/// <summary>
/// Helper, automates the loading of sources items from DB.
/// </summary>
/// <param name="source"></param>
void LoadSourceItemsFromPersistence(EventSource source)
{
List <EventBase> items =
_persistenceHelper.SelectDynamicType <EventBase>(new MatchExpression("SourceId", source.Id), null);
Dictionary <string, List <EventBase> > itemsByChannel = new Dictionary <string, List <EventBase> >();
foreach (RssNewsEvent item in items)
{
item.Channel = source.GetChannelByName(item.ChannelId, true);
if (itemsByChannel.ContainsKey(item.ChannelId) == false)
{
itemsByChannel.Add(item.ChannelId, new List <EventBase>());
}
itemsByChannel[item.ChannelId].Add(item);
}
foreach (string name in itemsByChannel.Keys)
{
// Handle the relation to persistence.
EventSourceChannel channel = source.GetChannelByName(name, false);
channel.AddItems(itemsByChannel[name]);
}
}
/// <summary>
/// Helper. Not thread safe.
/// </summary>
void AddChannel(string name, string uri)
{
EventSourceChannel channel = new EventSourceChannel(name, true);
channel.Initialize(this);
channel.Address = uri;
base.AddChannel(channel);
}
/// <summary>
/// Intercept call to gaether locally items for filtering.
/// </summary>
protected override void channel_ItemsAddedEvent(EventSource source, EventSourceChannel channel, IEnumerable <EventBase> items)
{
foreach (RssNewsEvent item in items)
{
if ((DateTime.Now - item.DateTime) < TimeSpan.FromDays(7) &&
_latestNewsItemsTitles.ContainsKey(item.Title) == false)
{// Gather items from the last 3 days.
lock (this)
{
_latestNewsItemsTitles.Add(item.Title, item);
}
}
}
base.channel_ItemsAddedEvent(source, channel, items);
}
/// <summary>
/// Result is new items found on page.
/// Page corresponds to a channel.
/// </summary>
/// <param name="uri"></param>
List <EventBase> ProcessPage(EventSourceChannel channel)
{
List <EventBase> result = new List <EventBase>();
HtmlDocument document = GenerateDocument(channel.Address);
if (document == null)
{
return(result);
}
foreach (HtmlNode node in document.DocumentNode.SelectNodes("//a[@class]"))
{
if (node.ParentNode.Name == "p" &&
node.ParentNode.Attributes["class"] != null &&
node.ParentNode.Attributes["class"].Value == "summ")
{
string itemTitle = node.ChildNodes[0].InnerText;
lock (this)
{
if (_latestNewsItemsTitles.ContainsKey(itemTitle))
{// News already listed.
continue;
}
RssNewsEvent item = CreateNewsItem(node, true);
if (item != null)
{
_latestNewsItemsTitles.Add(itemTitle, item);
item.Initialize(channel);
result.Add(item);
}
}
}
}
return(result);
}
