这是原本的代码,它已经运行了几周的时间。在我的测试中,100次尝试中有0次失败。
using (var httpClient = new HttpClient())
{
var tasks = new List<Task>();
tasks.Add(httpClient.GetAsync(new Uri("..."))
.ContinueWith(request =>
{
request.Result.Content.ReadAsAsync<IEnumerable<Foo>>()
.ContinueWith(response =>
{
foos = response.Result;
});
}));
tasks.Add(httpClient.GetAsync(new Uri("..."))
.ContinueWith(request =>
{
request.Result.Content.ReadAsAsync<Bar>()
.ContinueWith(response =>
{
bar = response.Result;
});
}));
await Task.WhenAll(tasks);
}
在100次尝试中,这段代码失败了9次,其中一个或两个元组值为null
。
var APIresponses = await HttpClientHelper.GetAsync
<
IEnumerable<Foo>,
Bar
>
(
new Uri("..."),
new Uri("...")
);
foos = APIresponses.Item1;
bar = APIresponses.Item2;
private static Task GetAsync<T>(HttpClient httpClient, Uri URI, Action<Task<T>> continuationAction)
{
return httpClient.GetAsync(URI)
.ContinueWith(request =>
{
request.Result.EnsureSuccessStatusCode();
request.Result.Content.ReadAsAsync<T>()
.ContinueWith(continuationAction);
});
}
public static async Task<Tuple<T1, T2>> GetAsync<T1, T2>(Uri URI1, Uri URI2)
{
T1 item1 = default(T1);
T2 item2 = default(T2);
var httpClient = new HttpClient();
var tasks = new List<Task>()
{
GetAsync<T1>(httpClient, URI1, response =>
{
item1 = response.Result;
}),
GetAsync<T2>(httpClient, URI2, response =>
{
item2 = response.Result;
})
};
await Task.WhenAll(tasks);
return Tuple.Create(item1, item2);
}
将代码修改为以下内容,那么在进行100次尝试时,将会再次失败0次。
await Task.WhenAll(tasks);
System.Diagnostics.Debug.WriteLine("tasks complete");
System.Diagnostics.Debug.WriteLine(item1);
System.Diagnostics.Debug.WriteLine(item2);
return Tuple.Create(item1, item2);
}
我已经看了半个小时了,但我没有看出错误在哪里。有人看到了吗?
HttpClient
不是线程安全的。您尝试过为每个请求使用单独的实例吗? - svickGetAsync
是线程安全的方法之一。我会尝试使用单独的实例来查看发生了什么。 - user247702