dotNet

Actually, the title should be "The Next Great Mid-Level Language", but doesn't sound quite as snappy...

There has been a lot of talk in the last year or two about Java losing ground to newer languages and about which language is going to replace Java as the dominant language going into the next decade. Various factions from the Ruby and Scala camps have weighed in on the debate in earnest, leaving even some die-hard Java programmers wondering if they should be learning a new language (and soon). After all the smoke clears, what should the reasonable person conclude? Is it time to move on?

If you want to get XML data from a different domain you will need to use a server side proxy. While you could use JSON to get around this there are times when a JSON feed may not be available and a proxy must be used.

In the past I have written posts about creating such a proxy, however all of the example code was is PHP. Well, if you are a .NET developer then you are in luck, because the CodeProject has posted a tutorial on creating a Server Side Proxy in .NET.

Below is an excerpt from the post.

A Basic Proxy Such a content proxy is also available in my open source Ajax Web Portal Dropthings.com. You can see from its code from CodePlex how such a proxy is implemented. The following is a very simple synchronous, non-streaming, blocking Proxy:

[WebMethod]
[ScriptMethod(UseHttpGet=true)]

public string GetString(string url)
{
        using (WebClient client = new WebClient())
        {
            string response = client.DownloadString(url);
            return response;
        }
    }
}   
 

Although it shows the general principle, but it's no where close to a real proxy because:

• It's a synchronous proxy and thus not scalable. Every call to this
  web method causes the ASP.NET thread to wait until the call to the
  external URL completes.
• It's non streaming. It first downloads the entire
  content on the server, storing it in a string and then uploading that
  entire content to the browser. If you pass MSDN feed URL,
  it will download that gigantic 220 KB RSS XML on the server and store
  it on a 220 KB long string (actually double the size as .NET strings
  are all Unicode string) and then write 220 KB to ASP.NET Response
  buffer, consuming another 220 KB UTF8 byte array in memory. Then that
  220 KB will be passed to IIS in chunks so that it can transmit it to
  the browser.
• It does not produce proper response header to cache the response on the server. Nor does it deliver important headers like Content-Type from the source.
• If external URL is providing gzipped content, it decompresses
  the content into a string representation and thus wastes server memory.
• It does not cache the content on the server. So, repeated
  call to the same external URL within the same second or minute will
  download content from the external URL and thus waste bandwidth on your
  server.

So, we need an asynchronous streaming proxy that transmits
the content to the browser while it downloads from the external domain
server. So, it will download bytes from external URL in small chunks
and immediately transmit that to the browser. As a result, browser will
see a continuous transmission of bytes right after calling the web
service. There will be no delay while the content is fully downloaded
on the server.

You can read the full tutorial here.

This post not only shows you haw to make a basic server side proxy, but also shows you how to make it streaming. If you are a .NET developer looking to make a server side proxy, I recommend this post.