Extend this program:

- add a database for devices
- read devices from database and present this data on a simple web/REST
interface

The code or model is from a blog entry from Alex Edward:
https://www.alexedwards.net/blog/organising-database-access

models/db.go

@@ -0,0 +1,33 @@
+package models
+
+import (
+	"database/sql"
+
+	_ "github.com/mattn/go-sqlite3"
+)
+
+type Datastore interface {
+	AllDevices() ([]*Device, error)
+}
+
+type DB struct {
+	*sql.DB
+}
+
+func NewDB(dataSourceName string) (*DB, error) {
+	db, err := sql.Open("sqlite3", dataSourceName)
+	if err != nil {
+		return nil, err
+	}
+	if err = db.Ping(); err != nil {
+		return nil, err
+	}
+
+	sqlStmt := "CREATE TABLE IF NOT EXISTS devices (id TEXT not null primary key, mac TEXT, sn TEXT, lastMsg TEXT);"
+	_, err = db.Exec(sqlStmt)
+	if err != nil {
+		return nil, err
+	}
+
+	return &DB{db}, nil
+}

models/devices.go

@@ -0,0 +1,36 @@
+package models
+
+type Device struct {
+	ID string
+	MAC string
+	SN string
+	LastMsg string
+}
+
+
+
+
+
+func (db *DB) AllDevices() ([]*Device, error) {
+    rows, err := db.Query("SELECT * FROM devices")
+    if err != nil {
+        return nil, err
+    }
+    defer rows.Close()
+
+    devices := make([]*Device, 0)
+    for rows.Next() {
+        device := new(Device)
+        err := rows.Scan(&device.ID, &device.MAC, &device.SN, &device.LastMsg)
+        if err != nil {
+            return nil, err
+        }
+        devices = append(devices, device)
+    }
+    if err = rows.Err(); err != nil {
+        return nil, err
+    }
+    return devices, nil
+}
+
+