Output widget fails: can't clean datetime for JSON

Hi,

the Output widget doesn’t appear to work with rich display data:

In the notebook,

from ipywidgets import Output
w = Output()
w.clear_output()

results in

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-5-c7669a04e60f> in <module>()
      1 from ipywidgets import Output
      2 w = Output()
----> 3 w.clear_output()

/home/rick/src/ipywidgets/ipywidgets/widgets/widget_output.py in clear_output(self, *pargs, **kwargs)
     36     def clear_output(self, *pargs, **kwargs):
     37         with self:
---> 38             clear_output(*pargs, **kwargs)
     39 
     40     def __enter__(self):

/home/rick/src/ipython/IPython/core/display.py in clear_output(wait)
    900     from IPython.core.interactiveshell import InteractiveShell
    901     if InteractiveShell.initialized():
--> 902         InteractiveShell.instance().display_pub.clear_output(wait)
    903     else:
    904         from IPython.utils import io

/home/rick/src/notebook/src/ipykernel/ipykernel/zmqshell.py in clear_output(self, wait)
     92         self.session.send(
     93             self.pub_socket, u'clear_output', content,
---> 94             parent=self.parent_header, ident=self.topic,
     95         )
     96 

/home/rick/src/ipywidgets/ipywidgets/widgets/widget_output.py in send_hook(stream, msg_or_type, content, parent, ident, buffers, track, header, metadata)
     61             # If this is a message type that we want to forward, forward it.
     62             if stream is kernel.iopub_socket and msg_type in ['clear_output', 'stream', 'display_data']:
---> 63                 self.send(msg)
     64             else:
     65                 send(stream, msg, ident=ident, buffers=buffers, track=track)

/home/rick/src/ipywidgets/ipywidgets/widgets/widget.py in send(self, content, buffers)
    303             Binary buffers to send with message
    304         """
--> 305         self._send({"method": "custom", "content": content}, buffers=buffers)
    306 
    307     def on_msg(self, callback, remove=False):

/home/rick/src/ipywidgets/ipywidgets/widgets/widget.py in _send(self, msg, buffers)
    454     def _send(self, msg, buffers=None):
    455         """Sends a message to the model in the front-end."""
--> 456         self.comm.send(data=msg, buffers=buffers)
    457 
    458 

/home/rick/src/notebook/src/ipykernel/ipykernel/comm/comm.py in send(self, data, metadata, buffers)
    127         """Send a message to the frontend-side version of this comm"""
    128         self._publish_msg('comm_msg',
--> 129             data=data, metadata=metadata, buffers=buffers,
    130         )
    131 

/home/rick/src/notebook/src/ipykernel/ipykernel/comm/comm.py in _publish_msg(self, msg_type, data, metadata, buffers, **keys)
     75         with open('/home/rick/foo', 'at') as f:
     76             f.write('Sending %s\n\n' % dict(data=data, comm_id=self.comm_id, **keys))
---> 77         content = json_clean(dict(data=data, comm_id=self.comm_id, **keys))
     78         self.session.send(self.iopub_socket, msg_type,
     79             content,

/home/rick/src/notebook/src/ipykernel/ipykernel/jsonutil.py in json_clean(obj)
    161         out = {}
    162         for k,v in iteritems(obj):
--> 163             out[unicode_type(k)] = json_clean(v)
    164         return out
    165 

/home/rick/src/notebook/src/ipykernel/ipykernel/jsonutil.py in json_clean(obj)
    161         out = {}
    162         for k,v in iteritems(obj):
--> 163             out[unicode_type(k)] = json_clean(v)
    164         return out
    165 

/home/rick/src/notebook/src/ipykernel/ipykernel/jsonutil.py in json_clean(obj)
    161         out = {}
    162         for k,v in iteritems(obj):
--> 163             out[unicode_type(k)] = json_clean(v)
    164         return out
    165 

/home/rick/src/notebook/src/ipykernel/ipykernel/jsonutil.py in json_clean(obj)
    161         out = {}
    162         for k,v in iteritems(obj):
--> 163             out[unicode_type(k)] = json_clean(v)
    164         return out
    165 

/home/rick/src/notebook/src/ipykernel/ipykernel/jsonutil.py in json_clean(obj)
    165 
    166     # we don't understand it, it's probably an unserializable object
--> 167     raise ValueError("Can't clean for JSON: %r" % obj)

ValueError: Can't clean for JSON: datetime.datetime(2015, 5, 26, 16, 13, 44, 86776)

I can’t tell if more of the message header is being directed down the comm channel than it should be, bringing in the datetime, or of the datetime should have been converted to a string at some point (or some other problem…)

[mind6]

That works for me now, thanks!

This still doesn’t work when it’s datetime.date(…) instead of datetime.datetime(…)

[ricklupton]

That works for me now, thanks!