串流疊代器

呼叫 GoogleAdsService.search_stream 時，系統會傳回串流回應疊代器。在使用時，這個疊代器應與 GoogleAdsService 用戶端位於相同範圍內，以免發生串流中斷或區隔錯誤。這是因為在開啟的 GoogleAdsService 物件超出範圍時，gRPC Channel 物件會經過垃圾收集。如果在疊代 search_stream 的結果時，GoogleAdsService 物件不再位於範圍內，表示 Channel 物件可能已刪除，導致疊代器嘗試擷取下一個值時發生未定義的行為。

下列程式碼示範串流疊代器的「錯誤」使用方式：

def stream_response(client, customer_id, query):
    return client.get_service("GoogleAdsService", version="v16").search_stream(customer_id, query=query)

def main(client, customer_id):
    query = "SELECT campaign.name FROM campaign LIMIT 10"
    response = stream_response(client, customer_id, query=query)
    # Access the iterator in a different scope from where the service object was created.
    try:
        for batch in response:
            # Iterate through response, expect undefined behavior.

在上述程式碼中，GoogleAdsService 物件建立在疊代器存取位置的不同範圍內。因此，在疊代器耗用整個回應前，系統可能會刪除 Channel 物件。

如果使用串流疊代器，串流疊代器應保持在與 GoogleAdsService 用戶端相同的範圍內：

def main(client, customer_id):
    ga_service = client.get_service("GoogleAdsService", version="v16")
    query = "SELECT campaign.name FROM campaign LIMIT 10"
    response = ga_service.search_stream(customer_id=customer_id, query=query)
    # Access the iterator in the same scope as where the service object was created.
    try:
        for batch in response:
            # Successfully iterate through response.