feat: streaming poc

examples/variant.js

@@ -1,11 +1,12 @@
-const { initialize, getVariant } = require('../lib');
+const { initialize, isEnabled } = require('../lib');
 
 const client = initialize({
   appName: 'my-application',
-  url: 'https://unleash.herokuapp.com/api/',
+  url: 'http://localhost:4242/api/',
   customHeaders: {
-    Authorization: '3bd74da5b341d868443134377ba5d802ea1e6fa2d2a948276ade1f092bec8d92',
+    Authorization: '*:development.35a4fe08c112c8d98cc7a21bdf4d077796920c5e86b0f98eed467b23',
   },
+  streaming: true,
 });
 
 client.on('error', console.error);
@@ -14,5 +15,5 @@ client.on('warn', console.log);
 console.log('Fetching toggles from: http://unleash.herokuapp.com');
 
 setInterval(() => {
-  console.log('Variant config', getVariant('Test.variants', { userId: `${Math.random()}` }));
+  console.log('Enabled:', isEnabled('sadfsdaf', { userId: `${Math.random()}` }));
 }, 1000);

package.json

@@ -30,6 +30,7 @@
   },
   "homepage": "https://github.com/Unleash/unleash-client-node",
   "dependencies": {
+    "eventsource": "2.0.2",
     "http-proxy-agent": "^7.0.2",
     "https-proxy-agent": "^7.0.5",
     "ip-address": "^9.0.5",
@@ -50,6 +51,7 @@
     "@ava/typescript": "^4.0.0",
     "@tsconfig/node12": "^12.0.0",
     "@types/express": "^4.17.17",
+    "@types/eventsource": "^1.1.15",
     "@types/jsbn": "^1.2.33",
     "@types/make-fetch-happen": "^10.0.4",
     "@types/murmurhash3js": "^3.0.3",

src/repository/index.ts

@@ -2,7 +2,7 @@ import { EventEmitter } from 'events';
 import { ClientFeaturesResponse, EnhancedFeatureInterface, FeatureInterface } from '../feature';
 import { get } from '../request';
 import { CustomHeaders, CustomHeadersFunction } from '../headers';
-import getUrl from '../url-utils';
+import getUrl, { resolveUrl } from '../url-utils';
 import { HttpOptions } from '../http-options';
 import { TagFilter } from '../tags';
 import { BootstrapProvider } from './bootstrap-provider';
@@ -13,6 +13,7 @@ import {
   Segment,
   StrategyTransportInterface,
 } from '../strategy/strategy';
+const EventSource = require('eventsource');
 
 export const SUPPORTED_SPEC_VERSION = '4.3.0';
 
@@ -39,6 +40,7 @@ export interface RepositoryOptions {
   bootstrapProvider: BootstrapProvider;
   bootstrapOverride?: boolean;
   storageProvider: StorageProvider<ClientFeaturesResponse>;
+  streaming?: boolean;
 }
 
 interface FeatureToggleData {
@@ -90,6 +92,10 @@ export default class Repository extends EventEmitter implements EventEmitter {
 
   private segments: Map<number, Segment>;
 
+  private streaming: boolean = false;
+
+  private eventSource: EventSource | undefined;
+
   constructor({
     url,
     appName,
@@ -105,6 +111,7 @@ export default class Repository extends EventEmitter implements EventEmitter {
     bootstrapProvider,
     bootstrapOverride = true,
     storageProvider,
+    streaming = false,
   }: RepositoryOptions) {
     super();
     this.url = url;
@@ -122,10 +129,23 @@ export default class Repository extends EventEmitter implements EventEmitter {
     this.bootstrapOverride = bootstrapOverride;
     this.storageProvider = storageProvider;
     this.segments = new Map();
+    this.streaming = streaming;
+    if (this.streaming) {
+      this.eventSource = new EventSource(resolveUrl(this.url, './client/streaming'), {
+        headers: this.headers,
+      } as any);
+      this.eventSource?.addEventListener('message', (event) => {
+        console.log('ES event', event);
+        this.fetch();
+      });
+      this.eventSource?.addEventListener('error', (error) => {
+        console.log('ES error', error);
+      });
+    }
   }
 
   timedFetch(interval: number) {
-    if (interval > 0) {
+    if (interval > 0 && !this.streaming) {
       this.timer = setTimeout(() => this.fetch(), interval);
       if (process.env.NODE_ENV !== 'test' && typeof this.timer.unref === 'function') {
         this.timer.unref();

src/unleash-config.ts

@@ -32,4 +32,5 @@ export interface UnleashConfig {
   storageProvider?: StorageProvider<ClientFeaturesResponse>;
   disableAutoStart?: boolean;
   skipInstanceCountWarning?: boolean;
+  streaming?: boolean;
 }

src/unleash.ts

@@ -73,6 +73,7 @@ export class Unleash extends EventEmitter {
     storageProvider,
     disableAutoStart = false,
     skipInstanceCountWarning = false,
+    streaming = false,
   }: UnleashConfig) {
     super();
 
@@ -123,6 +124,7 @@ export class Unleash extends EventEmitter {
         tags,
         bootstrapProvider,
         bootstrapOverride,
+        streaming,
         storageProvider: storageProvider || new FileStorageProvider(backupPath),
       });
 

yarn.lock

@@ -635,6 +635,11 @@
   dependencies:
     "@types/node" "*"
 
+"@types/eventsource@^1.1.15":
+  version "1.1.15"
+  resolved "https://registry.yarnpkg.com/@types/eventsource/-/eventsource-1.1.15.tgz#949383d3482e20557cbecbf3b038368d94b6be27"
+  integrity sha512-XQmGcbnxUNa06HR3VBVkc9+A2Vpi9ZyLJcdS5dwaQQ/4ZMWFO+5c90FnMUpbtMZwB/FChoYHwuVg8TvkECacTA==
+
 "@types/express-serve-static-core@^4.17.33":
   version "4.17.41"
   resolved "https://registry.yarnpkg.com/@types/express-serve-static-core/-/express-serve-static-core-4.17.41.tgz#5077defa630c2e8d28aa9ffc2c01c157c305bef6"
@@ -2178,6 +2183,11 @@ eventemitter3@^5.0.1:
   resolved "https://registry.yarnpkg.com/eventemitter3/-/eventemitter3-5.0.1.tgz#53f5ffd0a492ac800721bb42c66b841de96423c4"
   integrity sha512-GWkBvjiSZK87ELrYOSESUYeVIc9mvLLf/nXalMOS5dYrgZq9o5OVkbZAVM06CVxYsCwH9BDZFPlQTlPA1j4ahA==
 
+[email protected]:
+  version "2.0.2"
+  resolved "https://registry.yarnpkg.com/eventsource/-/eventsource-2.0.2.tgz#76dfcc02930fb2ff339520b6d290da573a9e8508"
+  integrity sha512-IzUmBGPR3+oUG9dUeXynyNmf91/3zUSJg1lCktzKw47OXuhco54U3r9B7O4XX+Rb1Itm9OZ2b0RkTs10bICOxA==
+
 [email protected], execa@^7.1.1:
   version "7.2.0"
   resolved "https://registry.yarnpkg.com/execa/-/execa-7.2.0.tgz#657e75ba984f42a70f38928cedc87d6f2d4fe4e9"