private async void Run(HttpClient client)
{
var hadFailed = false;
for (; ;)
{
Item item;
lock (_Items)
{
for (; ;)
{
if (_Items.Count == 0)
{
return;
}
item = _Items[0];
if (item.Retry <= 0 || item.CompletionSource.Task.IsCompleted)
{
_Items.RemoveAt(0);
}
else
{
break;
}
}
}
try
{
var wait = _LastRequest.AddMilliseconds(_Interval) - DateTime.Now;
if (wait > TimeSpan.Zero)
{
await Task.Delay(wait);
}
var url = new SignedRequestHelper(AccessKeyId, SecretKey, "webservices." + item.Destination).Sign(new Dictionary <string, string>()
{
["Service"] = "AWSECommerceService",
["Operation"] = "ItemLookup",
["AWSAccessKeyId"] = AccessKeyId,
["AssociateTag"] = AssociateTag,
["ItemId"] = item.Asin,
["IdType"] = "ASIN",
["ResponseGroup"] = "Images,ItemAttributes,EditorialReview",
});
var res = (await client.FollowRedirectAsync(url.ToUri()).ConfigureAwait(false)).Message;
_LastRequest = DateTime.Now;
if (res.StatusCode == HttpStatusCode.ServiceUnavailable)
{
if (hadFailed)
{
_Interval = Math.Min(1280, _Interval << 1);
}
else
{
hadFailed = true;
}
continue;
}
hadFailed = false;
res.EnsureSuccessStatusCode();
var s = await res.Content.ReadAsStringAsync().ConfigureAwait(false);
item.CompletionSource.TrySetResult(ParseResponse(s, item));
}
catch (Exception ex)
{
lock (_Items)
{
if (--item.Retry > 0)
{
continue;
}
else
{
_Items.Remove(item);
}
}
item.CompletionSource.TrySetException(ex);
}
}
}