Format and remove 06.2.md spaces
This commit is contained in:
vCaesar
224
zh/06.2.md
224
zh/06.2.md
@@ -34,40 +34,40 @@ session的基本原理是由服务器为每个会话维护一份信息数据，
|
||||
定义一个全局的session管理器
|
||||
```Go
|
||||
|
||||
type Manager struct {
|
||||
cookieName string //private cookiename
|
||||
lock sync.Mutex // protects session
|
||||
provider Provider
|
||||
maxlifetime int64
|
||||
}
|
||||
type Manager struct {
|
||||
cookieName string //private cookiename
|
||||
lock sync.Mutex // protects session
|
||||
provider Provider
|
||||
maxlifetime int64
|
||||
}
|
||||
|
||||
func NewManager(provideName, cookieName string, maxlifetime int64) (*Manager, error) {
|
||||
provider, ok := provides[provideName]
|
||||
if !ok {
|
||||
return nil, fmt.Errorf("session: unknown provide %q (forgotten import?)", provideName)
|
||||
}
|
||||
return &Manager{provider: provider, cookieName: cookieName, maxlifetime: maxlifetime}, nil
|
||||
func NewManager(provideName, cookieName string, maxlifetime int64) (*Manager, error) {
|
||||
provider, ok := provides[provideName]
|
||||
if !ok {
|
||||
return nil, fmt.Errorf("session: unknown provide %q (forgotten import?)", provideName)
|
||||
}
|
||||
return &Manager{provider: provider, cookieName: cookieName, maxlifetime: maxlifetime}, nil
|
||||
}
|
||||
|
||||
```
|
||||
Go实现整个的流程应该也是这样的，在main包中创建一个全局的session管理器
|
||||
```Go
|
||||
|
||||
var globalSessions *session.Manager
|
||||
//然后在init函数中初始化
|
||||
func init() {
|
||||
globalSessions, _ = NewManager("memory","gosessionid",3600)
|
||||
}
|
||||
var globalSessions *session.Manager
|
||||
//然后在init函数中初始化
|
||||
func init() {
|
||||
globalSessions, _ = NewManager("memory","gosessionid",3600)
|
||||
}
|
||||
```
|
||||
我们知道session是保存在服务器端的数据，它可以以任何的方式存储，比如存储在内存、数据库或者文件中。因此我们抽象出一个Provider接口，用以表征session管理器底层存储结构。
|
||||
```Go
|
||||
|
||||
type Provider interface {
|
||||
SessionInit(sid string) (Session, error)
|
||||
SessionRead(sid string) (Session, error)
|
||||
SessionDestroy(sid string) error
|
||||
SessionGC(maxLifeTime int64)
|
||||
}
|
||||
type Provider interface {
|
||||
SessionInit(sid string) (Session, error)
|
||||
SessionRead(sid string) (Session, error)
|
||||
SessionDestroy(sid string) error
|
||||
SessionGC(maxLifeTime int64)
|
||||
}
|
||||
```
|
||||
- SessionInit函数实现Session的初始化，操作成功则返回此新的Session变量
|
||||
- SessionRead函数返回sid所代表的Session变量，如果不存在，那么将以sid为参数调用SessionInit函数创建并返回一个新的Session变量
|
||||
@@ -77,31 +77,31 @@ Go实现整个的流程应该也是这样的，在main包中创建一个全局
|
||||
那么Session接口需要实现什么样的功能呢？有过Web开发经验的读者知道，对Session的处理基本就 设置值、读取值、删除值以及获取当前sessionID这四个操作，所以我们的Session接口也就实现这四个操作。
|
||||
```Go
|
||||
|
||||
type Session interface {
|
||||
Set(key, value interface{}) error //set session value
|
||||
Get(key interface{}) interface{} //get session value
|
||||
Delete(key interface{}) error //delete session value
|
||||
SessionID() string //back current sessionID
|
||||
}
|
||||
type Session interface {
|
||||
Set(key, value interface{}) error //set session value
|
||||
Get(key interface{}) interface{} //get session value
|
||||
Delete(key interface{}) error //delete session value
|
||||
SessionID() string //back current sessionID
|
||||
}
|
||||
```
|
||||
>以上设计思路来源于database/sql/driver，先定义好接口，然后具体的存储session的结构实现相应的接口并注册后，相应功能这样就可以使用了，以下是用来随需注册存储session的结构的Register函数的实现。
|
||||
|
||||
```Go
|
||||
|
||||
var provides = make(map[string]Provider)
|
||||
var provides = make(map[string]Provider)
|
||||
|
||||
// Register makes a session provide available by the provided name.
|
||||
// If Register is called twice with the same name or if driver is nil,
|
||||
// it panics.
|
||||
func Register(name string, provider Provider) {
|
||||
if provider == nil {
|
||||
panic("session: Register provide is nil")
|
||||
}
|
||||
if _, dup := provides[name]; dup {
|
||||
panic("session: Register called twice for provide " + name)
|
||||
}
|
||||
provides[name] = provider
|
||||
// Register makes a session provide available by the provided name.
|
||||
// If Register is called twice with the same name or if driver is nil,
|
||||
// it panics.
|
||||
func Register(name string, provider Provider) {
|
||||
if provider == nil {
|
||||
panic("session: Register provide is nil")
|
||||
}
|
||||
if _, dup := provides[name]; dup {
|
||||
panic("session: Register called twice for provide " + name)
|
||||
}
|
||||
provides[name] = provider
|
||||
}
|
||||
```
|
||||
### 全局唯一的Session ID
|
||||
|
||||
@@ -109,49 +109,49 @@ Session ID是用来识别访问Web应用的每一个用户，因此必须保证
|
||||
|
||||
```Go
|
||||
|
||||
func (manager *Manager) sessionId() string {
|
||||
b := make([]byte, 32)
|
||||
if _, err := io.ReadFull(rand.Reader, b); err != nil {
|
||||
return ""
|
||||
}
|
||||
return base64.URLEncoding.EncodeToString(b)
|
||||
func (manager *Manager) sessionId() string {
|
||||
b := make([]byte, 32)
|
||||
if _, err := io.ReadFull(rand.Reader, b); err != nil {
|
||||
return ""
|
||||
}
|
||||
return base64.URLEncoding.EncodeToString(b)
|
||||
}
|
||||
```
|
||||
### session创建
|
||||
我们需要为每个来访用户分配或获取与他相关连的Session，以便后面根据Session信息来验证操作。SessionStart这个函数就是用来检测是否已经有某个Session与当前来访用户发生了关联，如果没有则创建之。
|
||||
```Go
|
||||
|
||||
func (manager *Manager) SessionStart(w http.ResponseWriter, r *http.Request) (session Session) {
|
||||
manager.lock.Lock()
|
||||
defer manager.lock.Unlock()
|
||||
cookie, err := r.Cookie(manager.cookieName)
|
||||
if err != nil || cookie.Value == "" {
|
||||
sid := manager.sessionId()
|
||||
session, _ = manager.provider.SessionInit(sid)
|
||||
cookie := http.Cookie{Name: manager.cookieName, Value: url.QueryEscape(sid), Path: "/", HttpOnly: true, MaxAge: int(manager.maxlifetime)}
|
||||
http.SetCookie(w, &cookie)
|
||||
} else {
|
||||
sid, _ := url.QueryUnescape(cookie.Value)
|
||||
session, _ = manager.provider.SessionRead(sid)
|
||||
}
|
||||
return
|
||||
func (manager *Manager) SessionStart(w http.ResponseWriter, r *http.Request) (session Session) {
|
||||
manager.lock.Lock()
|
||||
defer manager.lock.Unlock()
|
||||
cookie, err := r.Cookie(manager.cookieName)
|
||||
if err != nil || cookie.Value == "" {
|
||||
sid := manager.sessionId()
|
||||
session, _ = manager.provider.SessionInit(sid)
|
||||
cookie := http.Cookie{Name: manager.cookieName, Value: url.QueryEscape(sid), Path: "/", HttpOnly: true, MaxAge: int(manager.maxlifetime)}
|
||||
http.SetCookie(w, &cookie)
|
||||
} else {
|
||||
sid, _ := url.QueryUnescape(cookie.Value)
|
||||
session, _ = manager.provider.SessionRead(sid)
|
||||
}
|
||||
return
|
||||
}
|
||||
```
|
||||
我们用前面login操作来演示session的运用：
|
||||
```Go
|
||||
|
||||
func login(w http.ResponseWriter, r *http.Request) {
|
||||
sess := globalSessions.SessionStart(w, r)
|
||||
r.ParseForm()
|
||||
if r.Method == "GET" {
|
||||
t, _ := template.ParseFiles("login.gtpl")
|
||||
w.Header().Set("Content-Type", "text/html")
|
||||
t.Execute(w, sess.Get("username"))
|
||||
} else {
|
||||
sess.Set("username", r.Form["username"])
|
||||
http.Redirect(w, r, "/", 302)
|
||||
}
|
||||
func login(w http.ResponseWriter, r *http.Request) {
|
||||
sess := globalSessions.SessionStart(w, r)
|
||||
r.ParseForm()
|
||||
if r.Method == "GET" {
|
||||
t, _ := template.ParseFiles("login.gtpl")
|
||||
w.Header().Set("Content-Type", "text/html")
|
||||
t.Execute(w, sess.Get("username"))
|
||||
} else {
|
||||
sess.Set("username", r.Form["username"])
|
||||
http.Redirect(w, r, "/", 302)
|
||||
}
|
||||
}
|
||||
```
|
||||
### 操作值：设置、读取和删除
|
||||
SessionStart函数返回的是一个满足Session接口的变量，那么我们该如何用他来对session数据进行操作呢？
|
||||
@@ -159,25 +159,25 @@ SessionStart函数返回的是一个满足Session接口的变量，那么我们
|
||||
上面的例子中的代码`session.Get("uid")`已经展示了基本的读取数据的操作，现在我们再来看一下详细的操作:
|
||||
```Go
|
||||
|
||||
func count(w http.ResponseWriter, r *http.Request) {
|
||||
sess := globalSessions.SessionStart(w, r)
|
||||
createtime := sess.Get("createtime")
|
||||
if createtime == nil {
|
||||
sess.Set("createtime", time.Now().Unix())
|
||||
} else if (createtime.(int64) + 360) < (time.Now().Unix()) {
|
||||
globalSessions.SessionDestroy(w, r)
|
||||
sess = globalSessions.SessionStart(w, r)
|
||||
}
|
||||
ct := sess.Get("countnum")
|
||||
if ct == nil {
|
||||
sess.Set("countnum", 1)
|
||||
} else {
|
||||
sess.Set("countnum", (ct.(int) + 1))
|
||||
}
|
||||
t, _ := template.ParseFiles("count.gtpl")
|
||||
w.Header().Set("Content-Type", "text/html")
|
||||
t.Execute(w, sess.Get("countnum"))
|
||||
func count(w http.ResponseWriter, r *http.Request) {
|
||||
sess := globalSessions.SessionStart(w, r)
|
||||
createtime := sess.Get("createtime")
|
||||
if createtime == nil {
|
||||
sess.Set("createtime", time.Now().Unix())
|
||||
} else if (createtime.(int64) + 360) < (time.Now().Unix()) {
|
||||
globalSessions.SessionDestroy(w, r)
|
||||
sess = globalSessions.SessionStart(w, r)
|
||||
}
|
||||
ct := sess.Get("countnum")
|
||||
if ct == nil {
|
||||
sess.Set("countnum", 1)
|
||||
} else {
|
||||
sess.Set("countnum", (ct.(int) + 1))
|
||||
}
|
||||
t, _ := template.ParseFiles("count.gtpl")
|
||||
w.Header().Set("Content-Type", "text/html")
|
||||
t.Execute(w, sess.Get("countnum"))
|
||||
}
|
||||
```
|
||||
通过上面的例子可以看到，Session的操作和操作key/value数据库类似:Set、Get、Delete等操作
|
||||
|
||||
@@ -187,36 +187,36 @@ SessionStart函数返回的是一个满足Session接口的变量，那么我们
|
||||
我们知道，Web应用中有用户退出这个操作，那么当用户退出应用的时候，我们需要对该用户的session数据进行销毁操作，上面的代码已经演示了如何使用session重置操作，下面这个函数就是实现了这个功能：
|
||||
```Go
|
||||
|
||||
//Destroy sessionid
|
||||
func (manager *Manager) SessionDestroy(w http.ResponseWriter, r *http.Request){
|
||||
cookie, err := r.Cookie(manager.cookieName)
|
||||
if err != nil || cookie.Value == "" {
|
||||
return
|
||||
} else {
|
||||
manager.lock.Lock()
|
||||
defer manager.lock.Unlock()
|
||||
manager.provider.SessionDestroy(cookie.Value)
|
||||
expiration := time.Now()
|
||||
cookie := http.Cookie{Name: manager.cookieName, Path: "/", HttpOnly: true, Expires: expiration, MaxAge: -1}
|
||||
http.SetCookie(w, &cookie)
|
||||
}
|
||||
//Destroy sessionid
|
||||
func (manager *Manager) SessionDestroy(w http.ResponseWriter, r *http.Request){
|
||||
cookie, err := r.Cookie(manager.cookieName)
|
||||
if err != nil || cookie.Value == "" {
|
||||
return
|
||||
} else {
|
||||
manager.lock.Lock()
|
||||
defer manager.lock.Unlock()
|
||||
manager.provider.SessionDestroy(cookie.Value)
|
||||
expiration := time.Now()
|
||||
cookie := http.Cookie{Name: manager.cookieName, Path: "/", HttpOnly: true, Expires: expiration, MaxAge: -1}
|
||||
http.SetCookie(w, &cookie)
|
||||
}
|
||||
}
|
||||
|
||||
```
|
||||
### session销毁
|
||||
我们来看一下Session管理器如何来管理销毁,只要我们在Main启动的时候启动：
|
||||
```Go
|
||||
|
||||
func init() {
|
||||
go globalSessions.GC()
|
||||
}
|
||||
func init() {
|
||||
go globalSessions.GC()
|
||||
}
|
||||
|
||||
func (manager *Manager) GC() {
|
||||
manager.lock.Lock()
|
||||
defer manager.lock.Unlock()
|
||||
manager.provider.SessionGC(manager.maxlifetime)
|
||||
time.AfterFunc(time.Duration(manager.maxlifetime), func() { manager.GC() })
|
||||
}
|
||||
func (manager *Manager) GC() {
|
||||
manager.lock.Lock()
|
||||
defer manager.lock.Unlock()
|
||||
manager.provider.SessionGC(manager.maxlifetime)
|
||||
time.AfterFunc(time.Duration(manager.maxlifetime), func() { manager.GC() })
|
||||
}
|
||||
```
|
||||
我们可以看到GC充分利用了time包中的定时器功能，当超时`maxLifeTime`之后调用GC函数，这样就可以保证`maxLifeTime`时间内的session都是可用的，类似的方案也可以用于统计在线用户数之类的。
|
||||
|
||||
|
||||
Reference in New Issue
Block a user