fischertechnik community forum

Code: Alles auswählen

/**
 * POC (proof of concept)
 * RoboPro SLI element for sending (push) information about the joysticks and 2 motors
 * over a web socket to the connected clients.
 * This example is Json based, however for more speed binary is also possible.
 * This SLI is using the embedded c++ version of CivetWeb. 
 * For the POC: because the focus in this example is about the use of the web socket, 
 * so reading the actual value from the TA has been left out,
 * instead it is using dummy values.
 * @return Error = -1, otherwise the number of byte which has been sent
 * [url=https://github.com/fischertechnik/txt_demo_ROBOPro_SLI]for SLI basics [/url]
 */
 int setSendShort(short v) {
	int res = -1;
	int joyStickLeftRL = 0, joyStickLeftUD = 0, joystickID = 1; /* 1== off, off*/
	Json::Value root, joystick, motor1, motor2, input, counter;
	char const *c = "error";	//NULL;
	Json::StreamWriterBuilder builder;
	try {  //creating the JSON string structure
		joyStickLeftRL = 0;
		joyStickLeftUD = 0;
		motor1["id"] = 1;
		motor1["power1"] = 256;
		motor1["power2"] = 0;
		motor2["id"] = 2;
		motor2["power1"] = 0;
		motor2["power2"] = 158;
		joystick["id"] = joystickID;
		joystick["leftUD"] = joyStickLeftRL;
		joystick["leftRL"] = joyStickLeftUD;
		root["TXT"] = joystick;
		root["TXT"] = motor1;
		root["TXT"] = motor2;
		const std::string json_file = Json::writeString(builder, root);
		std::cout << json_file << std::endl;//for testing only
		c = json_file.c_str();
	} catch (const std::exception &e) {
		printf("######### setSendShort: error=%s\n", e.what());//for testing only
		std::cout << "######### setSendShort: Json exception" << e.what() << std::endl;//for testing only
	}
	if (c == NULL) {
		c = "error";
	};
	res = ft_h_websocket.pushMessage01(c, (unsigned int) strlen(c));//handover to the CivetWeb web socket connection handler
	return res;//-1:error, otherwise number of transmitted bytes
}