Provide support for proxy installs about electron-prebuilt

[max-mapper]

Sorry about that. To support this it looks like we would need to read .npmrc and if there is a http-proxy or https-proxy set we should pass it to the request options here: https://github.com/request/request#proxies

Should be pretty easy to implement. Patch welcome!

[uchidake]

Hi, all.
The request module supports http_proxy and https_proxy on environment variables.
https://www.npmjs.com/package/request#controlling-proxy-behaviour-using-environment-variables

I tried setting them and succeeded to install via proxy.

[max-mapper]

@uchidake nice find! I added a note to the readme

[neocotic]

I think it would be better to support {{.npmrc}} settings since {{node install.js}} is kicked off as part of an "postinstall" npm script, meaning the install fails because of a proxy issue even if the {{.npmrc}} file contains all of the necessary proxy information.

It's not always just the proxy as well as the {{ca}} and/or {{cafile}} configurations might be required as well.

[max-mapper]

this landed in electron-download 1.4.0

[Qilly]

I'm using 1.4.12 on Windows and still get exactly the same problem. I've set HTTP_PROXY and HTTPS_PROXY correctly (npm is using them to get to its server) but I still fail with a 403 in the electron post-build step. Any ideas?