Post Username and Password to login page programmatically

问题

I want to post username and password to a login page of a remote website using asp.net and pass it, to access login-required pages on website. In the other words suppose there is a page on a website that i would to surf it an grab something from it ,but login is required before it . how to call that Login page and post username and password from the asp.net application to pass it.

Thanks in advance

回答1:

The comment with passing them as the query string only works for GET parameters. This works for POST. As you can see I use the form entries username, password and login (the button) but in your case it might be entirely different values. So use a tool like Fiddler to catch which values a normal login is sending. When I did something similar I had to use a cookie-aware webclient because the service used cookies for session values. The service you are trying to access could use a query-session string - it entirely depends on the service.

Another problem I ran into when doing this, was that I had to fetch a session id from the html page and sent it for logging it. I have not included the code for that here, but I have it if you need it :)

var client = new CookieAwareWebClient();
client.Encoding = Encoding.UTF8;

// Post values

var values = new NameValueCollection();
values.Add("username", someusername);
values.Add("password", somepassword);
values.Add("login", "Login");   //The button

// Logging in
client.UploadValues(loginPageUrl, values); // You may verify the result. It works with https :)

// Download some secret page

var html= client.DownloadString(someurl);

CookieAwareWebClient

public class CookieAwareWebClient : WebClient
{
    private CookieContainer cookieContainer = new CookieContainer();

    protected override WebRequest GetWebRequest(Uri address)
    {
        WebRequest request = base.GetWebRequest(address);
        if (request is HttpWebRequest)
        {
            (request as HttpWebRequest).CookieContainer = cookieContainer;
        }
        return request;
    }
}

回答2:

try reading this -> http://www.terminally-incoherent.com/blog/2008/05/05/send-a-https-post-request-with-c/

if you use firefox - download "tamper-data" and "live http-headers" to see what information is passed to the login site

with live http-headers you can see which data is passed in the POST

回答3:

Lets suppose you want to redriect to www.ABC.com

construct querystring like

http://abc.com/products.aspx?field1=value1&field2=value2

And get this value on the other page. But it is recomended to use the POST method, hope this help

来源：https://stackoverflow.com/questions/5869785/post-username-and-password-to-login-page-programmatically

标签

ASP.NET

httpwebrequest

web-crawler