内存键值对存储
场景 验证码
package base64Captcha
// Store An object implementing Store interface can be registered with SetCustomStore
// function to handle storage and retrieval of captcha ids and solutions for
// them, replacing the default memory store.
//
// It is the responsibility of an object to delete expired and used captchas
// when necessary (for example, the default memory store collects them in Set
// method after the certain amount of captchas has been stored.)
type Store interface {
// Set sets the digits for the captcha id.
Set(id string, value string) error
// Get returns stored digits for the captcha id. Clear indicates
// whether the captcha must be deleted from the store.
Get(id string, clear bool) string
//Verify captcha's answer directly
Verify(id, answer string, clear bool) bool
}
github.com\mojocn\base64!captcha@v1.3.5\interface_store.go
github.com\mojocn\base64!captcha@v1.3.5\store_memory.go
package base64Captcha
import (
"container/list"
"sync"
"time"
)
// expValue stores timestamp and id of captchas. It is used in the list inside
// memoryStore for indexing generated captchas by timestamp to enable garbage
// collection of expired captchas.
type idByTimeValue struct {
timestamp time.Time
id string
}
// memoryStore is an internal store for captcha ids and their values.
type memoryStore struct {
sync.RWMutex
digitsById map[string]string
idByTime *list.List
// Number of items stored since last collection.
numStored int
// Number of saved items that triggers collection.
collectNum int
// Expiration time of captchas.
expiration time.Duration
}
// NewMemoryStore returns a new standard memory store for captchas with the
// given collection threshold and expiration time (duration). The returned
// store must be registered with SetCustomStore to replace the default one.
func NewMemoryStore(collectNum int, expiration time.Duration) Store {
s := new(memoryStore)
s.digitsById = make(map[string]string)
s.idByTime = list.New()
s.collectNum = collectNum
s.expiration = expiration
return s
}
func (s *memoryStore) Set(id string, value string) error {
s.Lock()
s.digitsById[id] = value
s.idByTime.PushBack(idByTimeValue{time.Now(), id})
s.numStored++
s.Unlock()
if s.numStored > s.collectNum {
go s.collect()
}
return nil
}
func (s *memoryStore) Verify(id, answer string, clear bool) bool {
v := s.Get(id, clear)
return v == answer
}
func (s *memoryStore) Get(id string, clear bool) (value string) {
if !clear {
// When we don't need to clear captcha, acquire read lock.
s.RLock()
defer s.RUnlock()
} else {
s.Lock()
defer s.Unlock()
}
value, ok := s.digitsById[id]
if !ok {
return
}
if clear {
delete(s.digitsById, id)
}
return
}
func (s *memoryStore) collect() {
now := time.Now()
s.Lock()
defer s.Unlock()
for e := s.idByTime.Front(); e != nil; {
e = s.collectOne(e, now)
}
}
func (s *memoryStore) collectOne(e *list.Element, specifyTime time.Time) *list.Element {
ev, ok := e.Value.(idByTimeValue)
if !ok {
return nil
}
if ev.timestamp.Add(s.expiration).Before(specifyTime) {
delete(s.digitsById, ev.id)
next := e.Next()
s.idByTime.Remove(e)
s.numStored--
return next
}
return nil
}
Go进阶37:重构我的base64Captcha图形验证码项目 | 🐶❤️🦀 https://mojotv.cn/go/refactor-base64-captcha
