Better way to apply token headers.

Author: ehsannas

packages/firestore/src/api/credentials.ts

@@ -68,17 +68,16 @@ export interface Token {
    */
   user?: User;
 
-  /** Extra header values to be passed along with a request */
-  headers: { [header: string]: string };
+  /** Invokes the given callback with the token's key and value. */
+  applyHeaders(callback: (tokenKey: string, tokenValue: string) => void): void;
 }
 
 export class OAuthToken implements Token {
   type = 'OAuth' as TokenType;
-  headers: { [header: string]: string };
-  constructor(value: string, public user: User) {
-    this.headers = {};
-    // Set the headers using Object Literal notation to avoid minification
-    this.headers['Authorization'] = `Bearer ${value}`;
+  constructor(private value: string, public user: User) {}
+
+  applyHeaders(callback: (tokenKey: string, tokenValue: string) => void): void {
+    callback('Authorization', `Bearer ${this.value}`);
   }
 }
 
@@ -403,19 +402,15 @@ export class FirstPartyToken implements Token {
     private iamToken: string | null
   ) {}
 
-  get headers(): { [header: string]: string } {
-    const result: { [header: string]: string } = {
-      'X-Goog-AuthUser': this.sessionIndex
-    };
-    // Use array notation to prevent minification
+  applyHeaders(callback: (tokenKey: string, tokenValue: string) => void): void {
+    callback('X-Goog-AuthUser', this.sessionIndex);
     const authHeader = this.gapi['auth']['getAuthHeaderValueForFirstParty']([]);
     if (authHeader) {
-      result['Authorization'] = authHeader;
+      callback('Authorization', authHeader);
     }
     if (this.iamToken) {
-      result['X-Goog-Iam-Authorization-Token'] = this.iamToken;
+      callback('X-Goog-Iam-Authorization-Token', this.iamToken);
     }
-    return result;
   }
 }
 
@@ -454,13 +449,11 @@ export class FirstPartyAuthCredentialsProvider
 
 export class AppCheckToken implements Token {
   type = 'AppCheck' as TokenType;
-  headers: { [header: string]: string };
+  constructor(private value: string) {}
 
-  constructor(value: string) {
-    this.headers = {};
-    if (value && value.length > 0) {
-      // Set the headers using Object Literal notation to avoid minification
-      this.headers['x-firebase-appcheck'] = value;
+  applyHeaders(callback: (tokenKey: string, tokenValue: string) => void): void {
+    if (this.value && this.value.length > 0) {
+      callback('x-firebase-appcheck', this.value);
     }
   }
 }

packages/firestore/src/platform/node/grpc_connection.ts

@@ -57,16 +57,16 @@ function createMetadata(
     authToken === null || authToken.type === 'OAuth',
     'If provided, token must be OAuth'
   );
-
   const metadata = new Metadata();
-  for (const token of [authToken, appCheckToken]) {
-    if (token) {
-      for (const header in token.headers) {
-        if (token.headers.hasOwnProperty(header)) {
-          metadata.set(header, token.headers[header]);
-        }
-      }
-    }
+  if (authToken) {
+    authToken.applyHeaders((tokenKey, tokenValue) =>
+      metadata.set(tokenKey, tokenValue)
+    );
+  }
+  if (appCheckToken) {
+    appCheckToken.applyHeaders((tokenKey, tokenValue) =>
+      metadata.set(tokenKey, tokenValue)
+    );
   }
   if (appId) {
     metadata.set('X-Firebase-GMPID', appId);

packages/firestore/src/remote/rest_connection.ts

@@ -143,14 +143,16 @@ export abstract class RestConnection implements Connection {
     if (this.databaseInfo.appId) {
       headers['X-Firebase-GMPID'] = this.databaseInfo.appId;
     }
-    for (const token of [authToken, appCheckToken]) {
-      if (token) {
-        for (const header in token.headers) {
-          if (token.headers.hasOwnProperty(header)) {
-            headers[header] = token.headers[header];
-          }
-        }
-      }
+
+    if (authToken) {
+      authToken.applyHeaders(
+        (tokenKey, tokenValue) => (headers[tokenKey] = tokenValue)
+      );
+    }
+    if (appCheckToken) {
+      appCheckToken.applyHeaders(
+        (tokenKey, tokenValue) => (headers[tokenKey] = tokenValue)
+      );
     }
   }
 

packages/firestore/test/unit/remote/rest_connection.test.ts

@@ -17,7 +17,7 @@
 
 import { expect } from 'chai';
 
-import { AppCheckToken, Token } from '../../../src/api/credentials';
+import { AppCheckToken, OAuthToken, Token } from '../../../src/api/credentials';
 import { User } from '../../../src/auth/user';
 import { DatabaseId, DatabaseInfo } from '../../../src/core/database_info';
 import { SDK_VERSION } from '../../../src/core/version';
@@ -87,15 +87,8 @@ describe('RestConnection', () => {
       'RunQuery',
       'projects/testproject/databases/(default)/documents/foo',
       {},
-      {
-        user: User.UNAUTHENTICATED,
-        type: 'OAuth',
-        headers: { 'Authorization': 'Bearer owner' }
-      },
-      {
-        type: 'AppCheck',
-        headers: { 'x-firebase-appcheck': 'some-app-check-token' }
-      }
+      new OAuthToken('owner', User.UNAUTHENTICATED),
+      new AppCheckToken('some-app-check-token')
     );
     expect(connection.lastHeaders).to.deep.equal({
       'Authorization': 'Bearer owner',