# Error while adding missing .ddl files to pvpython
**URL:** https://discourse.vtk.org/t/error-while-adding-missing-ddl-files-to-pvpython/6370
**Category:** Web
**Created:** [August 13, 2021, 3:21pm UTC](https://discourse.vtk.org/t/error-while-adding-missing-ddl-files-to-pvpython/6370 "2021-08-13T15:21:51Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@BadCookie](https://discourse.vtk.org/u/BadCookie)
#### Post date: [August 13, 2021, 3:21pm UTC](https://discourse.vtk.org/t/error-while-adding-missing-ddl-files-to-pvpython/6370/1 "2021-08-13T15:21:52Z")
Hi all,
As an example, I’m using vtk as a server, paraview web as a client and running them with pvpython of Paraview 5.9.0.I want to be able to use vtkImageViewer2. For some reason, vtkInteractionImage is not included in the bin/Lib/site-package/vtkmodules of Paraview 5.9.0 Therefore the vtkmodules/all.py is not recognizing vtkmodules.vtkInteractionImage.vtkImageViewer2.
Whereas, vtkImageViewer2 is present in a normal vtk 9.0.3 version installed in an anaconda environment.
I want to be able to use vtkImageViewer2 with the vtkmodules inside bin/Lib/site-package of Paraview 5.9.0. How would I include the vtkInteractionImage .dll files.
What I’ve tried so far…
Copy pasting the .dll file and .pyd file of vtkInteractionImage from the vtkmodules in the anaconda environment to the bin/Lib/site-package/vtkmodules of Paraview 5.9.0 and adding this line, “from .vtkInteractionImage import \*” in the all.py module of bin/Lib/site-package/vtkmodules of Paraview 5.9.0. But, still I’m getting an error like,
“ImportError: DLL load failed while importing vtkInteractionImage: The specified module could not be found.”
Below are the images for your reference.
Copied the .dll and .pyd file.
Adding the .vtkinteractionImage import to all.py
The error message:
What am I missing? Any help on this is highly appreciated. Thanks in advance!
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### Author:  [@Sebastien\_Jourdain](https://discourse.vtk.org/u/Sebastien_Jourdain)
#### Post date: [August 13, 2021, 4:36pm UTC](https://discourse.vtk.org/t/error-while-adding-missing-ddl-files-to-pvpython/6370/2 "2021-08-13T16:36:56Z")
It might be easier to use any [pre-release version of vtk](https://pypi.org/project/vtk/#history) instead of ParaView for running your server.
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### Author:  [@BadCookie](https://discourse.vtk.org/u/BadCookie)
#### Post date: [August 13, 2021, 5:16pm UTC](https://discourse.vtk.org/t/error-while-adding-missing-ddl-files-to-pvpython/6370/3 "2021-08-13T17:16:37Z")
Hi Sebastien,
I tried doing that. I’m so confused. But, I’m facing a lot of issues. For eg: I used flask as a web server instead of pvpython. And pip install vtk instead of the vtk in paraview. The problem is flask’s app.run() and wslink.server’s start\_server() are both blocking calls. I guess I have to do some multi-threading. But, I’m not sure. How is pvpython handling it? Also I’m confused. If I use flask, for the requests, say you visit a url, like [http://localhost:5000](http://localhost:5000) after that you create a websocket connection, then I guess I’ll have to use flask socket io instead of ws link right? If I replace wslink, then I won’t be able to use the exportRPC for easy callbacks. That’s why I thought adding the required .dll files would be the best way.
Any direction on any of these 2 approaches is appreciated.
Thank you.
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### Author:  [@Sebastien\_Jourdain](https://discourse.vtk.org/u/Sebastien_Jourdain)
#### Post date: [August 13, 2021, 7:05pm UTC](https://discourse.vtk.org/t/error-while-adding-missing-ddl-files-to-pvpython/6370/4 "2021-08-13T19:05:41Z")
What do you serve with Flask? Do you need to share memory with the VTK (wslink) that get used by the client?
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### Author:  [@Sebastien\_Jourdain](https://discourse.vtk.org/u/Sebastien_Jourdain)
#### Post date: [August 13, 2021, 8:08pm UTC](https://discourse.vtk.org/t/error-while-adding-missing-ddl-files-to-pvpython/6370/5 "2021-08-13T20:08:17Z")
If you can, keep the 2 process separate. Ideally you want to use a launcher to start 1 wslink process per client. And you can use your flask for serving the static content to the client along with other dynamic resources.
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### Author:  [@BadCookie](https://discourse.vtk.org/u/BadCookie)
#### Post date: [August 14, 2021, 4:18am UTC](https://discourse.vtk.org/t/error-while-adding-missing-ddl-files-to-pvpython/6370/6 "2021-08-14T04:18:33Z")
To answer your questions…
What do you server with Flask? - just static files like html and js
Do you need to share memory with wslink that is being used by client? - yes
Basically, just like this example here, [paraviewweb-examples/multiviews at master · Kitware/paraviewweb-examples · GitHub](https://github.com/Kitware/paraviewweb-examples/tree/master/multiviews)
Have the exact same tech stack and only replace pvpython with flask as server.
Okay, i’ll try the way you suggested. What you’re suggesting is something like this? [ParaView Lite](https://kitware.github.io/paraview-lite/docs/python_launcher.html) and modify to fit my requirement?