Tag Archives: microblogging

Reading Twitter with JavaFX

twitter bird

Twitter is a social network and micro-blogging service that allow you to create and read tweets, 140 characters text-based posts. It’s becoming a popular tool to keep in touch with your friends, coworkers, bloggers, etc. Here we’ll create a very simple application that show us tweets related with a given word.

Twitter offers a very simple and powerfull REST API which supports XML, JSON, and the RSS and Atom formats. As we are aiming just to read tweets we’ll use just the Search API.

We do that in three steps:

  1. Query Tweets
  2. Parser the Atom result
  3. Show tweets into a GUI

Let’s see them in the order of dependence beetween them.

Displaying a Tweet

var gradient = LinearGradient {
    startX: 0.0,
    startY: 0.0,
    endX: 0.0,
    endY: 150.0
    proportional: false
    stops: [Stop {offset: 0.0 color: Color.DARKGRAY },
        Stop { offset: 1.0 color: Color.BLACK }]
}
 
public class Tweet extends CustomNode {
    public var image: Image;
    public var username: String;
    public var message: String;
    public override function create(): Node {
        var txt = Text {
            x: 65  y: 35 wrappingWidth: 150 fill: Color.WHITE
            content: "{message}"
        }
        return Group {
            content: [
                Rectangle {
                    width: 220 height: txt.boundsInLocal.height + 40
                    arcHeight: 10 arcWidth: 10 fill: gradient
                },
                ImageView {
                    x: 5 y: 20 image: image
                },
                Text {
                    x: 65  y: 20 fill: Color.BLACK content: "{username} said"
                },
                txt
            ]
        };
    }
}

For example, this tweet would become:

tweet example

Parsing ATOM result

In my last post about JavaFX I showed how to parse XML documents (and make sandwiches) with JavaFX. Here we’ll use the Atom format, but use any other would be almost the same. Parsing XML or JSON documents with JavaFX is both very simple using the javafx.data.pull.PullParser class.

A query output is a Atom XML document with several information. We are interested only in the fields that holds the avatar image, the message and the user name.

var tweets = VBox {}
def parser = PullParser {
    var avatar;
    var firstname;
    var text;
    documentType: PullParser.XML;
 
    onEvent: function(event: Event) {
        if(event.type == PullParser.START_ELEMENT){
            if(event.qname.name.equals("link")){
                if(event.getAttributeValue(QName{name: "rel"}) == "image"){
                    avatar = event.getAttributeValue(QName{name:"href"});
                }
            }
        }
 
        if(event.type == PullParser.END_ELEMENT) {
            if(event.qname.name == "title"){
                    text = event.text;
            }
            if((event.qname.name == "name")and(event.level==3)){
                var names: String[] = event.text.split(" ");
                firstname = names[0];
                insert Tweet {
                        image: Image {
                            url: avatar
                        }
                        message: text
                        username: firstname
                    } into tweets.content;
            }
        }
    }
}

Querying Tweets

We can get Atom results through url queries like that:

Notice that queries should be URL encoded. We will use a additional parameters &rpp=4 to receive only 4 results per page. To know more about search queries read the Search API Documentation. We get these results as InputStreams making asynchronous HTTP requests using the javafx.io.http.HttpRequest class, which it’s perfect to invoke RESTful Web Services.

word = "Beatles";
var request = HttpRequest {
    location: "http://search.twitter.com/search.atom?q={word}&rpp=4";
    onInput: function(stream: java.io.InputStream) {
        parser.input = stream;
        parser.parse();
    }
}
request.enqueue();

Conclusion

Here is the application running for the word “House”.

twitter with javafx

Is not a complete Twitter client, as it’s not intended to be, but can show you how to handle a simple asynchronous call and handle Twitter documents. There’s already a few beta JavaFX Twitter clients like Tweetbox and Twitterfx and certanly others will appears.

Download

Sources and Netbeans project, fxtwitter.tar.bz2.

Achei uma utilidade pro Twitter!

Eu sempre achei o Twitter inútil e ridículo, mas hoje, depois de ter uma conta lá há anos finalmente eu consegui enxergar uma face útil nos mini-blogs como o twitter.

Garota usando celular

Por uma série de motivos que envolvem:

  • uma sacanagem de uma assistência técnica.
  • eu ficar sem meu Nokia 6600
  • eu ficar puto e comprar um Nokia 6610i usado de um gringo Norueguês.
  • eu finalmente conseguir configurar a porra do GPRS no celular

Finalmente eu vi que eu posso ficar blogando/microblogando/twitando, como queiram, enquanto eu estou dentro do ônibus ou esperando na fila do dentista. Pronto, acabou a monotonia! Não tenho mais que ler as mesmas revistinhas da Turma da Mônica pela milésima vez ou ler aquelas Caras que tem em absolutamente qualquer consultório de qualquer coisa.

E tem mais!

Para a coisa fazer sentido eu estou colocando aqui na barra lateral direita uma seção mini-blog que é conectada com o RSS do meu twitter. Se a coisa ficar legal eu coloco um também no eupodiatamatando.com.