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113 lines
3.1 KiB
C++
113 lines
3.1 KiB
C++
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#include "boost/mysql/connection.hpp"
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#include <boost/asio/io_service.hpp>
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#include <boost/system/system_error.hpp>
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#include <boost/asio/spawn.hpp>
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#include <iostream>
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using boost::mysql::error_code;
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using boost::mysql::error_info;
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/**
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* For this example, we will be using the 'mysql_asio_examples' database.
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* You can get this database by running db_setup.sql.
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* This example assumes you are connecting to a localhost MySQL server.
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*
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* This example uses asynchronous functions with coroutines.
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*
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* This example assumes you are already familiar with the basic concepts
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* of mysql-asio (tcp_connection, resultset, rows, values). If you are not,
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* please have a look to the query_sync.cpp example.
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*/
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void print_employee(const boost::mysql::row& employee)
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{
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using boost::mysql::operator<<; // Required for mysql::value objects to be streamable, due to ADL rules
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std::cout << "Employee '"
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<< employee.values()[0] << " " // first_name (type std::string_view)
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<< employee.values()[1] << "' earns " // last_name (type std::string_view)
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<< employee.values()[2] << " dollars yearly\n"; // salary (type double)
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}
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void check_error(
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const error_code& err,
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const boost::mysql::error_info& info = boost::mysql::error_info()
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)
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{
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if (err)
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{
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throw boost::system::system_error(err, info.message());
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}
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}
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void main_impl(int argc, char** argv)
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{
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if (argc != 3)
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{
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std::cerr << "Usage: " << argv[0] << " <username> <password>\n";
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exit(1);
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}
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// Context and connections
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boost::asio::io_context ctx;
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boost::mysql::tcp_connection conn (ctx);
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boost::asio::ip::tcp::endpoint ep (
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boost::asio::ip::address_v4::loopback(), // host
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boost::mysql::default_port // port
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);
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boost::mysql::connection_params params (
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argv[1], // username
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argv[2], // password
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"mysql_asio_examples" // database to use; leave empty or omit the parameter for no database
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);
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// Entry point
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boost::asio::spawn(ctx.get_executor(), [&conn, ep, params](boost::asio::yield_context yield) {
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boost::mysql::error_code ec;
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// TCP connect
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conn.next_level().async_connect(ep, yield[ec]);
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check_error(ec);
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// MySQL handshake
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boost::mysql::error_info errinfo = conn.async_handshake(params, yield[ec]);
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check_error(ec, errinfo);
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// Issue the query to the server
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const char* sql = "SELECT first_name, last_name, salary FROM employee WHERE company_id = 'HGS'";
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boost::mysql::async_handler_arg<boost::mysql::tcp_resultset> result =
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conn.async_query(sql, yield[ec]);
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check_error(ec, result.error());
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// Get all the rows in the resultset
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while (true)
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{
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boost::mysql::async_handler_arg<const boost::mysql::row*> row =
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result.get().async_fetch_one(yield[ec]);
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check_error(ec, row.error());
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if (!row.get()) break;
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print_employee(*row.get());
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}
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});
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}
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int main(int argc, char** argv)
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{
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try
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{
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main_impl(argc, argv);
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}
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catch (const boost::system::system_error& err)
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{
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std::cerr << "Error: " << err.what() << ", error code: " << err.code() << std::endl;
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return 1;
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}
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catch (const std::exception& err)
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{
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std::cerr << "Error: " << err.what() << std::endl;
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return 1;
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}
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}
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