C++：gloox库进行协议扩展(使用自定义标签)

客官°小女子只卖身不卖艺 2022-03-18 07:04 181阅读 0赞

# 前言 #

直接使用gloox库源码中examples下面的示例，采用开源的openfire搭建的xmpp的服务器，是可以直接进行连接、注册和消息推送。 使用AndroidPN作为xmpp服务器可以可以直接使用 gloox的示例进行注册，但是连接 和 消息推送不行。连接的问题咋们就不说了，咋们直接说 消息推送的问题。

因为AndroidPN作为服务器 给客户端推送的消息是扩展了协议，所以直接使用示例代码是不行。笔者也是看官方文档查看 gloox源代码，将这个问题调通了。**其实就是Protocol Extensions 协议扩展问题，如果你仔细去看stanzaextension.h也能解决**。自己在网上没有找到一个完整的示例，所以在这里本着奉献自我的精神，写一个使用 gloox 进行协议扩展的案例。

下面是AndroidPN服务器给的消息推送报文结构

<iq type='set' id='193-0' to='cotest2@127.0.0.1/gloox'>
        <notification xmlns='androidpn:iq:notification'>
            <id>65d24038</id><apiKey>1234567890</apiKey>
            <title>Dokdo Island</title>
            <message>Dokdo is a Korean island, the far east of the Korean territory. No doubt! No question! Don't mention it any more!</message>
            <uri>www.baidu.com</uri>
        </notification>
    </iq>

我们需要的title、message和uri，我们通过协议扩展来获取到我们想要的信息。

这里额外说下**gloox使用的是1.0.22版本**，**AndroidPN服务器使用的是**[androidpn-server-0.5.0-bin][] 。

# 代码 #

定义我们自己的扩展类

myextension.h

#pragma once
    
    #include "stanzaextension.h"
    #include <string>
    using namespace gloox;
    
    class MyExtension :public StanzaExtension
    {
    public:
    	  MyExtension();
    	  MyExtension( const Tag* tag );
    	  //MyExtension( const MyExtension& one );
          virtual ~MyExtension();
    
          /**
           * This function returns the embedded Stanza, if any.
           * You only have to reimplement it if your protocol flow contains embedded Stanzas.
           *
           * @return The embedded Stanza. May be 0.
           */
          virtual Stanza* embeddedStanza() const { return 0; }
    
          /**
           * This function returns the embedded Tag that the embedded Stanza is based on, if any.
           * You only have to reimplement it if your protocol flow contains embedded Stanzas.
           *
           * @return The embedded Tag. May be 0.
           */
          virtual Tag* embeddedTag() const { return 0; }
    
          /**
           * Returns an XPath expression that describes a path to child elements of a
           * stanza that an extension handles.
           *
           * @return The extension's filter string.
           */
          virtual const std::string& filterString() const;
    
          /**
           * Returns a new Instance of the derived type. Usually, for a derived class FooExtension,
           * the implementation of this function looks like:
           * @code
           * StanzaExtension* FooExtension::newInstance( const Tag* tag ) const
           * {
           *   return new FooExtension( tag );
           * }
           * @endcode
           * @return The derived extension's new instance.
           */
          virtual StanzaExtension* newInstance( const Tag* tag ) const;
    
          /**
           * Returns a Tag representation of the extension.
           * @return A Tag representation of the extension.
           */
          virtual Tag* tag() const;
    
          /**
           * Returns an identical copy of the current StanzaExtension.
           * @return An identical copy of the current StanzaExtension.
           */
          virtual StanzaExtension* clone() const;
    
    	  std::string getTitle();
    	  std::string getMsg();
    	  std::string getUrl();
    
    private:
    	std::string m_title;
    	std::string m_msg;
    	std::string m_url;
    };

myextension.cpp

#include "myextension.h"
    #include "tag.h"
    #include "gloox.h"
    #include <stdlib.h>
    using namespace gloox;
    
    #define OPEN_TEST 0
    
    MyExtension::MyExtension():StanzaExtension(ExtUser)
    {
    #if OPEN_TEST
    	printf("MyExtension() \n");
    #endif
    }	
    
    MyExtension::MyExtension( const Tag* tag ):StanzaExtension(ExtUser)
    {
    	/*
    	<notification xmlns='androidpn:iq:notification'>
    		<id>65d24038</id>
    		<apiKey>1234567890</apiKey>
    		<title>Dokdo Island</title>
    		<message>Dokdo is a Korean island, the far east of the Korean territory.</message>
    		<url>www.baidu.com</url>
    	</notification>
    	*/
    	#if OPEN_TEST
    		printf("MyExtension( const Tag* tag ) enter \n");
    	#endif
    
    	Tag* titleTag = tag->findChild("title");
    	if( NULL != titleTag )
    	{
    		m_title = titleTag->cdata();
    	}
    
    	Tag* msgTag = tag->findChild("message");
    	if( NULL != titleTag )
    	{
    		m_msg = msgTag->cdata();
    	}
    
    	Tag* urlTag = tag->findChild("uri");
    	if( NULL != urlTag )
    	{
    		m_url = urlTag->cdata();
    	}
    }
    
    MyExtension::~MyExtension() 
    {
    #if OPEN_TEST
    	printf("~MyExtension() \n");
    #endif
    }
    
    // 返回自定义协议的xmlns进行过滤匹配
    const std::string& MyExtension::filterString() const
    {
    	#if OPEN_TEST
    		printf("filterString() enter \n");
    	#endif
    	static const std::string filter = "/iq/notification[\@xmlns='androidpn:iq:notification']";
    	return filter;
    }
    
    StanzaExtension* MyExtension::newInstance( const Tag* tag ) const
    {
    	#if OPEN_TEST
    		printf("newInstance( const Tag* tag ) enter \n");
    	#endif
    	StanzaExtension* ret = new MyExtension( tag );
    	return ret;
    }
    
    Tag*  MyExtension::tag() const
    {
    	/*
    	<notification xmlns='androidpn:iq:notification'>
    		<id>65d24038</id>
    		<apiKey>1234567890</apiKey>
    		<title>Dokdo Island</title>
    		<message>Dokdo is a Korean island, the far east of the Korean territory.</message>
    		<url>www.baidu.com</url>
    	</notification>
    	*/
    	#if OPEN_TEST
    		printf("MyExtension::tag() enter \n");
    	#endif
    
    	Tag* root = new Tag("notification");
    	root->addAttribute("xmlns","androidpn:iq:notification");
    
    	Tag* titleTag = new Tag("title");
    	Tag* msgTag = new Tag("message");
    	Tag* urlTag = new Tag("uri");
    	titleTag->setCData(m_title);
    	msgTag->setCData(m_msg);
    	urlTag->setCData(m_url);
    	
    	root->addChild(titleTag);
    	root->addChild(msgTag);
    	root->addChild(urlTag);
    
    	return root;
    }
    
    StanzaExtension* MyExtension::clone() const
    {
    	StanzaExtension* ret = new MyExtension(*this);
    	return ret;
    }
    
    std::string MyExtension::getTitle()
    {
    	return m_title;
    }
    
    std::string MyExtension::getMsg()
    {
    	return m_msg;
    }
    
    std::string MyExtension::getUrl()
    {
    	return m_url;
    }

在使用的地方进行注册，并且继承 IqHandler并重写对应的纯虚函数。

MyExtension* ex = new MyExtension(); // 自定义xmpp协议扩展
    	  j->registerIqHandler(this,ExtUser);
    	  j->registerStanzaExtension(ex);

重写

virtual bool handleIq( const IQ& iq ) 
    	{
    		MyExtension* ex = (MyExtension*)iq.findExtension(ExtUser);
    		if( NULL == ex )
    		{
    			return false;
    		}
    		std::cout <<"title:" << ex->getTitle() << std::endl;
    		std::cout << "msg:" << ex->getMsg() << std::endl; 
    		std::cout << "url:" << ex->getUrl() << std::endl;
    		return true;
    	}
    	virtual void handleIqID( const IQ& iq, int context )
    	{
    		return;
    	}

# 效果截图 #

![在这里插入图片描述][20190219214605711.png]

[androidpn-server-0.5.0-bin]: https://jaist.dl.sourceforge.net/project/androidpn/androidpn-server/androidpn-server-0.5.0-bin.zip
[20190219214605711.png]: /images/20220318/ec3e6677818048978cae225a1c6990a3.png