React Native

Refresh Access Token on 401 Unauthorized and Retry (Service Account)

See more Google Cloud Storage Examples

Demonstrates how to handle an expired access token error, refresh the token, and retry the request. (In this case, the request is to download an object from Google Cloud Storage.) React Native

import { AuthGoogle, BinData, FileAccess, Http, Socket, StringBuilder } from '@chilkat/react-native'

async function chilkatExample() {
  let success = false;

  // This example requires the Chilkat API to have been previously unlocked.
  // See Global Unlock Sample for sample code.

  // This example uses a previously obtained access token having permission for the 
  // scope "https://www.googleapis.com/auth/cloud-platform"

  // In this example, Get Google Cloud Storage OAuth2 Access Token, 
  // the service account access token was saved to a text file.  This example fetches the access token from the file..
  const sbToken = new StringBuilder();
  try {
    sbToken.loadFile('qa_data/tokens/googleCloudStorageAccessToken.txt', 'utf-8');
  } catch {
    console.log('Failed to load access token.');
    return;
  }

  const http = new Http();

  http.authToken = sbToken.getAsString();

  // Construct a URL to download an object named "starfish.jpg" from the "chilkat-ocean" bucket.
  http.setUrlVar('bucket_name', 'chilkat-ocean');
  http.setUrlVar('object_name', 'starfish.jpg');
  const url = 'https://www.googleapis.com/storage/v1/b/{$bucket_name}/o/{$object_name}?alt=media';

  // If there is an error response, then we didn't actually download the file data,
  // but instead we downloaded an error response..
  const fileData = new BinData();
  success = true;
  try {
    await http.downloadBdAsync(url, fileData);
  } catch {
    success = false;
  }
  const responseCode = http.lastStatus;
  if ((!success) && (responseCode !== 401)) {
    console.log(http.lastErrorText);
    return;
  }

  if (responseCode === 401) {
    console.log('Received 401 Unauthorized response. Attempting to refresh the access token...');

    // May be that the access token expired.
    // Load our JSON key and request a new access token, then retry the original request.
    const fac = new FileAccess();
    let jsonKey: string;
    try {
      jsonKey = fac.readEntireTextFile('qa_data/googleApi/ChilkatCloud-13a07a2e8b3f.json', 'utf-8');
    } catch {
      console.log(fac.lastErrorText);
      return;
    }

    const gAuth = new AuthGoogle();
    gAuth.jsonKey = jsonKey;
    gAuth.scope = 'https://www.googleapis.com/auth/cloud-platform';
    gAuth.expireNumSeconds = 3600;
    gAuth.subEmailAddress = '';

    const tlsSock = new Socket();
    try {
      await tlsSock.connectAsync('www.googleapis.com', 443, true, 5000);
    } catch {
      console.log(tlsSock.lastErrorText);
      return;
    }

    try {
      await gAuth.obtainAccessTokenAsync(tlsSock);
    } catch {
      console.log(gAuth.lastErrorText);
      return;
    }

    fac.writeEntireTextFile('qa_data/tokens/googleCloudStorageAccessToken.txt', gAuth.accessToken, 'utf-8', false);

    // Retry the original request.
    http.authToken = gAuth.accessToken;
    try {
      await http.downloadBdAsync(url, fileData);
    } catch {
      console.log(http.lastErrorText);
      return;
    }
  }

  if (responseCode !== 200) {
    // Get the error response
    const sbErrorResponse = new StringBuilder();
    sbErrorResponse.appendBd(fileData, 'utf-8', 0, 0);
    console.log(`Error response code = ${responseCode}`);
    console.log('Error:');
    console.log(sbErrorResponse.getAsString());
    return;
  }

  console.log('Success.');

  // Save the downloaded data to a file.
  success = true;
  try {
    fileData.writeFile('qa_output/starfish.jpg');
  } catch {
    success = false;
  }
}