Implement oauth2 client

src/google/auth/base.ts

@@ -1,5 +1,5 @@
-import * as google from 'googleapis';
+import * as google from 'googleapis'
 
 export interface AuthClient {
-    getAuth(): google.Auth.GoogleAuth
+    getAuthHeadersClient(): google.Auth.GoogleAuth | google.Auth.OAuth2Client
 }

src/google/auth/index.ts

@@ -1,4 +1,5 @@
 export * from './base'
 export * from './models'
+export * from './oauth2'
 export * from './service_account'
 export * from './models'

src/google/auth/oauth2.ts

@@ -0,0 +1,65 @@
+import * as google from 'googleapis';
+import { authenticate } from '@google-cloud/local-auth'
+
+import * as fs from 'fs';
+import { AuthClient } from './base';
+
+export class Oauth2GoogleAuthClient implements AuthClient {
+    private auth!: google.Auth.OAuth2Client;
+
+    private constructor(auth: google.Auth.OAuth2Client) {
+        this.auth = auth;
+    }
+
+    public static async fromFile(
+        secretFilePath: string,
+        credsFilePath: string,
+        scopes: string[],
+    ): Promise<Oauth2GoogleAuthClient> {
+        const storedClient = await this.loadCredsIfExists(credsFilePath);
+        if (storedClient) {
+            return new Oauth2GoogleAuthClient(storedClient);
+        }
+
+        const newClient = await authenticate({
+            scopes: scopes,
+            keyfilePath: secretFilePath,
+        });
+
+        if (newClient.credentials) {
+            await this.storeCredentials(secretFilePath, credsFilePath, newClient);
+        }
+        return new Oauth2GoogleAuthClient(newClient);
+    }
+
+    private static async loadCredsIfExists(credsFilePath: string): Promise<google.Auth.OAuth2Client | null> {
+        try {
+            const content = await fs.promises.readFile(credsFilePath);
+            const credentials = JSON.parse(content.toString());
+            return google.google.auth.fromJSON(credentials) as google.Auth.OAuth2Client;
+        } catch (err) {
+            return null;
+        }
+    }
+
+    private static async storeCredentials(
+        secretFilePath: string,
+        credsFilePath: string,
+        client: google.Auth.OAuth2Client,
+    ) {
+        const content = await fs.promises.readFile(secretFilePath);
+        const keys = JSON.parse(content.toString());
+        const key = keys.installed || keys.web;
+        const payload = JSON.stringify({
+            type: 'authorized_user',
+            client_id: key.client_id,
+            client_secret: key.client_secret,
+            refresh_token: client.credentials.refresh_token,
+        });
+        await fs.promises.writeFile(credsFilePath, payload);
+    }
+
+    public getAuthHeadersClient(): google.Auth.GoogleAuth | google.Auth.OAuth2Client {
+        return this.auth!;
+    }
+}

src/google/auth/service_account.ts

@@ -25,7 +25,7 @@ export class ServiceAccountGoogleAuthClient implements AuthClient {
         return new ServiceAccountGoogleAuthClient(authClient);
     }
 
-    public getAuth(): google.Auth.GoogleAuth {
+    public getAuthHeadersClient(): google.Auth.GoogleAuth | google.Auth.OAuth2Client {
         return this.auth!;
     }
 }

src/google/sheets/wrapper.ts

@@ -1,6 +1,5 @@
-import { google, sheets_v4 } from 'googleapis';
+import * as google from 'googleapis';
 import axios, { AxiosInstance } from 'axios';
-import { GoogleAuth } from 'google-auth-library';
 
 import { AuthClient } from '../auth/base';
 import {
@@ -20,13 +19,13 @@ import {
 } from './models';
 
 export class Wrapper {
-    private googleAuth: GoogleAuth;
-    private service: sheets_v4.Sheets;
+    private authClient: google.Auth.GoogleAuth | google.Auth.OAuth2Client;
+    private service: google.sheets_v4.Sheets;
     private rawClient: AxiosInstance;
 
     constructor(auth: AuthClient) {
-        this.googleAuth = auth.getAuth();
-        this.service = google.sheets({ version: 'v4', auth: this.googleAuth });
+        this.authClient = auth.getAuthHeadersClient();
+        this.service = google.google.sheets({ version: 'v4', auth: this.authClient });
         this.rawClient = axios.create({ validateStatus: () => true });
     }
 
@@ -284,7 +283,7 @@ export class Wrapper {
         // This ensures the latest access token is used (and refreshed if needed).
         const response = await this.rawClient.get(
             url,
-            { headers: await this.googleAuth.getRequestHeaders() },
+            { headers: await this.authClient.getRequestHeaders() },
         );
         if (response.status !== 200) {
             throw new Error(`Failed to query rows, status: ${response.status}`);

tests/google/sheets/models.test.ts

@@ -73,7 +73,7 @@ describe('RawQueryRowsResult', () => {
             };
 
             const expected: QueryRowsResult = { rows: [] };
-            const mockAuth = { getAuth: jest.fn() };
+            const mockAuth = { getAuthHeadersClient: jest.fn() };
             const wrapper = new Wrapper(mockAuth);
             const result = wrapper['toQueryRowsResult'](rawResult);
             expect(result).toEqual(expected);
@@ -121,7 +121,7 @@ describe('RawQueryRowsResult', () => {
                 ],
             };
 
-            const mockAuth = { getAuth: jest.fn() };
+            const mockAuth = { getAuthHeadersClient: jest.fn() };
             const wrapper = new Wrapper(mockAuth);
             const result = wrapper['toQueryRowsResult'](rawResult);
             expect(result).toEqual(expected);
@@ -147,7 +147,7 @@ describe('RawQueryRowsResult', () => {
                 },
             };
 
-            const mockAuth = { getAuth: jest.fn() };
+            const mockAuth = { getAuthHeadersClient: jest.fn() };
             const wrapper = new Wrapper(mockAuth);
             expect(() => wrapper['toQueryRowsResult'](rawResult)).toThrow('Unsupported cell value type: something');
         });

tests/google/sheets/wrapper.test.ts

@@ -26,7 +26,7 @@ describe('Wrapper', () => {
     let mockSheetsService: jest.Mocked<sheets_v4.Sheets>;
 
     beforeEach(() => {
-        mockAuth = { getAuth: jest.fn() };
+        mockAuth = { getAuthHeadersClient: jest.fn() };
         wrapper = new Wrapper(mockAuth);
         mockSheetsService = wrapper['service'] as unknown as jest.Mocked<sheets_v4.Sheets>;
     });