Using SCSS with Flask

Question

I'm trying to use scss with Flask and get it to auto-compile.

I've tried using Flask-Scss — unfortunately, when I set it up, I get Scanning acceleration disabled (_speedups not found)! errors, and no CSS file. Anyone know how to fix this, or get it to generate CSS files?

Answer 1

The error results from an error in the installation process. If you install through pip on an Ubuntu system and you get this warning:

==========================================================================
WARNING: The C extension could not be compiled, speedups are not enabled.
Plain-Python installation succeeded.
==========================================================================

Then you should make sure you have the libpcre3-dev library pre-installed (this is the module that contains pcre.h, the module that the C-installation fails on):

 apt-get install libpcre3-dev

After doing this, re-install Flask-Scss:

pip install Flask-scss --force-reinstall -I

After restarting the Flask server, the error should now be a thing of the past.

But, please note

Even though the above will solve the problem of the _speedups not found error showing up, there is another likely reason for your files not getting compiled. If you have code like this:

app = Flask(__name__)

from flask.ext.scss import Scss
Scss(app, static_dir='static', asset_dir='assets')

...

if __name__ == "__main__":
    app.run(debug=True)

, and you are not setting debug anywhere else, then you should make sure to put

app.debug = True

before the invocation of the Scss object:

app.debug = True
Scss(app, static_dir='static', asset_dir='assets')

Happiness! That should do the trick for getting your .scss files to compile every time you load a page in debug mode.