The Go Git Service (gogs.io) is already the "easiest, fastest, and most painless way of setting up a self-hosted Git service." And now because of a small pull request that got accepted, I am excited to announce that on 2018-03-31 with the release of Gogs v0.11.43, Gogs became the first git server to fully support CORS with the Git Smart HTTP protocol!! This means you can do cross-domain fetch and push operations in the browser using isomorphic-git without using a proxy server.
To enable CORS, edit the Gogs main config file,
custom/conf/app.ini, and add the following:
[http] ACCESS_CONTROL_ALLOW_ORIGIN = *
Hopefully Gitlab, Bitbucket, and Github will follow suit, enabling a new generation of web applications that interact directly with source code repositories. Until then, you can continue using cors-buster to interact with these sites.