Scala Cookbook

15.9. Creating a Simple GET Request Client

Problem

You want an HTTP client you can use to make GET request calls.

Solution

There are many potential solutions to this problem. This recipe demonstrates three approaches:

• A simple use of the scala.io.Source.fromURL method

• Adding a timeout wrapper around scala.io.Source.fromURL to make it more robust

• Using the Apache HttpClient library

These solutions are demonstrated in the following sections.

A simple use of scala.io.Source.fromURL

If it doesn’t matter that your web service client won’t time out in a controlled manner, you can use this simple method to download the contents from a URL:

/**
 * Returns the text (content) from a URL as a String.
 * Warning: This method does not time out when the service is non-responsive.
 */
def get(url: String) = scala.io.Source.fromURL(url).mkString

This GET request method lets you call the given RESTful URL to retrieve its content. You can use it to download web pages, RSS feeds, or any other content using an HTTP GET request.

Under the covers, the Source.fromURL method uses classes like java.net.URL and java.io.InputStream, so this method can throw exceptions that extend from java.io.IOException. As a result, you may want to annotate your method to indicate that:

@throws(classOf[java.io.IOException])
def get(url: String) = io.Source.fromURL(url).mkString

Setting the timeout while using scala.io.Source.fromURL

As mentioned, that simple solution suffers from a significant problem: it doesn’t time out if the URL you’re ...