Gulp build fails with: Error: Broken @import declaration of “http://fonts.googleapis.com/css?family=Open+Sans”

I am currently working on a project that involves an Angular.js frontend and the build server running on a machine behind a corporate proxy. From time to time this error occurs:

Error: Broken @import declaration of “http://fonts.googleapis.com/css?family=Open+Sans

All the other tasks such as bower install work fine because we set the proxy for bower, npm and git. After some research it became clear that the clean-css dependency that is used by gulp-minify-css  is the problem. This plugin ignores the proxy settings and tries to resolve the import declaration directly. Solution is very easy: just set a HTTP_PROXY environment variable with your proxy and everything works just fine.

This issue here describes some more possibilities to get around this problem.

Bower install / NPM install behind a proxy

Often when you work in a company network your are using a proxy to connect to the internet and it is not uncommon that you receive the following error when trying to execute bower install or npm install

ECMDERR Failed to execute "git ls-remote --tags --heads git://github.com/jquery/jquery.git", exit code of #128

The proxy is blocking the connection to Github because most proxy do not allow git://-urls. The solution for this is very simple. Just change the git urls to https and everything will work. This command changes all github urls to https:

git config --global url.https://github.com/.insteadOf git://github.com/