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字段掩码

在 Google Ads API 中，更新是使用字段掩码来完成的。字段掩码列出您打算随更新而更改的所有字段，以及任何指定的字段字段掩码以外的指定字段将被忽略，即使发送到服务器也是如此。您可以手动创建字段掩码 Google\Protobuf\FieldMask、使用您要更改的所有字段的名称填充一个数组，然后将其分配给字段掩码的路径字段

您还可以使用我们的内置字段掩码实用程序 (FieldMasks)、该选项隐藏了许多特定细节，可让您生成自动遮盖实体的字段。

以下是一个更新广告系列的示例：

    $campaign = new Campaign([
        'resource_name' => ResourceNames::forCampaign($customerId, $campaignId),
        'status' => CampaignStatus::PAUSED
    ]);

    $campaignOperation = new CampaignOperation();
    $campaignOperation->setUpdate($campaign);
    $campaignOperation->setUpdateMask(FieldMasks::allSetFieldsOf($campaign));

此代码首先创建一个 Campaign 对象，然后使用 ResourceNames，以便 API 了解投放的是哪个广告系列已更新。status 也设置为 PAUSED。

然后，该代码会创建一个 CampaignOperation 对象，并设置之前的创建的广告系列之后，它使用 FieldMasks::allSetFieldsOf() 使用所有已更改的字段为广告系列创建字段掩码。最后，将返回的掩码传递给广告系列操作对象。

请注意， FieldMasks::allSetFieldsOf 是一种便捷的方法， FieldMasks::compare()。它会将传递的对象与同一类的空对象进行比较。对于例如，在前面的代码中，您可以使用 FieldMasks::compare(new Campaign(), $campaign) 而不是 allSetFieldsOf()。

更新消息字段及其子字段

MESSAGE 字段可以包含子字段（例如 MaximizeConversions，其中包含三个： target_cpa_micros, cpc_bid_ceiling_micros 和 cpc_bid_floor_micros），也可以不将任何（例如 ManualCpm）。

没有已定义子字段的消息字段

在更新未使用任何子字段定义的 MESSAGE 字段时，请使用用于生成字段掩码的 FieldMasks，如前所述。

包含已定义子字段的消息字段

更新使用不包含子字段的子字段定义的 MESSAGE 字段时因此您必须手动设置将每个可变的 MESSAGE 子字段添加到 FieldMask，类似于上一个从头开始创建字段掩码的示例。

一个常见的例子是，在未设置任何选项的情况下更新广告系列的出价策略新出价策略的字段。以下代码演示了如何更新广告系列以使用 MaximizeConversions出价策略而不必为出价策略设置任何子字段。

在本例中，使用 allSetFieldsOf() 和 compare() 方法的 FieldMasks没有达到预期目标。

以下代码会生成包含 maximize_conversions 的字段掩码。不过，为防止滥用，Google Ads API 不允许意外清除了字段 FieldMaskError.FIELD_HAS_SUBFIELDS 错误。

// Creates a campaign with the proper resource name and an empty
// MaximizeConversions field.
$campaign = new Campaign([
    'resource_name' => ResourceNames::forCampaign($customerId, $campaignId),
    'maximize_conversions' => new MaximizeConversions()
]);

// Constructs an operation, using the FieldMasks' allSetFieldsOf utility to
// derive the update mask. The field mask will include 'maximize_conversions`,
// which will produce a FieldMaskError.FIELD_HAS_SUBFIELDS error.
$campaignOperation = new CampaignOperation();
$campaignOperation->setUpdate($campaign);
$campaignOperation->setUpdateMask(FieldMasks::allSetFieldsOf($campaign));

// Sends the operation in a mutate request that will result in a
// FieldMaskError.FIELD_HAS_SUBFIELDS error because empty MESSAGE fields cannot
// be included in a field mask.
$campaignServiceClient = $googleAdsClient->getCampaignServiceClient();
$response = $campaignServiceClient->mutateCampaigns($customerId, [$campaignOperation]);

以下代码演示了如何正确更新广告系列以使用 MaximizeConversions出价策略，但未设置任何子字段。

// Creates a Campaign object with the proper resource name.
$campaign = new Campaign([
    'resource_name' => ResourceNames::forCampaign($customerId, $campaignId)
]);

// Creates a field mask from the existing campaign and adds all of the mutable
// fields (only one in this case) on the MaximizeConversions bidding strategy to
// the field mask. Because this field is 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 without any of its subfields
// set.
fieldMask = FieldMasks::allSetFieldsOf($campaign);
// 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
$fieldMask->setPaths(array_merge(
    iterator_to_array($fieldMask->getPaths()->getIterator()),
    ['maximize_conversions.target_cpa_micros']
));

// Creates an operation to update the campaign with the specified fields.
$campaignOperation = new CampaignOperation();
$campaignOperation->setUpdate($campaign);
$campaignOperation->setUpdateMask($fieldMask);

清除字段

某些字段是可以明确清除的。与前面的示例类似，您必须明确地将这些字段添加到字段掩码中。例如，假设您有一个广告系列，该广告系列采用的是MaximizeConversions出价策略，并且 “target_cpa_micros”字段的值大于 0。

系统会运行以下代码：不过，maximize_conversions.target_cpa_micros 因此也不会对 target_cpa_micros 字段：

// Creates a campaign with the proper resource name and a MaximizeConversions
// object with target_cpa_micros set to 0.
$campaign = new Campaign([
    'resource_name' => ResourceNames::forCampaign($customerId, $campaignId),
    'maximize_conversions' => new MaximizeConversions(['target_cpa' => 0]),
    'status' => CampaignStatus::PAUSED
]);

// Constructs an operation, using the FieldMasks' allSetFieldsOf utility to
// derive the update mask. However, the field mask will NOT include
// 'maximize_conversions.target_cpa_micros'.
$campaignOperation = new CampaignOperation();
$campaignOperation->setUpdate($campaign);
$campaignOperation->setUpdateMask(FieldMasks::allSetFieldsOf($campaign));

// Sends the operation in a mutate request that will succeed but will NOT update
// the 'target_cpa_micros' field because
// 'maximize_conversions.target_cpa_micros' was not included in the field mask.
$campaignServiceClient = $googleAdsClient->getCampaignServiceClient();
$response = $campaignServiceClient->mutateCampaigns($customerId, [$campaignOperation]);

以下代码演示了如何正确清除 target_cpa_micros 字段（MaximizeConversions 出价策略）。

// Creates a Campaign object with the proper resource name.
$campaign = new Campaign([
    'resource_name' => ResourceNames::forCampaign($customerId, $campaignId)
]);

// Constructs a field mask from the existing campaign and adds the
// 'maximize_conversions.target_cpa_micros' field to the field mask, which will
// clear this field from the bidding strategy without impacting any other fields
// on the bidding strategy.
$fieldMask = FieldMasks::allSetFieldsOf($campaign);
$fieldMask->setPaths(array_merge(
    iterator_to_array($fieldMask->getPaths()->getIterator()),
    ['maximize_conversions.target_cpa_micros']
));

// Creates an operation to update the campaign with the specified field.
$campaignOperation = new CampaignOperation();
$campaignOperation->setUpdate($campaign);
$campaignOperation->setUpdateMask($fieldMask);

请注意，对于已定义的字段在 Google Ads API protocol buffers 中以 optional 的形式指定。但自从使用 target_cpa_micros 不是 optional 字段，则“不正确”代码不会更新清除 target_cpa 字段。