cgeier 187 Junior Poster

I am trying to automate a login to a website and then navigate to a webpage and retrieve the html from the page. I found some examples of how to login, but am having difficulty figuring out how to navigate to another page once logged in. I've read some information about using cookies, but I haven't done much website programming and am not sure how to implement cookies into the code I've found. Any guidance would be appreciated

import java.net.*;
import java.io.*;



public class WebsiteLogin {

	 private static final String POST_CONTENT_TYPE = "application/x-www-form-urlencoded";
	    private static final String LOGIN_USER_NAME_PARAMETER_NAME = "username";
	    private static final String LOGIN_PASSWORD_PARAMETER_NAME = "password";

	    private static final String LOGIN_USER_NAME = "myusername";
	    private static final String LOGIN_PASSWORD = "mypass";

	    private static final String TARGET_URL = "http://<mysite>.com/cgi-bin/member.cgi";

	public static void main(String[] args)
	{
        System.out.println("Running the program...\n");
        WebsiteLogin httpUrlBasicAuthentication = new WebsiteLogin();
        httpUrlBasicAuthentication.httpPostLogin();

	}

	   /**
     * The single public method of this class that
     * 1. Prepares a login message
     * 2. Makes the HTTP POST to the target URL
     * 3. Reads and returns the response
     *
     * @throws IOException
     * Any problems while doing the above.
     *
     */
    public void httpPostLogin ()
    {
        try
        {
            // Prepare the content to be written
            // throws UnsupportedEncodingException
            String urlEncodedContent = preparePostContent(LOGIN_USER_NAME, LOGIN_PASSWORD);

            System.out.println(urlEncodedContent);
            HttpURLConnection urlConnection = doHttpPost(TARGET_URL, urlEncodedContent);

            String response = readResponse(urlConnection);

            System.out.println("Successfully made the HTPP POST.");
            System.out.println("Recevied response is: '/n" + response + "'");

        }
        catch(IOException ioException)
        {
            System.out.println("Problems encounterd.");
        }
    }

    /**
     * Using the given username and password, and using the static string variables, prepare
     * the login message. Note that the username and password will encoded to the
     * UTF-8 standard.
     *
     * @param loginUserName
     * The user name for login
     *
     * @param loginPassword
     * The password for login
     *
     * @return
     * The complete login message that can be HTTP Posted
     *
     * @throws UnsupportedEncodingException
     * Any problems during URL encoding
     */
    private String preparePostContent(String loginUserName, String loginPassword) throws UnsupportedEncodingException
    {
        // Encode the user name and password to UTF-8 encoding standard
        // throws UnsupportedEncodingException
        String encodedLoginUserName = URLEncoder.encode(loginUserName, "UTF-8");
        String encodedLoginPassword = URLEncoder.encode(loginPassword, "UTF-8");

       /* String content = "login=" + LOGIN_ACTION_NAME +" &" + LOGIN_USER_NAME_PARAMETER_NAME +"="
        + encodedLoginUserName + "&" + LOGIN_PASSWORD_PARAMETER_NAME + "=" + encodedLoginPassword;*/

        String content = LOGIN_USER_NAME_PARAMETER_NAME +"="
        + encodedLoginUserName + "&" + LOGIN_PASSWORD_PARAMETER_NAME + "=" + encodedLoginPassword;

        return content;

    }

    /**
     * Makes a HTTP POST to the target URL by using an HttpURLConnection.
     *
     * @param targetUrl
     * The URL to which the HTTP POST is made.
     *
     * @param content
     * The contents which will be POSTed to the target URL.
     *
     * @return
     * The open URLConnection which can be used to read any response.
     *
     * @throws IOException
     */
    public HttpURLConnection doHttpPost(String targetUrl, String content) throws IOException
    {
        HttpURLConnection urlConnection = null;
        DataOutputStream dataOutputStream = null;
        try
        {
            // Open a connection to the target URL
            // throws IOException
            urlConnection = (HttpURLConnection)(new URL(targetUrl).openConnection());

            // Specifying that we intend to use this connection for input
            urlConnection.setDoInput(true);

            // Specifying that we intend to use this connection for output
            urlConnection.setDoOutput(true);

            // Specifying the content type of our post
            urlConnection.setRequestProperty("Content-Type", POST_CONTENT_TYPE);
            urlConnection.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows; U; Windows NT 6.1; en-GB; rv:1.9.2.8) Gecko/20100722 Firefox/3.6.8");

            HttpURLConnection.setFollowRedirects(true);
            // Specifying the method of HTTP request which is POST
            // throws ProtocolException
            urlConnection.setRequestMethod("POST");

            // Prepare an output stream for writing data to the HTTP connection
            // throws IOException
            dataOutputStream = new DataOutputStream(urlConnection.getOutputStream());

            // throws IOException
            dataOutputStream.writeBytes(content);
            dataOutputStream.flush();
            dataOutputStream.close();

            return urlConnection;
        }
        catch(IOException ioException)
        {
            System.out.println("I/O problems while trying to do a HTTP post.");
            ioException.printStackTrace();

            // Good practice: clean up the connections and streams
            // to free up any resources if possible
            if (dataOutputStream != null)
            {
                try
                {
                    dataOutputStream.close();
                }
                catch(Throwable ignore)
                {
                    // Cannot do anything about problems while
                    // trying to clean up. Just ignore
                }
            }
            if (urlConnection != null)
            {
                urlConnection.disconnect();
            }

            // throw the exception so that the caller is aware that
            // there was some problems
            throw ioException;
        }
    }

    /**
     * Read response from the URL connection
     *
     * @param urlConnection
     * The URLConncetion from which the response will be read
     *
     * @return
     * The response read from the URLConnection
     *
     * @throws IOException
     * When problems encountered during reading the response from the
     * URLConnection.
     */
    private String readResponse(HttpURLConnection urlConnection) throws IOException
    {

        BufferedReader bufferedReader = null;
        try
        {
            // Prepare a reader to read the response from the URLConnection
            // throws IOException
            bufferedReader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
            String responeLine;

            // Good Practice: Use StringBuilder in this case
            StringBuilder response = new StringBuilder();

            // Read until there is nothing left in the stream
            // throws IOException
            while ((responeLine = bufferedReader.readLine()) != null)
            {
                response.append(responeLine);
            }

            return response.toString();
        }
        catch(IOException ioException)
        {
            System.out.println("Problems while reading the response");
            ioException.printStackTrace();

            // throw the exception so that the caller is aware that
            // there was some problems
            throw ioException;

        }
        finally
        {
            // Good practice: clean up the connections and streams
            // to free up any resources if possible
            if (bufferedReader != null)
            {
                try
                {
                    // throws IOException
                    bufferedReader.close();
                }
                catch(Throwable ignore)
                {
                    // Cannot do much with exceptions doing clean up
                    // Ignoring all exceptions
                }
            }

        }
    }

}

Here is the web page code:

<html>
<head>
	<title>Member Login</title>

</head>
<body>
<form action="/cgi-bin/login.cgi" method=POST>
	<input type="hidden" name="go" value="1">
	<table>
	<tr>
		<td align=right valign=top>
		<b>Username:</b>
		</td>
		<td align=left valign=top>
		<input type="text" name="username">
		</td>
	</tr>
	<tr>
		<td align=right valign=top>
		<b>Password:</b>
		</td>
		<td align=left valign=top>
			<input type="password" name="password">
		</td>
	</tr>
	<tr>
		<td align=center valign=top colspan="2">
			<input type="submit" value="Login">
		</td>
	</tr>
	</table>
</form>
</body>
</html>
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