[feature] Add MySQL storage engine

engine/mysqlstore/README.md

@@ -0,0 +1,8 @@
+```sql
+CREATE TABLE IF NOT EXISTS sessions (
+  token CHAR(43) PRIMARY KEY,
+  data BLOB NOT NULL,
+  expiry TIMESTAMP(6) NOT NULL
+);
+INDEX ON EXPIRY.....
+```

engine/mysqlstore/mysqlstore.go

@@ -0,0 +1,75 @@
+package mysqlstore
+
+import (
+	"database/sql"
+	"log"
+	"time"
+
+	_ "github.com/go-sql-driver/mysql"
+)
+
+type MySQLStore struct {
+	*sql.DB
+	stopSweeper chan bool
+}
+
+func New(db *sql.DB, sweepInterval time.Duration) *MySQLStore {
+	m := &MySQLStore{DB: db}
+	if sweepInterval > 0 {
+		go m.startSweeper(sweepInterval)
+	}
+	return m
+}
+
+func (m *MySQLStore) Find(token string) ([]byte, bool, error) {
+	var b []byte
+	row := m.DB.QueryRow("SELECT data FROM sessions WHERE token = ? AND UTC_TIMESTAMP(6) < expiry", token)
+	err := row.Scan(&b)
+	if err == sql.ErrNoRows {
+		return nil, false, nil
+	} else if err != nil {
+		return nil, false, err
+	}
+	return b, true, nil
+}
+
+func (m *MySQLStore) Save(token string, b []byte, expiry time.Time) error {
+	_, err := m.DB.Exec("INSERT INTO sessions (token, data, expiry) VALUES (?, ?, ?) ON DUPLICATE KEY UPDATE data = VALUES(data), expiry = VALUES(expiry)", token, b, expiry.UTC())
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (m *MySQLStore) Delete(token string) error {
+	_, err := m.DB.Exec("DELETE FROM sessions WHERE token = ?", token)
+	return err
+}
+
+func (m *MySQLStore) startSweeper(interval time.Duration) {
+	m.stopSweeper = make(chan bool)
+	ticker := time.NewTicker(interval)
+	for {
+		select {
+		case <-ticker.C:
+			err := m.deleteExpired()
+			if err != nil {
+				log.Println(err)
+			}
+		case <-m.stopSweeper:
+			ticker.Stop()
+			return
+		}
+	}
+}
+
+func (m *MySQLStore) StopSweeper() {
+	if m.stopSweeper != nil {
+		m.stopSweeper <- true
+	}
+}
+
+func (m *MySQLStore) deleteExpired() error {
+	_, err := m.DB.Exec("DELETE FROM sessions WHERE expiry < UTC_TIMESTAMP(6)")
+	return err
+}

engine/mysqlstore/mysqlstore_test.go

@@ -0,0 +1,291 @@
+package mysqlstore
+
+import (
+	"bytes"
+	"database/sql"
+	"os"
+	"reflect"
+	"testing"
+	"time"
+
+	"github.com/alexedwards/scs/session"
+)
+
+func TestNew(t *testing.T) {
+	dsn := os.Getenv("SESSION_MYSQL_TEST_DSN")
+	db, err := sql.Open("mysql", dsn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	if err = db.Ping(); err != nil {
+		t.Fatal(err)
+	}
+
+	m := New(db, 0)
+	_, ok := interface{}(m).(session.Engine)
+	if ok == false {
+		t.Fatalf("got %v: expected %v", ok, true)
+	}
+}
+
+func TestFind(t *testing.T) {
+	dsn := os.Getenv("SESSION_MYSQL_TEST_DSN")
+	db, err := sql.Open("mysql", dsn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	if err = db.Ping(); err != nil {
+		t.Fatal(err)
+	}
+	_, err = db.Exec("TRUNCATE TABLE sessions")
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = db.Exec("INSERT INTO sessions VALUES('session_token', 'encoded_data', UTC_TIMESTAMP(6) + INTERVAL 1 MINUTE)")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	m := New(db, 0)
+
+	b, found, err := m.Find("session_token")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if found != true {
+		t.Fatalf("got %v: expected %v", found, true)
+	}
+	if bytes.Equal(b, []byte("encoded_data")) == false {
+		t.Fatalf("got %v: expected %v", b, []byte("encoded_data"))
+	}
+}
+
+func TestFindMissing(t *testing.T) {
+	dsn := os.Getenv("SESSION_MYSQL_TEST_DSN")
+	db, err := sql.Open("mysql", dsn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	if err = db.Ping(); err != nil {
+		t.Fatal(err)
+	}
+	_, err = db.Exec("TRUNCATE TABLE sessions")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	m := New(db, 0)
+
+	_, found, err := m.Find("missing_session_token")
+	if err != nil {
+		t.Fatalf("got %v: expected %v", err, nil)
+	}
+	if found != false {
+		t.Fatalf("got %v: expected %v", found, false)
+	}
+}
+
+func TestSaveNew(t *testing.T) {
+	dsn := os.Getenv("SESSION_MYSQL_TEST_DSN")
+	db, err := sql.Open("mysql", dsn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	if err = db.Ping(); err != nil {
+		t.Fatal(err)
+	}
+	_, err = db.Exec("TRUNCATE TABLE sessions")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	m := New(db, 0)
+
+	err = m.Save("session_token", []byte("encoded_data"), time.Now().Add(time.Minute))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	row := db.QueryRow("SELECT data FROM sessions WHERE token = 'session_token'")
+	var data []byte
+	err = row.Scan(&data)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if reflect.DeepEqual(data, []byte("encoded_data")) == false {
+		t.Fatalf("got %v: expected %v", data, []byte("encoded_data"))
+	}
+}
+
+func TestSaveUpdated(t *testing.T) {
+	dsn := os.Getenv("SESSION_MYSQL_TEST_DSN")
+	db, err := sql.Open("mysql", dsn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	if err = db.Ping(); err != nil {
+		t.Fatal(err)
+	}
+	_, err = db.Exec("TRUNCATE TABLE sessions")
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = db.Exec("INSERT INTO sessions VALUES('session_token', 'encoded_data', UTC_TIMESTAMP(6) + INTERVAL 1 MINUTE)")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	m := New(db, 0)
+
+	err = m.Save("session_token", []byte("new_encoded_data"), time.Now().Add(time.Minute))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	row := db.QueryRow("SELECT data FROM sessions WHERE token = 'session_token'")
+	var data []byte
+	err = row.Scan(&data)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if reflect.DeepEqual(data, []byte("new_encoded_data")) == false {
+		t.Fatalf("got %v: expected %v", data, []byte("new_encoded_data"))
+	}
+}
+
+func TestExpiry(t *testing.T) {
+	dsn := os.Getenv("SESSION_MYSQL_TEST_DSN")
+	db, err := sql.Open("mysql", dsn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	if err = db.Ping(); err != nil {
+		t.Fatal(err)
+	}
+	_, err = db.Exec("TRUNCATE TABLE sessions")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	m := New(db, 0)
+
+	err = m.Save("session_token", []byte("encoded_data"), time.Now().Add(100*time.Millisecond))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, found, _ := m.Find("session_token")
+	if found != true {
+		t.Fatalf("got %v: expected %v", found, true)
+	}
+
+	time.Sleep(100 * time.Millisecond)
+	_, found, _ = m.Find("session_token")
+	if found != false {
+		t.Fatalf("got %v: expected %v", found, false)
+	}
+}
+
+func TestDelete(t *testing.T) {
+	dsn := os.Getenv("SESSION_MYSQL_TEST_DSN")
+	db, err := sql.Open("mysql", dsn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	if err = db.Ping(); err != nil {
+		t.Fatal(err)
+	}
+	_, err = db.Exec("TRUNCATE TABLE sessions")
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = db.Exec("INSERT INTO sessions VALUES('session_token', 'encoded_data', UTC_TIMESTAMP(6) + INTERVAL 1 MINUTE)")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	m := New(db, 0)
+
+	err = m.Delete("session_token")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	row := db.QueryRow("SELECT COUNT(*) FROM sessions WHERE token = 'session_token'")
+	var count int
+	err = row.Scan(&count)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if count != 0 {
+		t.Fatalf("got %d: expected %d", count, 0)
+	}
+}
+
+func TestSweeper(t *testing.T) {
+	dsn := os.Getenv("SESSION_MYSQL_TEST_DSN")
+	db, err := sql.Open("mysql", dsn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	if err = db.Ping(); err != nil {
+		t.Fatal(err)
+	}
+	_, err = db.Exec("TRUNCATE TABLE sessions")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	m := New(db, 200*time.Millisecond)
+	defer m.StopSweeper()
+
+	err = m.Save("session_token", []byte("encoded_data"), time.Now().Add(100*time.Millisecond))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	row := db.QueryRow("SELECT COUNT(*) FROM sessions WHERE token = 'session_token'")
+	var count int
+	err = row.Scan(&count)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if count != 1 {
+		t.Fatalf("got %d: expected %d", count, 1)
+	}
+
+	time.Sleep(300 * time.Millisecond)
+	row = db.QueryRow("SELECT COUNT(*) FROM sessions WHERE token = 'session_token'")
+	err = row.Scan(&count)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if count != 0 {
+		t.Fatalf("got %d: expected %d", count, 0)
+	}
+}
+
+func TestStopNilSweeper(t *testing.T) {
+	dsn := os.Getenv("SESSION_MYSQL_TEST_DSN")
+	db, err := sql.Open("mysql", dsn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	if err = db.Ping(); err != nil {
+		t.Fatal(err)
+	}
+
+	m := New(db, 0)
+	time.Sleep(100 * time.Millisecond)
+	// A send to a nil channel will block forever
+	m.StopSweeper()
+}