Changed endpoints and db queries, chart now shows suggested mins and maxes

Database.go

@@ -39,6 +39,27 @@ func writeSnapshotToDb(snapshotSub *SnapshotSubmission) error {
 	return nil
 }
 
+func getLastSnapshotRecordFromDb() (*SnapshotRecord, error) {
+	var snapshotRecord SnapshotRecord
+	query := "SELECT `%s`, `%s`, `%s`, `%s`, `%s` FROM `snapshots` ORDER BY `id` DESC LIMIT 1;"
+	rows, err := ClimateDb.Query(fmt.Sprintf(query, "id", "temp", "humidity", "co2", "time"))
+	if err != nil {
+		return nil, err
+	}
+	rows.Next()
+	err = rows.Scan(
+		&snapshotRecord.Id,
+		&snapshotRecord.Temp,
+		&snapshotRecord.Humidity,
+		&snapshotRecord.Co2,
+		&snapshotRecord.Timestamp,
+	)
+	if err != nil {
+		return nil, err
+	}
+	return &snapshotRecord, nil
+}
+
 func getSnapshotRecordsFromDb(minuteAgo int) ([]*SnapshotRecord, error) {
 	snapshots := make([]*SnapshotRecord, 0)
 	query := "SELECT `%s`, `%s`, `%s`, `%s`, `%s` FROM `snapshots` WHERE `%s` > date_sub(now(), interval %v minute) ORDER BY `id` DESC;"

climate-server.go

@@ -39,6 +39,7 @@ func startServer() {
 	r.HandleFunc("/since/{mins}", showCharts).Methods("GET")
 	r.HandleFunc("/data/", sendData).Methods("GET")
 	r.HandleFunc("/data/since/{mins}", sendData).Methods("GET")
+	r.HandleFunc("/data/last/", sendLastSnapshot).Methods("GET")
 	r.HandleFunc("/", saveSnapshot).Methods("POST")
 	r.PathPrefix("/static/").Handler(http.StripPrefix("/static/", http.FileServer(http.Dir("static/"))))
 	http.Handle("/", r)
@@ -84,6 +85,25 @@ func sendData(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+func sendLastSnapshot(w http.ResponseWriter, r *http.Request) {
+	record, err := getLastSnapshotRecordFromDb()
+	if err != nil {
+		sendInternalError(fmt.Errorf("couldn't read last snapshot from the database: %w", err), w, r)
+		return
+	}
+	json, err := createJsonFromSnapshotRecords(record)
+	if err != nil {
+		sendInternalError(fmt.Errorf("couldn't create a json from the last record: %w", err), w, r)
+		return
+	}
+	w.Header().Set("Content-Type", "application/json")
+	_, err = fmt.Fprintf(w, string(json))
+	if err != nil {
+		sendInternalError(err, w, r)
+		return
+	}
+}
+
 func saveSnapshot(w http.ResponseWriter, r *http.Request) {
 	snapshotSub, err := createSnapshotSubFromJsonBodyStream(r.Body)
 	if err != nil {