c# - 有时我向苹果服务器发送 APN 时出现超时异常

Question

我的代码:

var uri = new Uri($"{domain}/3/device/{deviceToken}");

var client = new Http2Client(uri); // using HttpTwo

var headers = new NameValueCollection
{
    {"apns-id", Guid.NewGuid().ToString()},
    {"apns-expiration", "0"},
    {"apns-priority", "10"},
    {"apns-topic", topic},
    {"authorization", $"bearer {jwtToken}"}
};

var body = Encoding.ASCII.GetBytes(JsonConvert.SerializeObject(payload));

var response = await client.Send(uri,HttpMethod.Post, headers, body);

这段代码大部分时间都能给出正确的响应，但偶尔我会收到操作超时异常。

---> System.TimeoutException: The operation has timed out. at HttpTwo.Http2Client.d__19.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at HttpTwo.Http2Client.d__17.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at HttpTwo.Http2Client.d__15.MoveNext()

Answer 1

您可以为您的连接设置 Http2Client.ConnectionSettings.ConnectionTimeout，这样它会更容易预测 )))并且您应该为 apns 连接实现重新连接逻辑。像这样:

int retry = 0;
 while (retry < 1)
 {
     try
    {
        var response = await client.Send(uri,HttpMethod.Post, headers, body);
        break;
    }
    catch (TimeoutException)
    {
        retry++;
    }
}

来自文档:

在多个通知中保持与 APNs 的连接；不要反复打开和关闭连接。 APNs 将快速连接和断开连接视为拒绝服务攻击。除非您知道连接会长时间闲置，否则您应该保持连接打开——例如，如果您每天只向用户发送一次通知，则每天使用一个新连接是可以接受的做法。