{"id":2644,"date":"2019-11-15T18:11:33","date_gmt":"2019-11-15T17:11:33","guid":{"rendered":"https:\/\/ridgesolutions.ie\/?p=2644"},"modified":"2022-05-17T16:08:09","modified_gmt":"2022-05-17T15:08:09","slug":"fire-and-forget-wrapper-for-sending-of-simple-udp-data-using-boostasio-libraries","status":"publish","type":"post","link":"https:\/\/www.ridgesolutions.ie\/index.php\/2019\/11\/15\/fire-and-forget-wrapper-for-sending-of-simple-udp-data-using-boostasio-libraries\/","title":{"rendered":"Fire-And-Forget wrapper for sending simple UDP data using boost::asio libraries"},"content":{"rendered":"

So I had a problem, as part of an embedded software system I was working on I needed to periodically send some GPS information via UDP datagrams to other devices on the network – really simple stuff, transmit a string to an IP address on a given port, Fire And Forget<\/b>, send a string from here to there – end of story!<\/p>\n

Now my normal port of call these days for networking in C++ is to reach for the boost::asio<\/b> libs, as mentioned here<\/a>, this library is very powerful and flexible and can handle a huge number of different networking scenarios.<\/p>\n

All well and good, but sometimes I wish that I could just call a simple function and not have to remember or worry about all of boost stuff as it can be a proper head-wreck and there’s a lot of typing as the namespaces are so long! Python has me really spoiled, it makes so many things simple and easy to use!<\/p>\n

So I wrote a little C++ wrapper class that just has 1 function called send()<\/b> that can send a string or the contents of a binary buffer, the class is called: boost_udp_send_faf<\/b> (faf stands for Fire-and-Forget!).<\/p>\n

It is a very basic wrapper around the boost libs and only handles very simple transmission use-cases, but these use-cases probably cover about 80% of my UDP transmission needs!<\/p>\n

To use the class for a single Fire-and-Forget send:<\/p>\n

\/\/\r\n#include \"boost_udp_send_faf.h\"\r\nboost_udp_send_faf(\"192.168.1.44\", 8861).send(\"The message!\");\r\n\/\/<\/pre>\n
This sends the message to 192.168.1.44 on port 8861.<\/p>\n
If your program needs send multiple datagrams, then we can keep the socket open and reuse the end-point like this:<\/p>\n
\/\/\r\n#include \"boost_udp_send_faf.h\"\r\nboost_udp_send_faf sender(\"192.168.1.44\", 8861);\r\nfor (auto i = 0; i != 10; i++) { sender.send(\"Lots of messages! :-\/\"); }\r\n\/\/<\/pre>\n
The socket will remain open until the ‘sender’ object goes out of scope.<\/p>\n
It’s probably best to add exception handling to your calls as they can fail for lots of reasons and as ever networking is very flaky & unpredictable.<\/p>\n
\/\/\r\ntry {\r\n    boost_udp_send_faf(\"192.168.1.44\", 8861).send(\"The message!\");\r\n} catch (const boost::system::system_error& ex) { cerr << \"Send failed: \" << ex.what(); }\r\n\/\/<\/pre>\n
This will also ensure that the socket is closed once the message is sent as the object will go out of scope when execution leaves the try block.<\/p>\n
The code for boost_udp_send_faf can be found in this<\/a> repo on GitHub, but I have in-lined it below as well.<\/p>\n
For an easier way to receive UDP data see: boost_udp_receive_rar <\/a><\/p>\n
 <\/p>\n
#pragma once\r\n\r\n\/\/   Copyright 2018 Kevin Godden\r\n\/\/\r\n\/\/   Licensed under the Apache License, Version 2.0 (the \"License\");\r\n\/\/   you may not use this file except in compliance with the License.\r\n\/\/   You may obtain a copy of the License at\r\n\/\/\r\n\/\/       http:\/\/www.apache.org\/licenses\/LICENSE-2.0\r\n\/\/\r\n\/\/   Unless required by applicable law or agreed to in writing, software\r\n\/\/   distributed under the License is distributed on an \"AS IS\" BASIS,\r\n\/\/   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\r\n\/\/   See the License for the specific language governing permissions and\r\n\/\/   limitations under the License.\r\n\r\n#include <boost\/asio.hpp>\r\n#include <string>\r\n\r\n\/\/\r\n\/\/ Fire-and-Forget (FAF) transmission for UDP\r\n\/\/ using the boost::asio lib. Very simple wrapper\r\n\/\/ around the boost libs.\r\n\/\/\r\n\/\/ Can throw the following exception:\r\n\/\/\tboost::system::system_error\r\n\/\/\r\n\/\/ Synopsis --->\r\n\/\/\r\n\/\/ For a single Fire-and-Forget send:\r\n\/\/\r\n\/\/ #include \"boost_udp_send_faf.h\"\r\n\/\/\r\n\/\/ boost_udp_send_faf(\"192.168.1.44\", 8861).send(\"The message!\");\r\n\/\/\r\n\/\/\r\n\/\/ To send multiple datagrams while keeping the socket open and\r\n\/\/ reusing end-point:\r\n\/\/\r\n\/\/ #include \"boost_udp_send_faf.h\"\r\n\/\/\r\n\/\/ boost_udp_send_faf sender(\"192.168.1.44\", 8861);\r\n\/\/\t\t\r\n\/\/ for (auto i = 0; i != 10; i++) {\r\n\/\/     sender.send(\"Lots of messages! :-\/\");\r\n\/\/ }\r\n\/\/\r\n\/\/ The socket will remain open while the boost_udp_send_faf object is in scope\r\n\/\/ so to control when the socket is closed, control the scope of the object.\r\n\/\/\r\n\/\/ If you want to do anything fancy like using scatter-gather buffers etc. then\r\n\/\/ just use the boost libs!  This is for real simple stuff!\r\n\/\/\r\n\r\n\r\nclass boost_udp_send_faf {\r\n    boost::asio::io_service io_service;\r\n    boost::asio::ip::udp::socket socket;\r\n    boost::asio::ip::udp::endpoint remote_endpoint;\r\n\r\npublic:\r\n\r\n    boost_udp_send_faf(const std::string& ip_address, const int port, const bool broadcast = false) : socket(io_service) {\r\n        \r\n        \/\/ Open socket\r\n        socket.open(boost::asio::ip::udp::v4());\r\n\r\n        \/\/ I wouldn't recommend broadcasting unless you are\r\n        \/\/ in complete control of your subnet and know\r\n        \/\/ what's on it and how it will react\r\n        if (broadcast) {\r\n            boost::asio::socket_base::broadcast option(true);\r\n            socket.set_option(option);\r\n        }\r\n\r\n        \/\/ make endpoint\r\n        remote_endpoint = boost::asio::ip::udp::endpoint(boost::asio::ip::address::from_string(ip_address.c_str()), port);\r\n    }\r\n\r\n    \/\/ Send a string to the preconfigured endpoint\r\n    \/\/ via the open socket.\r\n    void send(const std::string& message) {\r\n        boost::system::error_code ignored_error;\r\n        socket.send_to(boost::asio::buffer(message), remote_endpoint, 0, ignored_error);\r\n    }\r\n\r\n    \/\/ Send some binary data to the preconfigured endpoint\r\n    \/\/ via the open socket.\r\n    void send(const unsigned char* data, const int len) {\r\n        boost::system::error_code ignored_error;\r\n        socket.send_to(boost::asio::buffer(data, len), remote_endpoint, 0, ignored_error);\r\n    }\r\n};<\/pre>\n
 <\/p>\n
 <\/p>\n","protected":false},"excerpt":{"rendered":"
So I had a problem, as part of an embedded software system I was working on I needed to periodically send some GPS information via UDP datagrams to other devices on the network – really simple stuff, transmit a string to an IP address on a given port, Fire And Forget, send a string from […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[301],"tags":[],"class_list":["post-2644","post","type-post","status-publish","format-standard","hentry","category-by-kevin-godden"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t