Initial commit

common/verification.go

@@ -0,0 +1,77 @@
+package common
+
+import (
+	"github.com/google/uuid"
+	"strings"
+	"sync"
+	"time"
+)
+
+type verificationValue struct {
+	code string
+	time time.Time
+}
+
+const (
+	EmailVerificationPurpose = "v"
+	PasswordResetPurpose     = "r"
+)
+
+var verificationMutex sync.Mutex
+var verificationMap map[string]verificationValue
+var verificationMapMaxSize = 10
+var VerificationValidMinutes = 10
+
+func GenerateVerificationCode(length int) string {
+	code := uuid.New().String()
+	code = strings.Replace(code, "-", "", -1)
+	if length == 0 {
+		return code
+	}
+	return code[:length]
+}
+
+func RegisterVerificationCodeWithKey(key string, code string, purpose string) {
+	verificationMutex.Lock()
+	defer verificationMutex.Unlock()
+	verificationMap[purpose+key] = verificationValue{
+		code: code,
+		time: time.Now(),
+	}
+	if len(verificationMap) > verificationMapMaxSize {
+		removeExpiredPairs()
+	}
+}
+
+func VerifyCodeWithKey(key string, code string, purpose string) bool {
+	verificationMutex.Lock()
+	defer verificationMutex.Unlock()
+	value, okay := verificationMap[purpose+key]
+	now := time.Now()
+	if !okay || int(now.Sub(value.time).Seconds()) >= VerificationValidMinutes*60 {
+		return false
+	}
+	return code == value.code
+}
+
+func DeleteKey(key string, purpose string) {
+	verificationMutex.Lock()
+	defer verificationMutex.Unlock()
+	delete(verificationMap, purpose+key)
+}
+
+// no lock inside, so the caller must lock the verificationMap before calling!
+func removeExpiredPairs() {
+	now := time.Now()
+	for key := range verificationMap {
+		if int(now.Sub(verificationMap[key].time).Seconds()) >= VerificationValidMinutes*60 {
+			delete(verificationMap, key)
+		}
+	}
+}
+
+func init() {
+	verificationMutex.Lock()
+	defer verificationMutex.Unlock()
+	verificationMap = make(map[string]verificationValue)
+}