Downloading a file using C#

Question

I have some code to download a text file from a website. When the requested file does not exist, my application downloads a text file which has html content. I need to filter this html content (should not download a text file with html content if the requested file does not exist) and need to download only text files which has the correct content. Below is my code.

string FilePath = @"C:\TextFiles\" + FileName + String.Format("{0:00000}", i) + ".TXT";
Directory.CreateDirectory(Path.GetDirectoryName(FilePath));
//MessageBox.Show(FilePath);

using (FileStream download = new FileStream(FilePath, FileMode.Create))
{
    Stream stream = clientx.GetResponse().GetResponseStream();
    while ((read = stream.Read(buffer, 0, buffer.Length)) != 0)
    {

        download.Write(buffer, 0, read);

    }
}

Please advice

Answer 1

Assuming clientx is HttpWebRequest then just check the StatusCode of the response:

HttpWebResponse response = (HttpWebResponse)clientx.GetResponse();
if (response.StatusCode != HttpStatusCode.OK)
{
    MessageBox.Show("Error reading page: " + response.StatusCode);
}
else
{
    string FilePath = @"C:\TextFiles\" + FileName + String.Format("{0:00000}", i) + ".TXT";
    Directory.CreateDirectory(Path.GetDirectoryName(FilePath));
    //MessageBox.Show(FilePath);
    using (FileStream download = new FileStream(FilePath, FileMode.Create))
    {
        Stream stream = response .GetResponseStream();
        while ((read = stream.Read(buffer, 0, buffer.Length)) != 0)
        {
            download.Write(buffer, 0, read);
        }
    }
}

Answer 2

You can also use WebClient instead of HttpWebRequest:

var client = new WebClient();
client.DownloadFile("http://someurl/doesnotexist.txt", "doesnotexist.txt");

This will throw a System.Net.WebException if the file does not exist.

Answer 3

I would suggest you ought to test the ReponseCode.

You would expect a 200 "OK" code if the file exists and is transmitted to you, or a 404 "Not Found" code.

Try:

var response = clientx.GetResponse();
HttpStatusCode code = response.StatusCode;

if (code == HttpStatusCode.OK)
{
    //get and download stream....
}

EDIT:

You need to cast the WebReponse into a HttpWebResponse (see http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest.getresponse.aspx)

Try:

using(HttpWebReponse response = (HttpWebResponse)clientx.GetResponse())
{
    if (response.StatusCode == HttpStatusCode.OK)
    {
        string FilePath = @"C:\TextFiles\" + FileName + String.Format("{0:00000}", i) + ".TXT";
        Directory.CreateDirectory(Path.GetDirectoryName(FilePath));

        using (FileStream download = new FileStream(FilePath, FileMode.Create))
        {
            Stream stream = clientx.GetResponse().GetResponseStream();
            while ((read = stream.Read(buffer, 0, buffer.Length)) !=0)
            {
                download.Write(buffer, 0, read);
            }
        } 
    }
}