proxy-setting: Feature to use system proxy settings.

This PR uses resolveProxy to read system proxy settings and store
them in proper proxy format string using ConfigUtil. It removes the previous
use proxy option and replaces it with use system proxy and manual proxy
options.

Fixes: #296.

app/renderer/js/utils/proxy-util.js

@@ -0,0 +1,96 @@
+'use strict';
+
+const ConfigUtil = require('./config-util.js');
+
+let instance = null;
+
+class ProxyUtil {
+	constructor() {
+		if (instance) {
+			return instance;
+		} else {
+			instance = this;
+		}
+
+		return instance;
+	}
+
+	resolveSystemProxy(mainWindow) {
+		const page = mainWindow.webContents;
+		const ses = page.session;
+		const resolveProxyUrl = 'www.google.com';
+
+		// Check HTTP Proxy
+		const httpProxy = new Promise(resolve => {
+			ses.resolveProxy('http://' + resolveProxyUrl, proxy => {
+				let httpString = '';
+				if (proxy !== 'DIRECT') {
+					// in case of proxy HTTPS url:port, windows gives first word as HTTPS while linux gives PROXY
+					// for all other HTTP or direct url:port both uses PROXY
+					if (proxy.includes('PROXY') || proxy.includes('HTTPS')) {
+						httpString = 'http=' + proxy.split('PROXY')[1] + ';';
+					}
+				}
+				resolve(httpString);
+			});
+		});
+		// Check HTTPS Proxy
+		const httpsProxy = new Promise(resolve => {
+			ses.resolveProxy('https://' + resolveProxyUrl, proxy => {
+				let httpsString = '';
+				if (proxy !== 'DIRECT' || proxy.includes('HTTPS')) {
+					// in case of proxy HTTPS url:port, windows gives first word as HTTPS while linux gives PROXY
+					// for all other HTTP or direct url:port both uses PROXY
+					if (proxy.includes('PROXY' || proxy.includes('HTTPS'))) {
+						httpsString += 'https=' + proxy.split('PROXY')[1] + ';';
+					}
+				}
+				resolve(httpsString);
+			});
+		});
+
+		// Check FTP Proxy
+		const ftpProxy = new Promise(resolve => {
+			ses.resolveProxy('ftp://' + resolveProxyUrl, proxy => {
+				let ftpString = '';
+				if (proxy !== 'DIRECT') {
+					if (proxy.includes('PROXY')) {
+						ftpString += 'ftp=' + proxy.split('PROXY')[1] + ';';
+					}
+				}
+				resolve(ftpString);
+			});
+		});
+
+		// Check SOCKS Proxy
+		const socksProxy = new Promise(resolve => {
+			ses.resolveProxy('socks4://' + resolveProxyUrl, proxy => {
+				let socksString = '';
+				if (proxy !== 'DIRECT') {
+					if (proxy.includes('SOCKS5')) {
+						socksString += 'socks=' + proxy.split('SOCKS5')[1] + ';';
+					} else if (proxy.includes('SOCKS4')) {
+						socksString += 'socks=' + proxy.split('SOCKS4')[1] + ';';
+					} else if (proxy.includes('PROXY')) {
+						socksString += 'socks=' + proxy.split('PROXY')[1] + ';';
+					}
+				}
+				resolve(socksString);
+			});
+		});
+
+		Promise.all([httpProxy, httpsProxy, ftpProxy, socksProxy]).then(values => {
+			let proxyString = '';
+			values.forEach(proxy => {
+				proxyString += proxy;
+			});
+			ConfigUtil.setConfigItem('systemProxyRules', proxyString);
+			const useSystemProxy = ConfigUtil.getConfigItem('useSystemProxy');
+			if (useSystemProxy) {
+				ConfigUtil.setConfigItem('proxyRules', proxyString);
+			}
+		});
+	}
+}
+
+module.exports = new ProxyUtil();