WIP: move add_encrypted_key to a Python file (not an interface)

Author: mxamin

src/xmlsec/template.py

@@ -0,0 +1,42 @@
+from lxml.etree import _Element
+from xmlsec.constants import __Transform as Transform
+import ctypes
+
+# Load the shared library (assuming it's named `libxmlsec.so` or similar)
+libxmlsec = ctypes.CDLL("../template.c")
+
+# Define the Python wrapper for the C function
+libxmlsec.PyXmlSec_TemplateAddEncryptedKey.argtypes = [
+    ctypes.POINTER(_Element),  # Assuming _Element is compatible
+    ctypes.POINTER(Transform),
+    ctypes.c_char_p,  # id
+    ctypes.c_char_p,  # type
+    ctypes.c_char_p   # recipient
+]
+libxmlsec.PyXmlSec_TemplateAddEncryptedKey.restype = ctypes.POINTER(_Element)
+
+def add_encrypted_key(
+    node: _Element, method: Transform, id: str | None = None, type: str | None = None, recipient: str | None = None
+) -> _Element:
+    """
+    Python wrapper for the C function `PyXmlSec_TemplateAddEncryptedKey`.
+
+    :param node: The XML node to which the encrypted key will be added.
+    :param method: The encryption method.
+    :param id: Optional ID for the key.
+    :param type: Optional type for the key.
+    :param recipient: Optional recipient for the key.
+    :return: The modified XML node.
+    """
+    # Convert Python strings to C strings
+    c_id = ctypes.c_char_p(id.encode('utf-8') if id else None)
+    c_type = ctypes.c_char_p(type.encode('utf-8') if type else None)
+    c_recipient = ctypes.c_char_p(recipient.encode('utf-8') if recipient else None)
+
+    # Call the C function
+    result = libxmlsec.PyXmlSec_TemplateAddEncryptedKey(node, method, c_id, c_type, c_recipient)
+
+    if not result:
+        raise RuntimeError("Failed to add encrypted key")
+
+    return result