[杂七杂八] cookie管理(1)

package sessionimport (    "fmt"    "log"    "net/http"    "net/url"    "sync"    "time")type Manager struct {    cookieName  string    lock        sync.Mutex    provider    Provider    maxlifetime int64}var (    provides map[string]Provider = make(map[string]Provider))func RegisterProvider(name string, provider Provider) {    if nil == provider {        panic("session: Register provider is nil")    }    if _, dup := provides[name]; dup {        panic("session: Register called twice for provider " + name)    }    provides[name] = provider}func NewManager(providerName string, cookieName string, maxlifetime int64) (*Manager, error) {    provider, ok := provides[providerName]    if !ok {        return nil, fmt.Errorf("sessions: unknown provider %q (forgotten import?)", providerName)    }    return &Manager{        provider:    provider,        cookieName:  cookieName,        maxlifetime: maxlifetime,    }, nil}var doStartGC sync.Oncefunc (manager *Manager) DoStartGC() {    doStartGC.Do(func() {        manager.doGC()    })}func (manager *Manager) doGC() {    manager.lock.Lock()    defer manager.lock.Unlock()    log.Println("manager gc ...")    manager.provider.SessionGC(manager.maxlifetime)    log.Println("manager gc done")    time.AfterFunc(time.Duration(manager.maxlifetime)*time.Millisecond, func() {        manager.doGC()    })}func (manager *Manager) SessionStart(writer http.ResponseWriter, req *http.Request) (session Session) {    manager.lock.Lock()    defer manager.lock.Unlock()    cookie, err := req.Cookie(manager.cookieName)    if err != nil || cookie.Value == "" {        sid := makeSessionId()        session, _ = manager.provider.SessionInit(sid)        http.SetCookie(            writer,            &http.Cookie{                Name:     manager.cookieName,                Value:    url.QueryEscape(sid),                Path:     "/",                HttpOnly: true,                MaxAge:   int(manager.maxlifetime),            },        )        return    }    sid, _ := url.QueryUnescape(cookie.Value)    session, _ = manager.provider.SessionRead(sid)    //log.Printf("Using old session <%v>", sid)    return}func (manager *Manager) SessionDestroy(writer http.ResponseWriter, req *http.Request) {    cookie, err := req.Cookie(manager.cookieName)    if err != nil || cookie.Value == "" {        return    }    manager.lock.Lock()    defer manager.lock.Unlock()    manager.provider.SessionDestroy(cookie.Value)    http.SetCookie(        writer,        &http.Cookie{            Name:     manager.cookieName,            Path:     "/",            HttpOnly: true,            Expires:  time.Now(),            MaxAge:   -1,        },    )}

类别定义

package sessiontype Provider interface {    SessionInit(sid string) (Session, error)    SessionRead(sid string) (Session, error)    SessionDestroy(sid string) error    SessionGC(maxlifetime int64)}type Session interface {    Set(key, value interface{}) error    Get(key interface{}) interface{}    Delete(key interface{}) error    GetString(key     SessionID() string}

以及生成sessionid的方式:

package sessionimport (    "crypto/rand"    "encoding/base64"    "io"    "log")func makeSessionId() string {    b := make([]byte, 32)    if _, err := io.ReadFull(rand.Reader, b); err != nil {        log.Println("abnormal rand read for generating session-id")        return ""    }    return base64.URLEncoding.EncodeToString(b)}

参考文章:
https://astaxie.gitbooks.io/build-web-application-with-golang/content/en/06.1.html