C++ boost beast服务器的io_context.run（）
我使用boost.beast实现了一个C++ boost beast服务器的io_context.run（）,c++,c++11,boost,boost-asio,boost-beast,C++,C++11,Boost,Boost Asio,Boost Beast,我使用boost.beast实现了一个RESTServer.hpp，如下所示 #pragma once #include <boost/property_tree/json_parser.hpp> #include <boost/beast/core.hpp> #include <boost/beast/http.hpp> #include <boost/beast/version.hpp> #include <boost/asio.hpp
RESTServer.hpp#pragma once
#include <boost/property_tree/json_parser.hpp>
#include <boost/beast/core.hpp>
#include <boost/beast/http.hpp>
#include <boost/beast/version.hpp>
#include <boost/asio.hpp>
#include <chrono>
#include <cstdlib>
#include <ctime>
#include <iostream>
#include <memory>
#include <string>
namespace beast = boost::beast;
namespace http = beast::http;
namespace net = boost::asio;
using tcp = boost::asio::ip::tcp;
class RESTServer : public std::enable_shared_from_this<RESTServer> {
public:
RESTServer(tcp::socket socket)
: m_socket(std::move(socket)) {
}
void start() {
readRequest();
checkDeadline();
}
private:
tcp::socket m_socket;
beast::flat_buffer m_buffer{8192};
http::request<http::dynamic_body> m_request;
http::response<http::dynamic_body> m_response;
net::steady_timer m_deadline{m_socket.get_executor(), std::chrono::seconds(60)};
void readRequest() {
auto self = shared_from_this();
http::async_read(m_socket, m_buffer, m_request, [self](beast::error_code ec, std::size_t bytes_transferred) {
boost::ignore_unused(bytes_transferred);
if (!ec) {
self->processRequest();
}
});
}
void processRequest() {
m_response.version(m_request.version());
m_response.keep_alive(false);
switch (m_request.method()) {
case http::verb::get:
m_response.result(http::status::ok);
m_response.set(http::field::server, "Beast");
createResponse();
break;
case http::verb::post:
m_response.result(http::status::ok);
m_response.set(http::field::server, "Beast");
createResponse();
break;
default:
m_response.result(http::status::bad_request);
m_response.set(http::field::content_type, "text/plain");
beast::ostream(m_response.body())
<< "Invalid request-method '"
<< std::string(m_request.method_string())
<< "'";
break;
}
writeResponse();
}
void createResponse() {
if(request_.target() == "/count")
{
response_.set(http::field::content_type, "text/html");
beast::ostream(response_.body())
<< "<html>\n"
<< "<head><title>Request count</title></head>\n"
<< "<body>\n"
<< "<h1>Request count</h1>\n"
<< "<p>There have been "
<< my_program_state::request_count()
<< " requests so far.</p>\n"
<< "</body>\n"
<< "</html>\n";
}
else if(request_.target() == "/time")
{
response_.set(http::field::content_type, "text/html");
beast::ostream(response_.body())
<< "<html>\n"
<< "<head><title>Current time</title></head>\n"
<< "<body>\n"
<< "<h1>Current time</h1>\n"
<< "<p>The current time is "
<< my_program_state::now()
<< " seconds since the epoch.</p>\n"
<< "</body>\n"
<< "</html>\n";
}
else
{
response_.result(http::status::not_found);
response_.set(http::field::content_type, "text/plain");
beast::ostream(response_.body()) << "File not found\r\n";
}
}
void writeResponse() {
auto self = shared_from_this();
m_response.set(http::field::content_length, m_response.body().size());
http::async_write(m_socket, m_response,
[self](beast::error_code ec, std::size_t) {
self->m_socket.shutdown(tcp::socket::shutdown_send, ec);
self->m_deadline.cancel();
});
}
void checkDeadline() {
auto self = shared_from_this();
m_deadline.async_wait([self](beast::error_code ec) {
if (!ec) {
self->m_socket.close(ec);
}
});
}
};
void httpServer(tcp::acceptor& acceptor, tcp::socket& socket) {
acceptor.async_accept(socket, [&](beast::error_code ec) {
if (!ec) {
std::make_shared<RESTServer>(std::move(socket))->start();
}
httpServer(acceptor, socket);
});
}
class MyTest : public ::testing::Test{
virtual void SetUp(){
httpServer(m_acceptor, m_socket);
}
net::ip::address m_address = net::ip::make_address("0.0.0.0");
unsigned short m_port = static_cast<unsigned short>(8080);
net::io_context m_ioc{1};
tcp::acceptor m_acceptor{m_ioc, {m_address, m_port}};
tcp::socket m_socket{m_ioc};
};
#include <boost/beast/core.hpp>
#include <boost/beast/http.hpp>
#include <boost/beast/version.hpp>
#include <boost/asio/strand.hpp>
#include <boost/lexical_cast.hpp>
#include <cstdlib>
#include <iostream>
#include <memory>
#include <string>
#include "RESTClient.hpp"
namespace beast = boost::beast;
namespace http = beast::http;
namespace net = boost::asio;
using tcp = boost::asio::ip::tcp;
void fail(beast::error_code ec, char const* what) {
std::cerr << what << ": " << ec.message() << "\n";
}
RESTClient::RESTClient(net::io_context& ioc)
: m_resolver(net::make_strand(ioc)), m_stream(net::make_strand(ioc)) {
}
RESTClient::~RESTClient() = default;
void RESTClient::run(char const* host, char const* port, char const* target, int version) {
createPostRequest(host, target, version, createBody().c_str());
m_resolver.async_resolve(host, port, beast::bind_front_handler(
&RESTClient::onResolve,
shared_from_this()));
}
void RESTClient::onResolve(beast::error_code ec, tcp::resolver::results_type results) {
if (ec) {
return fail(ec, "resolve");
}
std::cout << "onResolve ******" << std::endl;
m_stream.expires_after(std::chrono::seconds(30));
m_stream.async_connect(results, beast::bind_front_handler(
&RESTClient::onConnect,
shared_from_this()));
}
void
RESTClient::onConnect(beast::error_code ec, tcp::resolver::results_type::endpoint_type) {
if (ec) {
return fail(ec, "connect");
}
std::cout << "onConnect ******" << std::endl;
m_stream.expires_after(std::chrono::seconds(30));
http::async_write(m_stream, m_httpRequest,
beast::bind_front_handler(
&RESTClient::onWrite,
shared_from_this()));
}
void
RESTClient::onWrite(beast::error_code ec, std::size_t bytes_transferred) {
boost::ignore_unused(bytes_transferred);
if (ec) {
return fail(ec, "write");
}
std::cout << "onWrite ******" << std::endl;
http::async_read(m_stream, m_buffer, m_httpResponse, beast::bind_front_handler(
&RESTClient::onRead,
shared_from_this()));
}
void RESTClient::onRead(beast::error_code ec, std::size_t bytes_transferred) {
boost::ignore_unused(bytes_transferred);
if (ec) {
return fail(ec, "read");
}
std::cout << "onRead ******" << std::endl;
std::cout << m_httpResponse << std::endl;
m_stream.socket().shutdown(tcp::socket::shutdown_both, ec);
if (ec && ec != beast::errc::not_connected) {
return fail(ec, "shutdown");
}
}
void RESTClient::createGetRequest(char const* host, char const* target, int version) {
m_httpRequest.version(version);
m_httpRequest.method(http::verb::get);
m_httpRequest.target(target);
m_httpRequest.set(http::field::host, host);
m_httpRequest.set(http::field::user_agent, BOOST_BEAST_VERSION_STRING);
}
void RESTClient::createPostRequest(char const* host, char const* target, int version, char const* body) {
m_httpRequest.version(version);
m_httpRequest.method(http::verb::post);
m_httpRequest.target(target);
m_httpRequest.set(http::field::host, host);
m_httpRequest.set(http::field::user_agent, BOOST_BEAST_VERSION_STRING);
m_httpRequest.set(http::field::content_length, boost::lexical_cast<std::string>(strlen(body)));
m_httpRequest.set(http::field::body, body);
m_httpRequest.prepare_payload();
}
std::string RESTClient::createBody() {
boost::property_tree::ptree tree;
boost::property_tree::read_json("test.json",tree);
std::basic_stringstream<char> jsonStream;
boost::property_tree::json_parser::write_json(jsonStream, tree, false);
std::cout << "json stream :" << jsonStream.str() << std::endl;
return jsonStream.str();
}
int main(int argc, char** argv) {
// Check command line arguments.
if (argc != 4 && argc != 5) {
std::cerr <<
"Usage: http-client-async <host> <port> <target> [<HTTP version: 1.0 or 1.1(default)>]\n" <<
"Example:\n" <<
" http-client-async www.example.com 80 /\n" <<
" http-client-async www.example.com 80 / 1.0\n";
return EXIT_FAILURE;
}
auto const host = argv[1];
auto const port = argv[2];
auto const target = argv[3];
int version = argc == 5 && !std::strcmp("1.0", argv[4]) ? 10 : 11;
// The io_context is required for all I/O
net::io_context ioc;
std::cout << "version: " << version << std::endl;
// Launch the asynchronous operation
std::make_shared<RESTClient>(ioc)->run(host, port, target, version);
// Run the I/O service. The call will return when
// the get operation is complete.
ioc.run();
return EXIT_SUCCESS;
}
类MyTesthttpServerRESTClientio\u上下文。是否应将相同的io_上下文同时传递给客户端和服务器？或者io_上下文应该有所不同。有人能解释一下吗？并解释原因。我想了解io_上下文实际上意味着什么
是否应将相同的io_上下文同时传递给客户端和服务器？或者io_上下文应该有所不同
有人能解释一下吗？并解释原因。我想了解io_上下文实际上意味着什么
这完全取决于您：io_上下文提供异步调用（如async_resolve
和async_write
在其中运行）的上下文。将io\u context:：run
视为事件循环
你通常的步骤包括
- 创建
io\u上下文
- 提供
io\u上下文
和一些要做的工作（例如，异步\u解析、异步\u连接、异步\u读取和异步\u写入、异步\u等待计时器等）
- 在某个线程中调用
run
run
调用将阻塞，直到io\u上下文
失效，除非您为其提供了
对象
其他要点：
- 您应该注意到，通常异步处理程序会向
io\u上下文添加更多的工作
，从而导致run
不仅仅是耗尽工作并退出
- 是否创建显式工作对象取决于特定的应用程序设计。就我个人而言，我更愿意控制执行的每个异步操作，并负责“干净”的关机，即取消所有未完成的工作，让所有已启动的操作干净地完成。也可以简单地停止
io\u上下文
，但这样做可能会很粗心。如果需要调用runio\u context，则需要创建一个工作对象。通常，如果您编写一个服务器，您已经有了一个侦听套接字，并且已经有了工作，因此不需要添加工作对象。类似地，您可能有一个周期计时器，等等
- 其他线程模型也可以使用
run\u one
调用。通常在运行其他事件循环/库时使用此选项
- 更高级的线程模型和跨多个线程的扩展工作可以由asio作者使用来完成
回到您的问题：请记住，为了执行io调用，您仍然需要为io\U上下文提供一个执行线程。因此，一个io_上下文
更易于管理（一个上下文+一个阻塞调用来运行class MyTest : public ::testing::Test{
virtual void SetUp(){
httpServer(m_acceptor, m_socket);
}
net::ip::address m_address = net::ip::make_address("0.0.0.0");
unsigned short m_port = static_cast<unsigned short>(8080);
net::io_context m_ioc{1};
tcp::acceptor m_acceptor{m_ioc, {m_address, m_port}};
tcp::socket m_socket{m_ioc};
};