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Android 自定义Packet&Provider Android XMPP通讯自定义Packet&Provider

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想了解Android XMPP通讯自定义Packet&Provider的相关内容吗,IamOkay在本文为您仔细讲解Android 自定义Packet&Provider的相关知识和一些Code实例,欢迎阅读和指正,我们先划重点:Android,XMPP,Android,Packet&Provider,下面大家一起来学习吧。

摘要

在xmpp通信过程中,asmack中提供的Packet组件是IQ,Message,Presence三种: IQ用于查询 Message用于消息传递 Presence用于状态交互 他们都是Packet的子类,实质是用于将消息封装成响应的xml格式来进行数据交换,都有着良好的可扩展性。

简介

我们以开源项目androidpn为例:

androidpn (Android Push Notification)是一个基于XMPP协议的java开源Android push notification实现。它包含了完整的客户端和服务器端。

androidpn包括Server端和Client端,项目名称是androidpn-server和androidpn-client。

事实上,androidpn-server可以支持app运行于iOS,UWP,Windows,Linux等平台,不仅限于android,因此,希望项目的名称改为XPN(Xmpp Push Notification)似乎更加符合其实际场景,我们以后涉及到Android Push Notification统称为XPN。

XNP目前状态

项目自2014年1月就已经停止更新了,此外,asmack项目也停止更新了,作者建议使用openfire官方的smack4.0,不过这样的话引入的jar会特别多,特别大。当然,我们下载到了asmack8.10.0比较新的稳定版本,可以完全用于学习和扩展。

项目相关下载站点

asmack-github.com - asmack项目地址

asmack-asmack.freakempire.de - asmack镜像地址

androidpn(XPN)-github.com - androidpn下载地址

一.关于Packet数据包

Packet是IQ,Message,Presence的父类,用于实现消息组件类型。

消息语义学message

message是一种基本推送消息方法,它不要求响应。主要用于IM、groupChat、alert和notification之类的应用中。
主要 属性如下:

    type属性,它主要有5种类型:
        normal:类似于email,主要特点是不要求响应;
        chat:类似于qq里的好友即时聊天,主要特点是实时通讯;
        groupchat:类似于聊天室里的群聊;
        headline:用于发送alert和notification;
        error:如果发送message出错,发现错误的实体会用这个类别来通知发送者出错了;

to属性:标识消息的接收方。

from属性:指发送方的名字或标示。为防止地址外泄,这个地址通常由发送者的server填写,而不是发送者。
载荷(payload):例如body,subject

<message to="lily@jabber.org/contact" 
 type="chat" > 
  <body> 你好,在忙吗</body> 
</message>

出席信息语义学presence

presence用来表明用户的状态,如:online、away、dnd(请勿打扰)等。当改变自己的状态时,就会在stream的上下文中插入一个Presence元素,来表明自身的状态。要想接受presence消息,必须经过一个叫做presence subscription的授权过程。
属性:

type属性,非必须。有以下类别
    subscribe:订阅其他用户的状态
    probe:请求获取其他用户的状态
    unavailable:不可用,离线(offline)状态

to属性:标识消息的接收方。

from属性:指发送方的名字或标示。

载荷(payload):
    show:
    chat:聊天中
    away:暂时离开
    xa:eXtend Away,长时间离开
    dnd:勿打扰
status:格式自由,可阅读的文本。也叫做rich presence或者extended presence,常用来表示用户当前心情,活动,听的歌曲,看的视频,所在的聊天室,访问的网页,玩的游戏等等。
priority:范围-128~127。高优先级的resource能接受发送到bare JID的消息,低优先级的resource不能。优先级为
<presence from="alice@wonderland.lit/pda">
  <show>xa</show>
  <status>down the rabbit hole!</status>
</presence>

IQ语义学

一种请求/响应机制,从一个实体从发送请求,另外一个实体接受请求,并进行响应。例如,client在stream的上下文中插入一个元素,向Server请求得到自己的好友列表,Server返回一个,里面是请求的结果。
主要的属性是type。包括:
    Get :获取当前域值。类似于http get方法。
    Set :设置或替换get查询的值。类似于http put方法。
    Result :说明成功的响应了先前的查询。类似于http状态码200。
    Error: 查询和响应中出现的错误。
<iq from="alice@wonderland.lit/pda
    id="rr82a1z7"
    to="alice@wonderland.lit
    type="get">
  <query xmlns="jabber:iq:roster"/>
</iq>

二.自定义Packet

由于服务器和客户端使用的Packet不同,但是他们交互的数据格式都是xml,因此,这个过程我们理解xml实现过程即可。

1.定义Packet封装对象

由于asmack标签解析的限制,我们不能自定义解析,除非修改源码,这里出于简单,这里只能继承现有标签之一。

我么按照项目代码NotificationIQ为例,这里没有继承Packet,而是继承了IQ

import org.jivesoftware.smack.packet.IQ;
/** 
 * This class represents a notifcatin IQ packet.
 *
 * @author Sehwan Noh (devnoh@gmail.com)
 */
public class NotificationIQ extends IQ {
  private String id;
  private String apiKey;
  private String title;
  private String message;
  private String uri;
  public NotificationIQ() {
  }
  @Override
  public String getChildElementXML() {
    StringBuilder buf = new StringBuilder();
    buf.append("<").append("notification").append(" xmlns=\"").append(
        "androidpn:iq:notification").append("\">");
    if (id != null) {
      buf.append("<id>").append(id).append("</id>");
    }
    buf.append("</").append("notification").append("> ");
    return buf.toString();
  }
  public String getId() {
    return id;
  }
  public void setId(String id) {
    this.id = id;
  }
  public String getApiKey() {
    return apiKey;
  }
  public void setApiKey(String apiKey) {
    this.apiKey = apiKey;
  }
  public String getTitle() {
    return title;
  }
  public void setTitle(String title) {
    this.title = title;
  }
  public String getMessage() {
    return message;
  }
  public void setMessage(String message) {
    this.message = message;
  }
  public String getUri() {
    return uri;
  }
  public void setUri(String url) {
    this.uri = url;
  }
}

其中,getChildElementXml()是IQ的子类,用来拼接成<iq>下的直接点。

public abstract class IQ extends Packet {
  private Type type = Type.GET;
  public IQ() {
    super();
  }
  public IQ(IQ iq) {
    super(iq);
    type = iq.getType();
  }
  /**
   * Returns the type of the IQ packet.
   *
   * @return the type of the IQ packet.
   */
  public Type getType() {
    return type;
  }
  /**
   * Sets the type of the IQ packet.
   *
   * @param type the type of the IQ packet.
   */
  public void setType(Type type) {
    if (type == null) {
      this.type = Type.GET;
    }
    else {
      this.type = type;
    }
  }
  public String toXML() {
    StringBuilder buf = new StringBuilder();
    buf.append("<iq ");
    if (getPacketID() != null) {
      buf.append("id=\"" + getPacketID() + "\" ");
    }
    if (getTo() != null) {
      buf.append("to=\"").append(StringUtils.escapeForXML(getTo())).append("\" ");
    }
    if (getFrom() != null) {
      buf.append("from=\"").append(StringUtils.escapeForXML(getFrom())).append("\" ");
    }
    if (type == null) {
      buf.append("type=\"get\">");
    }
    else {
      buf.append("type=\"").append(getType()).append("\">");
    }
    // Add the query section if there is one.
    String queryXML = getChildElementXML();
    if (queryXML != null) {
      buf.append(queryXML);
    }
    // Add the error sub-packet, if there is one.
    XMPPError error = getError();
    if (error != null) {
      buf.append(error.toXML());
    }
    buf.append("</iq>");
    return buf.toString();
  }
  /**
   * Returns the sub-element XML section of the IQ packet, or <tt>null</tt> if there
   * isn't one. Packet extensions <b>must</b> be included, if any are defined.<p>
   *
   * Extensions of this class must override this method.
   *
   * @return the child element section of the IQ XML.
   */
  public abstract String getChildElementXML();
  /**
   * Convenience method to create a new empty {@link Type#RESULT IQ.Type.RESULT}
   * IQ based on a {@link Type#GET IQ.Type.GET} or {@link Type#SET IQ.Type.SET}
   * IQ. The new packet will be initialized with:<ul>
   *   <li>The sender set to the recipient of the originating IQ.
   *   <li>The recipient set to the sender of the originating IQ.
   *   <li>The type set to {@link Type#RESULT IQ.Type.RESULT}.
   *   <li>The id set to the id of the originating IQ.
   *   <li>No child element of the IQ element.
   * </ul>
   *
   * @param iq the {@link Type#GET IQ.Type.GET} or {@link Type#SET IQ.Type.SET} IQ packet.
   * @throws IllegalArgumentException if the IQ packet does not have a type of
   *   {@link Type#GET IQ.Type.GET} or {@link Type#SET IQ.Type.SET}.
   * @return a new {@link Type#RESULT IQ.Type.RESULT} IQ based on the originating IQ.
   */
  public static IQ createResultIQ(final IQ request) {
    if (!(request.getType() == Type.GET || request.getType() == Type.SET)) {
      throw new IllegalArgumentException(
          "IQ must be of type 'set' or 'get'. Original IQ: " + request.toXML());
    }
    final IQ result = new IQ() {
      public String getChildElementXML() {
        return null;
      }
    };
    result.setType(Type.RESULT);
    result.setPacketID(request.getPacketID());
    result.setFrom(request.getTo());
    result.setTo(request.getFrom());
    return result;
  }
  /**
   * Convenience method to create a new {@link Type#ERROR IQ.Type.ERROR} IQ
   * based on a {@link Type#GET IQ.Type.GET} or {@link Type#SET IQ.Type.SET}
   * IQ. The new packet will be initialized with:<ul>
   *   <li>The sender set to the recipient of the originating IQ.
   *   <li>The recipient set to the sender of the originating IQ.
   *   <li>The type set to {@link Type#ERROR IQ.Type.ERROR}.
   *   <li>The id set to the id of the originating IQ.
   *   <li>The child element contained in the associated originating IQ.
   *   <li>The provided {@link XMPPError XMPPError}.
   * </ul>
   *
   * @param iq the {@link Type#GET IQ.Type.GET} or {@link Type#SET IQ.Type.SET} IQ packet.
   * @param error the error to associate with the created IQ packet.
   * @throws IllegalArgumentException if the IQ packet does not have a type of
   *   {@link Type#GET IQ.Type.GET} or {@link Type#SET IQ.Type.SET}.
   * @return a new {@link Type#ERROR IQ.Type.ERROR} IQ based on the originating IQ.
   */
  public static IQ createErrorResponse(final IQ request, final XMPPError error) {
    if (!(request.getType() == Type.GET || request.getType() == Type.SET)) {
      throw new IllegalArgumentException(
          "IQ must be of type 'set' or 'get'. Original IQ: " + request.toXML());
    }
    final IQ result = new IQ() {
      public String getChildElementXML() {
        return request.getChildElementXML();
      }
    };
    result.setType(Type.ERROR);
    result.setPacketID(request.getPacketID());
    result.setFrom(request.getTo());
    result.setTo(request.getFrom());
    result.setError(error);
    return result;
  }
  /**
   * A class to represent the type of the IQ packet. The types are:
   *
   * <ul>
   *   <li>IQ.Type.GET
   *   <li>IQ.Type.SET
   *   <li>IQ.Type.RESULT
   *   <li>IQ.Type.ERROR
   * </ul>
   */
  public static class Type {
    public static final Type GET = new Type("get");
    public static final Type SET = new Type("set");
    public static final Type RESULT = new Type("result");
    public static final Type ERROR = new Type("error");
    /**
     * Converts a String into the corresponding types. Valid String values
     * that can be converted to types are: "get", "set", "result", and "error".
     *
     * @param type the String value to covert.
     * @return the corresponding Type.
     */
    public static Type fromString(String type) {
      if (type == null) {
        return null;
      }
      type = type.toLowerCase();
      if (GET.toString().equals(type)) {
        return GET;
      }
      else if (SET.toString().equals(type)) {
        return SET;
      }
      else if (ERROR.toString().equals(type)) {
        return ERROR;
      }
      else if (RESULT.toString().equals(type)) {
        return RESULT;
      }
      else {
        return null;
      }
    }
    private String value;
    private Type(String value) {
      this.value = value;
    }
    public String toString() {
      return value;
    }
  }
}

最终可生成如下结构的数据

<iq from="">
 <nofitication xlns="">
<iq>

我们在项目中的使用很简单

xmppManager.getConnection().sendPacket(<NotificationIQ>niq)

当然,上面只是实现了object->xml,接下来我们实现xml->data

2.实现IQProvider

先来看看IQProvider源码

public interface IQProvider {

  /**
   * Parse the IQ sub-document and create an IQ instance. Each IQ must have a
   * single child element. At the beginning of the method call, the xml parser
   * will be positioned at the opening tag of the IQ child element. At the end
   * of the method call, the parser <b>must</b> be positioned on the closing tag
   * of the child element.
   *
   * @param parser an XML parser.
   * @return a new IQ instance.
   * @throws Exception if an error occurs parsing the XML.
   */
  public IQ parseIQ(XmlPullParser parser) throws Exception;
}

实现自定义的解析工具

public class NotificationIQProvider implements IQProvider {
  public NotificationIQProvider() {
  }
  @Override
  public IQ parseIQ(XmlPullParser parser) throws Exception {
    NotificationIQ notification = new NotificationIQ();
    for (boolean done = false; !done;) {
      int eventType = parser.next();
      if (eventType == 2) {
        if ("id".equals(parser.getName())) {
          notification.setId(parser.nextText());
        }
        if ("apiKey".equals(parser.getName())) {
          notification.setApiKey(parser.nextText());
        }
        if ("title".equals(parser.getName())) {
          notification.setTitle(parser.nextText());
        }
        if ("message".equals(parser.getName())) {
          notification.setMessage(parser.nextText());
        }
        if ("uri".equals(parser.getName())) {
          notification.setUri(parser.nextText());
        }
      } else if (eventType == 3
          && "notification".equals(parser.getName())) {
        done = true;
      }
    }
    return notification;
  }
}

项目中使用方法

ProviderManager.getInstance().addIQProvider("notification",
              "androidpn:iq:notification",
              new NotificationIQProvider());

在asmack中PacketParserUtils类中会进行如下调用

 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);
            }
          }

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