add ability to pass custom http headers (#81)

* add ability to pass custom http headers * Update README.md Fixes: #80 Co-authored-by: Thomas Heartman <thomasheartman+github@gmail.com> Co-authored-by: sighphyre <liquidwicked64@gmail.com> Co-authored-by: Thomas Heartman <thomasheartman+github@gmail.com>
Unleash · Apr 21, 2022 · 99b186a · 99b186a
1 parent dc4833b
commit 99b186a
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Showing 3 changed files with 43 additions and 6 deletions.
diff --git a/README.md b/README.md
@@ -106,6 +106,7 @@ The Unleash SDK takes the following options:
 | bootstrap         | no | `[]` | Allows you to bootstrap the cached feature toggle configuration.                                                                               | 
 | bootstrapOverride | no| `true` | Should the boostrap automatically override cached data in the local-storage. Will only be used if boostrap is not an empty array.     | 
 | headerName        | no| `Authorization` | Provides possiblity to specify custom header that is passed to Unleash / Unleash Proxy with the `clientKey` | 
+| customHeaders     | no| `{}` | Additional headers to use when making HTTP requests to the Unleash proxy. In case of name collisions with the default headers, the `customHeaders` value will be used. | 
 
 
 ### Listen for updates via the EventEmitter

diff --git a/src/index.test.ts b/src/index.test.ts
@@ -1006,6 +1006,30 @@ test('Should call isEnabled event when impressionData is true', (done) => {
     });
 });
 
+test('Should pass custom headers', async() => {
+    fetchMock.mockResponses(
+        [JSON.stringify(data), { status: 200 }],
+        [JSON.stringify(data), { status: 200 }]
+    );
+   const config: IConfig = {
+       url: 'http://localhost/test',
+       clientKey: 'extrakey',
+       appName: 'web',
+       customHeaders: {
+           'customheader1': 'header1val',
+           'customheader2': 'header2val'
+       }
+   };
+   const client = new UnleashClient(config);
+   await client.start();
+
+   jest.advanceTimersByTime(1001);
+
+   expect(fetchMock.mock.calls[0][1].headers.customheader2).toEqual(
+       'header2val'
+   );
+});
+
 test('Should call getVariant event when impressionData is true', (done) => {
     const bootstrap = [
         {

diff --git a/src/index.ts b/src/index.ts
@@ -37,6 +37,7 @@ interface IConfig extends IStaticContext {
     bootstrap?: IToggle[];
     bootstrapOverride?: boolean;
     headerName?: string;
+    customHeaders?: Record<string, string>;
 }
 
 interface IVariant {
@@ -101,6 +102,7 @@ export class UnleashClient extends TinyEmitter {
     private bootstrapOverride: boolean;
     private headerName: string;
     private eventsHandler: EventsHandler;
+    private customHeaders: Record<string, string>;
 
     constructor({
         storageProvider,
@@ -117,6 +119,8 @@ export class UnleashClient extends TinyEmitter {
         bootstrap,
         bootstrapOverride = true,
         headerName = 'Authorization',
+        customHeaders = {},
+
     }: IConfig) {
         super();
         // Validations
@@ -134,6 +138,7 @@ export class UnleashClient extends TinyEmitter {
         this.url = new URL(`${url}`);
         this.clientKey = clientKey;
         this.headerName = headerName;
+        this.customHeaders = customHeaders;
         this.storage = storageProvider || new LocalStorageProvider();
         this.refreshInterval = disableRefresh ? 0 : refreshInterval * 1000;
         this.context = { appName, environment, ...context };
@@ -308,6 +313,18 @@ export class UnleashClient extends TinyEmitter {
         }
     }
 
+    private getHeaders() {
+        const  headers = {[this.headerName]: this.clientKey,
+                            'Accept': 'application/json',
+                            'Content-Type': 'application/json',
+                            'If-None-Match': this.etag
+                        }
+        Object.entries(this.customHeaders).filter(notNullOrUndefined).forEach(([name, value]) => 
+              headers[name] = value);
+        return headers;
+
+    }
+
     private async storeToggles(toggles: IToggle[]): Promise<void> {
         this.toggles = toggles;
         this.emit(EVENTS.UPDATE);
@@ -346,12 +363,7 @@ export class UnleashClient extends TinyEmitter {
                 );
                 const response = await this.fetch(urlWithQuery.toString(), {
                     cache: 'no-cache',
-                    headers: {
-                        [this.headerName]: this.clientKey,
-                        Accept: 'application/json',
-                        'Content-Type': 'application/json',
-                        'If-None-Match': this.etag,
-                    },
+                    headers: this.getHeaders(),
                 });
                 if (response.ok && response.status !== 304) {
                     this.etag = response.headers.get('ETag') || '';