Merge pull request #1 from chliang2030598/master

add session store in ledis

+package session
+
+import (
+	"net/http"
+	"sync"
+
+	"github.com/astaxie/beego/session"
+	"github.com/siddontang/ledisdb/config"
+	"github.com/siddontang/ledisdb/ledis"
+)
+
+var ledispder = &LedisProvider{}
+var c *ledis.DB
+
+// ledis session store
+type LedisSessionStore struct {
+	sid         string
+	lock        sync.RWMutex
+	values      map[interface{}]interface{}
+	maxlifetime int64
+}
+
+// set value in ledis session
+func (ls *LedisSessionStore) Set(key, value interface{}) error {
+	ls.lock.Lock()
+	defer ls.lock.Unlock()
+	ls.values[key] = value
+	return nil
+}
+
+// get value in ledis session
+func (ls *LedisSessionStore) Get(key interface{}) interface{} {
+	ls.lock.RLock()
+	defer ls.lock.RUnlock()
+	if v, ok := ls.values[key]; ok {
+		return v
+	} else {
+		return nil
+	}
+}
+
+// delete value in ledis session
+func (ls *LedisSessionStore) Delete(key interface{}) error {
+	ls.lock.Lock()
+	defer ls.lock.Unlock()
+	delete(ls.values, key)
+	return nil
+}
+
+// clear all values in ledis session
+func (ls *LedisSessionStore) Flush() error {
+	ls.lock.Lock()
+	defer ls.lock.Unlock()
+	ls.values = make(map[interface{}]interface{})
+	return nil
+}
+
+// get ledis session id
+func (ls *LedisSessionStore) SessionID() string {
+	return ls.sid
+}
+
+// save session values to ledis
+func (ls *LedisSessionStore) SessionRelease(w http.ResponseWriter) {
+	b, err := session.EncodeGob(ls.values)
+	if err != nil {
+		return
+	}
+	c.Set([]byte(ls.sid), b)
+	c.Expire([]byte(ls.sid), ls.maxlifetime)
+}
+
+// ledis session provider
+type LedisProvider struct {
+	maxlifetime int64
+	savePath    string
+}
+
+// init ledis session
+// savepath like ledis server saveDataPath,pool size
+// e.g. 127.0.0.1:6379,100,astaxie
+func (lp *LedisProvider) SessionInit(maxlifetime int64, savePath string) error {
+	lp.maxlifetime = maxlifetime
+	lp.savePath = savePath
+	cfg := new(config.Config)
+	cfg.DataDir = lp.savePath
+	var err error
+	nowLedis, err := ledis.Open(cfg)
+	c, err = nowLedis.Select(0)
+	if err != nil {
+		println(err)
+		return nil
+	}
+	return nil
+}
+
+// read ledis session by sid
+func (lp *LedisProvider) SessionRead(sid string) (session.SessionStore, error) {
+	kvs, err := c.Get([]byte(sid))
+	var kv map[interface{}]interface{}
+	if len(kvs) == 0 {
+		kv = make(map[interface{}]interface{})
+	} else {
+		kv, err = session.DecodeGob(kvs)
+		if err != nil {
+			return nil, err
+		}
+	}
+	ls := &LedisSessionStore{sid: sid, values: kv, maxlifetime: lp.maxlifetime}
+	return ls, nil
+}
+
+// check ledis session exist by sid
+func (lp *LedisProvider) SessionExist(sid string) bool {
+	count, _ := c.Exists([]byte(sid))
+	if count == 0 {
+		return false
+	} else {
+		return true
+	}
+}
+
+// generate new sid for ledis session
+func (lp *LedisProvider) SessionRegenerate(oldsid, sid string) (session.SessionStore, error) {
+	count, _ := c.Exists([]byte(sid))
+	if count == 0 {
+		// oldsid doesn't exists, set the new sid directly
+		// ignore error here, since if it return error
+		// the existed value will be 0
+		c.Set([]byte(sid), []byte(""))
+		c.Expire([]byte(sid), lp.maxlifetime)
+	} else {
+		data, _ := c.Get([]byte(oldsid))
+		c.Set([]byte(sid), data)
+		c.Expire([]byte(sid), lp.maxlifetime)
+	}
+	kvs, err := c.Get([]byte(sid))
+	var kv map[interface{}]interface{}
+	if len(kvs) == 0 {
+		kv = make(map[interface{}]interface{})
+	} else {
+		kv, err = session.DecodeGob([]byte(kvs))
+		if err != nil {
+			return nil, err
+		}
+	}
+	ls := &LedisSessionStore{sid: sid, values: kv, maxlifetime: lp.maxlifetime}
+	return ls, nil
+}
+
+// delete ledis session by id
+func (lp *LedisProvider) SessionDestroy(sid string) error {
+	c.Del([]byte(sid))
+	return nil
+}
+
+// Impelment method, no used.
+func (lp *LedisProvider) SessionGC() {
+	return
+}
+
+// @todo
+func (lp *LedisProvider) SessionAll() int {
+	return 0
+}
+func init() {
+	session.Register("ledis", ledispder)
+}