UncompressableFileError When Deploy Django Project on Heroku

I was using Django as my website backend framework, and it was my first time to do the backend stuff myself. After some days ramp up and search, I found the Cookiecutter Django provides a very good project template which could be used in a production level.

Few days struggling, I finally get into the last deployment step. I followed the document to deploy the website on Heroku.

However, after I got an error, the website shows “Internal Service Error” and opbeat send me this error:

**UncompressableFileError:** 'https://s3.amazonaws.com:443/*bucket-name*/static/css/project.css' **isn't accessible via COMPRESS_URL** ('https://s3.amazonaws.com/*bucket-name*/static/') **and can't be compressed.**

However, I was able to open the project.css directly in the browser, how come I don’t have access to the directory?

It took me hours to search and I still couldn’t figure it out. Then I decided to look into the source code and found this:

if not url.startswith(base_url):
    raise UncompressableFileError("'%s' isn't accessible via"
                                 "COMPRESS_URL ('%s') and can't be"
                                 "compressed"%(url, base_url))

Comparing to the error I received, we could conclude that:

• url: https://s3.amazonaws.com:443/*bucket-name*/static/css/project.css
• base_url: https://s3.amazonaws.com/*bucket-name*/static/

Found the difference?

YEP, the baseurl missing the port number! Because in the source code, the Python code used _url.startswith() method, thus the url should be exactly match!

So in the production.py file modify the STATIC_URL as following:

STATIC_URL = 'https://s3.amazonaws.com:443/%s/static/' % AWS_STORAGE_BUCKET_NAME
COMPRESS_URL = STATIC_URL

Commit the change, the website is alive!