key: SSlibKey.from_file -> SSlibKey.from_pem

If needed we can add a from_file wrapper on top of from_pem (bytes).

Signed-off-by: Lukas Puehringer <[email protected]>

securesystemslib/signer/_key.py

@@ -301,9 +301,9 @@ def _from_crypto_public_key(
         return SSlibKey(keyid, keytype, scheme, keyval)
 
     @classmethod
-    def from_file(
+    def from_pem(
         cls,
-        path: str,
+        pem: bytes,
         scheme: Optional[str] = None,
         keyid: Optional[str] = None,
     ) -> "SSlibKey":
@@ -314,7 +314,7 @@ def from_file(
         may but are not guaranteed to work.
 
         Args:
-            path: Path to public key file.
+            pem: Public key PEM data.
             scheme: SSlibKey signing scheme. Defaults are "rsassa-pss-sha256",
                 "ecdsa-sha2-nistp256", and "ed25519" according to the keytype
             keyid: Key identifier. If not passed, a default keyid is computed.
@@ -333,8 +333,6 @@ def from_file(
         if CRYPTO_IMPORT_ERROR:
             raise UnsupportedLibraryError(CRYPTO_IMPORT_ERROR)
 
-        with open(path, "rb") as f:
-            pem = f.read()
         public_key = load_pem_public_key(pem)
         return cls._from_crypto_public_key(public_key, keyid, scheme)
 

tests/check_public_interfaces.py

@@ -308,13 +308,13 @@ def test_gpg_functions(self):
             securesystemslib.gpg.functions.export_pubkey("f00")
         self.assertEqual(expected_error_msg, str(ctx.exception))
 
-    def test_sslib_key_from_file(self):
-        """Assert raise UnsupportedLibraryError on SSlibKey.from_file()."""
+    def test_sslib_key_from_pem(self):
+        """Assert raise UnsupportedLibraryError on SSlibKey.from_pem()."""
         with self.assertRaises(UnsupportedLibraryError):
-            SSlibKey.from_file("should/fail/before/file/open")
+            SSlibKey.from_pem(b"fail")
 
     def test_crypto_signer_from_priv_key_uri(self):
-        """Assert raise UnsupportedLibraryError on SSlibKey.from_file()."""
+        """Assert raise UnsupportedLibraryError on 'from_priv_key_uri'."""
 
         public_key = SSlibKey(
             "aa", "rsa", "rsa-pkcs1v15-sha512", {"public": "val"}

tests/test_signer.py

@@ -287,8 +287,8 @@ def to_dict(self) -> Dict[str, Any]:
 class TestSSlibKey(unittest.TestCase):
     """SSlibKey tests."""
 
-    def test_from_file(self):
-        """Test load PEM/subjectPublicKeyInfo files for each SSlibKey keytype"""
+    def test_from_pem(self):
+        """Test load PEM/subjectPublicKeyInfo for each SSlibKey keytype"""
         test_data = [
             (
                 "rsa",
@@ -307,14 +307,22 @@ def test_from_file(self):
             ),
         ]
 
+        def _from_file(path):
+            with open(path, "rb") as f:
+                pem = f.read()
+            return pem
+
         for keytype, default_scheme, default_keyid in test_data:
-            key = SSlibKey.from_file(PEMS_DIR / f"{keytype}_public.pem")
+            pem = _from_file(PEMS_DIR / f"{keytype}_public.pem")
+            key = SSlibKey.from_pem(pem)
             self.assertEqual(key.keytype, keytype)
             self.assertEqual(key.scheme, default_scheme)
             self.assertEqual(key.keyid, default_keyid)
 
-        key = SSlibKey.from_file(
-            PEMS_DIR / "rsa_public.pem",
+        # Test with non-default scheme/keyid
+        pem = _from_file(PEMS_DIR / "rsa_public.pem")
+        key = SSlibKey.from_pem(
+            pem,
             scheme="rsa-pkcs1v15-sha224",
             keyid="abcdef",
         )