The other day I was working on a application at work that needed to use the twitter search api. I Figured I might just as well build a small wrapper for the api as I will probably use it in other applications as well. I decided to make a fluent interface, as I think that is the most readable way of cunstructing a query like the one I need for the api.

I started by creating a model of two classes. One class to represent a "tweet" and one to represent a author. They look like this:

public class Tweet
{
    public virtual string Id { get; set; }
    public virtual DateTime Published { get; set; }
    public virtual string Link { get; set; }
    public virtual string Title { get; set; }
    public virtual string ImageUrl { get; set; }
    public virtual Author Author { get; set; }
}

public class Author
{
    public virtual string Name { get; set; }
    public virtual string Uri { get; set; }
}

I the devided the search options I needed in different logical groups. Here is, for example, the user part of the query:

public interface IPersonQuery : ISubQuery
{
    IPersonQuery From(string name);
    IPersonQuery To(string name);
    IPersonQuery Referencing(string name);
}

Then I have a "main class" that handels the query. This class looks like this:

public class TwitterQuery : IQuery
{
    private readonly StringBuilder _querySb = new StringBuilder();

    internal TwitterQuery()
    {
        Users = new PersonQuery(this);
        Words = new WordQuery(this);
        Paging = new PagingQuery(this);
        Places = new PlacesQuery(this);
        Date = new DateQuery(this);
    }

    internal StringBuilder QuerySb
    {
        get { return _querySb; }
    }

    public static IQuery BuildQuery()
    {
        return new TwitterQuery();
    }

    public virtual IPersonQuery Users { get; private set; }
    public virtual IWordQuery Words { get; private set; }
    public virtual IPagingQuery Paging { get; private set; }
    public virtual IPlacesQuery Places { get; private set; }
    public virtual IDateQuery Date { get; private set; }

    public virtual IEnumerable<Tweet> ExecuteQuery()
    {
        return new SearchEngine(QuerySb.ToString()).RunQuery();
    }
}

I use this class to execute the query:

internal class SearchEngine
{
    private readonly string _searchString;
    private const string UrlTemplate = "http://search.twitter.com/search.atom?q={0}";
    private static readonly XNamespace AtomNS = "http://www.w3.org/2005/Atom";

    internal SearchEngine(string searchString)
    {
        _searchString = searchString;
    }

    internal IEnumerable<Tweet> RunQuery()
    {
        var xDoc = XDocument.Load(string.Format(UrlTemplate, _searchString));

        var tweets =
        (from tweet in xDoc.Descendants(AtomNS + "entry")
         select new Tweet
         {
             Title = (string)tweet.Element(AtomNS + "title"),
             Published =
               DateTime.Parse((string)tweet.Element(AtomNS + "published")),
             Id = (string)tweet.Element(AtomNS + "id"),
             Link = tweet.Elements(AtomNS + "link")
                 .Where(link => (string)link.Attribute("rel") == "alternate")
                 .Select(link => (string)link.Attribute("href"))
                 .First(),
             ImageUrl = tweet.Elements(AtomNS + "link")
                .Where(link => (string)link.Attribute("rel") == "image")
                .Select(link => (string)link.Attribute("href"))
                .First(),
             Author = (from author in tweet.Descendants(AtomNS + "author")
                       select new Author
                       {
                           Name = (string)author.Element(AtomNS + "name"),
                           Uri = (string)author.Element(AtomNS + "uri"),
                       }).First(),
         });

        return tweets.ToList();
    }
}

Those are pretty much all the parts of this API. And I can use it like this to get all "tweets" by the user Jakobsson (me):

var tweets = TwitterQuery.BuildQuery().Users.From("Jakobsson").End().ExecuteQuery();

Pretty simple and readable in my opinion. I have plans to extend this with the rest of the twitter API as well when I find the time. But for now, this will have to do.

You can download the whole source from my svn repository at: https://87.237.213.147:8443/svn/Mattias_TwitterAPI and log in with username: "User" and no password.