由於 Google Ads API 使用 Protobuf 做為預設酬載格式,因此在使用 API 時,請務必瞭解幾個 Protobuf 慣例和類型。
選填欄位
Google Ads API 中的許多欄位都會標示為 optional
。這可讓您區分欄位有空值的情況,以及伺服器未傳回欄位值的情況。這些欄位的運作方式與一般欄位相同,但它們也提供額外的方法來清除欄位,並檢查欄位是否已設定。
舉例來說,Campaign
物件的 Name
欄位會標示為選填。因此,您可以使用下列方法處理這個欄位。
// Get the name.
string name = campaign.Name;
// Set the name.
campaign.Name = name;
// Check if the campaign object has the name field set.
bool hasName = campaign.HasName();
// Clear the name field. Use this method to exclude Name field from
// being sent to the server in a subsequent API call.
campaign.ClearName();
// Set the campaign to empty string value. This value will be
// sent to the server if you use this object in a subsequent API call.
campaign.Name = "";
// This will throw a runtime error. Use ClearName() instead.
campaign.Name = null;
重複類型
欄位陣列在 Google Ads API 中會以只讀 RepeatedField
表示。
舉例來說,如果廣告活動的 url_custom_parameters
欄位是重複欄位,則會在 .NET 用戶端程式庫中以唯讀 RepeatedField<CustomParameter>
表示。
RepeatedField
會實作 IList<T>
介面。
填入 RepeatedField
欄位的方式有兩種。
舊版 C#:使用 AddRange 方法新增值
請參考下方範例。
Campaign campaign = new Campaign()
{
ResourceName = ResourceNames.Campaign(customerId, campaignId),
Status = CampaignStatus.Paused,
};
// Add values to UrlCustomParameters using AddRange method.
campaign.UrlCustomParameters.AddRange(new CustomParameter[]
{
new CustomParameter { Key = "season", Value = "christmas" },
new CustomParameter { Key = "promocode", Value = "NY123" }
});
較新的 C# 版本:使用集合初始化子語法
// Option 1: Initialize the field directly.
Campaign campaign = new Campaign()
{
ResourceName = ResourceNames.Campaign(customerId, campaignId),
Status = CampaignStatus.Paused,
// Directly initialize the field.
UrlCustomParameters =
{
new CustomParameter { Key = "season", Value = "christmas" },
new CustomParameter { Key = "promocode", Value = "NY123" }
}
};
// Option 2: Initialize using an intermediate variable.
CustomParameter[] parameters = new CustomParameter[]
{
new CustomParameter { Key = "season", Value = "christmas" },
new CustomParameter { Key = "promocode", Value = "NY123" }
}
Campaign campaign1 = new Campaign()
{
ResourceName = ResourceNames.Campaign(customerId, campaignId),
Status = CampaignStatus.Paused,
// Initialize from an existing array.
UrlCustomParameters = { parameters }
};
OneOf 類型
Google Ads API 中的部分欄位會標示為 OneOf
欄位,表示該欄位可容納不同類型的值,但在特定時間內只能容納一個值。OneOf 欄位類似於 C 中的聯合型別。
.NET 程式庫會為 OneOf 欄位中可保留的每個值類型提供一個屬性,並更新共用類別欄位的所有屬性,藉此實作 OneOf 欄位。
舉例來說,廣告活動的 campaign_bidding_strategy
會標示為 OneOf 欄位。這個類別的實作方式如下 (為了簡化程式碼,我們會簡化程式碼):
public sealed partial class Campaign : pb::IMessage<Campaign>
{
object campaignBiddingStrategy_ = null;
CampaignBiddingStrategyOneofCase campaignBiddingStrategyCase_;
public ManualCpc ManualCpc
{
get
{
return campaignBiddingStrategyCase_ == CampaignBiddingStrategyOneofCase.ManualCpc ?
(ManualCpc) campaignBiddingStrategy_ : null;
}
set
{
campaignBiddingStrategy_ = value;
campaignBiddingStrategyCase_ = CampaignBiddingStrategyOneofCase.ManualCpc;
}
}
public ManualCpm ManualCpm
{
get
{
return campaignBiddingStrategyCase_ == CampaignBiddingStrategyOneofCase.ManualCpm ?
(ManualCpm) campaignBiddingStrategy_ : null;
}
set
{
campaignBiddingStrategy_ = value;
campaignBiddingStrategyCase_ = CampaignBiddingStrategyOneofCase.ManualCpm;
}
}
public CampaignBiddingStrategyOneofCase CampaignBiddingStrategyCase
{
get { return campaignBiddingStrategyCase_; }
}
}
由於 OneOf 屬性共用儲存空間,因此一個指派作業可以覆寫先前的指派作業,導致細微的錯誤。例如:
Campaign campaign = new Campaign()
{
ManualCpc = new ManualCpc()
{
EnhancedCpcEnabled = true
},
ManualCpm = new ManualCpm()
{
}
};
在這種情況下,campaign.ManualCpc
會變成 null
,因為初始化 campaign.ManualCpm
欄位會覆寫 campaign.ManualCpc
先前的初始化。
轉換為其他格式
您可以輕鬆將 protobuf 物件轉換為 JSON 格式,反之亦然。在建構需要與其他系統連結的系統時,這項功能就很實用,因為這些系統需要以 JSON 或 XML 等文字格式提供資料。
GoogleAdsRow row = new GoogleAdsRow()
{
Campaign = new Campaign()
{
Id = 123,
Name = "Campaign 1",
ResourceName = ResourceNames.Campaign(1234567890, 123)
}
};
// Serialize to JSON and back.
string json = JsonFormatter.Default.Format(row);
row = GoogleAdsRow.Parser.ParseJson(json);
您也可以將物件序列化為位元組,然後再將其反序列化。二進位序列化比 JSON 格式更有效率,可節省記憶體和儲存空間。
GoogleAdsRow row = new GoogleAdsRow()
{
Campaign = new Campaign()
{
Id = 123,
Name = "Campaign 1",
ResourceName = ResourceNames.Campaign(1234567890, 123)
}
};
// Serialize to bytes and back.
byte[] bytes = row.ToByteArray();
row = GoogleAdsRow.Parser.ParseFrom(bytes);