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4ac9af9 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 | package helps
import (
"crypto/sha256"
"encoding/hex"
"sync"
"time"
"github.com/google/uuid"
)
type sessionIDCacheEntry struct {
value string
expire time.Time
}
var (
sessionIDCache = make(map[string]sessionIDCacheEntry)
sessionIDCacheMu sync.RWMutex
sessionIDCacheCleanupOnce sync.Once
)
const (
sessionIDTTL = time.Hour
sessionIDCacheCleanupPeriod = 15 * time.Minute
)
func startSessionIDCacheCleanup() {
go func() {
ticker := time.NewTicker(sessionIDCacheCleanupPeriod)
defer ticker.Stop()
for range ticker.C {
purgeExpiredSessionIDs()
}
}()
}
func purgeExpiredSessionIDs() {
now := time.Now()
sessionIDCacheMu.Lock()
for key, entry := range sessionIDCache {
if !entry.expire.After(now) {
delete(sessionIDCache, key)
}
}
sessionIDCacheMu.Unlock()
}
func sessionIDCacheKey(apiKey string) string {
sum := sha256.Sum256([]byte(apiKey))
return hex.EncodeToString(sum[:])
}
// CachedSessionID returns a stable session UUID per apiKey, refreshing the TTL on each access.
func CachedSessionID(apiKey string) string {
if apiKey == "" {
return uuid.New().String()
}
sessionIDCacheCleanupOnce.Do(startSessionIDCacheCleanup)
key := sessionIDCacheKey(apiKey)
now := time.Now()
sessionIDCacheMu.RLock()
entry, ok := sessionIDCache[key]
valid := ok && entry.value != "" && entry.expire.After(now)
sessionIDCacheMu.RUnlock()
if valid {
sessionIDCacheMu.Lock()
entry = sessionIDCache[key]
if entry.value != "" && entry.expire.After(now) {
entry.expire = now.Add(sessionIDTTL)
sessionIDCache[key] = entry
sessionIDCacheMu.Unlock()
return entry.value
}
sessionIDCacheMu.Unlock()
}
newID := uuid.New().String()
sessionIDCacheMu.Lock()
entry, ok = sessionIDCache[key]
if !ok || entry.value == "" || !entry.expire.After(now) {
entry.value = newID
}
entry.expire = now.Add(sessionIDTTL)
sessionIDCache[key] = entry
sessionIDCacheMu.Unlock()
return entry.value
}
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