tempestas

commit fb529558596f8b4ac1bd76cc2c36473324ddd2a7
parent 40fda0087b62c8a91923fa5615b51ebe691e0e67
Author: Chris Bracken <chris@bracken.jp>
Date:   Fri, 12 Nov 2021 10:25:30 -0800

Add JSON API to query list of sensors

Adds a JSON API with endpoint /sensor/sensors/ to query the list of
avaialble sensors.

Diffstat:
M
http/http.go
 | 
12
++++++++++++
M
storage/storage.go
 | 
32
++++++++++++++++++++++++++++++++

2 files changed, 44 insertions(+), 0 deletions(-)
diff --git a/http/http.go b/http/http.go
@@ -26,6 +26,7 @@ func (s HttpServer) ListenAndServe(addr string) error {
 	mux := goji.NewMux()
 	mux.HandleFunc(pat.Post("/sensor/airrohr/"), s.PostAirrohr)
 	mux.HandleFunc(pat.Get("/sensor/reading/:sensorId/:readingType"), s.QueryReadings)
+	mux.HandleFunc(pat.Get("/sensor/sensors/"), s.QuerySensors)
 	return http.ListenAndServe(addr, mux)
 }
 
@@ -72,6 +73,17 @@ func (s HttpServer) QueryReadings(w http.ResponseWriter, r *http.Request) {
 	writeResponse(w, resp, http.StatusOK)
 }
 
+func (s HttpServer) QuerySensors(w http.ResponseWriter, r *http.Request) {
+	sensors, err := s.ds.QuerySensors()
+	if err != nil {
+		fmt.Println("Error: failed to query sensors: " + err.Error())
+		errorResponse(w, "Bad Request. "+err.Error(), http.StatusBadRequest)
+		return
+	}
+	resp, _ := json.Marshal(sensors)
+	writeResponse(w, resp, http.StatusOK)
+}
+
 func errorResponse(w http.ResponseWriter, message string, httpStatusCode int) {
 	resp := make(map[string]string)
 	resp["message"] = message
diff --git a/storage/storage.go b/storage/storage.go
@@ -11,6 +11,7 @@ const (
 	INSERT_READING = "INSERT INTO " +
 		"sensor_data(sensor_id, sw_version, reading_time, reading_type, reading_value) " +
 		"VALUES($1, $2, $3, $4, $5)"
+	QUERY_SENSORS  = "SELECT DISTINCT sensor_id FROM sensor_data ORDER BY sensor_id"
 	QUERY_READINGS = "SELECT " +
 		"  sensor_id, sw_version, reading_time, reading_type, reading_value " +
 		"FROM " +
@@ -29,10 +30,15 @@ type Reading struct {
 	Value           float64   `json:"value"`
 }
 
+type Sensor struct {
+	SensorId string `json:"sensor_id"`
+}
+
 type DataStore interface {
 	Close()
 	StoreReading(r *Reading) error
 	QueryReadings(sensorId string, readingType string, start time.Time, end time.Time) ([]Reading, error)
+	QuerySensors() ([]Sensor, error)
 }
 
 type PostgresDataStore struct {
@@ -93,6 +99,27 @@ func (s *PostgresDataStore) QueryReadings(sensorId string,
 	return readings, nil
 }
 
+func (s *PostgresDataStore) QuerySensors() ([]Sensor, error) {
+	rows, err := s.db.Query(QUERY_SENSORS)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var sensors []Sensor
+	for rows.Next() {
+		var s Sensor
+		if err := rows.Scan(&s.SensorId); err != nil {
+			return sensors, err
+		}
+		sensors = append(sensors, s)
+	}
+	if err = rows.Err(); err != nil {
+		return sensors, err
+	}
+	return sensors, nil
+}
+
 type NullDataStore struct {
 }
 
@@ -116,3 +143,8 @@ func (s *NullDataStore) QueryReadings(
 	var readings []Reading
 	return readings, nil
 }
+
+func (s *NullDataStore) QuerySensors() ([]Sensor, error) {
+	var sensors []Sensor
+	return sensors, nil
+}