浏览器插件之ActiveX开发（一）

港控/mmm° 2022-05-30 05:36 183阅读 0赞

一般的Web应用对于浏览器插件能不使用的建议尽量不使用，因为其涉及到安全问题以及影响用户安装（或自动下载注册安装）体验问题。在有特殊需求（如涉及数据安全的金融业务数据交互、需插件才能实现的与本地设备的交互等）的情况下可以酌情慎用。

浏览器插件总体可以划分为两大阵营，即IE支持的插件以及非IE支持的插件。本来在Netscape时代，对于浏览器插件是有公用的规范的(NPAPI)，一开始所有浏览器都支持该规范，包括IE。后来出于商业原因，微软的IE不再支持NPAPI，改而自己开发了一套基于COM的ActiveX体系，但这个体系对于非IE浏览器是拒绝支持的。所以目前的状况基本是，IE浏览器仅支持ActiveX控件，而Firefox、Chrome等浏览器只支持另一类接口（XPCOM或NPAPI）。要想实现一个Web插件，至少需要同时考虑IE支持的AceiveX版以及非IE支持的Plugin版（Flash等插件对于IE与非IE浏览器都是不同的）。

ActiveX的开发可以用C\#、VB及C++等语言。用C++开发ActiveX既可以使用ATL，也可以使用MFC。ATL ActiveX输出文件较小，适合网络传输，但开发复杂度稍大；而MFC ActiveX输出文件稍大（附带必要的MFC dll），但易于上手。本文主要介绍基于MFC的ActiveX开发。

**一、创建项目及添加接口**

在Vs.net 2008中，新建一个MFC ActiveX Control项目：

[![image][]][image 1]

点击“OK”后将弹出如下对话框：

[![image][image 2]][image_image 2]

依次点击“Next”按钮直到“Control Settings”标签页:

[![image][image 3]][image_image 3]

由于本例子只演示仅提供函数接口不基于界面的ActiveX，故“Create control based on”选择“（none）”即可。点击"Finish”按钮，即完成了项目的创建，文件结构如下：

[![image][image 4]][image_image 4]

右击项目名称，选择“Properties”，在项目属性对话框中对“All Configurations”进行配置。在“Configurations Properties->General”标签页中，“Use of MFC”选择“Use MFC in a static Library”，以便编译时将MFC相关库自动和控件一起打包。对于“Character Set”的选择根据具体情况而定，须注意“Unicode Character Set”和“Mulity-Byte Character SEt”对字符处理是完全不一样的（字符编码不一样，需要进行MultiByteToWideChar或WideCharToMultiByte转换）。

注意：创建MFC ActiveX Control时已经自动给项目添加了.def文件并做好了相应关联。若对配置信息更改后导致编译的ocx注册不成功或提示找不到EntryPoint，可以检查一下Linker->Input的Module Definition File是否配置正确，正常情况下已经自动配置好了，如下图：

[![image][image 5]][image_image 5]

接下来就可以在ActiveX中添加我们需要与外部交互的接口方法和属性了。选择“Class View”，右击“MyTestActiveXLib->\_DMyTestActiveX”，在弹出的菜单中可以选择Add Function或Add Property来添加接口方法或接口属性：

[![image][image 6]][image_image 6]

这里以定义一个*LONG AddFun(LONG num1,LONG num2) *的接口函数为例，添加Menthod如下图所示：

[![image][image 7]][image_image 7]

点击Finish后，即可在“MyTestActiveXCtrl.cpp”文件找到刚添加的接口函数代码：

[![image][image 8]][image_image 8]

在函数体中完成自定义的业务逻辑即可。

**二、实现安全接口**

**      **上述项目编译后即可生成ocx文件，该ocx即可嵌入html在IE中运行。但如果该ocx对应页面是放在真实的web服务器上，访问该页面执行ActiveX里对应接口时IE将会提示“无相关属性,需要设置其初始化和脚本运行的安全性”等信息。这是因为ActiveX要在远程IE上执行，需要实现安全接口。有关控件的初始化和脚本安全问题，《[再谈IObjectSafety][IObjectSafety]》一文及其引用的Microsoft文章做了较详致描述。

对于ATL写的ActiveX，实现IObjectSafety即可，[这里][Link 1]有ATL实现安全接口的详细的描述。

对于MFC写的ActiveX，可以通过修改注册表的方式来实现控件的安全性，微软也提供的[详细的文档描述][Link 2]。具体实现步骤如下：

1、首先在项目中添加Cathelp.h和Cathelp.cpp两个文件，其内容如下所示。

**Cathelp.h**

#include "comcat.h"
    
    // Helper function to create a component category and associated
    // description
    HRESULT CreateComponentCategory(CATID catid, WCHAR* catDescription);
    
    // Helper function to register a CLSID as belonging to a component
    // category
    HRESULT RegisterCLSIDInCategory(REFCLSID clsid, CATID catid);
    
    // HRESULT UnRegisterCLSIDInCategory - Remove entries from the registry 
    HRESULT UnRegisterCLSIDInCategory(REFCLSID clsid, CATID catid);

Cathelp.cpp

#include "stdafx.h"
    #include "comcat.h"
    #include "strsafe.h"
    #include "objsafe.h"
    
    
    // HRESULT CreateComponentCategory - Used to register ActiveX control as safe 
    HRESULT CreateComponentCategory(CATID catid, WCHAR *catDescription)
    {
        ICatRegister *pcr = NULL ;
        HRESULT hr = S_OK ;
     
        hr = CoCreateInstance(CLSID_StdComponentCategoriesMgr, 
                NULL, CLSCTX_INPROC_SERVER, IID_ICatRegister, (void**)&pcr);
        if (FAILED(hr))
            return hr;
     
        // Make sure the HKCR\Component Categories\{..catid...}
        // key is registered.
        CATEGORYINFO catinfo;
        catinfo.catid = catid;
        catinfo.lcid = 0x0409 ; // english
        size_t len;
        // Make sure the provided description is not too long.
        // Only copy the first 127 characters if it is.
        // The second parameter of StringCchLength is the maximum
        // number of characters that may be read into catDescription.
        // There must be room for a NULL-terminator. The third parameter
        // contains the number of characters excluding the NULL-terminator.
        hr = StringCchLength(catDescription, STRSAFE_MAX_CCH, &len);
        if (SUCCEEDED(hr))
            {
            if (len>127)
              {
                len = 127;
              }
            }   
        else
            {
              // TODO: Write an error handler;
            }
        // The second parameter of StringCchCopy is 128 because you need 
        // room for a NULL-terminator.
        hr = StringCchCopy(catinfo.szDescription, len + 1, catDescription);
        // Make sure the description is null terminated.
        catinfo.szDescription[len + 1] = '\0';
     
        hr = pcr->RegisterCategories(1, &catinfo);
        pcr->Release();
     
        return hr;
    }
     
    // HRESULT RegisterCLSIDInCategory -
    //      Register your component categories information 
    HRESULT RegisterCLSIDInCategory(REFCLSID clsid, CATID catid)
    {
    // Register your component categories information.
        ICatRegister *pcr = NULL ;
        HRESULT hr = S_OK ;
        hr = CoCreateInstance(CLSID_StdComponentCategoriesMgr, 
                    NULL, CLSCTX_INPROC_SERVER, IID_ICatRegister, (void**)&pcr);
        if (SUCCEEDED(hr))
        {
           // Register this category as being "implemented" by the class.
           CATID rgcatid[1] ;
           rgcatid[0] = catid;
           hr = pcr->RegisterClassImplCategories(clsid, 1, rgcatid);
        }
     
        if (pcr != NULL)
            pcr->Release();
                
        return hr;
    }
     
    // HRESULT UnRegisterCLSIDInCategory - Remove entries from the registry 
    HRESULT UnRegisterCLSIDInCategory(REFCLSID clsid, CATID catid)
    {
        ICatRegister *pcr = NULL ;
        HRESULT hr = S_OK ;
     
        hr = CoCreateInstance(CLSID_StdComponentCategoriesMgr, 
                NULL, CLSCTX_INPROC_SERVER, IID_ICatRegister, (void**)&pcr);
        if (SUCCEEDED(hr))
        {
           // Unregister this category as being "implemented" by the class.
           CATID rgcatid[1] ;
           rgcatid[0] = catid;
           hr = pcr->UnRegisterClassImplCategories(clsid, 1, rgcatid);
        }
     
        if (pcr != NULL)
            pcr->Release();
     
        return hr;
    }

**注**：Cathelp.cpp中的代码是基于Unicode Character Set的。故项目配置时若改成Multi-Byte Character Set，需对Cathelp.cpp中代码做相应修改，否则编译不过；

2、在MyTestActiveX.cpp文件中，添加**CLSID\_SafeItem**的定义：

[![image][image 9]][image_image 9]

CLSID\_SafeItem的值是根据xxxCtrl.cpp（本例中是MyTestActiveXCtrl.cpp）文件中**IMPLEMENT\_OLECREATE\_EX**的定义而来的（实际上就是ActiveX的CLASSID）。本例中MyTestActiveXCtrl.cpp文件中**IMPLEMENT\_OLECREATE\_EX**的的值如下：

[![image][image 10]][image_image 10]

将“0x1345c26b, 0xe979, 0x45a5, 0x99, 0x7d, 0x94, 0x27, 0xfb, 0x81, 0xe7, 0x7”简单的在适当位置添加“\{”和“\}”括弧即变成了CLSID\_SafeItem的值“0x1345c26b, 0xe979, 0x45a5, **\{** 0x99, 0x7d, 0x94, 0x27, 0xfb, 0x81, 0xe7, 0x7**\}**”。

另外，MyTestActiveX.cpp文件起始处还需要引入如下两个文件方能正常编译：

[![image][image 11]][image_image 11]

3、修改MyTestActiveX.cpp中**DllRegisterServer**和**DllUnregisterServer**函数，代码如下（照抄即可）

// DllRegisterServer - Adds entries to the system registry
    
    STDAPI DllRegisterServer(void)
    {
        HRESULT hr;    // HResult used by Safety Functions
     
        AFX_MANAGE_STATE(_afxModuleAddrThis);
     
        if (!AfxOleRegisterTypeLib(AfxGetInstanceHandle(), _tlid))
          return ResultFromScode(SELFREG_E_TYPELIB);
     
        if (!COleObjectFactoryEx::UpdateRegistryAll(TRUE))
          return ResultFromScode(SELFREG_E_CLASS);
     
        // Mark the control as safe for initializing.
                                                 
        hr = CreateComponentCategory(CATID_SafeForInitializing, 
             L"Controls safely initializable from persistent data!");
        if (FAILED(hr))
          return hr;
     
        hr = RegisterCLSIDInCategory(CLSID_SafeItem, 
             CATID_SafeForInitializing);
        if (FAILED(hr))
            return hr;
     
        // Mark the control as safe for scripting.
     
        hr = CreateComponentCategory(CATID_SafeForScripting, 
                                     L"Controls safely  scriptable!");
        if (FAILED(hr))
            return hr;
     
        hr = RegisterCLSIDInCategory(CLSID_SafeItem, 
                            CATID_SafeForScripting);
        if (FAILED(hr))
            return hr;
     
        return NOERROR;
    }
    
    
    
    // DllUnregisterServer - Removes entries from the system registry
    
    STDAPI DllUnregisterServer(void)
    {
        AFX_MANAGE_STATE(_afxModuleAddrThis);  
    
        // 删除控件初始化安全入口.   
        HRESULT hr=UnRegisterCLSIDInCategory(CLSID_SafeItem, CATID_SafeForInitializing);  
    
        if (FAILED(hr))  
            return hr;  
    
        // 删除控件脚本安全入口   
        hr=UnRegisterCLSIDInCategory(CLSID_SafeItem, CATID_SafeForScripting);  
    
        if (FAILED(hr))  
            return hr;  
    
        if (!AfxOleUnregisterTypeLib(_tlid, _wVerMajor, _wVerMinor))  
            return ResultFromScode(SELFREG_E_TYPELIB);  
    
        if (!COleObjectFactoryEx::UpdateRegistryAll(FALSE))  
            return ResultFromScode(SELFREG_E_CLASS);  
    
        return NOERROR;
    }

**注**： 很多例子里**DllUnregisterServer**的写法与本文的写法不一致，结果导致卸载控件时(regsvr32 /u xxxx.ocx)出现“调用某某ocx文件的DllUnregisterServer函数出错，错误代码：0x80070002”错误。究其根源，是**DllUnregisterServer**中删除注册表的顺序出了问题，“[waxgourd0的专栏][waxgourd0]”中[有篇文章][Link 3]对此做了详尽描述。

4、在解决方案下点击资源文件（Resources->MyTestActiveX.rc），点击右键在弹出的菜单中选择“ ”， 编辑资源文件信息并确保以下几个项目的正确性：

[![image][image 12]][image_image 12]

a) BLOCK的值为“**040904e4**”

b) **OLESelfRegister**的值为“**\\0**”

c) VarFileInfo中的Translation后对应为“**0x0409, 1252**”

到目前为止，可以编译项目，输出的ocx控件是可以正常运行的了。~~~

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

**MFC ActiveX开发参考资料：**

1.  [A Complete ActiveX Web Control Tutorial][] 
2.  [Enable an MFC ActiveX Control to Self-Register][]

**ATL ActiveX开发参考资料：**

1.  [洞庭散人: COM组件开发实践（二）][COM]

**综合参考资料：**

1.  [杨峰- COM组件与设计应用][- COM]
2.  [COM开发推荐书籍（洞庭散人推荐）][COM 1]

=======================================================================  
**野文(Jasson Qian)**  
\------------------------------------------------------  
博客园： [http://qguohog.cnblogs.com][http_qguohog.cnblogs.com]  
CSDN： [http://blog.csdn.net/sallay][http_blog.csdn.net_sallay]

[image]: /images/20220530/d2add9215cc9447abce50122735791aa.png
[image 1]: https://images0.cnblogs.com/blog/32245/201301/22174611-6b5c09180a434d839c52c1e404303741.png
[image 2]: https://images0.cnblogs.com/blog/32245/201301/22174613-a683dd8abce44329aba81a3d18dd3454.png
[image_image 2]: /images/20220530/d3c4086a5de84153ae5fef75be553bc2.png
[image 3]: https://images0.cnblogs.com/blog/32245/201301/22174615-b777695737ee4867b9bfd898522df426.png
[image_image 3]: /images/20220530/09a1037ef2c34fc3923c5115c10c5bb9.png
[image 4]: https://images0.cnblogs.com/blog/32245/201301/22174616-edc619c0f3db4112866bde0dbb8b92b9.png
[image_image 4]: /images/20220530/41dec1ab0ab54bff89f00697261f3a3a.png
[image 5]: https://images0.cnblogs.com/blog/32245/201301/22174618-7dcac3841f2e4e418c92339e85638abb.png
[image_image 5]: /images/20220530/c5f97b34682f433aa39e9c8cfc7ec0c6.png
[image 6]: https://images0.cnblogs.com/blog/32245/201301/22174619-53a039533dc04cd3a60c27bf081b4225.png
[image_image 6]: /images/20220530/c6a1d75c0c7d4ce89a334a81d77934ca.png
[image 7]: https://images0.cnblogs.com/blog/32245/201301/22174620-8896f0345dae46e793b5bfb26a7655bc.png
[image_image 7]: /images/20220530/ae1430d6fb8941968b6c8a97e707b56b.png
[image 8]: https://images0.cnblogs.com/blog/32245/201301/22174621-5a97453de2fd4f85b425eec830782059.png
[image_image 8]: /images/20220530/ab8c137ba358466580de3de23dbd5c82.png
[IObjectSafety]: http://blog.csdn.net/optman/article/details/1698070
[Link 1]: http://support.microsoft.com/kb/168371/en-us
[Link 2]: http://support.microsoft.com/kb/161873/en-us
[image 9]: https://images0.cnblogs.com/blog/32245/201301/22174622-9fc9439b9ee349da9219e12aaa375fb0.png
[image_image 9]: /images/20220530/85181434d4c04b8ebdea07ae25935e86.png
[image 10]: https://images0.cnblogs.com/blog/32245/201301/22174623-b4784be8d642447db191b23ed5a1159a.png
[image_image 10]: /images/20220530/6469c9b9d5bd431eadad38ab19e85c79.png
[image 11]: https://images0.cnblogs.com/blog/32245/201301/22174624-236f201095ce4b2f895110b7e385f8f6.png
[image_image 11]: /images/20220530/550240d659534c4a85db2abad11d2a0f.png
[waxgourd0]: http://blog.csdn.net/waxgourd0
[Link 3]: http://blog.csdn.net/waxgourd0/article/details/7481245
[image 12]: https://images0.cnblogs.com/blog/32245/201301/24161955-1d5e1a2ab5a24933901468acc82eec03.png
[image_image 12]: /images/20220530/8657d3c49ee34066b6e1da79e816f301.png
[A Complete ActiveX Web Control Tutorial]: http://www.codeproject.com/Articles/14533/A-Complete-ActiveX-Web-Control-Tutorial
[Enable an MFC ActiveX Control to Self-Register]: http://www.codeproject.com/Articles/501/Enable-an-MFC-ActiveX-Control-to-Self-Register
[COM]: http://www.cnblogs.com/phinecos/archive/2008/07/28/1254963.html
[- COM]: http://blog.csdn.net/joeblackzqq/article/details/7102383
[COM 1]: http://www.cnblogs.com/phinecos/archive/2008/08/08/1263756.html
[http_qguohog.cnblogs.com]: http://qguohog.cnblogs.com/
[http_blog.csdn.net_sallay]: http://blog.csdn.net/sallay