It should be possible to set URLs via envvars

[imduffy15]

The download URL is hard coded: .src('http://downloads.sourceforge.net/project/optipng/OptiPNG/optipng-0.7.6/optipng-0.7.6.tar.gz')

This means if the system has limited access or no internet access through a proxy installing the module has a probability to fail.

The user has no way to override this url with some local web server or even a file:// path. Phantom JS handles this pretty well: https://www.npmjs.com/package/phantomjs#downloading-from-a-custom-url

[bdellegrazie]

+1

[dickeylth]

+1, downloading is very slow in China due to wall……

[tustvold]

+1, SourceForge has been having intermittent outages over the past few days (it is currently giving 502 and 404 errors), resulting in all CI jobs depending on this package failing .

[yikuo123]

+1

[happy-func]

+1