如何监听到asmack联系人资料变动

开发中的点滴，排版有点丑，博客也不常写，有点丑，别嫌弃。实在要嫌弃，网站有我照片，看完会心里平衡些。

 

场景：在开发一款xmpp的应用，需要获取好友资料变动并实时刷新。

1.确定问题：获取好友资料变动；

2.工具：spark和adt

3.解决问题：

 

我先用spark开启调试模式登录，在spark端和im移动客户端同时上线之后，im端修改了个人vcard数据保存，在spark端的调试窗口看到了发送过来的vcard包。说明好友更新了vcard之后服务器是有转发的。

 

然后我查看asmack 的api发现vcard需要添加一个provider：

pm.addIQProvider("vCard", "vcard-temp", new VCardProvider());

 

我们跟进去VCardProvider的源码：

 

/**
 * $RCSfile$
 * $Revision$
 * $Date$
 *
 * Copyright 2003-2007 Jive Software.
 *
 * All rights reserved. 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.jivesoftware.smackx.provider;

import org.jivesoftware.smack.packet.IQ;
import org.jivesoftware.smack.provider.IQProvider;
import org.jivesoftware.smack.util.StringUtils;
import org.jivesoftware.smackx.packet.VCard;
import org.w3c.dom.*;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * vCard provider.
 *
 * @author Gaston Dombiak
 * @author Derek DeMoro
 */
public class VCardProvider implements IQProvider {

    private static final String PREFERRED_ENCODING = "UTF-8";

    public IQ parseIQ(XmlPullParser parser) throws Exception {
        final StringBuilder sb = new StringBuilder();
        try {
            int event = parser.getEventType();
            // get the content
            while (true) {
                switch (event) {
                    case XmlPullParser.TEXT:
                        // We must re-escape the xml so that the DOM won't throw an exception
                        sb.append(StringUtils.escapeForXML(parser.getText()));
                        break;
                    case XmlPullParser.START_TAG:
                        sb.append('<').append(parser.getName()).append('>');
                        break;
                    case XmlPullParser.END_TAG:
                        sb.append("</").append(parser.getName()).append('>');
                        break;
                    default:
                }

                if (event == XmlPullParser.END_TAG && "vCard".equals(parser.getName())) break;

                event = parser.next();
            }
        }
        catch (XmlPullParserException e) {
            e.printStackTrace();
        }
        catch (IOException e) {
            e.printStackTrace();
        }

        String xmlText = sb.toString();
        return createVCardFromXML(xmlText);
    }

    /**
     * Builds a users vCard from xml file.
     *
     * @param xml the xml representing a users vCard.
     * @return the VCard.
     * @throws Exception if an exception occurs.
     */
    public static VCard createVCardFromXML(String xml) throws Exception {
        VCard vCard = new VCard();

        DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
        Document document = documentBuilder.parse(
                new ByteArrayInputStream(xml.getBytes(PREFERRED_ENCODING)));

        new VCardReader(vCard, document).initializeFields();
        return vCard;
    }

    private static class VCardReader {

        private final VCard vCard;
        private final Document document;

        VCardReader(VCard vCard, Document document) {
            this.vCard = vCard;
            this.document = document;
        }

        public void initializeFields() {
            vCard.setFirstName(getTagContents("GIVEN"));
            vCard.setLastName(getTagContents("FAMILY"));
            vCard.setMiddleName(getTagContents("MIDDLE"));
            setupPhoto();

            setupEmails();

            vCard.setOrganization(getTagContents("ORGNAME"));
            vCard.setOrganizationUnit(getTagContents("ORGUNIT"));

            setupSimpleFields();

            setupPhones();
            setupAddresses();
        }

        private void setupPhoto() {
            String binval = null;
            String mimetype = null;

            NodeList photo = document.getElementsByTagName("PHOTO");
            if (photo.getLength() != 1)
                return;

            Node photoNode = photo.item(0);
            NodeList childNodes = photoNode.getChildNodes();

            int childNodeCount = childNodes.getLength();
            List<Node> nodes = new ArrayList<Node>(childNodeCount);
            for (int i = 0; i < childNodeCount; i++)
                nodes.add(childNodes.item(i));

            String name = null;
            String value = null;
            for (Node n : nodes) {
                name = n.getNodeName();
                value = n.getTextContent();
                if (name.equals("BINVAL")) {
                    binval = value;
                }
                else if (name.equals("TYPE")) {
                    mimetype = value;
                }
            }

            if (binval == null || mimetype == null)
                return;

            vCard.setAvatar(binval, mimetype);
        }

        private void setupEmails() {
            NodeList nodes = document.getElementsByTagName("USERID");
            if (nodes == null) return;
            for (int i = 0; i < nodes.getLength(); i++) {
                Element element = (Element) nodes.item(i);
                if ("WORK".equals(element.getParentNode().getFirstChild().getNodeName())) {
                    vCard.setEmailWork(getTextContent(element));
                }
                else {
                    vCard.setEmailHome(getTextContent(element));
                }
            }
        }

        private void setupPhones() {
            NodeList allPhones = document.getElementsByTagName("TEL");
            if (allPhones == null) return;
            for (int i = 0; i < allPhones.getLength(); i++) {
                NodeList nodes = allPhones.item(i).getChildNodes();
                String type = null;
                String code = null;
                String value = null;
                for (int j = 0; j < nodes.getLength(); j++) {
                    Node node = nodes.item(j);
                    if (node.getNodeType() != Node.ELEMENT_NODE) continue;
                    String nodeName = node.getNodeName();
                    if ("NUMBER".equals(nodeName)) {
                        value = getTextContent(node);
                    }
                    else if (isWorkHome(nodeName)) {
                        type = nodeName;
                    }
                    else {
                        code = nodeName;
                    }
                }
                if (code == null || value == null) continue;
                if ("HOME".equals(type)) {
                    vCard.setPhoneHome(code, value);
                }
                else { // By default, setup work phone
                    vCard.setPhoneWork(code, value);
                }
            }
        }

        private boolean isWorkHome(String nodeName) {
            return "HOME".equals(nodeName) || "WORK".equals(nodeName);
        }

        private void setupAddresses() {
            NodeList allAddresses = document.getElementsByTagName("ADR");
            if (allAddresses == null) return;
            for (int i = 0; i < allAddresses.getLength(); i++) {
                Element addressNode = (Element) allAddresses.item(i);

                String type = null;
                List<String> code = new ArrayList<String>();
                List<String> value = new ArrayList<String>();
                NodeList childNodes = addressNode.getChildNodes();
                for (int j = 0; j < childNodes.getLength(); j++) {
                    Node node = childNodes.item(j);
                    if (node.getNodeType() != Node.ELEMENT_NODE) continue;
                    String nodeName = node.getNodeName();
                    if (isWorkHome(nodeName)) {
                        type = nodeName;
                    }
                    else {
                        code.add(nodeName);
                        value.add(getTextContent(node));
                    }
                }
                for (int j = 0; j < value.size(); j++) {
                    if ("HOME".equals(type)) {
                        vCard.setAddressFieldHome((String) code.get(j), (String) value.get(j));
                    }
                    else { // By default, setup work address
                        vCard.setAddressFieldWork((String) code.get(j), (String) value.get(j));
                    }
                }
            }
        }

        private String getTagContents(String tag) {
            NodeList nodes = document.getElementsByTagName(tag);
            if (nodes != null && nodes.getLength() == 1) {
                return getTextContent(nodes.item(0));
            }
            return null;
        }

        private void setupSimpleFields() {
            NodeList childNodes = document.getDocumentElement().getChildNodes();
            for (int i = 0; i < childNodes.getLength(); i++) {
                Node node = childNodes.item(i);
                if (node instanceof Element) {
                    Element element = (Element) node;

                    String field = element.getNodeName();
                    if (element.getChildNodes().getLength() == 0) {
                        vCard.setField(field, "");
                    }
                    else if (element.getChildNodes().getLength() == 1 &&
                            element.getChildNodes().item(0) instanceof Text) {
                        vCard.setField(field, getTextContent(element));
                    }
                }
            }
        }

        private String getTextContent(Node node) {
            StringBuilder result = new StringBuilder();
            appendText(result, node);
            return result.toString();
        }

        private void appendText(StringBuilder result, Node node) {
            NodeList childNodes = node.getChildNodes();
            for (int i = 0; i < childNodes.getLength(); i++) {
                Node nd = childNodes.item(i);
                String nodeValue = nd.getNodeValue();
                if (nodeValue != null) {
                    result.append(nodeValue);
                }
                appendText(result, nd);
            }
        }
    }
}

 

了解provider的人都知道，这是一个iq包的处理器类，这个VCardProvider是api提供的，跟踪到里面的代码发现，这个类主要是获取到了vcard数据然后封装成了vcard对象返回回去。

 

那么问题来了，我们要怎么才能拿到这个vcard数据呢？

 

那么我们回归到这段代码，
pm.addIQProvider("vCard", "vcard-temp", new VCardProvider());

我猜测providerManager一定有一个集合，里面有很多provider，当有iq包过来的时候会把这些iq包通过命名空间过滤然后交给相应的provider处理。现在我们看下源码：

 

 

private Map<String, Object> extensionProviders = new ConcurrentHashMap<String, Object>();
    private Map<String, Object> iqProviders = new ConcurrentHashMap<String, Object>();

查看源码我们发现确实是这样的。

 

 

那么在哪里要用到这个provider呢？我们跟踪进去看，发现在packetParseUtil下有一个parseIQ方法专门解析iq包，里面有关键的一段：

 

 

 Object provider = ProviderManager.getInstance().getIQProvider(elementName, namespace);
                    if (provider != null) {
                        if (provider instanceof IQProvider) {
                            iqPacket = ((IQProvider)provider).parseIQ(parser);
                        }
                        else if (provider instanceof Class) {
                            iqPacket = (IQ)PacketParserUtils.parseWithIntrospection(elementName,
                                    (Class<?>)provider, parser);
                        }
                    }

 

从代码我们很容易看明白，从这里获取到了provider，parseIQ又是谁在调用呢？我们继续跟进，发现是PacketReader的parsePackets(Thread)方法，我们继续跟进：

 

  private void processPacket(Packet packet) {
        if (packet == null) {
            return;
        }

        // Loop through all collectors and notify the appropriate ones.
        for (PacketCollector collector: connection.getPacketCollectors()) {
            collector.processPacket(packet);
        }

        // Deliver the incoming packet to listeners.
        listenerExecutor.submit(new ListenerNotification(packet));
    }

发现交给了、listenerExecutor处理，发现这里有一个类

 

 

  * A runnable to notify all listeners of a packet.
     */
    private class ListenerNotification implements Runnable {

        private Packet packet;

        public ListenerNotification(Packet packet) {
            this.packet = packet;
        }

        public void run() {
            for (ListenerWrapper listenerWrapper : connection.recvListeners.values()) {
                try {
                    listenerWrapper.notifyListener(packet);
                } catch (Exception e) {
                    System.err.println("Exception in packet listener: " + e);
                    e.printStackTrace();
                }
            }
        }
    }

这个类有一个重要的方法：

 

 

public void notifyListener(Packet packet) {
            if (packetFilter == null || packetFilter.accept(packet)) {
                packetListener.processPacket(packet);
            }
        }

到了这里我们就能明白了，原来iqprovider处理后的数据最终都是交给了packetListener处理，要想处理这个packet就需要制定filter匹配规则，然后我们发现在构造这个filter的时候有一种方式是通过制定类构造的，到了这里很明白了，之所以返回的是vcard对象就是要通过packet拿到的时候能直接转换成vcard对象拿来使用，一下子云开雾散。

 

 

其他的所有的provider的原理都是这样，搞了几个小时才搞出来的，希望大家尊敬我的劳动成果，在转载的时候添加上转载，谢谢。