plugins/experimental/wasm/examples/rust/src/lib.rs

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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 log::trace;
use proxy_wasm::traits::*;
use proxy_wasm::types::*;
use primes::is_prime;

proxy_wasm::main! {{
    proxy_wasm::set_log_level(LogLevel::Trace);
    proxy_wasm::set_root_context(|_| -> Box<dyn RootContext> { Box::new(HelloWorld) });
}}

struct HelloWorld;

impl Context for HelloWorld {}

impl RootContext for HelloWorld {
    fn on_vm_start(&mut self, _: usize) -> bool {
        trace!("Hello, World!");
        true
    }

    fn get_type(&self) -> Option<ContextType> {
        Some(ContextType::HttpContext)
    }

    fn create_http_context(&self, context_id: u32) -> Option<Box<dyn HttpContext>> {
        Some(Box::new(HttpHeaders { context_id }))
    }

}

struct HttpHeaders {
    context_id: u32,
}

impl Context for HttpHeaders {}

impl HttpContext for HttpHeaders {
    fn on_http_request_headers(&mut self, _: usize, _: bool) -> Action {
        for (name, value) in &self.get_http_request_headers() {
            let s3 = format!("In WASM: #{} -> {}: {}",self.context_id, name, value);
            trace!("{}", s3);
        }
        if let Some(ua) = self.get_http_request_header("User-Agent") {
            if ua != "" {
              trace!("UA is {}", ua);
            }
        }

        match self.get_http_request_header("token") {
            Some(token) if token.parse::<u64>().is_ok() && is_prime(token.parse().unwrap()) => {
                trace!("It is prime!!!");
                Action::Continue
            }
            _ => {
                trace!("It is not prime!!! That's true.");
                self.send_http_response(
                    403,
                    vec![("Powered-By", "proxy-wasm")],
                    Some(b"Access forbidden.\n"),
                );
                Action::Pause
            }
        }
    }

}