Serving JavaScript with Python's http.server

Posted on Wed 19 July 2023 in Python, JavaScript, Web • Tagged with Python, JavaScript, Web

I was trying to serve a JavaScript file with Python's http.server module, but I was getting this error:

Loading module from “http://localhost:9876/main.js” was blocked because of a disallowed MIME type (“text/plain”).

I saw in this StackOverflow answer that I needed to change the MIME type for JavaScript files. I'm using Windows, so I checked the key HKEY_CLASSES_ROOT\.js in RegEdit, and I found that it had this value:

(Default)     JSFile
ContentType   text/plain
PerceivedType text

I changed the ContentType to application/javascript, and now my JavaScript files are served with the correct MIME type.

I'm not sure why the MIME type was set to text/plain in the first place. I'm guessing that it was set by a program that I installed, but I don't know which one. I'm also not sure if changing the MIME type will cause any problems with other programs.


Pylance and mypy cannot find editable local imports

Posted on Thu 01 June 2023 in Pylance, Mypy, Python • Tagged with Pylance, Mypy, Python

The other day, I wrote a post about how I fixed a problem with Pylance not finding a local import. It worked, but now mypy was complaining about the same import.

The solution was installing the package in compat mode with:

pip install -e . --config-settings editable_mode=compat

Reading units from a pickle file with Pint

Posted on Tue 30 May 2023 in Pylance, Python, Pint • Tagged with Pylance, Python, Pint

I have a Python package called cloudmodel that uses Pint to define units and adds some to the default registry. When I read a pickle file that use these units, I get an error:

int.errors.UndefinedUnitError: 'usd' is not defined in the unit registry

The way to fix it is to set the application registry to the one used by cloudmodel:

from cloudmodel.unified.units import ureg
from pint import set_application_registry

set_application_registry(ureg)

Pylance cannot find editable local import

Posted on Sat 27 May 2023 in Pylance, Python • Tagged with Pylance, Python

I had a problem with Pylance not finding a local import. I had installed the package in editable mode with pip install -e . and it was working fine in the terminal, but Pylance was not able to find it.

The solution was installing the package in strict mode with:

pip install -e . --config-settings editable_mode=strict

I got there from this troubleshooting page and this explanation in the Setuptools documentation.


Click removal in audio files with Python

Posted on Tue 23 May 2023 in Audio, Python • Tagged with Audio, Python

A friend of mine had an audio file with many clicks in it. He asked me if I could remove them. I tried with the Audacity click removal tool, but it didn't work: it removed the clicks, but created a lot of artifacts in the audio, so I thought it would be a nice challenge to try to do it with Python.

The waveform looked like this:

Waveform with clicks

I did it using the pydub package. The basic idea is detecting the clicks and replacing them with the previous sample. I used two different criteria to detect the clicks:

  • If the average of the previous samples is below a threshold and the current sample is above another threshold.

  • If the difference between the previous sample and the current one is above a threshold.

The code is not very clean, but it worked. I had to play with the thresholds and the width of the samples to get the best results. I also had to play with the width of the clicks to avoid removing too much audio …


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