Bug: len of None on getChannels in Web

[jamoore]

Found this in the OMEROweb.log on gretzky and thought I'd pass it on, in case it's important.

Thu, 02 Jun 2011 09:21:21 views-feedback ERROR    Traceback (most recent call last):

  File "/home/omero/OMERO.server-4.3.0-DEV-ec9b8cde/lib/python/django/core/handlers/base.py", line 92, in get_response
    response = callback(request, *callback_args, **callback_kwargs)

  File "/home/omero/OMERO.server-4.3.0-DEV-ec9b8cde/lib/python/omeroweb/webgateway/views.py", line 594, in render_image_region
    pi = _get_prepared_image(request, iid, server_id=server_id, _conn=_conn, with_session=USE_SESSION)

  File "/home/omero/OMERO.server-4.3.0-DEV-ec9b8cde/lib/python/omeroweb/webgateway/views.py", line 543, in _get_prepared_image
    if not img.setActiveChannels(channels, windows, colors):

  File "/home/omero/OMERO.server-4.3.0-DEV-ec9b8cde/lib/python/omero/gateway/__init__.py", line 5294, in setActiveChannels
    for c in range(len(self.getChannels())):

TypeError: object of type 'NoneType' has no len()

[wmoore]

Currently, imageWrapper.getChannels() requires the rendering engine to have been initialised

return [ChannelWrapper(self._conn, c, idx=n, re=self._re, img=self) for n,c in enumerate(self._re.getPixels().iterateChannels())]

so if we have a big image etc then this fails.
This can be seen for example, in the web metadata panel, channel names are not displayed for images Missing Pyramids.

I started to include a test for this in OmeroPy/test/gatewaytest/missing_pyramid.py but turned it off for now. I think the solution is to use metadata service to load Channels in getChannels() if the rendering engine is not created. BUT this will mean that we will have to check every time if _re is None in ChannelWrapper? and setActiveChannels() etc (in stack trace above) will still fail.

[Will Moore <will@…>]

(In [f9d191dda7ddb6b6747b9ad5cc8ee607a5ef1d1d/ome.git] on branch develop) Blitz getChannels() does not rely on RenderingEngine. See #5766

[Will Moore <will@…>]

(In [b1257431e4734cb07d349672699211dfbdc158bc/ome.git] on branch develop) Turning on testGetChannels() for Missing Pyramid tests. Now passes. See #5766

[wmoore]

Will fix other bugs that arise from these changes as the occur. E.g #5773.