[C#] Error in WebRespons using API

Question

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C#

I am using a MacVendorLookUp API from this site: http://www.macvendorlookup.com[^]

Error:
"An unhandled exception of type 'System.Net.WebException' occurred in System.dll

Additional information: The remote server returned an error (407) Proxy Authentication Required."

Error in code:

C#

WebResponse response = request.GetResponse();

Full C# event code:

C#

private void findvendorButton_Click(object sender, EventArgs e)
        {
            string cell = "";
            System.IO.StreamReader reader;
            WebRequest request = WebRequest.Create("http://www.macvendorlookup.com/api/v2/{" + macaddressTextBox.Text + "}");
            request.Timeout = 120000;
            WebResponse response = request.GetResponse();
            reader = new System.IO.StreamReader(response.GetResponseStream());
            string get = reader.ReadToEnd();
            MatchCollection m1 = Regex.Matches(get, @"(company)(.*?)(}])", RegexOptions.Singleline);
            foreach (Match m in m1)
            {
                cell = m.Groups[0].Value;
            }
            vendorTextBox.Text = cell.Trim().Split('\"')[2].ToString();
        }

Anyone knows what i can do to prevent this error?
Sometimes i get the error, and sometimes i don't.. I don't understand..

Posted 8-Oct-14 22:36pm

Fail4FunTV

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*Suvabrata Roy* · Answer 1 · 2014-10-08T22:48:00

Solution 1

Hi,

You Need to provide credentials of your proxy server with the request.

Example : http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest.credentials(v=vs.110).aspx[^]

Get default Proxy : http://msdn.microsoft.com/en-us/library/system.net.webproxy.getdefaultproxy(v=vs.110).aspx[^]

Set the credentials to HttpWebRequest.

Posted 8-Oct-14 22:48pm

Suvabrata Roy

Comments

Fail4FunTV 9-Oct-14 4:50am

I don't get how to implement it into my code(?)

Suvabrata Roy 9-Oct-14 6:39am

WebRequest request = WebRequest.Create("http://www.macvendorlookup.com/api/v2/{" + macaddressTextBox.Text + "}");
request.Credentials = new NetworkCredential("ProxyUserName", "Password");
request.Timeout = 120000;

Fail4FunTV 9-Oct-14 7:17am

NetworkCredential("ProxyUserName", "Password"); ?

What is ProxyUserName and Password?

Suvabrata Roy 9-Oct-14 7:36am

How I could know that Ask your It Infra team.

Or pick default proxy.

Fail4FunTV 9-Oct-14 7:47am

What is default proxy?

Suvabrata Roy 9-Oct-14 9:54am

Which is already configured in your System.

Fail4FunTV 10-Oct-14 2:07am

How do i implement my default proxy?

Suvabrata Roy 10-Oct-14 2:24am

From .NET 2.0 you shouldn't need to do this. If you do not explicitly set the Proxy property on a web request it uses the value of the static WebRequest.DefaultWebProxy. If you wanted to change the proxy being used by all subsequent WebRequests, you can set this static DefaultWebProxy property.

The default behaviour of WebRequest.DefaultWebProxy is to use the same underlying settings as used by Internet Explorer.

If you wanted to use different proxy settings to the current user then you would need to code

WebRequest webRequest = WebRequest.Create("http://stackoverflow.com/");
webRequest.Proxy = new WebProxy("http://proxyserver:80/",true);
or

WebRequest.DefaultWebProxy = new WebProxy("http://proxyserver:80/",true);
You should also remember the object model for proxies includes the concept that the proxy can be different depending on the destination hostname. This can make things a bit confusing when debugging and checking the property of webRequest.Proxy. Call

webRequest.Proxy.GetProxy(new Uri("http://google.com.au")) to see the actual details of the proxy server that would be used.

There seems to be some debate about whether you can set webRequest.Proxy or WebRequest.DefaultWebProxy = null to prevent the use of any proxy. This seems to work OK for me but you could set it to new DefaultProxy() with no parameters to get the required behaviour. Another thing to check is that if a proxy element exists in your applications config file, the .NET Framework will NOT use the proxy settings in Internet Explorer.

The MSDN Magazine article Take the Burden Off Users with Automatic Configuration in .NET gives further details of what is happening under the hood.

Ref : http://stackoverflow.com/questions/299940/how-should-i-set-the-default-proxy-to-use-default-credentials