Merchant API code sample to list regions.

### Java

    // Copyright 2024 Google LLC
    //
    // Licensed under the Apache License, Version 2.0 (the "License");
    // you may not use this file except in compliance with the License.
    // You may obtain a copy of the License at
    //
    //     https://www.apache.org/licenses/LICENSE-2.0
    //
    // Unless required by applicable law or agreed to in writing, software
    // distributed under the License is distributed on an "AS IS" BASIS,
    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    // See the License for the specific language governing permissions and
    // limitations under the License.

    package shopping.merchant.samples.accounts.regions.v1;
    import com.google.api.gax.core.FixedCredentialsProvider;
    import com.google.auth.oauth2.GoogleCredentials;
    import com.google.shopping.merchant.accounts.v1.ListRegionsRequest;
    import com.google.shopping.merchant.accounts.v1.Region;
    import com.google.shopping.merchant.accounts.v1.RegionsServiceClient;
    import com.google.shopping.merchant.accounts.v1.RegionsServiceClient.ListRegionsPagedResponse;
    import com.google.shopping.merchant.accounts.v1.RegionsServiceSettings;
    import shopping.merchant.samples.utils.Authenticator;
    import shopping.merchant.samples.utils.Config;

    /** This class demonstrates how to list all the regions for a given Merchant Center account. */
    public class ListRegionsSample {

      private static String getParent(String accountId) {
        return String.format("accounts/%s", accountId);
      }

      public static void listRegions(Config config) throws Exception {

        // Obtains OAuth token based on the user's configuration.
        GoogleCredentials credential = new Authenticator().authenticate();

        // Creates service settings using the credentials retrieved above.
        RegionsServiceSettings regionsServiceSettings =
            RegionsServiceSettings.newBuilder()
                .setCredentialsProvider(FixedCredentialsProvider.create(credential))
                .build();

        // Creates parent to identify the account from which to list all regions.
        String parent = getParent(config.getAccountId().toString());

        // Calls the API and catches and prints any network failures/errors.
        try (RegionsServiceClient regionsServiceClient =
            RegionsServiceClient.create(regionsServiceSettings)) {

          // The parent has the format: accounts/{account}
          ListRegionsRequest request = ListRegionsRequest.newBuilder().setParent(parent).build();

          System.out.println("Sending list regions request:");
          ListRegionsPagedResponse response = regionsServiceClient.listRegions(request);

          int count = 0;

          // Iterates over all rows in all pages and prints the region
          // in each row.
          // `response.iterateAll()` automatically uses the `nextPageToken` and recalls the
          // request to fetch all pages of data.
          for (Region element : response.iterateAll()) {
            System.out.println(element);
            count++;
          }
          System.out.print("The following count of elements were returned: ");
          System.out.println(count);
        } catch (Exception e) {
          System.out.println(e);
        }
      }

      public static void main(String[] args) throws Exception {
        Config config = Config.load();

        listRegions(config);
      }
    }

### PHP

    <?php
    /**
     * Copyright 2025 Google LLC
     *
     * Licensed under the Apache License, Version 2.0 (the "License");
     * you may not use this file except in compliance with the License.
     * You may obtain a copy of the License at
     *
     *     https://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */
    require_once __DIR__ . '/../../../../vendor/autoload.php';
    require_once __DIR__ . '/../../../Authentication/Authentication.php';
    require_once __DIR__ . '/../../../Authentication/Config.php';
    use Google\ApiCore\ApiException;
    use Google\Shopping\Merchant\Accounts\V1\Client\RegionsServiceClient;
    use Google\Shopping\Merchant\Accounts\V1\ListRegionsRequest;

    /**
     * This class demonstrates how to list all the regions for a given Merchant Center account.
     */
    class ListRegionsSample
    {

        private static function getParent(string $accountId): string
        {
            return sprintf("accounts/%s", $accountId);
        }

        public static function listRegionsSample(array $config): void
        {
            // Gets the OAuth credentials to make the request.
            $credentials = Authentication::useServiceAccountOrTokenFile();

            // Creates options config containing credentials for the client to use.
            $options = ['credentials' => $credentials];

            // Creates a client.
            $regionsServiceClient = new RegionsServiceClient($options);

            // Creates parent to identify the account from which to list all regions.
            $parent = self::getParent($config['accountId']);

            try {
                $request = new ListRegionsRequest([
                    'parent' => $parent
                ]);

                print "Sending list regions request:\n";
                $response = $regionsServiceClient->listRegions($request);

                $count = 0;
                foreach ($response->iterateAllElements() as $element) {
                    print $element->getName() . PHP_EOL;
                    $count++;
                }
                print "The following count of elements were returned: ";
                print $count . PHP_EOL;

            } catch (ApiException $e) {
                print $e->getMessage();
            }
        }

        public function callSample(): void
        {
            $config = Config::generateConfig();
            self::listRegionsSample($config);
        }
    }

    $sample = new ListRegionsSample();
    $sample->callSample();

### Python

    # -*- coding: utf-8 -*-
    # Copyright 2024 Google LLC
    #
    # Licensed under the Apache License, Version 2.0 (the "License");
    # you may not use this file except in compliance with the License.
    # You may obtain a copy of the License at
    #
    #     http://www.apache.org/licenses/LICENSE-2.0
    #
    # Unless required by applicable law or agreed to in writing, software
    # distributed under the License is distributed on an "AS IS" BASIS,
    # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    # See the License for the specific language governing permissions and
    # limitations under the License.
    """A module to list all the Regions for a given Merchant Center account."""

    from examples.authentication import configuration
    from examples.authentication import generate_user_credentials
    from google.shopping.merchant_accounts_v1 import ListRegionsRequest
    from google.shopping.merchant_accounts_v1 import RegionsServiceClient

    _ACCOUNT = configuration.Configuration().read_merchant_info()


    def get_parent(account_id):
      return f"accounts/{account_id}"


    def list_regions():
      """Lists all the regions for a given Merchant Center account."""

      # Gets OAuth Credentials.
      credentials = generate_user_credentials.main()

      # Creates a client.
      client = RegionsServiceClient(credentials=credentials)

      # Creates parent to identify the account from which to list all regions.
      parent = get_parent(_ACCOUNT)

      # Creates the request.
      request = ListRegionsRequest(parent=parent)

      # Makes the request and catches and prints any error messages.
      try:
        response = client.list_regions(request=request)
        count = 0
        print("Sending list regions request:")
        for element in response:
          print(element)
          count += 1
        print(f"The following count of elements were returned: {count}")

      except RuntimeError as e:
        print("List region request failed!")
        print(e)


    if __name__ == "__main__":
      list_regions()