added extended attribute getter for notation-go (notaryproject#46)

* added extended attribute getter for notation-go Signed-off-by: Patrick Zheng <patrickzheng@microsoft.com> * update Signed-off-by: Patrick Zheng <patrickzheng@microsoft.com> Signed-off-by: Patrick Zheng <patrickzheng@microsoft.com>
JeyJeyGao · Sep 13, 2022 · 91bf816 · 91bf816
1 parent 9dcfa2b
commit 91bf816
Showing 1 changed file with 12 additions and 0 deletions.
diff --git a/signature/types.go b/signature/types.go
@@ -2,6 +2,7 @@ package signature
 
 import (
 	"crypto/x509"
+	"errors"
 	"time"
 )
 
@@ -119,3 +120,14 @@ type Payload struct {
 	// Content contains the raw bytes of the payload.
 	Content []byte
 }
+
+// ExtendedAttribute fetches the specified Attribute with provided key from
+// signerInfo.SignedAttributes.ExtendedAttributes
+func (signerInfo *SignerInfo) ExtendedAttribute(key string) (Attribute, error) {
+	for _, attr := range signerInfo.SignedAttributes.ExtendedAttributes {
+		if attr.Key == key {
+			return attr, nil
+		}
+	}
+	return Attribute{}, errors.New("key not in ExtendedAttributes")
+}