Can you turn on the browser debugger and have it pause on errors, and see what the lines of code are that are giving the problem (what are the lines of code, not just the line numbers)? I would probably debug this by also putting a breakpoint at the registration function and making sure that was working (i.e., step through the code and make sure that an entry was stored in the kernel's comm registry). I would also step through the code where the error happened and inspect the registry.
For reference, here is where we are registering a target in widgetsnbextension: https://github.com/jupyter-widgets/ipywidgets/blob/bbfc39ec0f9e49f730d25bc5347d39e18992a54b/widgetsnbextension/src/manager.js#L71 Thanks, Jason On Wed, Nov 22, 2017 at 2:30 PM John <[email protected]> wrote: > Hi > > I tried opening a Comm from the kernel as described in > > http://jupyter-notebook.readthedocs.io/en/stable/comms.html > > And I am getting the error > > utils.js:910 Could not open comm -- Error: Class my_comm_target not > found in registry > at utils.js:874 > at new Promise (<anonymous>) > at Object.load_class (utils.js:859) > at CommManager.comm_open (comm.js:84) > at i (jquery.min.js:4) > at Kernel._handle_iopub_message (kernel.js:1223) > at Kernel._finish_ws_message (kernel.js:1015) > at kernel.js:1006 > at <anonymous> > (anonymous) @ utils.js:910 > Promise rejected (async) > CommManager.comm_open @ comm.js:85 > i @ jquery.min.js:4 > Kernel._handle_iopub_message @ kernel.js:1223 > Kernel._finish_ws_message @ kernel.js:1015 > (anonymous) @ kernel.js:1006 > Promise resolved (async) > Kernel._handle_ws_message @ kernel.js:1006 > i @ jquery.min.js:4 > > I have have a custom javascript file called glowcomm.js that is installed > at the location > > nbextensions/vpython_libraries/glowcomm.js > > The javascript code comes from a python package called vpython that > installs some custom javascript code to this location using > > notebook.nbextensions.install_nbextension(path = > package_dir+"/vpython_libraries",overwrite = True,user = True,verbose = 0) > > > The contents of the glowcomm.js file looks like > > define(["nbextensions/vpython_libraries/jquery-ui.custom.min", > "nbextensions/vpython_libraries/glow.min"], function() { > > var comm > > IPython.notebook.kernel.comm_manager.register_target('my_comm_target', > > What do I need to do to register "my_comm_target" so that I don't get > this error. > > Error: Class my_comm_target not found in registry > > > > Thanks > > John > > > -- > You received this message because you are subscribed to the Google Groups > "Project Jupyter" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/jupyter/630e2d49-96e9-4f88-b927-42c36dfcf883%40googlegroups.com > <https://groups.google.com/d/msgid/jupyter/630e2d49-96e9-4f88-b927-42c36dfcf883%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Project Jupyter" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/jupyter/CAPDWZHxxqFXQi8sd06%3DU4qhyPda8AEbtakm%2BWg7wcwTfbk24BA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
