Integrating Google API with Salesforce

This blog will give step by step process of getting refresh token and access token from Google API. This access token and refresh token can be used to call any Google REST API.

1. Create user in Google Console
2. Create Apex/Lightning component for authorization

Create user in Google Console

1. 1. 1. Create user in Google cloud at https://console.developers.google.com . We can also use any existing gmail user.
      2. Create project in Google Console
      3. Once project is created, go to API library at https://console.developers.google.com/apis/library?project=stellar-day-269401. Select any google API which need to be integrated.
      4. Select API and enable it for use.
      5. Create Credential for API to be used. This credential will be used in Apex. Credential will be created from https://console.developers.google.com/apis/credentials/wizard?project=stellar-day-269401 after selection of project.
      6. Authorize domain in OAuth Consent Screen. Use Lightning url of your org without https. You can also use lightning community url here.
      7. We need to set redirect url which will be lighting component url for authenticating and getting access token.
         
      8. Add Google API https://www.googleapis.com in Remote Site setting.

Create Apex/Lightning component for authorization

1. Apex:

Now we have setup all pre-requisite in Google console. Let us create Lightning component to be used for authentication.

Below code is used to get Google Authentication screen. Use any gmail account for this.

public static String createAuthURL() {
        String key = EncodingUtil.urlEncode(key,'UTF-8');
        String uri = EncodingUtil.urlEncode(redirect_uri,'UTF-8');
        String authuri = '';
        authuri = authUrl+'?'+
            'client_id='+key+
            '&response_type=code'+
            '&scope='+scope+
            '&redirect_uri='+uri+
            '&access_type=offline';
        return authuri;
    }

getAccessToken is used to get access token and refresh token from Google for specific API.

2. Create custom metadata to store access token

Create custom metadata type to store access token for subsequent use. You can use custom setting, platform caching or custom object based on use case. For this blog, i have used custom metadata.

Create Custom metadata and add filed AccessToken in that to store value.

3. Lightning Component:

We have to create any page where we can redirect user after authentication. We can create Lightning component tab or Lighting  community page for this.

This lightning component will show google authentication screen and get access token on button click.

We can use this component for all Google API authentication with salesforce. Only change scope and redirect url in GoogleAuthService.