流式迭代器

search_stream 方法会返回一个 SearchGoogleAdsStreamResponse 对象的迭代器。

您可以遍历每个回答的 results 字段中的每个 GoogleAdsRow，如以下代码示例所示。 

def main(client: GoogleAdsClient, customer_id: str) -> None:
    ga_service: GoogleAdsServiceClient = client.get_service("GoogleAdsService")

    query: str = """
        SELECT
          campaign.id,
          campaign.name
        FROM campaign
        ORDER BY campaign.id"""

    # Issues a search request using streaming.
    stream: Iterator[SearchGoogleAdsStreamResponse] = ga_service.search_stream(
        customer_id=customer_id, query=query
    )

    for batch in stream:
        rows: List[GoogleAdsRow] = batch.results
        for row in rows:
            print(
                f"Campaign with ID {row.campaign.id} and name "
                f'"{row.campaign.name}" was found.'
            )

每个 GoogleAdsRow 的结构取决于您在 Google Ads 查询语言 (GAQL) 查询中选择的字段。如需详细了解响应结构，请参阅 Google Ads 查询语言。

调用 GoogleAdsService.search_stream 时，系统会返回流式响应迭代器。此迭代器在使用时应与 GoogleAdsService 客户端保持在同一作用域内，以避免出现数据流中断或内存段错误。这是因为，当打开的 GoogleAdsService 对象超出范围时，gRPC Channel 对象会被垃圾回收。如果在对 search_stream 的结果进行迭代时，GoogleAdsService 对象已不在作用域内，则 Channel 对象可能已被销毁，导致迭代器尝试检索下一个值时出现未定义的行为。

以下代码演示了流式迭代器的错误用法：

def stream_response(client, customer_id, query):
    return client.get_service("GoogleAdsService", version="v24").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.

在此代码中，GoogleAdsService 对象是在与迭代器访问范围不同的范围内创建的。因此，在迭代器使用整个响应之前，Channel 对象可能会被销毁。

相反，流式迭代器应与 GoogleAdsService 客户端保持在同一作用域内，只要它正在使用：

def main(client, customer_id):
    ga_service = client.get_service("GoogleAdsService", version="v24")
    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.