NuGet.Services.Metadata.Catalog.CommitCollector.Fetch C# (CSharp) Метод

        protected override async Task<bool> Fetch(CollectorHttpClient client, ReadWriteCursor front, ReadCursor back, CancellationToken cancellationToken)
        {
            JObject root = await client.GetJObjectAsync(Index, cancellationToken);

            IEnumerable<CatalogItem> rootItems = root["items"]
                .Select(item => new CatalogItem(item))
                .Where(item => item.CommitTimeStamp > front.Value)
                .OrderBy(item => item.CommitTimeStamp);

            bool acceptNextBatch = false;

            foreach (CatalogItem rootItem in rootItems)
            {
                JObject page = await client.GetJObjectAsync(rootItem.Uri, cancellationToken);

                JToken context = null;
                page.TryGetValue("@context", out context);
                
                var batches = await CreateBatches(page["items"]
                    .Select(item => new CatalogItem(item))
                    .Where(item => item.CommitTimeStamp > front.Value && item.CommitTimeStamp <= back.Value));

                var orderedBatches = batches
                    .OrderBy(batch => batch.CommitTimeStamp)
                    .ToList();

                var lastBatch = orderedBatches.LastOrDefault();

                foreach (var batch in orderedBatches)
                {
                    acceptNextBatch = await OnProcessBatch(
                        client, 
                        batch.Items.Select(item => item.Value), 
                        context, 
                        batch.CommitTimeStamp, 
                        batch.CommitTimeStamp == lastBatch.CommitTimeStamp, 
                        cancellationToken);

                    front.Value = batch.CommitTimeStamp;
                    await front.Save(cancellationToken);

                    Trace.TraceInformation("CommitCatalog.Fetch front.Save has value: {0}", front);

                    if (!acceptNextBatch)
                    {
                        break;
                    }
                }

                if (!acceptNextBatch)
                {
                    break;
                }
            }

            return acceptNextBatch;
        }