support CAS identity provider

Signed-off-by: hongming <talonwan@yunify.com>

vendor/gopkg.in/cas.v2/session_store.go

@@ -0,0 +1,52 @@
+package cas
+
+import "sync"
+
+// SessionStore store the session's ticket
+// SessionID is retrived from cookies
+type SessionStore interface {
+	// Get the ticket with the session id
+	Get(sessionID string) (string, bool)
+
+	// Set the session with a ticket
+	Set(sessionID, ticket string) error
+
+	// Delete the session
+	Delete(sessionID string) error
+}
+
+// NewMemorySessionStore create a default SessionStore that uses memory
+func NewMemorySessionStore() SessionStore {
+	return &memorySessionStore{
+		sessions: make(map[string]string),
+	}
+}
+
+type memorySessionStore struct {
+	mu       sync.RWMutex
+	sessions map[string]string
+}
+
+func (m *memorySessionStore) Get(sessionID string) (string, bool) {
+	m.mu.RLock()
+	ticket, ok := m.sessions[sessionID]
+	m.mu.RUnlock()
+
+	return ticket, ok
+}
+
+func (m *memorySessionStore) Set(sessionID, ticket string) error {
+	m.mu.Lock()
+	m.sessions[sessionID] = ticket
+	m.mu.Unlock()
+
+	return nil
+}
+
+func (m *memorySessionStore) Delete(sessionID string) error {
+	m.mu.Lock()
+	delete(m.sessions, sessionID)
+	m.mu.Unlock()
+
+	return nil
+}