feat: create a Rust sample for normalize HTTP header plugin.

plugins/samples/normalize_header/BUILD

@@ -15,11 +15,21 @@ proxy_wasm_plugin_go(
     srcs = ["plugin.go"],
 )
 
+proxy_wasm_plugin_rust(
+    name = "plugin_rust.wasm",
+    srcs = ["plugin.rs"],
+    deps = [
+        "//bazel/cargo/remote:log",
+        "//bazel/cargo/remote:proxy-wasm",
+    ],
+)
+
 proxy_wasm_tests(
     name = "tests",
     plugins = [
         ":plugin_cpp.wasm",
         ":plugin_go.wasm",
+        ":plugin_rust.wasm",
     ],
     tests = ":tests.textpb",
 )

plugins/samples/normalize_header/plugin.rs

@@ -0,0 +1,53 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// [START serviceextensions_plugin_normalize_header]
+use proxy_wasm::traits::*;
+use proxy_wasm::types::*;
+
+proxy_wasm::main! {{
+    proxy_wasm::set_log_level(LogLevel::Trace);
+    proxy_wasm::set_http_context(|_, _| -> Box<dyn HttpContext> { Box::new(MyHttpContext) });
+}}
+
+struct MyHttpContext;
+
+impl Context for MyHttpContext {}
+
+const DEVICE_TYPE_KEY: &str = "client-device-type";
+const DEVICE_TYPE_VALUE: &str = "mobile";
+
+// Determines client device type based on request headers.
+impl HttpContext for MyHttpContext {
+    fn on_http_request_headers(&mut self, _: usize, _: bool) -> Action {
+        // Change the key and value according to your needs.
+        let mobile_header = self.get_http_request_header("Sec-CH-UA-Mobile");
+        if mobile_header.unwrap_or_default() == "?1" {
+            self.add_http_request_header(DEVICE_TYPE_KEY, DEVICE_TYPE_VALUE);
+            return Action::Continue;
+        }
+
+        // Check "User-Agent" header for mobile substring (case insensitive)
+        let user_agent = self.get_http_request_header("User-Agent");
+        if user_agent.map_or(false, |s| s.to_lowercase().contains(DEVICE_TYPE_VALUE)) {
+            self.add_http_request_header(DEVICE_TYPE_KEY, DEVICE_TYPE_VALUE);
+            return Action::Continue;
+        }
+
+        // No specific device type identified, set to "unknown"
+        self.add_http_request_header(DEVICE_TYPE_KEY, "unknown");
+        return Action::Continue;
+    }
+}
+// [END serviceextensions_plugin_normalize_header]