Overview of web apps

The Google Picker API is a JavaScript API that you can use in your web apps to let users select or upload Google Drive files. Users can grant permission to your apps to access their Drive data, providing a secure and authorized way to interact with their files.

The Google Picker acts as a "File Open" dialog for information stored on Drive and has several features:

• A similar look and feel to the Google Drive UI.
• Several views showing previews and thumbnail images of Drive files.
• An inline, modal window, so users never leave the main app.

Note that the Google Picker doesn't allow users to organize, move, or copy files from one folder to another. To manage files, you must use either the Google Drive API or the Drive UI.

Prerequisites

Apps using the Google Picker must abide by all existing Terms of Service. Most importantly, you must correctly identify yourself in your requests.

You must also have a Google Cloud project.

Set up your environment

To start using the Google Picker API, you must set up your environment.

Enable the API

Before using Google APIs, you need to turn them on in a Google Cloud project. You can turn on one or more APIs in a single Google Cloud project.

• In the Google Cloud console, enable the Google Picker API.

  Enable the API

Create an API key

An API key is a long string containing upper and lower case letters, numbers, underscores, and hyphens, such as AIzaSyDaGmWKa4JsXZ-HjGw7ISLn_3namBGewQe. This authentication method is used to anonymously access publicly available data, such as Google Workspace files shared using the "Anyone on the Internet with this link" sharing setting. For more details, see Manage API keys.

To create an API key:

1. In the Google Cloud console, go to Menu > APIs & Services > Credentials.

   Go to Credentials

2. Click Create credentials > API key.
3. Your new API key is displayed.
   • Click Copy to copy your API key for use in your app's code. The API key can also be found in the "API Keys" section of your project's credentials.
   • To prevent unauthorized use, we recommend restricting where and for which APIs the API key can be used. For more details, see Add API restrictions.

Authorize credentials for a web app

To authenticate end users and access user data in your app, you need to create one or more OAuth 2.0 Client IDs. A client ID is used to identify a single app to Google's OAuth servers. If your app runs on multiple platforms, you must create a separate client ID for each platform.

In the Google Cloud console, go to Menu > Google Auth platform > Clients.

Go to Clients

Click Create Client.

Click Application type > Web application.

In the Name field, type a name for the credential. This name is only shown in the Google Cloud console.

Add authorized URIs related to your app:

• Client-side apps (JavaScript)–Under Authorized JavaScript origins, click Add URI. Then, enter a URI to use for browser requests. This identifies the domains from which your application can send API requests to the OAuth 2.0 server.
• Server-side apps (Java, Python, and more)–Under Authorized redirect URIs, click Add URI. Then, enter an endpoint URI to which the OAuth 2.0 server can send responses.

Click Create.

The newly created credential appears under OAuth 2.0 Client IDs.

Note the Client ID. Client secrets aren't used for Web applications.

Important: Your app must send an OAuth 2.0 access token with views that access private user data when creating a Picker object. To request an access token, see Using OAuth 2.0 to Access Google APIs.

Manage the Google Picker

The remainder of this guide covers how to load and display the Google Picker from a web app, as well as implement the callback. To view the full example, see Code sample for web apps.

Note: The @googleworkspace/drive-picker-element web component is a streamlined way to integrate the Google Picker into your web app.

Load the Google Picker library

To load the Google Picker library, call gapi.load with the library name and a callback function to invoke after a successful load:

    <script>
      let tokenClient;
      let accessToken = null;
      let pickerInited = false;
      let gisInited = false;

      // Use the API Loader script to load google.picker.
      function onApiLoad() {
        gapi.load('picker', onPickerApiLoad);
      }

      function onPickerApiLoad() {
        pickerInited = true;
      }

      function gisLoaded() {
        // Replace with your client ID and required scopes.
        tokenClient = google.accounts.oauth2.initTokenClient({
          client_id: 'CLIENT_ID',
          scope: 'SCOPES',
          callback: '', // defined later
        });
        gisInited = true;
    }
    </script>
    <!-- Load the Google API Loader script. -->
    <script async defer src="https://apis.google.com/js/api.js" onload="onApiLoad()"></script>
    <script async defer src="https://accounts.google.com/gsi/client" onload="gisLoaded()"></script>

Replace the following:

• CLIENT_ID: Your web app's client ID.
• SCOPES: One or more OAuth 2.0 scopes that you need to request to access Google APIs, depending on the level of access you need. For more information, see OAuth 2.0 Scopes for Google APIs.

The google.accounts.oauth2 JavaScript library helps you prompt for user consent and obtain an access token to work with user data. The initTokenClient method initializes a new token client with your web app's client ID. For more information, see Using the token model.

The onApiLoad function loads the Google Picker libraries. The onPickerApiLoad callback function is called after the Google Picker library successfully loads.

Note: If you're using TypeScript, you can install @types/google.picker to use window.google.picker. To report an issue with these types, open a support ticket.

Display the Google Picker

The createPicker function makes sure the Google Picker API finishes loading and that an OAuth 2.0 token is created. Use the PickerBuilder.setAppId method to set the Drive App ID using the Cloud project number to allow the app to access the user's files. This function then creates an instance of the Google Picker and displays it:

    // Create and render a Google Picker object for selecting from Drive.
    function createPicker() {
      const showPicker = () => {
        // Replace with your API key and App ID.
        const picker = new google.picker.PickerBuilder()
            .addView(google.picker.ViewId.DOCS)
            .setOAuthToken(accessToken)
            .setDeveloperKey('API_KEY')
            .setCallback(pickerCallback)
            .setAppId('APP_ID')
            .build();
        picker.setVisible(true);
      }

      // Request an access token.
      tokenClient.callback = async (response) => {
        if (response.error !== undefined) {
          throw (response);
        }
        accessToken = response.access_token;
        showPicker();
      };

      if (accessToken === null) {
        // Prompt the user to select a Google Account and ask for consent to share their data
        // when establishing a new session.
        tokenClient.requestAccessToken({prompt: 'consent'});
      } else {
        // Skip display of account chooser and consent dialog for an existing session.
        tokenClient.requestAccessToken({prompt: ''});
      }
    }

Replace the following:

• API_KEY: Your API key.
• APP_ID: Your Cloud project number.

To create a Google Picker instance, you must create a Picker object using the PickerBuilder. The PickerBuilder takes a View, an OAuth 2.0 token, a developer key, and a callback function to call upon success (pickerCallback).

The Picker object renders one View at a time. Specify at least one view, either by ViewId (google.picker.ViewId.*) or by creating an instance of a DocsView for additional control over how the view is rendered.

If more than one view is added to the Google Picker, users can switch from one view to another by clicking a tab on the left. Tabs can be logically grouped with ViewGroup objects.

For a list of valid views, see ViewId in the Google Picker reference. To obtain the token for any of these views, use the https://www.googleapis.com/auth/drive.file scope.

Implement the Google Picker callback

A Google Picker callback can be used to react to user interactions in the Google Picker, such as selecting a file or pressing Cancel. The ResponseObject interface conveys information about the user's selections.

    // A callback implementation.
    function pickerCallback(data) {
      let url = 'nothing';
      if (data[google.picker.Response.ACTION] == google.picker.Action.PICKED) {
        const doc = data[google.picker.Response.DOCUMENTS][0];
        url = doc[google.picker.Document.URL];
      }
      const message = `You picked: ${url}`;
      document.getElementById('result').textContent = message;
    }

The callback receives a JSON-encoded data object. This object contains an Action the user performs with the Google Picker (google.picker.Response.ACTION). If the user selects an item, the google.picker.Response.DOCUMENTS array is also populated. In this example, the google.picker.Document.URL is shown on the main page. For details on data fields, see the ResponseObject interface.

Filter specific file types

Use a ViewGroup as a way to filter specific items. The following code sample shows how the "Drive" subview shows only documents and presentations.

    const picker = new google.picker.PickerBuilder()
        .addViewGroup(
          new google.picker.ViewGroup(google.picker.ViewId.DOCS)
              .addView(google.picker.ViewId.DOCUMENTS)
              .addView(google.picker.ViewId.PRESENTATIONS))
        .setOAuthToken(oauthToken)
        .setDeveloperKey(developerKey)
        .setAppId(cloudProjectNumber)
        .setCallback(pickerCallback)
        .build();

For a list of valid view types, see ViewId.

Tune the Google Picker's appearance

You can use the Feature object to turn on or off features for various views. To fine-tune the appearance of the Google Picker window, use the PickerBuilder.enableFeature or PickerBuilder.disableFeature method. For example, if you only have a single view, you might want to hide the navigation pane (Feature.NAV_HIDDEN) to give users more space to see items.

The following code sample shows an example of a spreadsheet's search picker using this feature:

    const picker = new google.picker.PickerBuilder()
        .addView(google.picker.ViewId.SPREADSHEETS)
        .enableFeature(google.picker.Feature.NAV_HIDDEN)
        .setDeveloperKey(developerKey)
        .setCallback(pickerCallback)
        .build();

Note: If you're using a scope other than https://www.googleapis.com/auth/drive or https://www.googleapis.com/auth/drive.readonly it's recommended to use PickerBuilder.setMode(DocsViewMode.LIST) as the user hasn't granted access to thumbnails.