http_client_demo.cc

/*
 * This file is open source software, licensed to you under the terms
 * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
 * distributed with this work for additional information regarding copyright
 * ownership.  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.
 */
/*
 * Copyright (C) 2022 ScyllaDB Ltd.
 */

#include <seastar/core/app-template.hh>
#include <seastar/core/reactor.hh>
#include <seastar/core/shared_ptr.hh>
#include <seastar/core/iostream.hh>
#include <seastar/core/fstream.hh>
#include <seastar/core/thread.hh>
#include <seastar/http/client.hh>
#include <seastar/http/request.hh>
#include <seastar/http/reply.hh>
#include <seastar/net/inet_address.hh>
#include <seastar/net/dns.hh>
#include <seastar/net/tls.hh>

using namespace seastar;
namespace bpo = boost::program_options;

struct printer {
    future<consumption_result<char>> operator() (temporary_buffer<char> buf) {
        if (buf.empty()) {
            return make_ready_future<consumption_result<char>>(stop_consuming(std::move(buf)));
        }
        fmt::print("{}", sstring(buf.get(), buf.size()));
        return make_ready_future<consumption_result<char>>(continue_consuming());
    }
};

int main(int ac, char** av) {
    app_template app;
    app.add_options()
            ("https", bpo::bool_switch(), "Use HTTPS on port 443 (if off -- use HTTP on port 80)")
            ("host", bpo::value<std::string>(), "Host to connect")
            ("path", bpo::value<std::string>(), "Path to query upon")
            ("method", bpo::value<std::string>()->default_value("GET"), "Method to use")
            ("file", bpo::value<std::string>(), "File to get body from (no body if missing)")
    ;


    return app.run(ac, av, [&] {
        auto&& config = app.configuration();
        auto host = config["host"].as<std::string>();
        auto path = config["path"].as<std::string>();
        auto method = config["method"].as<std::string>();
        auto body = config.count("file") == 0 ? std::string("") : config["file"].as<std::string>();
        auto https = config["https"].as<bool>();

        return seastar::async([=] {
            net::hostent e = net::dns::get_host_by_name(host, net::inet_address::family::INET).get0();
            std::unique_ptr<http::experimental::client> cln;
            if (https) {
                auto certs = ::make_shared<tls::certificate_credentials>();
                certs->set_system_trust().get();
                fmt::print("{} {}:443{}\n", method, e.addr_list.front(), path);
                cln = std::make_unique<http::experimental::client>(socket_address(e.addr_list.front(), 443), std::move(certs), host);
            } else {
                fmt::print("{} {}:80{}\n", method, e.addr_list.front(), path);
                cln = std::make_unique<http::experimental::client>(socket_address(e.addr_list.front(), 80));
            }
            auto req = http::request::make(method, host, path);
            if (body != "") {
                future<file> f = open_file_dma(body, open_flags::ro);
                req.write_body("txt", [ f = std::move(f) ] (output_stream<char>&& out) mutable {
                    return seastar::async([f = std::move(f), out = std::move(out)] () mutable {
                        auto in = make_file_input_stream(f.get0());
                        copy(in, out).get();
                        out.flush().get();
                        out.close().get();
                        in.close().get();
                    });
                });
            }
            cln->make_request(std::move(req), [] (const http::reply& rep, input_stream<char>&& in) {
                fmt::print("Reply status {}\n--------8<--------\n", rep._status);
                return seastar::async([in = std::move(in)] () mutable {
                    in.consume(printer{}).get();
                    in.close().get();
                });
            }).get();

            cln->close().get();
        }).handle_exception([](auto ep) {
            fmt::print("Error: {}", ep);
        });
    });
}