Merge v2 changes

postgresstore/postgresstore.go

@@ -0,0 +1,101 @@
+package postgresstore
+
+import (
+	"database/sql"
+	"log"
+	"time"
+)
+
+// PostgresStore represents the session store.
+type PostgresStore struct {
+	db          *sql.DB
+	stopCleanup chan bool
+}
+
+// New returns a new PostgresStore instance, with a background cleanup goroutine
+// that runs every 5 minutes to remove expired session data.
+func New(db *sql.DB) *PostgresStore {
+	return NewWithCleanupInterval(db, 5*time.Minute)
+}
+
+// NewWithCleanupInterval returns a new PostgresStore instance. The cleanupInterval
+// parameter controls how frequently expired session data is removed by the
+// background cleanup goroutine. Setting it to 0 prevents the cleanup goroutine
+// from running (i.e. expired sessions will not be removed).
+func NewWithCleanupInterval(db *sql.DB, cleanupInterval time.Duration) *PostgresStore {
+	p := &PostgresStore{db: db}
+	if cleanupInterval > 0 {
+		go p.startCleanup(cleanupInterval)
+	}
+	return p
+}
+
+// Find returns the data for a given session token from the PostgresStore instance.
+// If the session token is not found or is expired, the returned exists flag will
+// be set to false.
+func (p *PostgresStore) Find(token string) (b []byte, exists bool, err error) {
+	row := p.db.QueryRow("SELECT data FROM sessions WHERE token = $1 AND current_timestamp < 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
+}
+
+// Commit adds a session token and data to the PostgresStore instance with the
+// given expiry time. If the session token already exists, then the data and expiry
+// time are updated.
+func (p *PostgresStore) Commit(token string, b []byte, expiry time.Time) error {
+	_, err := p.db.Exec("INSERT INTO sessions (token, data, expiry) VALUES ($1, $2, $3) ON CONFLICT (token) DO UPDATE SET data = EXCLUDED.data, expiry = EXCLUDED.expiry", token, b, expiry)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// Delete removes a session token and corresponding data from the PostgresStore
+// instance.
+func (p *PostgresStore) Delete(token string) error {
+	_, err := p.db.Exec("DELETE FROM sessions WHERE token = $1", token)
+	return err
+}
+
+func (p *PostgresStore) startCleanup(interval time.Duration) {
+	p.stopCleanup = make(chan bool)
+	ticker := time.NewTicker(interval)
+	for {
+		select {
+		case <-ticker.C:
+			err := p.deleteExpired()
+			if err != nil {
+				log.Println(err)
+			}
+		case <-p.stopCleanup:
+			ticker.Stop()
+			return
+		}
+	}
+}
+
+// StopCleanup terminates the background cleanup goroutine for the PostgresStore
+// instance. It's rare to terminate this; generally PostgresStore instances and
+// their cleanup goroutines are intended to be long-lived and run for the lifetime
+// of your application.
+//
+// There may be occasions though when your use of the PostgresStore is transient.
+// An example is creating a new PostgresStore instance in a test function. In this
+// scenario, the cleanup goroutine (which will run forever) will prevent the
+// PostgresStore object from being garbage collected even after the test function
+// has finished. You can prevent this by manually calling StopCleanup.
+func (p *PostgresStore) StopCleanup() {
+	if p.stopCleanup != nil {
+		p.stopCleanup <- true
+	}
+}
+
+func (p *PostgresStore) deleteExpired() error {
+	_, err := p.db.Exec("DELETE FROM sessions WHERE expiry < current_timestamp")
+	return err
+}