refactoring of network code into separate service

src/services/request.js

@@ -0,0 +1,86 @@
+"use strict";
+
+const utils = require('./utils');
+const url = require('url');
+
+// this service provides abstraction over node's HTTP/HTTPS and electron net.client APIs
+// this allows to support system proxy
+
+// TODO: add proxy support - see https://stackoverflow.com/questions/3862813/how-can-i-use-an-http-proxy-with-node-js-http-client
+
+function exec(opts) {
+    const client = getClient(opts);
+    const parsedUrl = url.parse(opts.url);
+
+    return new Promise(async (resolve, reject) => {
+        try {
+            const request = client.request({
+                method: opts.method,
+                // url is used by electron net module
+                url: opts.url,
+                // 4 fields below are used by http and https node modules
+                protocol: parsedUrl.protocol,
+                host: parsedUrl.hostname,
+                port: parsedUrl.port,
+                path: parsedUrl.path,
+                timeout: opts.timeout,
+                headers: {
+                    Cookie: (opts.cookieJar && opts.cookieJar.header) || "",
+                    'Content-Type': 'application/json'
+                }
+            });
+
+            request.on('response', response => {
+                if (opts.cookieJar && response.headers['set-cookie']) {
+                    opts.cookieJar.header = response.headers['set-cookie'];
+                }
+
+                let responseStr = '';
+
+                response.on('data', chunk => responseStr += chunk);
+
+                response.on('end', () => {
+                    try {
+                        const jsonObj = responseStr.trim() ? JSON.parse(responseStr) : null;
+
+                        resolve(jsonObj);
+                    }
+                    catch (e) {
+                        log.error("Failed to deserialize sync response: " + responseStr);
+
+                        reject(generateError(e));
+                    }
+                });
+            });
+
+            request.end(opts.body ? JSON.stringify(opts.body) : undefined);
+        }
+        catch (e) {
+            reject(generateError(e));
+        }
+    })
+}
+
+function getClient(opts) {
+    if (utils.isElectron()) {
+        return require('electron').net;
+    }
+    else {
+        const {protocol} = url.parse(opts.url);
+
+        if (protocol === 'http:' || protocol === 'https:') {
+            return require(protocol.substr(0, protocol.length - 1));
+        }
+        else {
+            throw new Error(`Unrecognized protocol "${protocol}"`);
+        }
+    }
+}
+
+function generateError(e) {
+    return new Error(`Request to ${method} ${syncServerHost}${requestPath} failed, error: ${e.message}`);
+}
+
+module.exports = {
+    exec
+};