrastructure/HTTP/Methods.h>
+#include <LibWeb/Infra/ByteSequences.h>
+
+namespace Web::Fetch {
+
+// https://fetch.spec.whatwg.org/#concept-method
+bool is_method(ReadonlyBytes method)
+{
+    // A method is a byte sequence that matches the method token production.
+    Regex<ECMA262Parser> regex { R"~~~(^[A-Za-z0-9!#$%&'*+\-.^_`|~]+$)~~~" };
+    return regex.has_match(StringView { method });
+}
+
+// https://fetch.spec.whatwg.org/#cors-safelisted-method
+bool is_cors_safelisted_method(ReadonlyBytes method)
+{
+    // A CORS-safelisted method is a method that is `GET`, `HEAD`, or `POST`.
+    return StringView { method }.is_one_of("GET"sv, "HEAD"sv, "POST"sv);
+}
+
+// https://fetch.spec.whatwg.org/#forbidden-method
+bool is_forbidden_method(ReadonlyBytes method)
+{
+    // A forbidden method is a method that is a byte-case-insensitive match for `CONNECT`, `TRACE`, or `TRACK`.
+    return StringView { method }.is_one_of_ignoring_case("CONNECT"sv, "TRACE"sv, "TRACK"sv);
+}
+
+// https://fetch.spec.whatwg.org/#concept-method-normalize
+ErrorOr<ByteBuffer> normalize_method(ReadonlyBytes method)
+{
+    // To normalize a method, if it is a byte-case-insensitive match for `DELETE`, `GET`, `HEAD`, `OPTIONS`, `POST`, or `PUT`, byte-uppercase it.
+    auto bytes = TRY(ByteBuffer::copy(method));
+    if (StringView { method }.is_one_of_ignoring_case("DELETE"sv, "GET"sv, "HEAD"sv, "OPTIONS"sv, "POST"sv, "PUT"sv))
+        Infra::byte_uppercase(bytes);
+    return bytes;
+}
+
+}