Add MessageP2P attachment encoding/decoding

modem/message_p2p.py

@@ -31,28 +31,41 @@ class MessageP2P:
         if 'attachments' in params: 
             for a in params['attachments']:
                 api_validations.validate_message_attachment(a)
-                attachments.append({
-                    'name': a['name'],
-                    'type': a['type'],
-                    'data': base64.decode(a['data']),
-                })
+                attachments.append(cls.__decode_attachment__(a))
 
         return cls(origin, dxcall, body, attachments)
         
+    @classmethod
+    def from_payload(cls, payload):
+        json_string = str(lzma.decompress(payload), 'utf-8')
+        payload_message = json.loads(json_string)
+        attachments = list(map(cls.__decode_attachment__, payload_message['attachments']))
+        return cls(payload_message['origin'], payload_message['destination'], 
+                   payload_message['body'], attachments)
+
     def get_id(self) -> str:
         return f"{self.origin}.{self.destination}.{self.timestamp}"
+
+    def __encode_attachment__(self, binary_attachment: dict):
+        encoded_attachment = binary_attachment.copy()
+        encoded_attachment['data'] = str(base64.b64encode(binary_attachment['data']), 'utf-8')
+        return encoded_attachment
     
+    def __decode_attachment__(encoded_attachment: dict):
+        decoded_attachment = encoded_attachment.copy()
+        decoded_attachment['data'] = base64.b64decode(encoded_attachment['data'])
+        return decoded_attachment
+
     def to_dict(self):
         """Make a dictionary out of the message data
         """
-        message = {
+        return {
             'id': self.get_id(),
             'origin': self.origin,
             'destination': self.destination,
             'body': self.body,
-            'attachments': self.attachments,
+            'attachments': list(map(self.__encode_attachment__, self.attachments)),
         }
-        return message
     
     def to_payload(self):
         """Make a byte array ready to be sent out of the message data"""

tests/test_message_p2p.py

@@ -1,5 +1,6 @@
 import sys
 sys.path.append('modem')
+import numpy as np
 
 import unittest
 from config import CONFIG
@@ -23,15 +24,20 @@ class TestDataFrameFactory(unittest.TestCase):
         self.assertEqual(message.destination, api_params['dxcall'])
         self.assertEqual(message.body, api_params['body'])
 
-    def testToPayload(self):
-        api_params = {
-            'dxcall': 'DJ2LS-3',
-            'body': 'Hello World!',
+    def testToPayloadWithAttachment(self):
+        attachment = {
+            'name': 'test.gif',
+            'type': 'image/gif',
+            'data': np.random.bytes(1024)
         }
-        message = MessageP2P.from_api_params(self.mycall, api_params)
+        message = MessageP2P(self.mycall, 'DJ2LS-3', 'Hello World!', [attachment])
         payload = message.to_payload()
-        self.assertGreater(len(payload), 0)
-        self.assertIsInstance(payload, bytes)
+
+        received_message = MessageP2P.from_payload(payload)
+        self.assertEqual(message.origin, received_message.origin)
+        self.assertEqual(message.destination, received_message.destination)
+        self.assertCountEqual(message.attachments, received_message.attachments)
+        self.assertEqual(attachment['data'], received_message.attachments[0]['data'])
 
 if __name__ == '__main__':
     unittest.main()