make URL path concatenation work right whether base URL has a trailing slash or not (#61)

* make URL path concatenation work right whether base URL has a trailing slash or not

* lint

Author: eli-darkly

src/EventProcessor.js

@@ -15,7 +15,7 @@ export default function EventProcessor(
 ) {
   const processor = {};
   const eventSender = sender || EventSender(platform, environmentId, options);
-  const mainEventsUrl = options.eventsUrl + '/events/bulk/' + environmentId;
+  const mainEventsUrl = utils.appendUrlPath(options.eventsUrl, '/events/bulk/' + environmentId);
   const summarizer = EventSummarizer();
   const userFilter = UserFilter(options);
   const inlineUsers = options.inlineUsersInEvents;

src/Requestor.js

@@ -75,7 +75,7 @@ export default function Requestor(platform, options, environment) {
   // Performs a GET request to an arbitrary path under baseUrl. Returns a Promise which will resolve
   // with the parsed JSON response, or will be rejected if the request failed.
   requestor.fetchJSON = function(path) {
-    return fetchJSON(baseUrl + path, null);
+    return fetchJSON(utils.appendUrlPath(baseUrl, path), null);
   };
 
   // Requests the current state of all flags for the given user from LaunchDarkly. Returns a Promise

src/Stream.js

@@ -1,5 +1,5 @@
 import * as messages from './messages';
-import { base64URLEncode, getLDHeaders, transformHeaders, objectHasOwnProperty } from './utils';
+import { appendUrlPath, base64URLEncode, getLDHeaders, transformHeaders, objectHasOwnProperty } from './utils';
 
 // The underlying event source implementation is abstracted via the platform object, which should
 // have these three properties:
@@ -20,7 +20,7 @@ export default function Stream(platform, config, environment, diagnosticsAccumul
   const baseUrl = config.streamUrl;
   const logger = config.logger;
   const stream = {};
-  const evalUrlPrefix = baseUrl + '/eval/' + environment;
+  const evalUrlPrefix = appendUrlPath(baseUrl, '/eval/' + environment);
   const useReport = config.useReport;
   const withReasons = config.evaluationReasons;
   const streamReconnectDelay = config.streamReconnectDelay;
@@ -98,7 +98,7 @@ export default function Stream(platform, config, environment, diagnosticsAccumul
           options.body = JSON.stringify(user);
         } else {
           // if we can't do REPORT, fall back to the old ping-based stream
-          url = baseUrl + '/ping/' + environment;
+          url = appendUrlPath(baseUrl, '/ping/' + environment);
           query = '';
         }
       } else {

src/__tests__/utils-test.js

@@ -1,4 +1,5 @@
 import {
+  appendUrlPath,
   base64URLEncode,
   getLDHeaders,
   transformHeaders,
@@ -10,6 +11,13 @@ import {
 import * as stubPlatform from './stubPlatform';
 
 describe('utils', () => {
+  it('appendUrlPath', () => {
+    expect(appendUrlPath('http://base', '/path')).toEqual('http://base/path');
+    expect(appendUrlPath('http://base', 'path')).toEqual('http://base/path');
+    expect(appendUrlPath('http://base/', '/path')).toEqual('http://base/path');
+    expect(appendUrlPath('http://base/', '/path')).toEqual('http://base/path');
+  });
+
   describe('wrapPromiseCallback', () => {
     it('should resolve to the value', done => {
       const promise = wrapPromiseCallback(Promise.resolve('woohoo'));

src/diagnosticEvents.js

@@ -5,6 +5,7 @@ const uuidv1 = require('uuid/v1');
 
 const { baseOptionDefs } = require('./configuration');
 const messages = require('./messages');
+const { appendUrlPath } = require('./utils');
 
 function DiagnosticId(sdkKey) {
   const ret = {
@@ -80,7 +81,7 @@ function DiagnosticsManager(
 ) {
   const combinedMode = !!platform.diagnosticUseCombinedEvent;
   const localStorageKey = 'ld:' + environmentId + ':$diagnostics';
-  const diagnosticEventsUrl = config.eventsUrl + '/events/diagnostic/' + environmentId;
+  const diagnosticEventsUrl = appendUrlPath(config.eventsUrl, '/events/diagnostic/' + environmentId);
   const periodicInterval = config.diagnosticRecordingInterval;
   const acc = accumulator;
   const initialEventSamplingInterval = 4; // used only in combined mode - see start()

src/utils.js

@@ -3,6 +3,13 @@ import fastDeepEqual from 'fast-deep-equal';
 
 const userAttrsToStringify = ['key', 'secondary', 'ip', 'country', 'email', 'firstName', 'lastName', 'avatar', 'name'];
 
+export function appendUrlPath(baseUrl, path) {
+  // Ensure that URL concatenation is done correctly regardless of whether the
+  // base URL has a trailing slash or not.
+  const trimBaseUrl = baseUrl.endsWith('/') ? baseUrl.substring(0, baseUrl.length - 1) : baseUrl;
+  return trimBaseUrl + (path.startsWith('/') ? '' : '/') + path;
+}
+
 // See http://ecmanaut.blogspot.com/2006/07/encoding-decoding-utf8-in-javascript.html
 export function btoa(s) {
   const escaped = unescape(encodeURIComponent(s));