47 lines
1000 B
Go
47 lines
1000 B
Go
package service
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import (
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"crypto/hmac"
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"crypto/sha256"
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"encoding/hex"
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"fmt"
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"time"
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)
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type URLService struct {
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secret string
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serverHost string
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}
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func NewURLService(secret, serverHost string) *URLService {
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return &URLService{secret: secret, serverHost: serverHost}
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}
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func (s *URLService) sign(fileID string, expires int64) string {
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data := fmt.Sprintf("%s:%d", fileID, expires)
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mac := hmac.New(sha256.New, []byte(s.secret))
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mac.Write([]byte(data))
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return hex.EncodeToString(mac.Sum(nil))
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}
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func (s *URLService) GenerateDownloadURL(fileUUID string) string {
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expires := time.Now().Add(10 * time.Minute).Unix()
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sig := s.sign(fileUUID, expires)
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return fmt.Sprintf(
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"%s/api/v1/files/download/%s?expires=%d&sig=%s",
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s.serverHost,
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fileUUID,
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expires,
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sig,
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)
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}
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func (s *URLService) Validate(fileID, sig string, expires int64) bool {
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if time.Now().Unix() > expires {
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return false
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}
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expected := s.sign(fileID, expires)
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return hmac.Equal([]byte(sig), []byte(expected))
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}
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