Name: paC48320 Date: 11/13/97


The JDK http handler implementation class:

    sun.net.www.protocol.HttpURLConnection

ignores any "IfModifiedSince" value that was set by calling

    java.net.URLConnection.setIfModifiedSince(long)

In other words, it fails to write the HTTP Header entry that,
according to RFC1945, should look like:

   If-Modified-Since = "If-Modified-Since" ":" HTTP-date

Run the module supplied below, as follows:

    % java HTTPTest http://<someValidURL>

And you should see a response code of 304 since I set the
if-modified-since date to be way in the future.

Instead, you'll see a response code of 200.

NOTE: If you look inside of sun.net.www.protocol.http.HttpURLConnection
      you will see that there is no code to handle
      the setting of the If-Modified-Since header entry.

      The code in writeRequests should look something like:

      if ( getModifiedSince() != 0 )
      {
          requests.setIfNotSet("If-Modified-Since", getModifiedSince());
      }


Except that you will have to use DateFormat to convert the getModifiedSince()
date into the HTTP-Date String format required by HTTP.


//
// Test module for broken If-Modified-Since HTTP Header...
//
// ###@###.###
//
import java.net.*;

public class HTTPTest extends Object
{
    public HTTPTest()
    {
    }

    public static final void main(String argv[])
    {
        try
        {
            URL testURL = new URL(argv[0]);
            URLConnection URLConn = testURL.openConnection();
            HttpURLConnection httpConn;

            if ( URLConn instanceof HttpURLConnection )
            {
                httpConn = (HttpURLConnection)URLConn;
                httpConn.setAllowUserInteraction(false);
                httpConn.setIfModifiedSince(999000000000l);
                httpConn.connect();

                System.out.println("URL:" + httpConn.getURL()
                                   + "\nContent-encoding:"
                                   + httpConn.getContentEncoding()
                                   + "\nContent-length:"
                                   + httpConn.getContentLength()
                                   + "\nContent-type:"
                                   + httpConn.getContentType()
                                   + "\nDate:"
                                   + httpConn.getDate()
                                   + "\nIf-Modified-Since:"
                                   + httpConn.getIfModifiedSince()
                                   + "\nLast-Modified:"
                                   + httpConn.getLastModified());
                System.out.println(httpConn.getRequestMethod()
                                   + " " + httpConn.getResponseCode()
                                   + " " + httpConn.getResponseMessage());

                for ( int i = 0; ;i++ )
                {
                    httpConn.getHeaderField(i);
                    if ( httpConn.getHeaderFieldKey(i) == null )
                    {
                        break;
                    }

                    System.out.println(httpConn.getHeaderFieldKey(i)
                                       + ":"
                                       + httpConn.getHeaderField(i));
                }
            }
            else
            {
                System.out.println("URL is not a cache candidate.");
            }
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }
}
(Review ID: 19884)
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