title: Document List API to Drive SDK and Client Login
body: <p>We used to have an application connector implementing the Document List Service v3 to upload documents to users account. Now that the service will be discontinued starting as of next Monday and we need to migrate to the Drive API/SDK we have the problem to migrate our current login schema .. we are unable to use the OAuth 2 protocol and we need to authenticate users with their username/password credentials.</p>
  
  <pre><code>DocumentsService myService = new DocumentsService("xxx");
  myService.setUserCredentials(username, password);
  </code></pre>
  
  <p>The reason is that our application scans and processes documents asynchronously from MFD devices (printers) and all processing/storage job is done in a different moment on processing servers, thus the limitation that the processing service cannot ask any consens to the user.</p>
  
  <p>We do the same for other online cloud storage application (e.g. Dropbox) where they allow special 'OAuth 1' schema on request for such 'enterprise' situations.</p>
  
  <p>How can we do this with the new Drive API/SDK? I couldn't find anything about that in the documentation rather than the service account, also looks like not suitable.</p>