public IMultiLevelCursorIterator<TInput, TOutput> Create<TDTO, TInput, TOutput>(
ITwitterPageIterator<ITwitterResult<TDTO>> pageIterator,
Func<TDTO, TInput[]> transform,
Func<TInput[], Task<TOutput[]>> getChildItems,
int maxPageSize)
{
var iterator = new MultiLevelCursorIterator<TInput, TOutput>(
async () =>
{
var userIdsPage = await pageIterator.NextPageAsync().ConfigureAwait(false);
return new CursorPageResult<TInput, string>
{
Items = transform(userIdsPage.Content.Model),
NextCursor = userIdsPage.NextCursor,
IsLastPage = userIdsPage.IsLastPage
};
}, async inputs =>
{
var userIdsToAnalyze = inputs.Take(maxPageSize).ToArray();
var friends = await getChildItems(userIdsToAnalyze).ConfigureAwait(false);
return new MultiLevelPageProcessingResult<TInput, TOutput>
{
Items = friends,
AssociatedParentItems = userIdsToAnalyze,
};
});
return iterator;
}
public async Task <IIteratorPageResult <TOutput, TCursor> > NextPageAsync()
{
var page = await _source.NextPageAsync().ConfigureAwait(false);
var output = _transform(page.Content);
NextCursor = page.NextCursor;
Completed = page.IsLastPage;
return(new IteratorPageResult <TOutput, TCursor>(output, page.NextCursor, page.IsLastPage));
}
public async Task ActAsync()
{
if (_iterator.NextCursor != null)
{
throw new InvalidOperationException("Cannot run with pre executed iterator");
}
while (!_iterator.Completed)
{
var page = await _iterator.NextPageAsync();
_resultPages.Add(page);
}
}