session: support memcache interface

@@ -137,9 +137,11 @@ func (rc *MemcacheCache) StartAndGC(config string) error {
 	}
 	}
 	rc.conninfo = cf["conn"]
 	rc.conninfo = cf["conn"]
 	var err error
 	var err error
-	rc.c, err = rc.connectInit()
-	if err != nil {
-		return errors.New("dial tcp conn error")
+	if rc.c != nil {
+		rc.c, err = rc.connectInit()
+		if err != nil {
+			return errors.New("dial tcp conn error")
+		}
 	}
 	}
 	return nil
 	return nil
 }
 }

+// Beego (http://beego.me/)
+// @description beego is an open-source, high-performance web framework for the Go programming language.
+// @link        http://github.com/astaxie/beego for the canonical source repository
+// @license     http://github.com/astaxie/beego/blob/master/LICENSE
+// @authors     astaxie
+
+package session
+
+import (
+	"net/http"
+	"sync"
+
+	"github.com/astaxie/beego/session"
+
+	"github.com/beego/memcache"
+)
+
+var mempder = &MemProvider{}
+
+// memcache session store
+type MemcacheSessionStore struct {
+	c           *memcache.Connection
+	sid         string
+	lock        sync.RWMutex
+	values      map[interface{}]interface{}
+	maxlifetime int64
+}
+
+// set value in memcache session
+func (rs *MemcacheSessionStore) Set(key, value interface{}) error {
+	rs.lock.Lock()
+	defer rs.lock.Unlock()
+	rs.values[key] = value
+	return nil
+}
+
+// get value in memcache session
+func (rs *MemcacheSessionStore) Get(key interface{}) interface{} {
+	rs.lock.RLock()
+	defer rs.lock.RUnlock()
+	if v, ok := rs.values[key]; ok {
+		return v
+	} else {
+		return nil
+	}
+}
+
+// delete value in memcache session
+func (rs *MemcacheSessionStore) Delete(key interface{}) error {
+	rs.lock.Lock()
+	defer rs.lock.Unlock()
+	delete(rs.values, key)
+	return nil
+}
+
+// clear all values in memcache session
+func (rs *MemcacheSessionStore) Flush() error {
+	rs.lock.Lock()
+	defer rs.lock.Unlock()
+	rs.values = make(map[interface{}]interface{})
+	return nil
+}
+
+// get redis session id
+func (rs *MemcacheSessionStore) SessionID() string {
+	return rs.sid
+}
+
+// save session values to redis
+func (rs *MemcacheSessionStore) SessionRelease(w http.ResponseWriter) {
+	defer rs.c.Close()
+	// if rs.values is empty, return directly
+	if len(rs.values) < 1 {
+		rs.c.Delete(rs.sid)
+		return
+	}
+
+	b, err := session.EncodeGob(rs.values)
+	if err != nil {
+		return
+	}
+	rs.c.Set(rs.sid, 0, uint64(rs.maxlifetime), b)
+}
+
+// redis session provider
+type MemProvider struct {
+	maxlifetime int64
+	savePath    string
+	poolsize    int
+	password    string
+}
+
+// init redis session
+// savepath like
+// e.g. 127.0.0.1:9090
+func (rp *MemProvider) SessionInit(maxlifetime int64, savePath string) error {
+	rp.maxlifetime = maxlifetime
+	rp.savePath = savePath
+	return nil
+}
+
+// read redis session by sid
+func (rp *MemProvider) SessionRead(sid string) (session.SessionStore, error) {
+	conn, err := rp.connectInit()
+	if err != nil {
+		return nil, err
+	}
+	kvs, err := conn.Get(sid)
+	if err != nil {
+		return nil, err
+	}
+	var contain []byte
+	if len(kvs) > 0 {
+		contain = kvs[0].Value
+	}
+	var kv map[interface{}]interface{}
+	if len(contain) == 0 {
+		kv = make(map[interface{}]interface{})
+	} else {
+		kv, err = session.DecodeGob(contain)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	rs := &MemcacheSessionStore{c: conn, sid: sid, values: kv, maxlifetime: rp.maxlifetime}
+	return rs, nil
+}
+
+// check redis session exist by sid
+func (rp *MemProvider) SessionExist(sid string) bool {
+	conn, err := rp.connectInit()
+	if err != nil {
+		return false
+	}
+	defer conn.Close()
+	if kvs, err := conn.Get(sid); err != nil || len(kvs) == 0 {
+		return false
+	} else {
+		return true
+	}
+}
+
+// generate new sid for redis session
+func (rp *MemProvider) SessionRegenerate(oldsid, sid string) (session.SessionStore, error) {
+	conn, err := rp.connectInit()
+	if err != nil {
+		return nil, err
+	}
+	var contain []byte
+	if kvs, err := conn.Get(sid); err != nil || len(kvs) == 0 {
+		// oldsid doesn't exists, set the new sid directly
+		// ignore error here, since if it return error
+		// the existed value will be 0
+		conn.Set(sid, 0, uint64(rp.maxlifetime), []byte(""))
+	} else {
+		conn.Delete(oldsid)
+		conn.Set(sid, 0, uint64(rp.maxlifetime), kvs[0].Value)
+		contain = kvs[0].Value
+	}
+
+	var kv map[interface{}]interface{}
+	if len(contain) == 0 {
+		kv = make(map[interface{}]interface{})
+	} else {
+		kv, err = session.DecodeGob(contain)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	rs := &MemcacheSessionStore{c: conn, sid: sid, values: kv, maxlifetime: rp.maxlifetime}
+	return rs, nil
+}
+
+// delete redis session by id
+func (rp *MemProvider) SessionDestroy(sid string) error {
+	conn, err := rp.connectInit()
+	if err != nil {
+		return err
+	}
+	defer conn.Close()
+
+	_, err = conn.Delete(sid)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// Impelment method, no used.
+func (rp *MemProvider) SessionGC() {
+	return
+}
+
+// @todo
+func (rp *MemProvider) SessionAll() int {
+	return 0
+}
+
+// connect to memcache and keep the connection.
+func (rp *MemProvider) connectInit() (*memcache.Connection, error) {
+	c, err := memcache.Connect(rp.savePath)
+	if err != nil {
+		return nil, err
+	}
+	return c, nil
+}
+
+func init() {
+	session.Register("memcache", mempder)
+}