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awaitable examples are simplified

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No need for `rebind_executor` as `asio::deferred` is now the default completion token.
This commit is contained in:
Mohammad Nejati
2024-07-07 14:58:49 +03:30
committed by Mohammad Nejati
parent aabd5b51d3
commit ff5672ec07
6 changed files with 695 additions and 1309 deletions
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example/websocket/client/awaitable/websocket_client_awaitable.cpp
+66 -73
View File
@@ -13,49 +13,39 @@
//
//------------------------------------------------------------------------------
#include <boost/beast/core.hpp>
#include <boost/beast/websocket.hpp>
#include <cstdlib>
#include <functional>
#include <iostream>
#include <string>
#include <boost/asio/awaitable.hpp>
#include <boost/asio/co_spawn.hpp>
#include <boost/asio/detached.hpp>
#include <boost/asio/use_awaitable.hpp>
#include <boost/asio/io_context.hpp>
#include <boost/beast/core.hpp>
#include <boost/beast/websocket.hpp>
#include <cstdlib>
#include <iostream>
#include <string>
#if defined(BOOST_ASIO_HAS_CO_AWAIT)
namespace beast = boost::beast; // from <boost/beast.hpp>
namespace http = beast::http; // from <boost/beast/http.hpp>
namespace websocket = beast::websocket; // from <boost/beast/websocket.hpp>
namespace net = boost::asio; // from <boost/asio.hpp>
using tcp = boost::asio::ip::tcp; // from <boost/asio/ip/tcp.hpp>
//------------------------------------------------------------------------------
namespace beast = boost::beast;
namespace http = beast::http;
namespace websocket = beast::websocket;
namespace net = boost::asio;
// Sends a WebSocket message and prints the response
net::awaitable<void>
do_session(
std::string host,
std::string port,
std::string text)
do_session(std::string host, std::string port, std::string text)
{
// These objects perform our I/O
auto resolver = net::use_awaitable.as_default_on(
tcp::resolver(co_await net::this_coro::executor));
auto ws = net::use_awaitable.as_default_on(
websocket::stream<beast::tcp_stream>(co_await net::this_coro::executor));
auto executor = co_await net::this_coro::executor;
auto resolver = net::ip::tcp::resolver{ executor };
auto stream = websocket::stream<beast::tcp_stream>{ executor };
// Look up the domain name
auto const results = co_await resolver.async_resolve(host, port);
// Set a timeout on the operation
beast::get_lowest_layer(ws).expires_after(std::chrono::seconds(30));
beast::get_lowest_layer(stream).expires_after(std::chrono::seconds(30));
// Make the connection on the IP address we get from a lookup
auto ep = co_await beast::get_lowest_layer(ws).async_connect(results);
auto ep = co_await beast::get_lowest_layer(stream).async_connect(results);
// Update the host_ string. This will provide the value of the
// Host HTTP header during the WebSocket handshake.
@@ -64,36 +54,36 @@ do_session(
// Turn off the timeout on the tcp_stream, because
// the websocket stream has its own timeout system.
beast::get_lowest_layer(ws).expires_never();
beast::get_lowest_layer(stream).expires_never();
// Set suggested timeout settings for the websocket
ws.set_option(
websocket::stream_base::timeout::suggested(
beast::role_type::client));
stream.set_option(
websocket::stream_base::timeout::suggested(beast::role_type::client));
// Set a decorator to change the User-Agent of the handshake
ws.set_option(websocket::stream_base::decorator(
stream.set_option(websocket::stream_base::decorator(
[](websocket::request_type& req)
{
req.set(http::field::user_agent,
req.set(
http::field::user_agent,
std::string(BOOST_BEAST_VERSION_STRING) +
" websocket-client-coro");
}));
// Perform the websocket handshake
co_await ws.async_handshake(host, "/");
co_await stream.async_handshake(host, "/");
// Send the message
co_await ws.async_write(net::buffer(std::string(text)));
co_await stream.async_write(net::buffer(text));
// This buffer will hold the incoming message
beast::flat_buffer buffer;
// Read a message into our buffer
co_await ws.async_read(buffer);
co_await stream.async_read(buffer);
// Close the WebSocket connection
co_await ws.async_close(websocket::close_code::normal);
co_await stream.async_close(websocket::close_code::normal);
// If we get here then the connection is closed gracefully
@@ -103,53 +93,56 @@ do_session(
//------------------------------------------------------------------------------
int main(int argc, char** argv)
int
main(int argc, char** argv)
{
// Check command line arguments.
if(argc != 4)
try
{
std::cerr <<
"Usage: websocket-client-awaitable <host> <port> <text>\n" <<
"Example:\n" <<
" websocket-client-awaitable echo.websocket.org 80 \"Hello, world!\"\n";
// Check command line arguments.
if(argc != 4)
{
std::cerr
<< "Usage: websocket-client-awaitable <host> <port> <text>\n"
<< "Example:\n"
<< " websocket-client-awaitable echo.websocket.org 80 \"Hello, world!\"\n";
return EXIT_FAILURE;
}
auto const host = argv[1];
auto const port = argv[2];
auto const text = argv[3];
// The io_context is required for all I/O
net::io_context ioc;
// Launch the asynchronous operation
net::co_spawn(
ioc,
do_session(host, port, text),
[](std::exception_ptr e)
{
if(e)
std::rethrow_exception(e);
});
// Run the I/O service. The call will return when
// the socket is closed.
ioc.run();
}
catch(std::exception const& e)
{
std::cerr << "Error: " << e.what() << std::endl;
return EXIT_FAILURE;
}
auto const host = argv[1];
auto const port = argv[2];
auto const text = argv[3];
// The io_context is required for all I/O
net::io_context ioc;
// Launch the asynchronous operation
net::co_spawn(ioc,
do_session(host, port, text),
[](std::exception_ptr e)
{
if (e)
try
{
std::rethrow_exception(e);
}
catch(std::exception & e)
{
std::cerr << "Error: " << e.what() << "\n";
}
});
// Run the I/O service. The call will return when
// the socket is closed.
ioc.run();
return EXIT_SUCCESS;
}
#else
int main(int, char * [])
int
main(int, char*[])
{
std::printf("awaitables require C++20\n");
return 1;
return EXIT_FAILURE;
}
#endif