InMemoryCaptchaDB is now within its own package alongside with an instance.

This commit is contained in:
Alexander Andreev 2022-10-20 22:52:13 +04:00
parent 0e0c91b5c2
commit 4078bb03bc
Signed by: Arav
GPG Key ID: 0388CC8FAA51063F

View File

@ -0,0 +1,157 @@
package inmemdb
import (
"image"
"justcaptcha/pkg/captcha"
"sync"
"time"
)
type InMemoryCaptchaDB struct {
sync.Mutex
db map[captcha.ID]captcha.Captcha
expiry time.Duration
expiryScanInterval time.Duration
}
// NewInMemoryCaptchaDB returns an initialised instance of an InMemoryCaptchaDB.
// An expiry duration is a time for how long CAPTCHA will be valid.
func NewInMemoryCaptchaDB(expiry time.Duration) *InMemoryCaptchaDB {
db := &InMemoryCaptchaDB{
db: make(map[captcha.ID]captcha.Captcha),
expiry: expiry}
if expiry < captcha.DefaultExpiredScanInterval {
db.expiryScanInterval = expiry
} else {
db.expiryScanInterval = captcha.DefaultExpiredScanInterval
}
go db.cleanExpired()
return db
}
// New accepts a CAPTHA instance, generates an ID and store it in a database.
// A data string is an additional random data used to generate an ID,
// e.g. an IP-address.
func (imcdb *InMemoryCaptchaDB) New(data string, cptcha captcha.Captcha) (captcha.Captcha, captcha.ID) {
id := captcha.NewID(data, cptcha.Answer())
imcdb.Lock()
imcdb.db[id] = cptcha
imcdb.Unlock()
return cptcha, id
}
// GetExpiry returns time for how long CAPTCHA will last.
func (imcdb *InMemoryCaptchaDB) GetExpiry() time.Duration {
return imcdb.expiry
}
// SetExpiry changes an expiry duration to a new one.
func (imcdb *InMemoryCaptchaDB) SetExpiry(expiry time.Duration) {
if expiry < captcha.DefaultExpiredScanInterval {
imcdb.expiryScanInterval = expiry
} else {
imcdb.expiryScanInterval = captcha.DefaultExpiredScanInterval
}
}
// Image returns a freshly generated image for a CAPTCHA.
func (imcdb *InMemoryCaptchaDB) Image(id captcha.ID, style string) (*image.Image, error) {
imcdb.Lock()
defer imcdb.Unlock()
if c, ok := imcdb.db[id]; ok {
return c.Image(style), nil
}
return nil, captcha.ErrorNotFound
}
// Solve compares given answer with a stored one and if failed
// deletes a CAPTCHA from database.
func (imcdb *InMemoryCaptchaDB) Solve(id captcha.ID, answer captcha.Answer) (bool, error) {
imcdb.Lock()
defer imcdb.Unlock()
if c, ok := imcdb.db[id]; ok {
ok = c.Solve(answer)
if !ok {
delete(imcdb.db, id)
}
return ok, nil
}
return false, captcha.ErrorNotFound
}
// IsSolved checks if CAPTCHA was solved and removes it
// from a database.
func (imcdb *InMemoryCaptchaDB) IsSolved(id captcha.ID) (bool, error) {
imcdb.Lock()
defer imcdb.Unlock()
if c, ok := imcdb.db[id]; ok {
delete(imcdb.db, id)
return c.IsSolved(), nil
}
return false, captcha.ErrorNotFound
}
// Remove a CAPTCHA from a database.
func (imcdb *InMemoryCaptchaDB) Remove(id captcha.ID) error {
imcdb.Lock()
defer imcdb.Unlock()
if _, ok := imcdb.db[id]; ok {
delete(imcdb.db, id)
return nil
}
return captcha.ErrorNotFound
}
// cleanExpired removes expired CAPTCHAs in a loop.
func (imcdb *InMemoryCaptchaDB) cleanExpired() {
for {
sleepFor := imcdb.expiryScanInterval - (time.Duration(time.Now().Second()) % imcdb.expiryScanInterval)
time.Sleep(sleepFor)
imcdb.Lock()
for id, captcha := range imcdb.db {
if time.Since(captcha.Expiry()) >= imcdb.expiry {
delete(imcdb.db, id)
}
}
imcdb.Unlock()
}
}
// An instance of InMemoryCaptchaDB
var imcdb = NewInMemoryCaptchaDB(captcha.DefaultExpiredScanInterval)
func GetExpiry() time.Duration {
return imcdb.GetExpiry()
}
func SetExpiry(expiry time.Duration) {
imcdb.SetExpiry(expiry)
}
func New(data string, captcha captcha.Captcha) (captcha.Captcha, captcha.ID) {
return imcdb.New(data, captcha)
}
func Image(id captcha.ID, style string) (*image.Image, error) {
return imcdb.Image(id, style)
}
func Solve(id captcha.ID, answer captcha.Answer) (bool, error) {
return imcdb.Solve(id, answer)
}
func IsSolved(id captcha.ID) (bool, error) {
return imcdb.IsSolved(id)
}
func Remove(id captcha.ID) error {
return imcdb.Remove(id)
}