Evolutionary Goo

I’ve been playing with Scala a bit lately. Tonight, I was fooling around with Scala using an online, interactive shell called lotrepls. I decided to write a script that would call the Twitter API and return me the status for a Twitter user. The script takes a Twitter user name as input and prints that user’s status to the screen. It turns out that Scala has some built-in XML parsing capabilities that makes this really easy.

This is the script.

import java.net._
import scala.xml._
val screenName = "robbr"    // Follow me!
val url =
  new URL("http://twitter.com/users/show.xml?screen_name=" +
  screenName)
val conn = url.openConnection
val xml = XML.load(conn.getInputStream)
val status = (xml\"status"\"text").text
println(screenName + ": " + status)

I’ll quickly break down the script line by line for non-Scala people. Not that I’m a Scala export myself.

1. Scala is completely interoperable with Java. Scala can call Java and Java can call Scala. In the first line, I am importing all classes in the java.net package to use for making a HTTP request later in the script.
2. In the second line I am importing all classes in the Scala XML package.
3. I set the screen name which is input to the Twitter status API call. I could instead prompt the user for the screen name using Console.readline(), but this doesn’t work with lotrepls.
4. Set the URL for the Twitter status API.
5. Open a URL connection.
6. Load the XML output of the HTTP request into a variable. The “val” modifier makes the variable final, therefore it can’t be changed.
7. I use an XPath like statement to navigate the XML for the data element I am looking for. I get only the text of that element.
8. Output the screen name and status to the screen.

This script can simply be cut and pasted into lotrepls. Remember to switch to Scala before running the script. Use CTRL+ENTER to execute. That’s all there is to it. Enjoy.

OK, I’ll play. I’m not sure how exciting twittering will be unless I find it to be a nice replacement or supplement for IM. You can follow me here. I can see how people are getting hooked on it, however, I think it will be interesting to see if Twitter can sustain the hype.