org.maodian.flyingcat.xmpp.state.StreamState.java Source code

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Here is the source code for org.maodian.flyingcat.xmpp.state.StreamState.java

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/*
 * Copyright 2013 - 2013 Cole Wen
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.maodian.flyingcat.xmpp.state;

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
import java.math.BigDecimal;

import javax.xml.XMLConstants;
import javax.xml.namespace.QName;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamWriter;

import org.apache.commons.lang3.RandomStringUtils;
import org.maodian.flyingcat.holder.XMLInputFactoryHolder;
import org.maodian.flyingcat.holder.XMLOutputFactoryHolder;
import org.maodian.flyingcat.xmpp.XmppNamespace;
import org.springframework.stereotype.Component;

/**
 * Handle <em>Stream Negotation</em> phase.
 * 
 * @author Cole Wen
 * @see State
 * @see AbstractState
 */
public abstract class StreamState implements State {
    private static final BigDecimal SUPPORTED_VERSION = new BigDecimal("1.0");

    /* (non-Javadoc)
     * @see org.maodian.flycat.xmpp.state.State#step(org.maodian.flycat.xmpp.state.XmppContext, java.lang.String)
     */
    @Override
    public Result step(XmppContext context, String xml) {
        try (Reader reader = new StringReader(xml); StringWriter writer = new StringWriter();) {
            try {
                XMLStreamReader xmlsr = XMLInputFactoryHolder.getXMLInputFactory().createXMLStreamReader(reader);
                XMLStreamWriter xmlsw = XMLOutputFactoryHolder.getXMLOutputFactory().createXMLStreamWriter(writer);
                doHandle(context, xmlsr, xmlsw);
                context.setStreamTag(xml);
                context.flush(writer.toString());
                Result result = new DefaultResult(context.getGlobalContext().getSelectState());
                return result;
            } catch (XMLStreamException e) {
                throw new XmppException(e, StreamError.BAD_FORMAT);
            }
        } catch (IOException ioe) {
            // close a StringReader/StringWriter should not cause IOException, though
            throw new XmppException(ioe, StreamError.INTERNAL_SERVER_ERROR);
        }
    }

    private void doHandle(XmppContext context, XMLStreamReader xmlsr, XMLStreamWriter xmlsw)
            throws XMLStreamException {
        xmlsr.nextTag();
        QName qname = new QName(XmppNamespace.STREAM, "stream");
        if (!xmlsr.getName().equals(qname)) {
            throw new XmppException(StreamError.INVALID_NAMESPACE).set("QName", xmlsr.getName());
        }

        // throw exception if client version > 1.0
        BigDecimal version = new BigDecimal(xmlsr.getAttributeValue("", "version"));
        if (version.compareTo(SUPPORTED_VERSION) > 0) {
            throw new XmppException(StreamError.UNSUPPORTED_VERSION);
        }

        xmlsw.writeStartDocument();
        xmlsw.writeStartElement("stream", "stream", XmppNamespace.STREAM);
        xmlsw.writeNamespace("stream", XmppNamespace.STREAM);
        xmlsw.writeDefaultNamespace(XmppNamespace.CLIENT_CONTENT);

        xmlsw.writeAttribute("id", RandomStringUtils.randomAlphabetic(32));
        xmlsw.writeAttribute("version", "1.0");
        xmlsw.writeAttribute("from", "localhost");
        xmlsw.writeAttribute(XMLConstants.XML_NS_PREFIX, XMLConstants.XML_NS_URI, "lang", "en");
        String from = xmlsr.getAttributeValue(null, "from");
        if (from != null) {
            xmlsw.writeAttribute("to", from);
        }

        // features
        xmlsw.writeStartElement(XmppNamespace.STREAM, "features");
        writeFeatures(xmlsw);
        xmlsw.writeEndElement();
    }

    /**
     * @param xmlsw
     * @throws XMLStreamException
     */
    protected abstract void writeFeatures(XMLStreamWriter xmlsw) throws XMLStreamException;

    @Component
    public static class OpeningStreamState extends StreamState {
        /**
         * @param xmlsw
         * @throws XMLStreamException
         */
        protected void writeFeatures(XMLStreamWriter xmlsw) throws XMLStreamException {
            xmlsw.writeStartElement("starttls");
            xmlsw.writeDefaultNamespace(XmppNamespace.TLS);
            xmlsw.writeEmptyElement("required");
            xmlsw.writeEndElement();
        }
    }

    @Component
    public static class TLSStreamState extends StreamState {

        /* (non-Javadoc)
         * @see org.maodian.flycat.xmpp.state.StreamState#writeFeatures(javax.xml.stream.XMLStreamWriter)
         */
        @Override
        protected void writeFeatures(XMLStreamWriter xmlsw) throws XMLStreamException {
            xmlsw.writeStartElement("mechanisms");
            xmlsw.writeDefaultNamespace(XmppNamespace.SASL);
            xmlsw.writeStartElement("mechanism");
            xmlsw.writeCharacters("PLAIN");
            xmlsw.writeEndElement();
            xmlsw.writeEndElement();
        }
    }

    @Component
    public static class AuthenticatedStreamState extends StreamState {

        /* (non-Javadoc)
         * @see org.maodian.flycat.xmpp.state.StreamState#writeFeatures(javax.xml.stream.XMLStreamWriter)
         */
        @Override
        protected void writeFeatures(XMLStreamWriter xmlsw) throws XMLStreamException {
            xmlsw.writeStartElement("bind");
            xmlsw.writeDefaultNamespace(XmppNamespace.BIND);
            xmlsw.writeEmptyElement("required");
            xmlsw.writeEndElement();

            // see http://xmpp.org/rfcs/rfc6121.html#intro-summary
            xmlsw.writeEmptyElement("session");
            xmlsw.writeDefaultNamespace(XmppNamespace.SESSION);
        }

    }
}