Boost ASIO async_read不从客户端读取数据 [英] Boost ASIO async_read is not reading data from the client
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问题描述
我有一个服务器/客户端应用程序，用于从客户端写入服务器上的读取内容.
I have a server/client application which works for a write from client to a read at server.
在服务器代码中的startHandlig函数中，如果我注释async_connect_1及其后的返回值，则它可以正常工作，其中涉及同步写入功能.
Inside the startHandlig function in the server code, if I comment async_connect_1 and the return after it, then it works fine which involves sync write function.
我在Service()类中添加了async_connect_1函数，以从套接字异步读取.
I added async_connect_1 function inside Service() class to asynchronously read from the socket.
当客户端连接到服务器并且此函数立即返回时，将调用此函数.
This function is called when a client connects to the server and this function returns immediately.
我希望与async_read相对应的回调函数被调用，但是那没有发生...
I expect the callback function corresponding to async_read to be called, but that is not happening...
很久以来我一直坚持这一点.在此方面提供帮助...
I'm stuck at this since a long time.. Appreciate help on this...
服务器代码
#include <boost/asio.hpp>
#include <boost/archive/text_iarchive.hpp>
#include <boost/archive/text_oarchive.hpp>
#include <boost/bind.hpp>
#include <boost/serialization/vector.hpp>
#include <boost/tuple/tuple.hpp>
#include <thread>
#include <atomic>
#include <memory>
#include <iostream>
#include "../stocks.hpp"
using namespace boost;
class Service {
public:
Service(){}
void StartHandligClient(
std::shared_ptr<asio::ip::tcp::socket> sock) {
read_async_1(sock);
return;
std::thread th(([this, sock]() {
HandleClient(sock);
}));
std::cout << "Detached \n";
th.detach();
}
private:
void read_async_1(std::shared_ptr<asio::ip::tcp::socket> sock)
{
if(!(*sock.get()).is_open())
{
std::cout << getpid() << " : Socket closed in sync_read \n" << std::flush;
return ;
}
std::cout << "haha_1\n" << std::flush;
boost::asio::async_read( (*sock.get()), boost::asio::buffer(inbound_header_),
[this](boost::system::error_code ec,
size_t bytesRead)
{
std::cout << "haha_2\n" << std::flush;
if (!ec)
{
int headerBytesReceived = bytesRead;
std::cout << "\n\n headerBytesReceived : " << headerBytesReceived << "\n" << std::flush ;
// this->async_read(sock);
}
else
{
// Terminate connection ?
if(ec == boost::asio::error::eof)
{
std::cout << getpid() << " : ** sync_read : Connection lost : boost::asio::error::eof ** \n";
}
std::cout << "Error occured in sync_read! Error code = " << ec.value() << ". Message: " << ec.message() << "\n" << std::flush;
return ;
}
return ;
}
);
std::cout << getpid() << " : final return from async_read \n" << std::flush;
return ;
}
void HandleClient(std::shared_ptr<asio::ip::tcp::socket> sock) {
while(1)
{
try {
// asio::streambuf request;
// asio::read_until(*sock.get(), request, '\n');
int headerBytesReceived = asio::read( *sock.get(), boost::asio::buffer(inbound_header_) );
std::cout << "headerBytesReceived : " << headerBytesReceived << "\n" << std::flush;
// Determine the length of the serialized data.
std::istringstream is(std::string(inbound_header_, header_length));
std::cout << "is : " << is.str() << ", inbound_header_ : " << inbound_header_ << "\n";
std::size_t inbound_data_size = 0;
if (!(is >> std::hex >> inbound_data_size))
{
// Header doesn't seem to be valid. Inform the caller.
// boost::system::error_code error(boost::asio::error::invalid_argument);
// boost::get<0>(handler)(error);
std::cout << "RET-1 \n";
return;
}
std::cout << "inbound_data_size : " << inbound_data_size << "\n" << std::flush;
// Start an asynchronous call to receive the data.
inbound_data_.resize(inbound_data_size);
std::cout << "inbound_data_.size() : " << inbound_data_.size() << "\n" << std::flush;
int bytesReceived = asio::read( *sock.get(), boost::asio::buffer(inbound_data_) );
std::string archive_data(&inbound_data_[0], inbound_data_.size());
std::istringstream archive_stream(archive_data);
boost::archive::text_iarchive archive(archive_stream);
archive >> stocks_;
std::cout << "bytesReceived : " << bytesReceived << " , stocks_.size() : " << stocks_.size() << "\n";
// Print out the data that was received.
for (std::size_t i = 0; i < stocks_.size(); ++i)
{
std::cout << "Stock number " << i << "\n";
std::cout << " code: " << stocks_[i].code << "\n";
std::cout << " name: " << stocks_[i].name << "\n";
std::cout << " open_price: " << stocks_[i].open_price << "\n";
std::cout << " high_price: " << stocks_[i].high_price << "\n";
std::cout << " low_price: " << stocks_[i].low_price << "\n";
std::cout << " last_price: " << stocks_[i].last_price << "\n";
std::cout << " buy_price: " << stocks_[i].buy_price << "\n";
std::cout << " buy_quantity: " << stocks_[i].buy_quantity << "\n";
std::cout << " sell_price: " << stocks_[i].sell_price << "\n";
std::cout << " sell_quantity: " << stocks_[i].sell_quantity << "\n";
}
}
catch (system::system_error &e)
{
boost::system::error_code ec = e.code();
if(ec == boost::asio::error::eof)
{
std::cout << "EOF Error \n";
}
std::cout << "Server Error occured! Error code = "
<< e.code() << ". Message: "
<< e.what() << "\n";
break;
}
}
// Clean-up.
delete this;
}
/// The size of a fixed length header.
enum { header_length = 8 };
/// Holds an outbound header.
std::string outbound_header_;
/// Holds the outbound data.
std::string outbound_data_;
/// Holds an inbound header.
char inbound_header_[header_length];
/// Holds the inbound data.
std::vector<char> inbound_data_;
std::vector<stock> stocks_;
};
class Acceptor {
public:
Acceptor(asio::io_service& ios, unsigned short port_num) :
m_ios(ios),
m_acceptor(m_ios,
asio::ip::tcp::endpoint(
asio::ip::address_v4::any(),
port_num))
{
m_acceptor.listen();
}
void Accept() {
std::cout << "Server Accept() \n" << std::flush;
std::shared_ptr<asio::ip::tcp::socket>
sock(new asio::ip::tcp::socket(m_ios));
m_acceptor.accept(*sock.get());
(new Service)->StartHandligClient(sock);
}
private:
asio::io_service& m_ios;
asio::ip::tcp::acceptor m_acceptor;
};
class Server {
public:
Server() : m_stop(false) {}
void Start(unsigned short port_num) {
m_thread.reset(new std::thread([this, port_num]() {
Run(port_num);
}));
}
void Stop() {
m_stop.store(true);
m_thread->join();
}
private:
void Run(unsigned short port_num) {
Acceptor acc(m_ios, port_num);
while (!m_stop.load()) {
std::cout << "Server accept\n" << std::flush;
acc.Accept();
}
}
std::unique_ptr<std::thread> m_thread;
std::atomic<bool> m_stop;
asio::io_service m_ios;
};
int main()
{
unsigned short port_num = 3333;
try {
Server srv;
srv.Start(port_num);
std::this_thread::sleep_for(std::chrono::seconds(100));
std::cout << "Stopping server \n";
srv.Stop();
}
catch (system::system_error &e) {
std::cout << "Error occured! Error code = "
<< e.code() << ". Message: "
<< e.what();
}
return 0;
}
客户代码
#include <boost/asio.hpp>
#include <boost/archive/text_iarchive.hpp>
#include <boost/archive/text_oarchive.hpp>
#include <boost/bind.hpp>
#include <boost/serialization/vector.hpp>
#include <iostream>
#include "../stocks.hpp"
using namespace boost;
class SyncTCPClient {
public:
SyncTCPClient(const std::string& raw_ip_address,
unsigned short port_num) :
m_ep(asio::ip::address::from_string(raw_ip_address),
port_num),
m_sock(m_ios) {
m_sock.open(m_ep.protocol());
}
void connect() {
m_sock.connect(m_ep);
}
void close() {
m_sock.shutdown(
boost::asio::ip::tcp::socket::shutdown_both);
m_sock.close();
}
std::string emulateLongComputationOp(
unsigned int duration_sec) {
std::string request = "EMULATE_LONG_COMP_OP "
+ std::to_string(duration_sec)
+ "\n";
sendRequest(request);
return receiveResponse();
};
private:
void sendRequest(const std::string& request) {
std::vector<stock> stocks_;
// Create the data to be sent to each client.
stock s;
s.code = "ABC";
s.name = "A Big Company";
s.open_price = 4.56;
s.high_price = 5.12;
s.low_price = 4.33;
s.last_price = 4.98;
s.buy_price = 4.96;
s.buy_quantity = 1000;
s.sell_price = 4.99;
s.sell_quantity = 2000;
stocks_.push_back(s);
// Serialize the data first so we know how large it is.
std::ostringstream archive_stream;
boost::archive::text_oarchive archive(archive_stream);
archive << stocks_;
outbound_data_ = archive_stream.str();
std::cout << "outbound_data_ : " << outbound_data_ << "\n" << std::flush;
std::cout << "outbound_data_.size() : " << outbound_data_.size() << "\n" << std::flush;
// Format the header.
std::ostringstream header_stream;
header_stream << std::setw(header_length) << std::hex << outbound_data_.size();
std::cout << "header_stream.str() : " << header_stream.str() << "\n" << std::flush;
std::cout << "header_stream.str().size() : " << header_stream.str().size() << "\n" << std::flush;
if (!header_stream || header_stream.str().size() != header_length)
{
// Something went wrong, inform the caller.
// boost::system::error_code error(boost::asio::error::invalid_argument);
// socket_.get_io_service().post(boost::bind(handler, error));
return;
}
outbound_header_ = header_stream.str();
std::cout << "outbound_header_ : " << outbound_header_ << "\n" << std::flush;
// Write the serialized data to the socket. We use "gather-write" to send
// both the header and the data in a single write operation.
std::vector<boost::asio::const_buffer> buffers;
buffers.push_back(boost::asio::buffer(outbound_header_));
buffers.push_back(boost::asio::buffer(outbound_data_));
std::size_t sizeSent = asio::write(m_sock, buffers);
std::cout << "sizeSent : " << sizeSent << "\n" << std::flush;
}
std::string receiveResponse() {
std::string response;
/*
asio::streambuf buf;
asio::read_until(m_sock, buf, '\n');
std::istream input(&buf);
std::getline(input, response);
*/
return response;
}
private:
asio::io_service m_ios;
asio::ip::tcp::endpoint m_ep;
asio::ip::tcp::socket m_sock;
enum { header_length = 8 };
std::string outbound_data_;
std::string outbound_header_;
};
int main()
{
const std::string raw_ip_address = "127.0.0.1";
const unsigned short port_num = 3333;
try {
SyncTCPClient client(raw_ip_address, port_num);
// Sync connect.
client.connect();
sleep(1);
std::cout << "Sending request to the server... "
<< std::endl;
std::string response = client.emulateLongComputationOp(10);
std::cout << "Response received: " << response << std::endl;
sleep(100);
std::cout << "\n\n Closing client connection \n\n";
// Close the connection and free resources.
client.close();
}
catch (system::system_error &e) {
std::cout << "Client Error occured! Error code = " << e.code()
<< ". Message: " << e.what();
return e.code().value();
}
return 0;
}
包含的文件(stocks.hpp)
#ifndef _STOCKS_HPP_
#define _STOCKS_HPP_
struct stock
{
std::string code;
std::string name;
double open_price;
double high_price;
double low_price;
double last_price;
double buy_price;
int buy_quantity;
double sell_price;
int sell_quantity;
template <typename Archive>
void serialize(Archive& ar, const unsigned int version)
{
ar & code;
ar & name;
ar & open_price;
ar & high_price;
ar & low_price;
ar & last_price;
ar & buy_price;
ar & buy_quantity;
ar & sell_price;
ar & sell_quantity;
}
};
#endif
推荐答案
您在先前的响应中已将Error code = 125. Message: Operation canceled作为注释编写，我认为套接字可能会在完成异步操作之前关闭.
You have written Error code = 125. Message: Operation canceled as comment in previous response, i think that socket may be closed before async operation will be done.
插座的使用寿命是多少?
What is lifetime of your socket ?
[1]套接字是用Accept方法创建的
[1] socket is created in Accept method
std::shared_ptr<asio::ip::tcp::socket>
sock(new asio::ip::tcp::socket(m_ios)); // ref count +1
//...
(new Service)->StartHandligClient(sock); // this function returns immediately
// so socket's ref count -1
StartHandligClient()中的
[2] sock按值传递，因此套接字+1的引用计数，但
[2] in StartHandligClient() sock is passed by value, so ref count of socket +1, but
void StartHandligClient(
std::shared_ptr<asio::ip::tcp::socket> sock) { // +1 ref count
read_async_1(sock); // this function returns immediately
return; // -1 ref count of socket
}
[3]按值传递，套接字的引用计数为+1，但此函数立即返回，当函数结束时，引用计数减少，套接字对象被删除. [3] in 您创建了lambda对象来执行异步操作，但是套接字对象可能会在执行前关闭. You created lambda object to execute asynchronus operation, but socket object may be closed before doing it. 这篇关于Boost ASIO async_read不从客户端读取数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！read_async_1 socket is passed by value, +1 on ref count of socket, but this function returns immediately, when function ends, ref count is decreased and socket object is deleted.
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