private async Task <IEnumerable <PackageInfo> > FindPackagesByIdAsyncCore(string id, CancellationToken cancellationToken)
{
for (var retry = 0; retry != 3; ++retry)
{
var uri = _baseUri + "FindPackagesById()?id='" + id + "'";
try
{
var results = new List <PackageInfo>();
var page = 1;
while (true)
{
// TODO: Pages for a package Id are cached separately.
// So we will get inaccurate data when a page shrinks.
// However, (1) In most cases the pages grow rather than shrink;
// (2) cache for pages is valid for only 30 min.
// So we decide to leave current logic and observe.
using (var data = await _httpSource.GetAsync(
uri,
new[] { new MediaTypeWithQualityHeaderValue("application/atom+xml"), new MediaTypeWithQualityHeaderValue("application/xml") },
$"list_{id}_page{page}",
CreateCacheContext(retry),
Logger,
ignoreNotFounds: false,
ensureValidContents: stream => HttpStreamValidation.ValidateXml(uri, stream),
cancellationToken: cancellationToken))
{
if (data.Status == HttpSourceResultStatus.NoContent)
{
// Team city returns 204 when no versions of the package exist
// This should result in an empty list and we should not try to
// read the stream as xml.
break;
}
var doc = V2FeedParser.LoadXml(data.Stream);
var result = doc.Root
.Elements(_xnameEntry)
.Select(x => BuildModel(id, x))
.Where(x => x != null);
results.AddRange(result);
// Find the next url for continuation
var nextUri = V2FeedParser.GetNextUrl(doc);
// Stop if there's nothing else to GET
if (string.IsNullOrEmpty(nextUri))
{
break;
}
uri = nextUri;
page++;
}
}
return(results);
}
catch (Exception ex) when(retry < 2)
{
string message = string.Format(CultureInfo.CurrentCulture, Strings.Log_RetryingFindPackagesById, nameof(FindPackagesByIdAsyncCore), uri)
+ Environment.NewLine
+ ExceptionUtilities.DisplayMessage(ex);
Logger.LogMinimal(message);
}
catch (Exception ex) when(retry == 2)
{
// Fail silently by returning empty result list
var message = string.Format(CultureInfo.CurrentCulture, Strings.Log_FailedToRetrievePackage, uri);
Logger.LogError(message + Environment.NewLine + ex.Message);
throw new FatalProtocolException(message, ex);
}
}
return(null);
}