Dart proxy.pac generator

proxypac.dart

import 'dart:io';
import 'dart:convert';

main() async {
    var server = await HttpServer.bind(InternetAddress.loopbackIPv4, 8080);
    print('Listening on localhost:${server.port}');

    await for (HttpRequest request in server) {
        var url = request.requestedUri;
        var params = url.queryParameters;
        var response = request.response;
        response.headers.contentType = new ContentType('application', 'x-ns-proxy-autoconfig', charset: 'utf-8');
        var body = proxyPac(params['host'], params['ip']);
        response.write(body);
        response.close();
    }
}


String proxyPac(String proxyHost, String proxyAddr) {
return """
function FindProxyForURL(url, host) {
    var clientIp = myIpAddress();
    var clientIpValid = (clientIp.length > 0 && clientIp != '127.0.0.1');

    var proxyPort = 8888;
    var proxyIp = dnsResolve('${proxyHost}.local');
    var proxyIpValid = (proxyIp.length > 0 && proxyIp != '127.0.0.1');

    if (!proxyIpValid) {
        if (clientIpValid) {
            var seg = clientIp.split('.');
            seg[3] = '46';
            proxyIp = seg.join('.')	
        } else {
            proxyIp = '${proxyAddr}';
        }
    }

    // proxy
    if (dnsDomainIs(host, '.disney.com') || dnsDomainIs(host, '.go.com')  || dnsDomainIs(host, '.starwave.com')) {
        return `PROXY \${proxyIp}:\${proxyPort}; DIRECT`;
    }

    // default
    return 'DIRECT';
}""";
}