61 lines
1,010 B
Go
61 lines
1,010 B
Go
package main
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import (
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"crypto/sha512"
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"encoding/base64"
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"sync"
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"text/template"
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"github.com/Masterminds/sprig/v3"
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)
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var (
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sriCacheStore = newSRICache()
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tplFuncs template.FuncMap
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)
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func init() {
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tplFuncs = sprig.FuncMap()
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tplFuncs["assetSRI"] = assetSRIHash
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}
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func assetSRIHash(assetName string) string {
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if sri, ok := sriCacheStore.Get(assetName); ok {
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return sri
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}
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data, err := assets.ReadFile(assetName)
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if err != nil {
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panic(err)
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}
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h := sha512.New384()
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h.Write(data)
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sum := h.Sum(nil)
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sri := "sha384-" + base64.StdEncoding.EncodeToString(sum)
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sriCacheStore.Set(assetName, sri)
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return sri
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}
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type sriCache struct {
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c map[string]string
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l sync.RWMutex
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}
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func newSRICache() *sriCache { return &sriCache{c: map[string]string{}} }
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func (s *sriCache) Get(assetName string) (string, bool) {
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s.l.RLock()
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defer s.l.RUnlock()
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h, ok := s.c[assetName]
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return h, ok
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}
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func (s *sriCache) Set(assetName, hash string) {
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s.l.Lock()
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defer s.l.Unlock()
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s.c[assetName] = hash
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}
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