Added endpoint for fetching the latest values

server/main.go

@@ -39,6 +39,7 @@ func main() {
 	// Routes that are only accessible after logging in
 	loginProtected := router.Group("/", middleware.LoginAuthMiddleware(server))
 	loginProtected.GET("/api/sensors", routes.GetSensors(server))
+	loginProtected.GET("/api/sensors/:sensor/values/latest", routes.GetSensorLatestValue(server))
 	loginProtected.GET("/api/sensors/:sensor/values", routes.GetSensorValues(server))
 	loginProtected.GET("/api/sensors/:sensor/config", routes.GetSensorConfig(server))
 	loginProtected.PUT("/api/sensors/:sensor/config/:key", routes.PutSensorConfig(server))

server/routes/sensor_values.go

@@ -55,3 +55,25 @@ func GetSensorValues(s *app.Server) gin.HandlerFunc {
 		c.JSON(http.StatusOK, values)
 	}
 }
+
+func GetSensorLatestValue(s *app.Server) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		var query getSensorQuery
+
+		sensor := c.Param("sensor")
+
+		if err := c.BindQuery(&query); err != nil {
+			c.AbortWithError(500, err)
+			return
+		}
+
+		value, err := s.Services.SensorValues.GetLatest(sensor, query.From, query.To)
+
+		if err != nil {
+			c.AbortWithError(500, err)
+			return
+		}
+
+		c.JSON(http.StatusOK, value)
+	}
+}

server/services/sensor_values_service.go

@@ -50,3 +50,16 @@ func (s *SensorValuesService) GetList(sensor string, from int64, to int64) ([]se
 
 	return values, nil
 }
+
+func (s *SensorValuesService) GetLatest(sensor string, from int64, to int64) (*sensorValue, error) {
+	var value = sensorValue{}
+
+	row := s.ctx.DB.QueryRow("SELECT timestamp, value FROM sensor_values WHERE sensor = ? AND timestamp > ? AND timestamp < ? ORDER BY timestamp DESC LIMIT 1", sensor, from, to)
+
+	err := row.Scan(&value.Timestamp, &value.Value)
+	if err != nil {
+		return nil, err
+	}
+
+	return &value, nil
+}