[PD2] Gateway login, logout and auth middleware done.

Co-authored-by: tsousa111 <tiagao2001@hotmail.com>

Projs/PD2/internal/gateway/datastore.go

@@ -0,0 +1,52 @@
+package gateway
+
+import(
+	"database/sql"
+	_ "github.com/mattn/go-sqlite3"
+)
+
+type DataStore struct {
+	db *sql.DB
+}
+
+func OpenDB() (DataStore, error) {
+	db, err := sql.Open("sqlite3", "gateway.db")
+	if err != nil {
+		return DataStore{}, err
+	}
+	ds := DataStore{db: db}
+	err = ds.CreateTables()
+	if err != nil {
+		return DataStore{}, err
+	}
+	return ds, nil
+}
+
+func (ds DataStore) CreateTables() error {
+	// Create users table
+	_, err := ds.db.Exec(`CREATE TABLE IF NOT EXISTS users (
+        UID TEXT PRIMARY KEY,
+        password BLOB
+    )`)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (ds DataStore) GetPassword(uid string) ([]byte, error) {
+	var password []byte
+	err := ds.db.QueryRow("SELECT password FROM users WHERE UID = ?", uid).Scan(&password)
+	if err != nil {
+		return nil, err
+	}
+	return password, nil
+}
+
+func (ds DataStore) InsertUser(uid string, password []byte) error {
+	_, err := ds.db.Exec("INSERT INTO users (UID, password) VALUES (?, ?)", uid, password)
+	if err != nil {
+		return err
+	}
+	return nil
+}