Add custom json encoder/decoder support.

Author: becurrie

eel/__init__.py

@@ -18,6 +18,7 @@
 mimetypes.add_type('application/javascript', '.js')
 _eel_js_file = pkg.resource_filename('eel', 'eel.js')
 _eel_js = open(_eel_js_file, encoding='utf-8').read()
+_eel_json_dumps_default_function = lambda o: None
 _websockets = []
 _call_return_values = {}
 _call_return_callbacks = {}
@@ -44,6 +45,8 @@
     'position':         None,                       # (left, top) of main window
     'geometry':         {},                         # Dictionary of size/position for all windows
     'close_callback':   None,                       # Callback for when all windows have closed
+    'json_encoder':     None,                       # Custom JSONEncoder to customize json data dumping
+    'json_decoder':     None,                       # Custom JSONDecoder to customize json data loading
     'app_mode':  True,                              # (Chrome specific option)
     'all_interfaces': False,                        # Allow bottle server to listen for connections on all interfaces
     'disable_cache': True,                          # Sets the no-store response header when serving assets
@@ -188,7 +191,7 @@ def _eel():
     page = _eel_js.replace('/** _py_functions **/',
                            '_py_functions: %s,' % list(_exposed_functions.keys()))
     page = page.replace('/** _start_geometry **/',
-                        '_start_geometry: %s,' % _safe_json(start_geometry))
+                        '_start_geometry: %s,' % _safe_json_dumps(start_geometry))
     btl.response.content_type = 'application/javascript'
     _set_response_headers(btl.response)
     return page
@@ -217,15 +220,15 @@ def _websocket(ws):
     page = btl.request.query.page
     if page not in _mock_queue_done:
         for call in _mock_queue:
-            _repeated_send(ws, _safe_json(call))
+            _repeated_send(ws, _safe_json_dumps(call))
         _mock_queue_done.add(page)
 
     _websockets += [(page, ws)]
 
     while True:
         msg = ws.receive()
         if msg is not None:
-            message = jsn.loads(msg)
+            message = _safe_json_loads(msg)
             spawn(_process_message, message, ws)
         else:
             _websockets.remove((page, ws))
@@ -242,8 +245,12 @@ def _websocket(ws):
 
 # Private functions
 
-def _safe_json(obj):
-    return jsn.dumps(obj, default=lambda o: None)
+def _safe_json_loads(obj):
+    return jsn.loads(obj, cls=_start_args['json_decoder'])
+
+def _safe_json_dumps(obj):
+    return jsn.dumps(obj, cls=_start_args['json_encoder'],
+                     default=_eel_json_dumps_default_function if not _start_args['json_encoder'] else None)
 
 
 def _repeated_send(ws, msg):
@@ -258,7 +265,7 @@ def _repeated_send(ws, msg):
 def _process_message(message, ws):
     if 'call' in message:
         return_val = _exposed_functions[message['name']](*message['args'])
-        _repeated_send(ws, _safe_json({ 'return': message['call'],
+        _repeated_send(ws, _safe_json_dumps({ 'return': message['call'],
                                         'value': return_val  }))
     elif 'return' in message:
         call_id = message['return']
@@ -303,7 +310,7 @@ def _mock_call(name, args):
 def _js_call(name, args):
     call_object = _call_object(name, args)
     for _, ws in _websockets:
-        _repeated_send(ws, _safe_json(call_object))
+        _repeated_send(ws, _safe_json_dumps(call_object))
     return _call_return(call_object)