Make private key optional for decoding JWT

Author: rrooij

prolog/jwt_io.pl

@@ -44,7 +44,7 @@
     * =kid=: key id for identifying the key to use
     * =type=: type of the key, one of HMAC, RSA or ECDSA.
     * =algorithm=: algorithm to use, one of HS256, HS384, HS512, RS256, RS384, RS512, ES256, ES384 or ES512.
-    * =key=: private key to use - string for HMAC, private key file for RSA and private PEM file for ECDSA.
+    * =key=: private key to use - string for HMAC, private key file for RSA and private PEM file for ECDSA. Optional for decoding, mandatory for encoding.
     * =public_key=: public key to use - irrelevant for HMAC, public key file for RSA and public PEM file for ECDSA.
 
 RSA keys can be generated by:
@@ -268,12 +268,21 @@
   !.
 read_key_file(Key,KeyRead) :-
   member(Key.type, ['RSA', 'ECDSA']),
-  read_file_to_string(Key.key, KeyStr, []),
+  get_dict('key', Key, PrivateKeyFile),
+  !,
+  read_file_to_string(PrivateKeyFile, KeyStr, []),
   read_file_to_string(Key.public_key, PublicKeyStr, []),
   atom_string(KeyAtom, KeyStr),
   atom_string(PublicKeyAtom, PublicKeyStr),
   KeyRead = Key.put(_{key: KeyAtom, public_key: PublicKeyAtom}),
   !.
+read_key_file(Key, KeyRead) :-
+  member(Key.type, ['RSA', 'ECDSA']),
+  read_file_to_string(Key.public_key, PublicKeyStr, []),
+  atom_string(PublicKeyAtom, PublicKeyStr),
+  KeyRead = Key.put(_{public_key: PublicKeyAtom}),
+  !.
+
 
 get_key_file(File, Key) :-
   read_file_to_string(File, KeyStr, []),