tempestas

commit 7de0142e927605acb0227590f756efa0ecd285d7
parent cbfa2fefb64ba825ff6abc72b364b7126f708f8a
Author: Chris Bracken <chris@bracken.jp>
Date:   Fri, 12 Nov 2021 09:52:55 -0800

Limit reading queries by type and sensor ID

Previously queries for readings returned all readings of any type for
all sensors over the specified time period -- though that time period is
currently still hard-coded to the last 24 hours.

This changes the query API to return readings at the following URL path:

    /sensor/reading/:sensorId/:readingType

and restricts readings to the specified sensor and reading type.

Further, this fixes a bug wherein the order of returned data was
previously not guaranteed to be in chronological order.

Diffstat:
M
http/http.go
 | 
8
++++++--
M
storage/storage.go
 | 
27
+++++++++++++++++++++------

2 files changed, 27 insertions(+), 8 deletions(-)
diff --git a/http/http.go b/http/http.go
@@ -25,7 +25,7 @@ func CreateServer(ds storage.DataStore) *HttpServer {
 func (s HttpServer) ListenAndServe(addr string) error {
 	mux := goji.NewMux()
 	mux.HandleFunc(pat.Post("/sensor/airrohr/"), s.PostAirrohr)
-	mux.HandleFunc(pat.Get("/sensor/reading/"), s.QueryReadings)
+	mux.HandleFunc(pat.Get("/sensor/reading/:sensorId/:readingType"), s.QueryReadings)
 	return http.ListenAndServe(addr, mux)
 }
 
@@ -56,8 +56,12 @@ func (s HttpServer) PostAirrohr(w http.ResponseWriter, r *http.Request) {
 func (s HttpServer) QueryReadings(w http.ResponseWriter, r *http.Request) {
 	start := time.Now().Add(time.Hour * -24)
 	end := time.Now()
+
+	sensorId := pat.Param(r, "sensorId")
+	readingType := pat.Param(r, "readingType")
+
 	// TODO: extract start/end from r.URL.Query() with a default if not present.
-	readings, err := s.ds.QueryReadings(start, end)
+	readings, err := s.ds.QueryReadings(sensorId, readingType, start, end)
 	if err != nil {
 		fmt.Println("Error: failed to query sensor data: " + err.Error())
 		errorResponse(w, "Bad Request. "+err.Error(), http.StatusBadRequest)
diff --git a/storage/storage.go b/storage/storage.go
@@ -11,8 +11,14 @@ const (
 	INSERT_READING = "INSERT INTO " +
 		"sensor_data(sensor_id, sw_version, reading_time, reading_type, reading_value) " +
 		"VALUES($1, $2, $3, $4, $5)"
-	QUERY_READINGS = "SELECT sensor_id, sw_version, reading_time, reading_type, reading_value " +
-		"FROM sensor_data WHERE reading_time >= $1 AND reading_time < $2"
+	QUERY_READINGS = "SELECT " +
+		"  sensor_id, sw_version, reading_time, reading_type, reading_value " +
+		"FROM " +
+		"  sensor_data " +
+		"WHERE " +
+		"  sensor_id = $1 AND reading_type = $2 AND reading_time >= $3 AND reading_time < $4 " +
+		"ORDER BY " +
+		"  reading_time"
 )
 
 type Reading struct {
@@ -26,7 +32,7 @@ type Reading struct {
 type DataStore interface {
 	Close()
 	StoreReading(r *Reading) error
-	QueryReadings(start time.Time, end time.Time) ([]Reading, error)
+	QueryReadings(sensorId string, readingType string, start time.Time, end time.Time) ([]Reading, error)
 }
 
 type PostgresDataStore struct {
@@ -62,8 +68,12 @@ func (s *PostgresDataStore) StoreReading(r *Reading) error {
 	return err
 }
 
-func (s *PostgresDataStore) QueryReadings(start time.Time, end time.Time) ([]Reading, error) {
-	rows, err := s.db.Query(QUERY_READINGS, start, end)
+func (s *PostgresDataStore) QueryReadings(sensorId string,
+	readingType string,
+	start time.Time,
+	end time.Time) ([]Reading, error) {
+
+	rows, err := s.db.Query(QUERY_READINGS, sensorId, readingType, start, end)
 	if err != nil {
 		return nil, err
 	}
@@ -97,7 +107,12 @@ func (s *NullDataStore) StoreReading(r *Reading) error {
 	return nil
 }
 
-func (s *NullDataStore) QueryReadings(start time.Time, end time.Time) ([]Reading, error) {
+func (s *NullDataStore) QueryReadings(
+	sensorId string,
+	readingType string,
+	start time.Time,
+	end time.Time) ([]Reading, error) {
+
 	var readings []Reading
 	return readings, nil
 }