feat: add sample for HTTP redirect.

Signed-off-by: Will Hayworth <[email protected]>

README.md

@@ -36,6 +36,8 @@ plugin. Extend them to fit your particular use case.
 *   [Rewrite the path using regex](samples/regex_rewrite): Remove a piece of the
     URI using regex replacement. Demonstrate a standard way to use regular
     expressions, compiling them at plugin initialization.
+*   [Send an HTTP redirect](samples/http_redirect): Send an HTTP 301 Moved
+    Permanently response for requests with specific paths.
 
 # Feature set / ABI
 

samples/http_redirect/BUILD

@@ -0,0 +1,41 @@
+load("//:plugins.bzl", "proxy_wasm_plugin_cpp", "proxy_wasm_plugin_rust")
+
+licenses(["notice"])  # Apache 2
+
+proxy_wasm_plugin_rust(
+    name = "plugin_rust.wasm",
+    srcs = ["plugin.rs"],
+    deps = [
+        "//cargo:url",
+        "@proxy_wasm_rust_sdk//:proxy_wasm",
+        "@proxy_wasm_rust_sdk//bazel/cargo:log",
+    ],
+)
+
+proxy_wasm_plugin_cpp(
+    name = "plugin_cpp.wasm",
+    srcs = ["plugin.cc"],
+    deps = [
+        "//:boost_exception",
+        "@boost//:url",
+        "@proxy_wasm_cpp_sdk//contrib:contrib_lib",
+    ],
+)
+
+cc_test(
+    name = "plugin_test",
+    srcs = ["test.cc"],
+    data = [
+        ":plugin_cpp.wasm",
+        ":plugin_rust.wasm",
+    ],
+    deps = [
+        "//test:framework",
+        "@com_google_absl//absl/status",
+        "@com_google_absl//absl/status:statusor",
+        "@com_google_googletest//:gtest_main",
+        "@proxy_wasm_cpp_host//:base_lib",
+        "@proxy_wasm_cpp_host//:v8_lib",
+        "@proxy_wasm_cpp_host//test:utility_lib",
+    ],
+)

samples/http_redirect/plugin.cc

@@ -0,0 +1,43 @@
+// Copyright 2023 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.
+
+#include <boost/url/parse.hpp>
+#include <boost/url/url.hpp>
+
+#include "proxy_wasm_intrinsics.h"
+
+class MyHttpContext : public Context {
+ public:
+  explicit MyHttpContext(uint32_t id, RootContext* root) : Context(id, root) {}
+
+  FilterHeadersStatus onRequestHeaders(uint32_t headers,
+                                       bool end_of_stream) override {
+    WasmDataPtr path = getRequestHeader(":path");
+    if (!path) {
+      return FilterHeadersStatus::Continue;
+    }
+    boost::system::result<boost::urls::url_view> url =
+        boost::urls::parse_uri_reference(path->view());
+    if (!url) {
+      return FilterHeadersStatus::Continue;
+    }
+    if (url->path() == "/index.php") {
+      sendLocalResponse(301, "", "", {{"Location", "http://www.example.com/"}});
+    }
+    return FilterHeadersStatus::Continue;
+  }
+};
+
+static RegisterContextFactory register_StaticContext(
+    CONTEXT_FACTORY(MyHttpContext), ROOT_FACTORY(RootContext));

samples/http_redirect/plugin.rs

@@ -0,0 +1,50 @@
+// Copyright 2023 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.
+
+use proxy_wasm::traits::*;
+use proxy_wasm::types::*;
+use url::Url;
+
+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 {}
+
+impl HttpContext for MyHttpContext {
+    fn on_http_request_headers(&mut self, _: usize, _: bool) -> Action {
+        let Some(path) = self.get_http_request_header(":path") else {
+            // This standard Envoy pseudo-header should always be present.
+            return Action::Continue
+        };
+        // Url requires a base for parsing relative URLs.
+        let base = Url::parse("http://www.example.com").ok();
+        let options = Url::options().base_url(base.as_ref());
+        let Ok(url) = options.parse(&path) else {
+            // Don't try to redirect on a malformed URL.
+            return Action::Continue
+        };
+        let redirect = match url.path() {
+            "/index.php" => base,
+            _ => None
+        };
+        if let Some(redirect_url) = redirect {
+            self.send_http_response(301, vec![("Location", redirect_url.as_str())], None);
+        }
+        Action::Continue
+    }
+}

samples/http_redirect/test.cc

@@ -0,0 +1,59 @@
+// Copyright 2023 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.
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "include/proxy-wasm/exports.h"
+#include "include/proxy-wasm/wasm.h"
+#include "test/framework.h"
+
+using ::testing::ElementsAre;
+using ::testing::Pair;
+
+namespace service_extensions_samples {
+
+INSTANTIATE_TEST_SUITE_P(
+    EnginesAndPlugins, HttpTest,
+    ::testing::Combine(
+        ::testing::ValuesIn(proxy_wasm::getWasmEngines()),
+        ::testing::Values("samples/http_redirect/plugin_cpp.wasm",
+                          "samples/http_redirect/plugin_rust.wasm")));
+
+TEST_P(HttpTest, RunPlugin) {
+  // Create VM + load plugin.
+  ASSERT_TRUE(CreatePlugin(engine(), path()).ok());
+
+  // Create stream context.
+  auto http_context = TestHttpContext(handle_);
+
+  // Expect no-op if no path is specified. (Never expected.)
+  auto res = http_context.SendRequestHeaders({});
+  EXPECT_EQ(res.http_code, 0);
+
+  // Send request with non-matching path. We have to supply the ":path"
+  // pseudo-header even though Envoy will do it automatically in production:
+  // https://github.com/GoogleCloudPlatform/service-extensions-samples/issues/10
+  auto res1 = http_context.SendRequestHeaders({{":path", "/"}});
+  EXPECT_EQ(res1.http_code, 0);
+
+  // Send request with matching path, expect redirect.
+  auto res2 = http_context.SendRequestHeaders({{":path", "/index.php"}});
+  EXPECT_EQ(res2.http_code, 301);
+  EXPECT_THAT(res2.headers,
+              ElementsAre(Pair("Location", "http://www.example.com/")));
+
+  EXPECT_FALSE(handle_->wasm()->isFailed());
+}
+
+}  // namespace service_extensions_samples