/// <summary>
/// Create a syndication feed from a list of page
/// </summary>
/// <param name="session">a session</param>
/// <param name="pages">the pages</param>
/// <param name="maxBlocks">limits the parsing of each page to the 1st 20 blocks. Max value: 100</param>
/// <param name="stopBeforeFirstSubHeader">when true, stop parsing a page when a line containing a sub_header is found</param>
/// <param name="cancel"></param>
/// <returns>A SyndicationFeed containing one SyndicationItem per page</returns>
/// <remarks>
/// The created feed has no title/description
/// </remarks>
public static async Task<SyndicationFeed> GetSyndicationFeed(this NotionSession session, IEnumerable<Guid> pages, int maxBlocks = 20, bool stopBeforeFirstSubHeader = true, CancellationToken cancel = default)
{
//notion's limitation
if (maxBlocks > 100)
throw new ArgumentOutOfRangeException(nameof(maxBlocks));
var feedItems = new List<SyndicationItem>();
foreach (var pageId in pages)
{
//get blocks and extract an html content
var chunks = await session.LoadPageChunk(pageId, 0, maxBlocks, cancel);
var pageBlock = chunks.RecordMap.Block[pageId];
//collection_view_page not supported
if (pageBlock.Permissions?.Any(p => p.Role == Permission.RoleReader && p.Type == Permission.TypePublic) == true
&& pageBlock.Type == "page")
{
//var content = chunks.RecordMap.GetHtmlAbstract(pageId);
var content = chunks.RecordMap.GetHtml(pageId, throwIfBlockMissing: false, stopBeforeFirstSubHeader: stopBeforeFirstSubHeader, throwIfCantDecodeTextData: false);
var pageUri = NotionUtils.GetPageUri(pageId, pageBlock.Title);
var item = new SyndicationItem(pageBlock.Title, content, pageUri)
{
Id = pageId.ToString("N"),
BaseUri = pageUri,
Summary = new TextSyndicationContent(content),
PublishDate = pageBlock.CreatedTime.EpochToDateTimeOffset(),
LastUpdatedTime = pageBlock.LastEditedTime.EpochToDateTimeOffset(),
};
if (!String.IsNullOrWhiteSpace(pageBlock.Format?.PageIcon))
{
if(Uri.TryCreate(pageBlock.Format.PageIcon, UriKind.Absolute, out _))
item.AttributeExtensions.Add(new XmlQualifiedName("iconUrl"), pageBlock.Format.PageIcon);
else
item.AttributeExtensions.Add(new XmlQualifiedName("iconString"), pageBlock.Format.PageIcon);
}
feedItems.Add(item);
}
}
var feed = new SyndicationFeed(feedItems)
{
LastUpdatedTime = feedItems.DefaultIfEmpty().Max(item => item?.LastUpdatedTime ?? DateTimeOffset.MinValue),
//Copyright =
};
return feed;
}