串流疊代器

呼叫 GoogleAdsService.search_stream 時，系統會傳回串流回應疊代器。使用時，此疊代器應與 GoogleAdsService 用戶端位於相同範圍，以免發生中斷的串流或區隔錯誤。這是因為當開放式 GoogleAdsService 物件超出範圍時，gRPC Channel 物件會遭到垃圾收集。如果在 search_stream 結果發生疊代時，GoogleAdsService 物件已不在範圍內，則 Channel 物件可能已遭到銷毀，導致疊代器嘗試擷取下一個值時發生未定義的行為。

以下程式碼示範如何錯誤使用串流疊代器：

def stream_response(client, customer_id, query):
    return client.get_service("GoogleAdsService", version="v19").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 物件是在與存取疊代器的不同範圍內建立。因此，在迭代器使用整個回應之前，Channel 物件可能會遭到銷毀。

相反地，只要串流疊代器仍在使用中，就應與 GoogleAdsService 用戶端保持在相同的範圍內：

def main(client, customer_id):
    ga_service = client.get_service("GoogleAdsService", version="v19")
    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.