优化

fernet/key.go

@@ -9,15 +9,27 @@ import (
 )
 
 var (
-    errKeyLen = errors.New("fernet: key decodes to wrong size")
-    errNoKeys = errors.New("fernet: no keys provided")
+    errKeyLen   = errors.New("fernet: key decodes to wrong size")
+    errNoKeys   = errors.New("fernet: no keys provided")
+    errKeyShort = errors.New("fernet: key too short")
 )
 
 // Key represents a key.
 type Key struct {
     Value [32]byte
 }
 
+func NewKey(k []byte) (*Key, error) {
+    if len(k) != 32 {
+        return nil, errKeyShort
+    }
+
+    key := &Key{}
+    copy(key.Value[:], k)
+
+    return key, nil
+}
+
 func (k *Key) cryptBytes() []byte {
     return k.Value[len(k.Value)/2:]
 }

fernet/key_test.go

@@ -1,6 +1,11 @@
 package fernet
 
-import "testing"
+import (
+    "io"
+    "bytes"
+    "testing"
+    "crypto/rand"
+)
 
 func setKey(in []byte) Key {
     k := Key{}
@@ -111,3 +116,20 @@ func Test_Encode(t *testing.T) {
         }
     }
 }
+
+func Test_NewKey(t *testing.T) {
+    k := make([]byte, 32)
+    _, err := io.ReadFull(rand.Reader, k)
+    if err != nil {
+        t.Fatal(err)
+    }
+
+    key, err := NewKey(k)
+    if err != nil {
+        t.Fatal(err)
+    }
+
+    if !bytes.Equal(key.Value[:], k) {
+        t.Errorf("NewKey fail, got %x, want %x", key.Value[:], k)
+    }
+}