Add Go server with POST LDR to Sqlite3 and GET graphs of historic data

2025-06-16 20:58:46 +02:00
parent a780ffc918
commit 7599b3f652
7 changed files with 445 additions and 0 deletions
@@ -0,0 +1,123 @@
+package main
+
+import (
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"html/template"
+	"log"
+	"net/http"
+	"time"
+
+	_ "github.com/mattn/go-sqlite3"
+)
+
+type LDRReading struct {
+	Value     int       `json:"value"`
+	Timestamp time.Time `json:"timestamp"`
+}
+
+var db *sql.DB
+
+func initDB() {
+	var err error
+	db, err = sql.Open("sqlite3", "./ldr_readings.db")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	createTable := `
+	CREATE TABLE IF NOT EXISTS ldr_readings (
+		id INTEGER PRIMARY KEY AUTOINCREMENT,
+		value INTEGER NOT NULL,
+		timestamp DATETIME DEFAULT CURRENT_TIMESTAMP
+	);`
+
+	_, err = db.Exec(createTable)
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+func handleLDRReading(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	var reading LDRReading
+	if err := json.NewDecoder(r.Body).Decode(&reading); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	_, err := db.Exec("INSERT INTO ldr_readings (value, timestamp) VALUES (?, ?)",
+		reading.Value, reading.Timestamp)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+}
+
+func handleGetReadings(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodGet {
+		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	period := r.URL.Query().Get("period")
+	var query string
+	var args []interface{}
+
+	switch period {
+	case "day":
+		query = "SELECT value, timestamp FROM ldr_readings WHERE timestamp >= datetime('now', '-1 day') ORDER BY timestamp"
+	case "week":
+		query = "SELECT value, timestamp FROM ldr_readings WHERE timestamp >= datetime('now', '-7 day') ORDER BY timestamp"
+	case "month":
+		query = "SELECT value, timestamp FROM ldr_readings WHERE timestamp >= datetime('now', '-30 day') ORDER BY timestamp"
+	default:
+		query = "SELECT value, timestamp FROM ldr_readings ORDER BY timestamp"
+	}
+
+	rows, err := db.Query(query, args...)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	defer rows.Close()
+
+	var readings []LDRReading
+	for rows.Next() {
+		var r LDRReading
+		if err := rows.Scan(&r.Value, &r.Timestamp); err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		readings = append(readings, r)
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	w.Header().Set("Access-Control-Allow-Origin", "*")
+	json.NewEncoder(w).Encode(readings)
+}
+
+func handleIndex(w http.ResponseWriter, r *http.Request) {
+	tmpl := template.Must(template.ParseFiles("web/templates/index.html"))
+	tmpl.Execute(w, nil)
+}
+
+func main() {
+	initDB()
+	defer db.Close()
+
+	http.HandleFunc("/", handleIndex)
+	http.HandleFunc("/api/ldr", handleLDRReading)
+	http.HandleFunc("/api/readings", handleGetReadings)
+	http.Handle("/static/", http.StripPrefix("/static/", http.FileServer(http.Dir("web/static"))))
+
+	fmt.Println("Server starting on :8080...")
+	log.Fatal(http.ListenAndServe(":8080", nil))
+}