/
cache.go
58 lines (50 loc) · 1.66 KB
/
cache.go
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/******************************************************************************
*
* Copyright 2020 SAP SE
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************/
package gopherpolicy
import (
"crypto/sha256"
"encoding/hex"
lru "github.com/hashicorp/golang-lru/v2"
)
type inMemoryCacher struct {
*lru.Cache[string, []byte]
}
// InMemoryCacher builds a Cacher that stores token payloads in memory. At most
// 256 token payloads will be cached, so this will never use more than 4-8 MiB
// of memory.
func InMemoryCacher() Cacher {
// lru.New() only fails if a non-negative size is given, so it's safe to
// ignore the error here
//nolint:errcheck
c, _ := lru.New[string, []byte](256)
return inMemoryCacher{c}
}
func (c inMemoryCacher) StoreTokenPayload(token string, payload []byte) {
c.Add(cacheKeyFor(token), payload)
}
func (c inMemoryCacher) LoadTokenPayload(token string) []byte {
payload, ok := c.Get(cacheKeyFor(token))
if !ok {
return nil
}
return payload
}
func cacheKeyFor(token string) string {
sha256Hash := sha256.Sum256([]byte(token))
return hex.EncodeToString(sha256Hash[:])
}