PROWAREtech
ASP.NET: Connect with WebClient
WebClient is a very basic, easy way to request data from a particular URI. The easiest method to use is DownloadFile() which takes a URI
and then the path to save it to.
<%@ Page Language="C#" %>
<script runat="server">
void Page_Load(object sender, System.EventArgs e)
{
using (System.Net.WebClient wc = new System.Net.WebClient())
{
wc.DownloadFile("http://www.prowaretech.com/", Server.MapPath("/") + "homepage.html");
Response.Redirect("homepage.html");
}
}
</script>
<html>
<head><title></title></head>
<body>
</body>
</html>
To process the data within the application, use the method OpenRead() to get a System.IO.Stream object.
<%@ Page Language="C#" %>
<script runat="server">
void Page_Load(object sender, System.EventArgs e)
{
using (System.Net.WebClient wc = new System.Net.WebClient())
{
using (System.IO.Stream stream = wc.OpenRead("http://www.prowaretech.com/"))
{
using (System.IO.StreamReader reader = new System.IO.StreamReader(stream))
{
Response.Write(reader.ReadToEnd());
}
}
}
}
</script>
To send a Cookie to the server, use the Headers.Add() method.
<%@ Page Language="C#" %>
<script runat="server">
void Page_Load(object sender, System.EventArgs e)
{
using (System.Net.WebClient wc = new System.Net.WebClient())
{
wc.Headers.Add("Cookie: username=mrsmith");
using (System.IO.Stream stream = wc.OpenRead("http://www.prowaretech.com/"))
{
using (System.IO.StreamReader reader = new System.IO.StreamReader(stream))
{
Response.Write(reader.ReadToEnd());
}
}
}
}
</script>
To send data like a file to a server, use the UploadFile() method.
<%@ Page Language="C#" %>
<script runat="server">
void Page_Load(object sender, System.EventArgs e)
{
using (System.Net.WebClient wc = new System.Net.WebClient())
{
wc.UploadFile("http://www.domain.com/NewFileName.jpg", @"C:\Images\File.jpg");
}
}
</script>
The UploadData() method allows uploading binary data.
<%@ Page Language="C#" %>
<script runat="server">
void Page_Load(object sender, System.EventArgs e)
{
using (System.Net.WebClient wc = new System.Net.WebClient())
{
byte[] bytes = { 1, 9, 2, 5, 3, 4, 7, 8, 9, 5, 3, 1, 7, 9, 0 };
wc.UploadData("http://www.domain.com/BinaryData.bin", bytes);
}
}
</script>
To send data (like a POST) to a URI and retrieve a response, use the more complicated but also more comprehensive
WebRequest & WebResponse objects.
There is another method not covered here: OpenWrite(), which allows for HTTP PUT operations. It does not get the response
and as such is not very useful. There is also a DownloadData() method used for downloading into a byte array.
