GoogleReader Service

gistfile1.cs

public class ReaderService : GoogleService
{
	/// <summary>
	/// Current username.
	/// </summary>
	private string username;

	/// <summary>
	/// Initialize the Google reader.
	/// </summary>
	/// <param name="username"></param>
	/// <param name="password"></param>
	/// <param name="source"></param>
	public ReaderService(string username, string password, string source)
		: base("reader", username, password, source)
	{
		this.username = username;           
	}

	#region Feed
	/// <summary>
	/// Get the contents of a feed.
	/// </summary>
	/// <param name="feedUrl">
	/// Must be exact URL of the feed, ex: http://sandrinodimattia.net/blog/syndication.axd
	/// </param>
	/// <param name="limit"></param>
	/// <returns></returns>
	public IEnumerable<ReaderItem> GetFeedContent(string feedUrl, int limit)
	{
		try
		{
			return GetItemsFromFeed(String.Format("{0}{1}", ReaderUrl.FeedUrl,
			   System.Uri.EscapeDataString(feedUrl)), limit);
		}
		catch (WebException wex)
		{
			HttpWebResponse rsp = wex.Response as HttpWebResponse;
			if (rsp != null && rsp.StatusCode == HttpStatusCode.NotFound)
				throw new FeedNotFoundException(feedUrl);
			else
				throw;
		}
	}
	#endregion
	#region Subscription
	/// <summary>
	/// Subscribe to a feed.
	/// </summary>
	/// <param name="feed"></param>
	public void AddSubscription(string feed)
	{
		PostRequest(ReaderCommand.SubscriptionAdd,
		   new GoogleParameter("quickadd",  feed));
	}

	/// <summary>
	/// Tag a subscription (remove it).
	/// </summary>
	/// <param name="feed"></param>
	/// <param name="folder"></param>
	public void TagSubscription(string feed, string folder)
	{
		PostRequest(ReaderCommand.SubscriptionEdit,
			new GoogleParameter("a", ReaderUrl.LabelPath + folder),
			new GoogleParameter("s", "feed/" + feed),
			new GoogleParameter("ac", "edit"));
	}

	/// <summary>
	/// Get a list of subscriptions.
	/// </summary>
	/// <returns></returns>
	public List<Subscription> GetSubscriptions()
	{
		// Get the XML for subscriptions.
		string xml = session.GetSource(ReaderCommand.SubscriptionList.GetFullUrl());

		// Get a list of subscriptions.
		return XElement.Parse(xml).Elements("list").Elements("object")
			 .Select(o => new Subscription(o)).ToList();
	}
	#endregion
	#region Tags
	/// <summary>
	/// Add tags to an item.
	/// </summary>
	/// <param name="feed"></param>
	/// <param name="folder"></param>
	public void AddTags(ReaderItem item, params string[] tags)
	{
		// Calculate the amount of parameters required.
		int arraySize = tags.Length + item.Tags.Count + 2;

		// Set all parameters.
		GoogleParameter[] parameters = new GoogleParameter[arraySize];
		parameters[0] = new GoogleParameter("s", "feed/" + item.Feed.Url);
		parameters[1] = new GoogleParameter("i", item.Id);

		int nextParam = 2;

		// Add parameters.
		for (int i = 0; i < item.Tags.Count; i++)
			parameters[nextParam++] = new GoogleParameter("a", ReaderUrl.LabelPath + item.Tags[i]);
		for (int i = 0; i < tags.Length; i++)
			parameters[nextParam++] = new GoogleParameter("a", ReaderUrl.LabelPath + tags[i]);

		// Send request.
		PostRequest(ReaderCommand.TagAdd, parameters);
	}

	/// <summary>
	/// Rename a tag.
	/// </summary>
	/// <param name="tag"></param>
	/// <param name="newName"></param>
	public void RenameTag(string tag, string newName)
	{
		PostRequest(ReaderCommand.TagRename,
			new GoogleParameter("s", ReaderUrl.LabelPath + tag),
			new GoogleParameter("t", tag),
			new GoogleParameter("dest", ReaderUrl.LabelPath + newName));
	}

	/// <summary>
	/// Remove tag (for all items).
	/// </summary>
	/// <param name="tag"></param>
	public void RemoveTag(string tag)
	{
		PostRequest(ReaderCommand.TagDelete,
			new GoogleParameter("s", ReaderUrl.LabelPath + tag),
			new GoogleParameter("t", tag));
	}

	/// <summary>
	/// Remove tag from a single item.
	/// </summary>
	/// <param name="item"></param>
	/// <param name="tag"></param>
	public void RemoveTag(ReaderItem item, string tag)
	{
		PostRequest(ReaderCommand.TagEdit,
			new GoogleParameter("r", ReaderUrl.LabelPath + tag),
			new GoogleParameter("s", "feed/" + item.Feed.Url),
			new GoogleParameter("i", item.Id));
	}

	/// <summary>
	/// Get a list of tags.
	/// </summary>
	/// <returns></returns>
	public List<string> GetTags()
	{           
		string xml = session.GetSource(ReaderCommand.TagList.GetFullUrl());

		// Get the list of tags.
		var tagElements = from t in XElement.Parse(xml).Elements("list").Descendants("string")
						  where t.Attribute("name").Value == "id"
						  where t.Value.Contains("/label/")
						  select t;

		// Create a list.
		List<string> tags = new List<string>();
		foreach (XElement element in tagElements)
		{
			string tag = element.Value.Substring(element.Value.LastIndexOf('/') + 1,
				element.Value.Length - element.Value.LastIndexOf('/') - 1);
			tags.Add(tag);
		}

		// Done.
		return tags;
	}

	/// <summary>
	/// Get all items for a tag.
	/// </summary>
	/// <param name="tag"></param>
	/// <param name="limit"></param>
	/// <returns></returns>
	public IEnumerable<ReaderItem> GetTagItems(string tag, int limit)
	{
		return GetItemsFromFeed(String.Format("{0}{1}", ReaderUrl.LabelPath,
			 System.Uri.EscapeDataString(tag)), limit);
	}
	#endregion
	#region State
	/// <summary>
	/// Add state for an item.
	/// </summary>
	/// <param name="item"></param>
	/// <param name="state"></param>
	public void AddState(ReaderItem item, State state)
	{
		PostRequest(ReaderCommand.TagEdit,
			new GoogleParameter("a", ReaderUrl.StatePath + StateFormatter.ToString(state)),
			new GoogleParameter("i", item.Id),
			new GoogleParameter("s", "feed/" + item.Feed.Url));
	}

	/// <summary>
	/// Remove a state from an item.
	/// </summary>
	/// <param name="item"></param>
	/// <param name="state"></param>
	public void RemoveState(ReaderItem item, State state)
	{
		PostRequest(ReaderCommand.TagEdit,
			new GoogleParameter("r", ReaderUrl.StatePath + StateFormatter.ToString(state)),
			new GoogleParameter("i", item.Id),
			new GoogleParameter("s", "feed/" + item.Feed.Url));
	}

	/// <summary>
	/// Get the content of a state.
	/// For example: Get all starred items.
	/// </summary>
	/// <param name="state"></param>
	/// <param name="limit"></param>
	/// <returns></returns>
	public IEnumerable<ReaderItem> GetStateItems(State state, int limit)
	{
		return GetItemsFromFeed(String.Format("{0}{1}", ReaderUrl.StateUrl,
		  StateFormatter.ToString(state)), limit);
	}
	#endregion

	/// <summary>
	/// Post a request using a reader command.
	/// </summary>
	/// <param name="command"></param>
	/// <param name="postFields"></param>
	private void PostRequest(ReaderCommand command, params GoogleParameter[] postFields)
	{
		session.PostRequest(ReaderCommandFormatter.GetFullUrl(command), postFields);
	}

	/// <summary>
	/// Get items from a feed and convert them to a GoogleReaderItem.
	/// </summary>
	/// <param name="url"></param>
	/// <param name="limit"></param>
	/// <returns></returns>
	private IEnumerable<ReaderItem> GetItemsFromFeed(string url, int limit)
	{
		SyndicationFeed feed = session.GetFeed(url, new GoogleParameter("n", limit.ToString()));
		return feed.Items.Select<SyndicationItem, ReaderItem>(o => new ReaderItem(o));
	}
}