plugin.rs

// 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_add_custom_response]
use proxy_wasm::traits::*;
use proxy_wasm::types::*;

static REDIRECT_PAGE: &str = "https://storage.googleapis.com/www.example.com/server-error.html";

proxy_wasm::main! {{
    proxy_wasm::set_http_context(|_, _| -> Box<dyn HttpContext> { Box::new(MyHttpContext) });
}}

struct MyHttpContext;

impl Context for MyHttpContext {}

impl HttpContext for MyHttpContext {
    fn on_http_response_headers(&mut self, _num_headers: usize, _end_of_stream: bool) -> Action {
        if let Some(status) = self.get_http_response_header(":status") {
            if let Ok(response_code) = status.parse::<u16>() {
                if response_code / 100 == 5 {
                    self.send_http_response(
                        302,
                        vec![
                            ("Origin-Status", &status),
                            ("Location", REDIRECT_PAGE),
                        ],
                        None,
                    );
                    return Action::Continue;
                }
            }
        }
        Action::Continue
    }
}
// [END serviceextensions_plugin_add_custom_response]