simulation of simulator... yeah...

simulatesimulator/.gitignore

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+main

simulatesimulator/build.sh

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+gcc -o main mqtt.c -lmosquitto main.c

simulatesimulator/main.c

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+#include <unistd.h>
+#include <stdio.h>
+#include <mosquitto.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "mqtt.h"
+#include "config.h"
+
+#define MAX_AIRSPEED 385
+#define MAX_MQTT_PAYLOAD_SIZE 512
+
+struct mosquitto *mqtt;
+
+int airspeed = 0;
+int heading = 0;
+
+struct test {
+	char *foo;
+};
+
+void onMessage(struct mosquitto *mqtt, void *obj, const struct mosquitto_message *message) {
+	char *mqttTopic;
+	char mqttPayload[MAX_MQTT_PAYLOAD_SIZE];
+
+	if (strcmp(message->topic, "/xplane/meta/rref") == 0) {
+		//requestRrefFromXPlane(message);
+	} else if (strcmp(message->topic, "/xplane/meta/cmnd") == 0) {
+		mqttTopic = NULL;
+		memset(mqttPayload, 0, sizeof(mqttPayload));
+
+		printf("CMD: %s\n", (char *)message->payload);
+		if (strcmp((char *)message->payload, "sim/autopilot/airspeed_up") == 0) {
+			airspeed++;
+			if (airspeed > MAX_AIRSPEED) {
+				airspeed = MAX_AIRSPEED;
+			} else {
+				// airspeed changed
+				mqttTopic = "/xplane/rref/2";
+				sprintf(mqttPayload, "%03d", airspeed);
+			}
+			printf("Airspeed: %d\n", airspeed);
+		} else if (strcmp((char *)message->payload, "sim/autopilot/airspeed_down") == 0) {
+			airspeed--;
+			if (airspeed < 0) {
+				airspeed = 0;
+			} else {
+				mqttTopic = "/xplane/rref/2";
+				sprintf(mqttPayload, "%03d", airspeed);
+			}
+			printf("Airspeed: %d\n", airspeed);
+		} else if (strcmp((char *)message->payload, "sim/autopilot/heading_up") == 0) {
+			heading++;
+			if (heading > 360) {
+				heading = 1;
+			}
+			mqttTopic = "/xplane/rref/1";
+			sprintf(mqttPayload, "%03d", heading);
+			printf("Heading: %d\n", heading);
+		} else if (strcmp((char *)message->payload, "sim/autopilot/heading_down") == 0) {
+			heading--;
+			if (heading < 0) {
+				heading = 359;
+			}
+			mqttTopic = "/xplane/rref/1";
+			sprintf(mqttPayload, "%03d", heading);
+			printf("Heading: %d\n", heading);
+		} else {
+			printf("unkown command %s\n", (char *)message->payload);
+		}
+
+		if (mqttTopic != NULL && mqttPayload != NULL) {
+			sendMqtt(mqtt, mqttTopic, mqttPayload, strlen(mqttPayload));
+		}
+	} else if (strcmp(message->topic, "/xplane/meta/log") == 0) {
+		printf("Log: %s\n", (char *)message->payload);
+	} else {
+		fprintf(stderr, "Unknown topic %s\n", message->topic);
+	}
+}
+
+void doit(struct test *blah) {
+	blah->foo = "moep";
+}
+
+int main() {
+	struct test bar = { "baz" };
+	doit(&bar);
+	printf("foo is %s\n", bar.foo);
+
+	mqtt = connectMqtt(MQTT_USER1, MQTT_PASS, onMessage);
+	if (mqtt == NULL) {
+		return -1;
+	}
+
+	recvMqtt(mqtt, "/xplane/meta/cmnd");
+
+	while (1) {
+		mosquitto_loop(mqtt, 0, 1);
+		usleep(10 * 1000);
+	}
+
+	disconnectMqtt(mqtt);
+}

simulatesimulator/mqtt.c

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+#include <stdio.h>
+
+#include <errno.h>
+#include <string.h>
+
+// https://mosquitto.org/api/files/mosquitto-h.html
+#include <mosquitto.h>
+
+struct mosquitto *connectMqtt(char *user, char *pass, void (*messageCallback)(struct mosquitto *, void *, const struct mosquitto_message *))
+{
+    int err;
+    struct mosquitto *mqtt;
+
+    err = mosquitto_lib_init();
+    if (err)
+    {
+        fprintf(stderr, "Error initalizing mosquitto lib (%d): %s\n", err, mosquitto_strerror(err));
+        return NULL;
+    }
+
+    mqtt = mosquitto_new(user, true, NULL);
+    if (mqtt == NULL)
+    {
+        fprintf(stderr, "Error creating mosquitto instance (%d): %s\n", errno, strerror(errno));
+        return NULL;
+    }
+
+    err = mosquitto_username_pw_set(mqtt, user, pass);
+    if (err)
+    {
+        fprintf(stderr, "Error setting username & password (%d): %s\n", err, mosquitto_strerror(err));
+        return NULL;
+    }
+
+    // FIXME: I am hard coded :(
+    err = mosquitto_connect(mqtt, "openhab.sugarland.lan", 1883, 10);
+    if (err)
+    {
+        fprintf(stderr, "Error on connection of type ");
+        if (err == MOSQ_ERR_ERRNO)
+        {
+            fprintf(stderr, "system (%d): %s\n", errno, strerror(errno));
+        }
+        else
+        {
+            fprintf(stderr, "mosquitto (%d): %s\n", err, mosquitto_strerror(err));
+        }
+        return NULL;
+    }
+
+    mosquitto_message_callback_set(mqtt, messageCallback);
+
+    return mqtt;
+}
+
+int sendMqtt(struct mosquitto *mqtt, char *topic, char *payload, int payloadLength)
+{
+    int err;
+
+    err = mosquitto_publish(mqtt, NULL, topic, payloadLength, payload, 0, false);
+    if (err)
+    {
+        fprintf(stderr, "Error publishing message to %s (%d): %s\n", topic, err, mosquitto_strerror(err));
+        return -1;
+    }
+    else
+    {
+        return 0;
+    }
+}
+
+int recvMqtt(struct mosquitto *mqtt, char *topic)
+{
+    int err;
+    
+    err = mosquitto_subscribe(mqtt, NULL, topic, 0);
+    if (err) {
+        fprintf(stderr, "Error subscribing to %s (%d): %s", topic, err, mosquitto_strerror(err));
+        return -1;
+    }
+    else
+    {
+        return 0;
+    }
+}
+
+void disconnectMqtt(struct mosquitto *mqtt)
+{
+    // ignore errors
+    mosquitto_disconnect(mqtt);
+    mosquitto_destroy(mqtt);
+    mosquitto_lib_cleanup();
+}

simulatesimulator/mqtt.h

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+struct mosquitto * connectMqtt(char *user, char *pass, void (*messageCallback)(struct mosquitto *, void *, const struct mosquitto_message *));
+int sendMqtt(struct mosquitto *mqtt, char *topic, char *payload, int payloadLength);
+int recvMqtt(struct mosquitto *mqtt, char *topic);
+void disconnectMqtt(struct mosquitto *mqtt);