rvm-downloader.js

var https = require('https'),
    http = require('http'),
    path = require('path'),
    unzip = require('unzip'),
    parse = require('url').parse,
    q = require('q');

function download(url, writePath){
    var deffered = q.defer(),
        isHttps,
        downloadStream,
        env = process.env,
        HTTP_PROXY = env.HTTP_PROXY || env.http_proxy,
        HTTPS_PROXY = env.HTTPS_PROXY || env.https_proxy,
        parsed;

    // prevent proxy errors
    if (HTTP_PROXY || HTTPS_PROXY){
        process.env.NODE_TLS_REJECT_UNAUTHORIZED = '0';
    }

    function setProxy(proxyString, options){
        if (proxyString){
            parsed = parse(proxyString);
            options.host = parsed.hostname;
            parsed.port && (options.port = parsed.port);
            parsed.auth && (options.auth = parsed.auth);
        }

        return options;
    }

    function onError(err){
        if (isHttps){
            console.log('HTTPS download failed, trying http');
            getRvm(url.replace('https', 'http'));
        } else {
            deffered.reject(new Error(err));
        }
    }

    function getRvm(rvmUrl){
        isHttps = rvmUrl.lastIndexOf('https') >= 0;
        downloadStream = isHttps ? https : http;

        var options = setProxy(isHttps ? HTTPS_PROXY : HTTP_PROXY, {
            path: rvmUrl,
            agent: false,
            method: 'GET'
        });

        downloadStream.request(options, function(response){
            if (response.statusCode !== 200){
                onError('Download Failed');
            } else {
                response.pipe(unzip.Extract({
                    path: path.dirname(writePath)
                })).on('close', function(){
                    deffered.resolve();
                });
            }
        }).on('error', onError).on('response', function(data){
            console.log('Download in progres...' /*, data.headers*/);
        });
    }

    getRvm(url);

    return deffered.promise;
}

module.exports = {
    download: download
};