Using OAuth Authentication
Use the OAuth authentication standard to connect to Google Contacts. You can authenticate with a user account or a service account. The component facilitates this as described below.
Using a User Account to Authenticate to Google Contacts
The user account flow requires the authenticating user to interact with Google Contacts via the browser.
Desktop ApplicationsSee Embedded Credentials to connect with the component's embedded credentials and skip creating a custom OAuth app.
Headless MachinesSee Headless Machines to skip creating a custom OAuth app and authenticate an application running on a headless server or another machine where the component is not authorized to open a browser.
Instead of connecting with the component's embedded credentials, you can register an app to obtain the OAuthClientId and OAuthClientSecret.
When to Create a Custom OAuth App
Creating a custom OAuth app is optional as the component is already registered with Google Contacts and you can connect with its embedded credentials. You might want to create a custom OAuth app to change the information displayed when users log into the Google Contacts OAuth endpoint to grant permissions to the component.
Creating a custom OAuth app is optional to authenticate a headless machine; the component is already registered with Google Contacts and you can connect with its embedded credentials. In the headless OAuth flow, users need to authenticate via a browser on another machine. You might want to create a custom OAuth app to change the information displayed when users log into the Google Contacts OAuth endpoint to grant permissions to the component.
Using a Service Account to Connect to Google Contacts
Service accounts have silent authentication, without user authentication in the browser. You can also use a service account to delegate enterprise-wide access scopes to the component.
You need to create an OAuth application in this flow. You can then connect to Google Contacts data that the service account has permission to access. See Custom Credentials for an authentication guide.
Creating a Custom OAuth App
See Creating a Custom OAuth App for a procedure.