XmlPullParserException when calling XMPPTCPConnection.disconnect()

zkoczkas · March 8, 2021, 4:28pm

I am using Smack V4.4.1. When I close a previously opened XMPP connection by calling XMPPTCPConnection.disconnect(), I get the following exception:

Mar 08, 2021 4:44:52 PM org.jivesoftware.smack.AbstractXMPPConnection waitForClosingStreamTagFromServer INFO: Exception while waiting for closing stream element from the server XMPPTCPConnection[85744@eu92b-fin002.labalz.aeat.allianz.at/AgentID@85744] (0) org.jivesoftware.smack.SmackException$SmackWrappedException: org.jivesoftware.smack.xml.XmlPullParserException: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[82,231] Message: XML document structures must start and end within the same entity. at org.jivesoftware.smack.AbstractXMPPConnection.setCurrentConnectionExceptionAndNotify(AbstractXMPPConnection.java:690) at org.jivesoftware.smack.AbstractXMPPConnection.notifyConnectionError(AbstractXMPPConnection.java:994) at org.jivesoftware.smack.tcp.XMPPTCPConnection.access$4100(XMPPTCPConnection.java:130) at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader.parsePackets(XMPPTCPConnection.java:1152) at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader.access$700(XMPPTCPConnection.java:913) at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader$1.run(XMPPTCPConnection.java:936) at java.base/java.lang.Thread.run(Thread.java:834) Caused by: org.jivesoftware.smack.xml.XmlPullParserException: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[82,231] Message: XML document structures must start and end within the same entity. at org.jivesoftware.smack.xml.stax.StaxXmlPullParser.next(StaxXmlPullParser.java:194) at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader.parsePackets(XMPPTCPConnection.java:1140) … 3 more Caused by: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[82,231] Message: XML document structures must start and end within the same entity. at java.xml/com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.next(XMLStreamReaderImpl.java:652) at org.jivesoftware.smack.xml.stax.StaxXmlPullParser.next(StaxXmlPullParser.java:192) … 4 more

The exception comes from XMPPTCPConnection.shutdown(false) after calling waitForClosingStreamTagFromServer().

My code for opening the XMPP connection is the following:


ReconnectionManager.setEnabledPerDefault(false);
Builder builder = XMPPTCPConnectionConfiguration.builder().setHost().setPort().addEnabledSaslMechanism(SASLPlainMechanism.NAME).setSecurityMode(SecurityMode.disabled);
builder.setXmppDomain();
XMPPTCPConnectionConfiguration config = builder.build();

XMPPTCPConnection xmppConnection = new XMPPTCPConnection(config); xmppConnection.connect();

The code for disconnect is simply:


xmppConnection.disconnect();

Any hints?

Thanks!

Zoltan

Flow · March 8, 2021, 5:52pm

Could be that the server is not terminating the stream with a closing stream tag. Hard to tell without further data. Enable SmackConfiguration.DEBUG and retrieve an XMPP trace of the connection.

zkoczkas · March 9, 2021, 7:32am

I don’t see any additional packets after the call of XMPPTCPConnection.waitForClosingStreamTagFromServer() in Smack Debug Window/Raw Recieved Packets. The last packet, that was received before the call was:

Flow · March 9, 2021, 8:07am

But you see that Smack sends a closing stream tag, i.e. </stream:stream>?

zkoczkas · March 9, 2021, 8:23am

Yes. These are the last packets sent by Smack before calling XMPPTCPConnection.waitForClosingStreamTagFromServer()

Flow · March 9, 2021, 8:50am

The server should response to a closing stream tag from the client with a clean stream shutdown. Could be possible that this is not the case, check the server log if one is send, and if not, report this to your server vendor.

Just to clarify: This does not cause any issues for you, or does it? As far as I can tell, you merely see a logged exception, recorded with ‘info’ log level.

zkoczkas · March 9, 2021, 9:26am

The server is a Cisco Finesse server. For failsafe operation, we have two Finesse servers running. When the ConnectionListener.connectionClosedOnError() is triggered, we switch to the other server. But during the switch (where we call XMPPConnection.disconnect()) this issue calls the listener again and we end up switching the servers until we give up. So it seems I have to build a workaround for that.

Flow · March 9, 2021, 9:31am

One second. This

github.com

igniterealtime/Smack/blob/3c4610d5007b1ae6ae955b969869abb5fe1a312a/smack-core/src/main/java/org/jivesoftware/smack/AbstractXMPPConnection.java#L1027


/**
 * Shuts the current connection down.
 */
protected abstract void shutdown();
protected final boolean waitForClosingStreamTagFromServer() {
    try {
        waitForConditionOrThrowConnectionException(() -> closingStreamReceived, "closing stream tag from the server");
    } catch (InterruptedException | SmackException | XMPPException e) {
        LOGGER.log(Level.INFO, "Exception while waiting for closing stream element from the server " + this, e);
        return false;
    }
    return true;
}
@Override
public void addConnectionListener(ConnectionListener connectionListener) {
    if (connectionListener == null) {
        return;
    }

should not result in the connectionClosedOnError() callback being invoked. If this happens, then it’s potentially a Smack bug.

Which exception do you see in the connectionClosedOnError() callback?

zkoczkas · March 9, 2021, 10:35am

This is the exception:
org.jivesoftware.smack.xml.XmlPullParserException: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[82,4153] Message: XML document structures must start and end within the same entity. at org.jivesoftware.smack.xml.stax.StaxXmlPullParser.next(StaxXmlPullParser.java:194) at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader.parsePackets(XMPPTCPConnection.java:1140) at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader.access$700(XMPPTCPConnection.java:913) at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader$1.run(XMPPTCPConnection.java:936) at java.base/java.lang.Thread.run(Thread.java:834) Caused by: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[82,4153] Message: XML document structures must start and end within the same entity. at java.xml/com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.next(XMLStreamReaderImpl.java:652) at org.jivesoftware.smack.xml.stax.StaxXmlPullParser.next(StaxXmlPullParser.java:192) … 4 more

Flow · March 9, 2021, 5:23pm

Should be fixed with

Which will probably land in Smack 4.4.2.

zkoczkas · March 9, 2021, 8:55pm

Thanks a lot!

Flow · March 10, 2021, 8:19am

You are welcome.

Are you able to test this fix and report back? I’ve just made this available as Smack 4.4.2-SNAPSHOT on Maven Central’s snapshot repositories: https://oss.sonatype.org/content/repositories/snapshots/org/igniterealtime/smack/

system · May 11, 2021, 8:19am

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