diff --git a/dataext/casMutex.go b/dataext/casMutex.go
new file mode 100644
index 0000000..4782a54
--- /dev/null
+++ b/dataext/casMutex.go
@@ -0,0 +1,254 @@
+package dataext
+
+import (
+	"context"
+	"golang.org/x/sync/semaphore"
+	"runtime"
+	"sync"
+	"sync/atomic"
+	"time"
+	"unsafe"
+)
+
+// from https://github.com/viney-shih/go-lock/blob/2f19fd8ce335e33e0ab9dccb1ff2ce820c3da332/cas.go
+
+// CASMutex is the struct implementing RWMutex with CAS mechanism.
+type CASMutex struct {
+	state     casState
+	turnstile *semaphore.Weighted
+
+	broadcastChan chan struct{}
+	broadcastMut  sync.RWMutex
+}
+
+func NewCASMutex() *CASMutex {
+	return &CASMutex{
+		state:         casStateNoLock,
+		turnstile:     semaphore.NewWeighted(1),
+		broadcastChan: make(chan struct{}),
+	}
+}
+
+type casState int32
+
+const (
+	casStateUndefined casState = iota - 2 // -2
+	casStateWriteLock                     // -1
+	casStateNoLock                        // 0
+	casStateReadLock                      // >= 1
+)
+
+func (m *CASMutex) getState(n int32) casState {
+	switch st := casState(n); {
+	case st == casStateWriteLock:
+		fallthrough
+	case st == casStateNoLock:
+		return st
+	case st >= casStateReadLock:
+		return casStateReadLock
+	default:
+		// actually, it should not happened.
+		return casStateUndefined
+	}
+}
+
+func (m *CASMutex) listen() <-chan struct{} {
+	m.broadcastMut.RLock()
+	defer m.broadcastMut.RUnlock()
+
+	return m.broadcastChan
+}
+
+func (m *CASMutex) broadcast() {
+	newCh := make(chan struct{})
+
+	m.broadcastMut.Lock()
+	ch := m.broadcastChan
+	m.broadcastChan = newCh
+	m.broadcastMut.Unlock()
+
+	close(ch)
+}
+
+func (m *CASMutex) tryLock(ctx context.Context) bool {
+	for {
+		broker := m.listen()
+		if atomic.CompareAndSwapInt32(
+			(*int32)(unsafe.Pointer(&m.state)),
+			int32(casStateNoLock),
+			int32(casStateWriteLock),
+		) {
+			return true
+		}
+
+		if ctx == nil {
+			return false
+		}
+
+		select {
+		case <-ctx.Done():
+			// timeout or cancellation
+			return false
+		case <-broker:
+			// waiting for signal triggered by m.broadcast() and trying again.
+		}
+	}
+}
+
+// TryLockWithContext attempts to acquire the lock, blocking until resources
+// are available or ctx is done (timeout or cancellation).
+func (m *CASMutex) TryLockWithContext(ctx context.Context) bool {
+	if err := m.turnstile.Acquire(ctx, 1); err != nil {
+		// Acquire failed due to timeout or cancellation
+		return false
+	}
+
+	defer m.turnstile.Release(1)
+
+	return m.tryLock(ctx)
+}
+
+// Lock acquires the lock.
+// If it is currently held by others, Lock will wait until it has a chance to acquire it.
+func (m *CASMutex) Lock() {
+	ctx := context.Background()
+
+	m.TryLockWithContext(ctx)
+}
+
+// TryLock attempts to acquire the lock without blocking.
+// Return false if someone is holding it now.
+func (m *CASMutex) TryLock() bool {
+	if !m.turnstile.TryAcquire(1) {
+		return false
+	}
+
+	defer m.turnstile.Release(1)
+
+	return m.tryLock(nil)
+}
+
+// TryLockWithTimeout attempts to acquire the lock within a period of time.
+// Return false if spending time is more than duration and no chance to acquire it.
+func (m *CASMutex) TryLockWithTimeout(duration time.Duration) bool {
+	ctx, cancel := context.WithTimeout(context.Background(), duration)
+	defer cancel()
+
+	return m.TryLockWithContext(ctx)
+}
+
+// Unlock releases the lock.
+func (m *CASMutex) Unlock() {
+	if ok := atomic.CompareAndSwapInt32(
+		(*int32)(unsafe.Pointer(&m.state)),
+		int32(casStateWriteLock),
+		int32(casStateNoLock),
+	); !ok {
+		panic("Unlock failed")
+	}
+
+	m.broadcast()
+}
+
+func (m *CASMutex) rTryLock(ctx context.Context) bool {
+	for {
+		broker := m.listen()
+		n := atomic.LoadInt32((*int32)(unsafe.Pointer(&m.state)))
+		st := m.getState(n)
+		switch st {
+		case casStateNoLock, casStateReadLock:
+			if atomic.CompareAndSwapInt32((*int32)(unsafe.Pointer(&m.state)), n, n+1) {
+				return true
+			}
+		}
+
+		if ctx == nil {
+			return false
+		}
+
+		select {
+		case <-ctx.Done():
+			// timeout or cancellation
+			return false
+		default:
+			switch st {
+			// read-lock failed due to concurrence issue, try again immediately
+			case casStateNoLock, casStateReadLock:
+				runtime.Gosched() // allow other goroutines to do stuff.
+				continue
+			}
+		}
+
+		select {
+		case <-ctx.Done():
+			// timeout or cancellation
+			return false
+		case <-broker:
+			// waiting for signal triggered by m.broadcast() and trying again.
+		}
+	}
+}
+
+// RTryLockWithContext attempts to acquire the read lock, blocking until resources
+// are available or ctx is done (timeout or cancellation).
+func (m *CASMutex) RTryLockWithContext(ctx context.Context) bool {
+	if err := m.turnstile.Acquire(ctx, 1); err != nil {
+		// Acquire failed due to timeout or cancellation
+		return false
+	}
+
+	m.turnstile.Release(1)
+
+	return m.rTryLock(ctx)
+}
+
+// RLock acquires the read lock.
+// If it is currently held by others writing, RLock will wait until it has a chance to acquire it.
+func (m *CASMutex) RLock() {
+	ctx := context.Background()
+
+	m.RTryLockWithContext(ctx)
+}
+
+// RTryLock attempts to acquire the read lock without blocking.
+// Return false if someone is writing it now.
+func (m *CASMutex) RTryLock() bool {
+	if !m.turnstile.TryAcquire(1) {
+		return false
+	}
+
+	m.turnstile.Release(1)
+
+	return m.rTryLock(nil)
+}
+
+// RTryLockWithTimeout attempts to acquire the read lock within a period of time.
+// Return false if spending time is more than duration and no chance to acquire it.
+func (m *CASMutex) RTryLockWithTimeout(duration time.Duration) bool {
+	ctx, cancel := context.WithTimeout(context.Background(), duration)
+	defer cancel()
+
+	return m.RTryLockWithContext(ctx)
+}
+
+// RUnlock releases the read lock.
+func (m *CASMutex) RUnlock() {
+	n := atomic.AddInt32((*int32)(unsafe.Pointer(&m.state)), -1)
+	switch m.getState(n) {
+	case casStateUndefined, casStateWriteLock:
+		panic("RUnlock failed")
+	case casStateNoLock:
+		m.broadcast()
+	}
+}
+
+// RLocker returns a Locker interface that implements the Lock and Unlock methods
+// by calling CASMutex.RLock and CASMutex.RUnlock.
+func (m *CASMutex) RLocker() sync.Locker {
+	return (*rlocker)(m)
+}
+
+type rlocker CASMutex
+
+func (r *rlocker) Lock()   { (*CASMutex)(r).RLock() }
+func (r *rlocker) Unlock() { (*CASMutex)(r).RUnlock() }
diff --git a/dataext/syncMap.go b/dataext/syncMap.go
index 4d1db41..ecf6b8a 100644
--- a/dataext/syncMap.go
+++ b/dataext/syncMap.go
@@ -50,6 +50,22 @@ func (s *SyncMap[TKey, TData]) Get(key TKey) (TData, bool) {
 	}
 }
 
+func (s *SyncMap[TKey, TData]) GetAndSetIfNotContains(key TKey, data TData) TData {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	if s.data == nil {
+		s.data = make(map[TKey]TData)
+	}
+
+	if v, ok := s.data[key]; ok {
+		return v
+	} else {
+		s.data[key] = data
+		return data
+	}
+}
+
 func (s *SyncMap[TKey, TData]) Delete(key TKey) bool {
 	s.lock.Lock()
 	defer s.lock.Unlock()
diff --git a/go.mod b/go.mod
index de8ce19..135d1f5 100644
--- a/go.mod
+++ b/go.mod
@@ -3,17 +3,19 @@ module gogs.mikescher.com/BlackForestBytes/goext
 go 1.22
 
 require (
-	github.com/gin-gonic/gin v1.9.1
+	github.com/gin-gonic/gin v1.10.0
 	github.com/glebarez/go-sqlite v1.22.0 // only needed for tests -.-
 	github.com/jmoiron/sqlx v1.4.0
 	github.com/rs/xid v1.5.0
 	github.com/rs/zerolog v1.32.0
 	go.mongodb.org/mongo-driver v1.15.0
-	golang.org/x/crypto v0.22.0
-	golang.org/x/sys v0.19.0
-	golang.org/x/term v0.19.0
+	golang.org/x/crypto v0.23.0
+	golang.org/x/sys v0.20.0
+	golang.org/x/term v0.20.0
 )
 
+require golang.org/x/sync v0.7.0
+
 require (
 	github.com/bytedance/sonic v1.11.6 // indirect
 	github.com/bytedance/sonic/loader v0.1.1 // indirect
@@ -47,11 +49,10 @@ require (
 	github.com/xdg-go/scram v1.1.2 // indirect
 	github.com/xdg-go/stringprep v1.0.4 // indirect
 	github.com/youmark/pkcs8 v0.0.0-20240424034433-3c2c7870ae76 // indirect
-	golang.org/x/arch v0.7.0 // indirect
-	golang.org/x/net v0.24.0 // indirect
-	golang.org/x/sync v0.7.0 // indirect
-	golang.org/x/text v0.14.0 // indirect
-	google.golang.org/protobuf v1.34.0 // indirect
+	golang.org/x/arch v0.8.0 // indirect
+	golang.org/x/net v0.25.0 // indirect
+	golang.org/x/text v0.15.0 // indirect
+	google.golang.org/protobuf v1.34.1 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 	modernc.org/libc v1.37.6 // indirect
 	modernc.org/mathutil v1.6.0 // indirect
diff --git a/go.sum b/go.sum
index e66a193..6047c68 100644
--- a/go.sum
+++ b/go.sum
@@ -50,6 +50,8 @@ github.com/gin-contrib/sse v0.1.0 h1:Y/yl/+YNO8GZSjAhjMsSuLt29uWRFHdHYUb5lYOV9qE
 github.com/gin-contrib/sse v0.1.0/go.mod h1:RHrZQHXnP2xjPF+u1gW/2HnVO7nvIa9PG3Gm+fLHvGI=
 github.com/gin-gonic/gin v1.9.1 h1:4idEAncQnU5cB7BeOkPtxjfCSye0AAm1R0RVIqJ+Jmg=
 github.com/gin-gonic/gin v1.9.1/go.mod h1:hPrL7YrpYKXt5YId3A/Tnip5kqbEAP+KLuI3SUcPTeU=
+github.com/gin-gonic/gin v1.10.0 h1:nTuyha1TYqgedzytsKYqna+DfLos46nTv2ygFy86HFU=
+github.com/gin-gonic/gin v1.10.0/go.mod h1:4PMNQiOhvDRa013RKVbsiNwoyezlm2rm0uX/T7kzp5Y=
 github.com/glebarez/go-sqlite v1.22.0 h1:uAcMJhaA6r3LHMTFgP0SifzgXg46yJkgxqyuyec+ruQ=
 github.com/glebarez/go-sqlite v1.22.0/go.mod h1:PlBIdHe0+aUEFn+r2/uthrWq4FxbzugL0L8Li6yQJbc=
 github.com/go-playground/assert/v2 v2.2.0 h1:JvknZsQTYeFEAhQwI4qEt9cyV5ONwRHC+lYKSsYSR8s=
@@ -191,6 +193,8 @@ go.mongodb.org/mongo-driver v1.15.0/go.mod h1:Vzb0Mk/pa7e6cWw85R4F/endUC3u0U9jGc
 golang.org/x/arch v0.0.0-20210923205945-b76863e36670/go.mod h1:5om86z9Hs0C8fWVUuoMHwpExlXzs5Tkyp9hOrfG7pp8=
 golang.org/x/arch v0.7.0 h1:pskyeJh/3AmoQ8CPE95vxHLqp1G1GfGNXTmcl9NEKTc=
 golang.org/x/arch v0.7.0/go.mod h1:FEVrYAQjsQXMVJ1nsMoVVXPZg6p2JE2mx8psSWTDQys=
+golang.org/x/arch v0.8.0 h1:3wRIsP3pM4yUptoR96otTUOXI367OS0+c9eeRi9doIc=
+golang.org/x/arch v0.8.0/go.mod h1:FEVrYAQjsQXMVJ1nsMoVVXPZg6p2JE2mx8psSWTDQys=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20200302210943-78000ba7a073/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
@@ -207,6 +211,8 @@ golang.org/x/crypto v0.21.0 h1:X31++rzVUdKhX5sWmSOFZxx8UW/ldWx55cbf08iNAMA=
 golang.org/x/crypto v0.21.0/go.mod h1:0BP7YvVV9gBbVKyeTG0Gyn+gZm94bibOW5BjDEYAOMs=
 golang.org/x/crypto v0.22.0 h1:g1v0xeRhjcugydODzvb3mEM9SQ0HGp9s/nh3COQ/C30=
 golang.org/x/crypto v0.22.0/go.mod h1:vr6Su+7cTlO45qkww3VDJlzDn0ctJvRgYbC2NvXHt+M=
+golang.org/x/crypto v0.23.0 h1:dIJU/v2J8Mdglj/8rJ6UUOM3Zc9zLZxVZwwxMooUSAI=
+golang.org/x/crypto v0.23.0/go.mod h1:CKFgDieR+mRhux2Lsu27y0fO304Db0wZe70UKqHu0v8=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
@@ -223,6 +229,8 @@ golang.org/x/net v0.22.0 h1:9sGLhx7iRIHEiX0oAJ3MRZMUCElJgy7Br1nO+AMN3Tc=
 golang.org/x/net v0.22.0/go.mod h1:JKghWKKOSdJwpW2GEx0Ja7fmaKnMsbu+MWVZTokSYmg=
 golang.org/x/net v0.24.0 h1:1PcaxkF854Fu3+lvBIx5SYn9wRlBzzcnHZSiaFFAb0w=
 golang.org/x/net v0.24.0/go.mod h1:2Q7sJY5mzlzWjKtYUEXSlBWCdyaioyXzRB2RtU8KVE8=
+golang.org/x/net v0.25.0 h1:d/OCCoBEUq33pjydKrGQhw7IlUPI2Oylr+8qLx49kac=
+golang.org/x/net v0.25.0/go.mod h1:JkAGAh7GEvH74S6FOH42FLoXpXbE/aqXSrIQjXgsiwM=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.6.0 h1:5BMeUDZ7vkXGfEr1x9B4bRcTH4lpkTkpdh0T/J+qjbQ=
@@ -248,6 +256,8 @@ golang.org/x/sys v0.18.0 h1:DBdB3niSjOA/O0blCZBqDefyWNYveAYMNF1Wum0DYQ4=
 golang.org/x/sys v0.18.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/sys v0.19.0 h1:q5f1RH2jigJ1MoAWp2KTp3gm5zAGFUTarQZ5U386+4o=
 golang.org/x/sys v0.19.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.20.0 h1:Od9JTbYCk261bKm4M/mw7AklTlFYIa0bIp9BgSm1S8Y=
+golang.org/x/sys v0.20.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/term v0.16.0 h1:m+B6fahuftsE9qjo0VWp2FW0mB3MTJvR0BaMQrq0pmE=
@@ -258,6 +268,8 @@ golang.org/x/term v0.18.0 h1:FcHjZXDMxI8mM3nwhX9HlKop4C0YQvCVCdwYl2wOtE8=
 golang.org/x/term v0.18.0/go.mod h1:ILwASektA3OnRv7amZ1xhE/KTR+u50pbXfZ03+6Nx58=
 golang.org/x/term v0.19.0 h1:+ThwsDv+tYfnJFhF4L8jITxu1tdTWRTZpdsWgEgjL6Q=
 golang.org/x/term v0.19.0/go.mod h1:2CuTdWZ7KHSQwUzKva0cbMg6q2DMI3Mmxp+gKJbskEk=
+golang.org/x/term v0.20.0 h1:VnkxpohqXaOBYJtBmEppKUG6mXpi+4O6purfc2+sMhw=
+golang.org/x/term v0.20.0/go.mod h1:8UkIAJTvZgivsXaD6/pH6U9ecQzZ45awqEOzuCvwpFY=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
@@ -266,6 +278,8 @@ golang.org/x/text v0.3.8/go.mod h1:E6s5w1FMmriuDzIBO73fBruAKo1PCIq6d2Q6DHfQ8WQ=
 golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
 golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
 golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
+golang.org/x/text v0.15.0 h1:h1V/4gjBv8v9cjcR6+AR5+/cIYK5N/WAgiv4xlsEtAk=
+golang.org/x/text v0.15.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
@@ -279,6 +293,8 @@ google.golang.org/protobuf v1.33.0 h1:uNO2rsAINq/JlFpSdYEKIZ0uKD/R9cpdv0T+yoGwGm
 google.golang.org/protobuf v1.33.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
 google.golang.org/protobuf v1.34.0 h1:Qo/qEd2RZPCf2nKuorzksSknv0d3ERwp1vFG38gSmH4=
 google.golang.org/protobuf v1.34.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
+google.golang.org/protobuf v1.34.1 h1:9ddQBjfCyZPOHPUiPxpYESBLc+T8P3E+Vo4IbKZgFWg=
+google.golang.org/protobuf v1.34.1/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/goextVersion.go b/goextVersion.go
index a1895e8..c2fac30 100644
--- a/goextVersion.go
+++ b/goextVersion.go
@@ -1,5 +1,5 @@
 package goext
 
-const GoextVersion = "0.0.445"
+const GoextVersion = "0.0.446"
 
-const GoextVersionTimestamp = "2024-05-03T15:28:53+0200"
+const GoextVersionTimestamp = "2024-05-10T21:31:36+0200"