字段掩码

在 Google Ads API 中，更新是使用字段掩码完成的。字段掩码会列出您打算在更新后更改的所有字段，并且系统会忽略未在字段掩码中的任何指定字段，即使发送到服务器也是如此。

FieldMasks 实用程序

建议使用我们的内置字段掩码实用程序 (FieldMasks) 生成字段掩码，该工具可让您根据经过修改的对象生成字段掩码，而不是从头开始构建。

以下是更新广告系列的示例：

my $campaign = Google::Ads::GoogleAds::V16::Resources::Campaign->new({
    resourceName =>
      Google::Ads::GoogleAds::V16::Utils::ResourceNames::campaign(
        $customer_id, $campaign_id
      ),
    status => PAUSED,
    networkSettings =>
      Google::Ads::GoogleAds::V16::Resources::NetworkSettings->new({
        targetSearchNetwork => "false"
      })
    });

my $campaign_operation =
  Google::Ads::GoogleAds::V16::Services::CampaignService::CampaignOperation->new({
    update     => $campaign,
    updateMask => all_set_fields_of($campaign)
  });

此示例首先使用 ResourceNames 实用程序设置资源名称来创建一个 Campaign 对象，以便 API 知道正在更新哪个广告系列。

该示例对广告系列使用 FieldMasks::all_set_fields_of() 方法，以自动生成枚举所有已设置字段的字段掩码。然后，您可以将返回的掩码直接传递给 update 调用。

FieldMasks::all_set_fields_of() 是 FieldMasks::field_mask() 的便捷方法。它会将您传递的对象与同一类的空对象进行比较。因此，在上面的代码中，您也可以使用

field_mask(Google::Ads::GoogleAds::V16::Resources::Campaign->new({}), $campaign)

而不是 all_set_fields_of($campaign)。

手动创建遮罩

如需从头开始创建字段掩码，首先创建一个 Google::Ads::GoogleAds::Common::FieldMask 对象，然后使用要更改的所有字段的名称填充数组引用，最后将数组引用分配给字段掩码的 paths 字段。

my $field_mask = Google::Ads::GoogleAds::Common::FieldMask->new({
    paths => ["status", "name"]
  });

更新对象字段及其子字段

对象字段可以有子字段（例如 MaximizeConversions，它有三个：target_cpa_micros、cpc_bid_ceiling_micros 和 cpc_bid_floor_micros）；也可以根本没有子字段（如 ManualCpm）。

未定义子字段的对象字段

Perl 中的对象字段相当于在 gRPC 上运行的客户端库中的 protobuf MESSAGE。更新未使用任何子字段定义的对象字段时，请使用 FieldMasks 实用程序生成字段掩码（如上所述）。

包含已定义的子字段的对象字段

更新使用子字段定义的对象字段时，如果未明确设置该消息的任何子字段，则必须手动将每个可变的对象子字段添加到 FieldMask，类似于上述从头开始创建字段掩码的示例。

一个常见的示例是，在未针对新出价策略设置任何字段的情况下更新广告系列的出价策略。以下示例演示了如何在不设置任何出价策略子字段的情况下，更新广告系列以使用 MaximizeConversions 出价策略。

在这种情况下，使用 FieldMasks 实用程序的 all_set_fields_of() 和 field_mask() 方法无法实现预期目标。

以下示例会生成包含 maximize_conversions 的字段掩码。但是，为防止意外清除字段并产生 FieldMaskError.FIELD_HAS_SUBFIELDS 错误，Google Ads API 不允许这种行为。

# Creates a campaign with the proper resource name and an empty
# MaximizeConversions field.
my $campaign = Google::Ads::GoogleAds::V16::Resources::Campaign->new({
    resourceName =>
      Google::Ads::GoogleAds::V16::Utils::ResourceNames::campaign(
        $customer_id, $campaign_id
      ),
    maximizeConversions =>
      Google::Ads::GoogleAds::V16::Resources::MaximizeConversions->new()
    });

# Constructs an operation, using the FieldMasks' all_set_fields_of utility to
# derive the update mask. The field mask will include 'maximize_conversions',
# which will produce a FieldMaskError.FIELD_HAS_SUBFIELDS error.
my $campaign_operation =
  Google::Ads::GoogleAds::V16::Services::CampaignService::CampaignOperation->new({
    update     => $campaign,
    updateMask => all_set_fields_of($campaign)
  });

# Sends the operation in a mutate request that will result in a
# FieldMaskError.FIELD_HAS_SUBFIELDS error because empty object fields cannot
# be included in a field mask.
my $response = $api_client->CampaignService()->mutate({
    customerId => $customer_id,
    operations => [$campaign_operation]
  });

以下示例演示了如何在未设置任何子字段的情况下正确更新广告系列，以使用 MaximizeConversions 出价策略。

# Creates a campaign with the proper resource name.
my $campaign = Google::Ads::GoogleAds::V16::Resources::Campaign->new({
    resourceName => Google::Ads::GoogleAds::V16::Utils::ResourceNames::campaign(
      $customer_id, $campaign_id
    )
  });

# Creates a field mask from the existing campaign and adds all of the fields
# on the MaximizeConversions bidding strategy to the field mask. Because these
# fields are included in the field mask but excluded from the campaign object,
# the Google Ads API will set the campaign's bidding strategy to a
# MaximizeConversions object with none of its subfields set.
# Only include 'maximize_conversions.target_cpa_micros' in the field mask
# as it is the only mutable subfield on MaximizeConversions when used as a
# standard bidding strategy.
#
# Learn more about standard and portfolio bidding strategies here:
# https://developers.google.com/google-ads/api/docs/campaigns/bidding/assign-strategies
my $field_mask = all_set_fields_of($campaign);
push @{$field_mask->{paths}}, "maximize_conversions.target_cpa_micros";

# Creates an operation to update the campaign with the specified fields.
my $campaign_operation =
  Google::Ads::GoogleAds::V16::Services::CampaignService::CampaignOperation->new({
    update     => $campaign,
    updateMask => $field_mask
  });

正在清除字段

您可以明确清除字段，方法是将其添加到字段掩码（如上所示），或将字段设置为空值或未定义值。例如，假设您有一个使用 MaximizeConversions 出价策略的广告系列，并且 target_cpa_micros 字段的值设置为大于 0。

# Creates a campaign with the proper resource name and a MaximizeConversions
# object with target_cpa_micros set to 0.
my $campaign =
  Google::Ads::GoogleAds::V16::Resources::Campaign->new({
    resourceName => Google::Ads::GoogleAds::V16::Utils::ResourceNames::campaign(
      $customer_id, $campaign_id
    ),
    maximizeConversions => Google::Ads::GoogleAds::V16::Resources::MaximizeConversions->new({
      targetCpaMicros => 0
    })
  });

# Constructs an operation, using the FieldMasks' all_set_fields_of utility to
# derive the update mask, which will include 'maximize_conversions.target_cpa_micros'.
my $campaign_operation =
  Google::Ads::GoogleAds::V16::Services::CampaignService::CampaignOperation->new({
    update     => $campaign,
    updateMask => all_set_fields_of($campaign)
  });

请注意，具有嵌套子字段的字段只能通过清除每个单独的子字段来清除，如包含已定义子字段的对象字段中所示。