Question

I have a VM that runs a few web crawling console applications. I’m wondering how do you use a different proxy per console application. Most of the proxy C# stuff I find changes the registry, however this changes all console apps not just one.

Anybody have an example of how to use a specific proxy for a specific console app without effective all other console apps?

Looking for a source code solution

Answer 1

Assuming your console application’s use one of the built-in methods for downloading web pages (WebClient, HttpWebRequest, etc.), they all have a Proxy Property which should do what you’re after. They pretty much all work the same so here’s the example provided by the MSDN documentation for HttpWebRequest.Proxy:

// Create a new request to the mentioned URL.               
HttpWebRequest myWebRequest=(HttpWebRequest)WebRequest.Create("http://www.microsoft.com");

// Obtain the 'Proxy' of the  Default browser.  
IWebProxy proxy = myWebRequest.Proxy;
// Print the Proxy Url to the console.
if (proxy != null)
{
    Console.WriteLine("Proxy: {0}", proxy.GetProxy(myWebRequest.RequestUri));
} 
else
{
    Console.WriteLine("Proxy is null; no proxy will be used");
}

WebProxy myProxy=new WebProxy();

Console.WriteLine("\nPlease enter the new Proxy Address that is to be set:");
Console.WriteLine("(Example:http://myproxy.example.com:port)");
string proxyAddress;

try
{
    proxyAddress =Console.ReadLine();
    if(proxyAddress.Length>0)
    {
    Console.WriteLine("\nPlease enter the Credentials (may not be needed)");
    Console.WriteLine("Username:");
    string username;
    username =Console.ReadLine();
    Console.WriteLine("\nPassword:");
    string password;
    password =Console.ReadLine();                   
    // Create a new Uri object.
    Uri newUri=new Uri(proxyAddress);
    // Associate the newUri object to 'myProxy' object so that new myProxy settings can be set.
    myProxy.Address=newUri;
    // Create a NetworkCredential object and associate it with the 
    // Proxy property of request object.
    myProxy.Credentials=new NetworkCredential(username,password);
    myWebRequest.Proxy=myProxy;
    }
    Console.WriteLine("\nThe Address of the  new Proxy settings are {0}",myProxy.Address);
    HttpWebResponse myWebResponse=(HttpWebResponse)myWebRequest.GetResponse();