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How to reduce url length in C#

I needed the other day to reduce the length of a URL - so I decided to use a URL reducing service like tinyurl.com And I thought I would share the C# .Net code - nothing new I'm sure and there are plenty of examples out there.

public sealed class TinyUrlReducer : IReduceUrls
{
private readonly string _tinyUrl;
private readonly string _proxyUrl;

public TinyUrlReducer(string tinyUrl) : this(tinyUrl, null)
{
}

public TinyUrlReducer(string tinyUrl, string proxyUrl)
{
_tinyUrl = tinyUrl;
_proxyUrl = proxyUrl;
}

public string Reduce(string url)
{
if (string.IsNullOrEmpty(url))
throw new ArgumentException("Can reduce a null or empty url!", "url");

var reducedUrl = "";
try
{
Trace.WriteLine(string.Format("Reduce: Url - '{0}'.", url));

var requestUrl = string.Format("{0}?url={1}", _tinyUrl, url);
var request = (HttpWebRequest)WebRequest.Create(requestUrl);
request.KeepAlive = false;
request.UseDefaultCredentials = true;
request.AllowAutoRedirect = true;
request.UseDefaultCredentials = true;

if (!string.IsNullOrEmpty(_proxyUrl))
request.Proxy = new WebProxy(_proxyUrl, true, null, CredentialCache.DefaultCredentials);

var response = (HttpWebResponse)request.GetResponse();
if (response.StatusCode != HttpStatusCode.OK)
throw new WebException(string.Format("Failed to call url - '{0}'!", requestUrl));

using (var stream = new StreamReader(response.GetResponseStream()))
{
reducedUrl = stream.ReadLine();
}

if (string.IsNullOrEmpty(reducedUrl))
throw new Exception("Reduced url is null or empty!");
}
catch (Exception exn)
{
Trace.WriteLine(string.Format("Reduce: Failed to reduce url, message - '{0}'.", exn.Message));
reducedUrl = url;
}
finally
{
Trace.WriteLine(string.Format("Reduce: Reduced Url - '{0}'.", reducedUrl));
}

return reducedUrl;
}
}

And a couple of tests...


[TestFixture]
public class TinyUrlReducerTests
{
[Test]
public void ShouldReduceUrl()
{
// Given we have url reducer...
var reducer = new TinyUrlReducer("http://tinyurl.com/api-create.php", "http://PROXY.MY.COM:8080");

// When we reduce a url..
var reducedUrl = reducer.Reduce("http://somereallylongurl/whichhasarelativelylongname/somepage.aspx");

// Then we expect the reduced url to start with...
Assert.IsTrue(reducedUrl.ToLower().StartsWith("http://tinyurl.com/"));
}

[Test, ExpectedException(typeof(ArgumentException))]
public void ShouldThrowExceptionIfUrlNull()
{
// Given we have url reducer...
var reducer = new TinyUrlReducer("http://tinyurl.com/api-create.php", "http://PROXY.MY.COM:8080");

// When we reduce a url..
var reducedUrl = reducer.Reduce(null);

// Then we expect the reduced url to start with...
Assert.IsTrue(reducedUrl.ToLower().StartsWith("http://tinyurl.com/"));
}

[Test, ExpectedException(typeof(ArgumentException))]
public void ShouldThrowExceptionIfUrlEmpty()
{
// Given we have url reducer...
var reducer = new TinyUrlReducer("http://tinyurl.com/api-create.php", "http://PROXY.MY.COM:8080");

// When we reduce a url..
var reducedUrl = reducer.Reduce(string.Empty);

// Then we expect the reduced url to start with...
Assert.IsTrue(reducedUrl.ToLower().StartsWith("http://tinyurl.com/"));
}

[Test]
public void ShouldReturnOrginalUrlWhenReducerFails()
{
// Given we have url reducer...
var reducer = new TinyUrlReducer("http://tinyurl.com/api-create.php");

// When we reduce a url and we know it will fail..
var url = "http://somereallylongurl/whichhasarelativelylongname/somepage.aspx";
var reducedUrl = reducer.Reduce(url);

// Then we expect the reduced url to the same as the original url...
Assert.AreEqual(url, reducedUrl);
}
}

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