KVM crashes when reading content with HTTP "302 Found" response on N90 and 6680

[Emmanuel Raulo]

Hello
I found that a MIDlet will silently die on Nokia N90 and 6680 when trying to read the content of an HTTP "302 Found" server response.
Here is a small code showing it :

import javax.microedition.midlet.*;
import javax.microedition.io.*;
import java.io.*;
import javax.microedition.lcdui.*;

public class Test
extends MIDlet
{
  private static final String URL = "http://server.domain/your_script.php"
  
  protected void startApp() throws MIDletStateChangeException
  {
    Form f = new Form( "Test" );
    String response="";
    try {
      HttpConnection con = 
        (HttpConnection)Connector.open( URL, Connector.READ );
      InputStream in = con.openInputStream();
      InputStreamReader reader = new InputStreamReader(in);
      char content[] = new char[1024];
      int len = reader.read( content, 0, 1024 );
      reader.close();
      in.close();
      response = String.valueOf(content,0,len);
    }
    catch( IOException e ) {}
    f.append( new StringItem("Reponse : ", response, StringItem.PLAIN) );
    Display.getDisplay(this).setCurrent(f);
  }

  protected void pauseApp() {}

  protected void destroyApp(boolean arg0) throws MIDletStateChangeException{}
}

And here is the server-side PHP code to generate a HTTP 302 reply with content :

<?php
header('Location: http://www.forum.nokia.com/' );
echo 'plop';
?>

It was REALLY hard to find out why my much more complicated app kept on crashing...
Isn't that part of the HTTP standard to send a content together with a 302 reply ?

[steven2ffff]

hey, i feel your pain, 6630/6680 crashes too, n70 does not , but conenction still can not get through, any idea?

[peterblazejewicz]

hi,

shouldn't getResponseCode/getResponseMessage of HTTPConnection be used to handle that situation correctly?

regards,
Peter

[Emmanuel Raulo]

peterblazejewicz, getResponseCode() would return (int)302 and getResponseMessage() "302 Found".
What I wanted was the actual content of the HTTP reply (i.e. what comes after the reply headers).

I had the developer of the web service change his API to let the MIDlet connect but this is a workaround. Even if a 302 HTTP reply means that the content has moved to another URI specified in the Location: header, it seems to me that some content can be sent together (and actual implementations allow it, e.g. Apache 2 for the server-side and Nokia 3230 for client-side).

See http://www.w3.org/Protocols/rfc2616/...html#sec10.3.3 for info on "302 Found" HTTP reply.

[peterblazejewicz]

hi Emmanuel,

well, I was under impression (remember that I'm still learner) that correct action is to:
- bypass read headers/content routine
- close current connection
- reopen current conenction using Location header to request correct data,
it's based on sample I've used some time ago:

private HttpConnection open(String url) throws IOException {
    HttpConnection c;
    int status = -1;

    // Open the connection and check for redirects
    while (true) {
      c = (HttpConnection) Connector.open(url);

      // Get the status code,
      // causing the connection to be made
      status = c.getResponseCode();

      if ((status == HttpConnection.HTTP_TEMP_REDIRECT)
          || (status == HttpConnection.HTTP_MOVED_TEMP)
          || (status == HttpConnection.HTTP_MOVED_PERM)) {

        // Get the new location and close the connection
        url = c.getHeaderField("location");
        c.close();
      } else {
        break;
      }
    }

    // Only HTTP_OK (200) means the content is returned.
    if (status != HttpConnection.HTTP_OK) {
      c.close();
      throw new IOException("Response status not OK");
    }
    return c;
  }

and notes from MIDP docs:

302: The requested resource resides temporarily under a different URI. (Note: the name of this status code reflects the earlier publication of RFC2068, which was changed in RFC2616 from "moved temporalily" to "found". The semantics were not changed. The Location header indicates where the application should resend the request.)

that's I've learned so far but could be wrong of course,
hth,
regards,
Peter

[steven2ffff]

keep watching the thread , hope to get a way to handle 302 on s50 properly....