由於 Google Ads API 使用 Protobuf 做為預設酬載格式,因此使用 API 時,請務必瞭解一些 Protobuf 的慣例和類型。
選填欄位
Google Ads API 中的許多欄位都標示為 optional
。這可讓您辨別欄位為空白值,以及伺服器未傳回該欄位值的情況。除了這些欄位的運作方式之外,這些欄位還提供清除欄位及檢查欄位是否已設定的其他方法。
舉例來說,Campaign
物件的 Name
欄位會標示為選用。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
在 Google Ads API 中,欄位陣列會以唯讀 RepeatedField
表示。
舉例來說,某個廣告活動的 url_custom_parameters
欄位是重複欄位,在 .NET 用戶端程式庫中以唯讀 RepeatedField<CustomParameter>
表示。
RepeatedField
會實作 IList<T>
介面。
您可以透過以下兩種方式填入 RepeatedField
欄位。
舊版 C# 版本:使用 AddRange 方法新增值
範例如下所示。
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:使用集合初始化工具語法
// 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 }
};
其中一種類型
Google Ads API 中有些欄位會標示為 OneOf
欄位,這表示該欄位可容納不同的類型,但在特定時間只能有一個值。oneOf 欄位與 C 中的聯集類型類似。
.NET 程式庫實作 OneOf 欄位,是為可在 OneOf 欄位中儲存的每種值提供一個屬性,以及所有更新共用類別欄位的屬性。
舉例來說,廣告活動的 campaign_bidding_strategy
會標示為 OneOf 欄位。此類別實作方式如下 (為求簡潔程式碼):
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 屬性會共用儲存空間,一項指派作業可以覆寫先前的指派設定,進而導致細微錯誤。比如
Campaign campaign = new Campaign()
{
ManualCpc = new ManualCpc()
{
EnhancedCpcEnabled = true
},
ManualCpm = new ManualCpm()
{
}
};
在本例中,campaign.ManualCpc
現在是 null
,因為初始化 campaign.ManualCpm
欄位會覆寫 campaign.ManualCpc
先前的初始化作業。
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。如要建構需要以文字格式 (例如 JSON 或 XML) 格式資料的其他系統建構系統時,這項功能非常實用。
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,然後再將物件序列化。二進位檔序列化比 JSON 格式更記憶體和儲存空間更有效率。
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);