by Mads Kristensen
14. February 2007 00:14
Some say that screen scraping is a lost art because it is no longer an advanced discipline.
That may be right, but there are different ways of doing it. Here are some different
ways that all are perfectly acceptable, but can be used for various different purposes.
Old school
It’s old school because this approach has existed since .NET 1.0. It is highly flexible
and lets you make the request asynchronously.
public static string ScreenScrape(string url)
{
System.Net.WebRequest request = System.Net.WebRequest.Create(url);
//
set properties of the request
using (System.Net.WebResponse
response = request.GetResponse())
{
using (System.IO.StreamReader reader = new System.IO.StreamReader(response.GetResponseStream()))
{
return reader.ReadToEnd();
}
}
}
Modern>
In .NET 2.0 we can use the WebClient class, which is a cleaner way of solving the
same problem. It is equally as flexible and can also work asynchronous.
public static string ScreenScrape(string url)
{
using (System.Net.WebClient
client = new System.Net.WebClient())
{
// set properties of the client
return client.DownloadString(url);
}
}
The one-liner>
This is a short version of the Modern approach, but it deserves to be on the list
because it is a one-liner. Tell a nineteen ninetees developer that you can
do screen scraping in one line of code and he wont believe you. The approach is not
flexible in any way and cannot be used asynchronously.
public static string ScreenScrape(string url)
{
return new System.Net.WebClient().DownloadString(url);
}
That concludes the medley of screen scraping approaches. Pick the one you find best
for the given situation.
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