Call JavaScript from Visual C++ v0.0.2

Usage

	CWebPage		m_webPage;
	CComPtr<IDispatch> spDisp = CHtmlView::GetHtmlDocument();
	m_webPage.SetDocument(spDisp);
	m_webPage.CallJScript("add","1","2");

WebPage.h

// WebPage.h: interface for the CWebPage class.
//
//////////////////////////////////////////////////////////////////////

#if !defined(AFX_WEBPAGE_H__AEBD50B8_EE66_40AB_8B92_C4EECB9BCD22__INCLUDED_)
#define AFX_WEBPAGE_H__AEBD50B8_EE66_40AB_8B92_C4EECB9BCD22__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#include <atlbase.h>
#include <Mshtml.h>

class CWebPage  
{
public:
	CWebPage();
	virtual ~CWebPage();

	bool SetDocument(IDispatch* pDisp);
	LPDISPATCH GetHtmlDocument() const;
	const CString GetLastError() const;
	bool GetJScript(CComPtr<IDispatch>& spDisp);
	bool GetJScripts(CComPtr<IHTMLElementCollection>& spColl);

	CString ScanJScript(CString& strAText, CStringArray& args);

	bool CallJScript(const CString strFunc,CComVariant* pVarResult = NULL);
	bool CallJScript(const CString strFunc,const CString strArg1,
			CComVariant* pVarResult = NULL);
	bool CallJScript(const CString strFunc,const CString strArg1,
			const CString strArg2,CComVariant* pVarResult = NULL);
	bool CallJScript(const CString strFunc,const CString strArg1,
			const CString strArg2,const CString strArg3,
			CComVariant* pVarResult = NULL);
	bool CallJScript(const CString strFunc,
		const CStringArray& paramArray,
		CComVariant* pVarResult = NULL);

protected:


	void ShowError(LPCSTR lpszText);

protected:

	CComPtr<IHTMLDocument2>	m_spDoc;
	CString	m_strError;

};

inline
void CWebPage::ShowError(LPCSTR lpszText)
{
	m_strError = "JSCall Error:\n" + CString(lpszText);
}
inline 
const CString CWebPage::GetLastError() const
{
	return m_strError;
}
inline
LPDISPATCH CWebPage::GetHtmlDocument() const
{
	return m_spDoc;
}

CString GetNextToken(CString& strSrc, const CString strDelim,
					 bool bTrim = false, 
					 bool bFindOneOf = true);

#endif // !defined(AFX_WEBPAGE_H__AEBD50B8_EE66_40AB_8B92_C4EECB9BCD22__INCLUDED_)

WebPage.cpp

/////////////////////////////////////////////////////////////////
//             By Eugene Khodakovsky                           //
//                  April,2002                                 //
//            Last Update: April, 2002                         //
/////////////////////////////////////////////////////////////////

#include "stdafx.h"
//#include "JSCall.h"
#include "WebPage.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

#define CHECK_POINTER(p)\
	ATLASSERT(p != NULL);\
	if(p == NULL)\
	{\
		ShowError("NULL pointer");\
		return false;\
	}

const CString GetSystemErrorMessage(DWORD dwError)
{
	CString strError;
	LPTSTR lpBuffer;

	if(!FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
			NULL,  dwError,
			MAKELANGID(LANG_NEUTRAL, SUBLANG_SYS_DEFAULT),
			(LPTSTR) &lpBuffer, 0, NULL))

	{
		strError = "FormatMessage Netive Error" ;
	}
	else
	{
		strError = lpBuffer;
		LocalFree(lpBuffer);
	}
	return strError;
}

CString GetNextToken(CString& strSrc, const CString strDelim,bool bTrim, bool bFindOneOf)
{
	CString strToken;
	int idx = bFindOneOf? strSrc.FindOneOf(strDelim) : strSrc.Find(strDelim);
	if(idx != -1)
	{
		strToken  = strSrc.Left(idx);
		strSrc = strSrc.Right(strSrc.GetLength() - (idx + 1) );
	}
	else
	{
		strToken = strSrc;
		strSrc.Empty();
	}
	if(bTrim)
	{
		strToken.TrimLeft();
		strToken.TrimRight();
	}
	return strToken;
}

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CWebPage::CWebPage()
{
}

CWebPage::~CWebPage()
{

}

bool CWebPage::SetDocument(IDispatch* pDisp)
{
	CHECK_POINTER(pDisp);

	m_spDoc = NULL;

	CComPtr<IDispatch> spDisp = pDisp;

	HRESULT hr = spDisp->QueryInterface(IID_IHTMLDocument2,(void**)&m_spDoc);
	if(FAILED(hr))
	{
		ShowError("Failed to get HTML document COM object");
		return false;
	}
	return true;
}

bool CWebPage::GetJScript(CComPtr<IDispatch>& spDisp)
{
	CHECK_POINTER(m_spDoc);
	HRESULT hr = m_spDoc->get_Script(&spDisp);
	ATLASSERT(SUCCEEDED(hr));
	return SUCCEEDED(hr);
}

bool CWebPage::GetJScripts(CComPtr<IHTMLElementCollection>& spColl)
{
	CHECK_POINTER(m_spDoc);
	HRESULT hr = m_spDoc->get_scripts(&spColl);
	ATLASSERT(SUCCEEDED(hr));
	return SUCCEEDED(hr);
}

bool CWebPage::CallJScript(const CString strFunc,CComVariant* pVarResult)
{
	CStringArray paramArray;
	return CallJScript(strFunc,paramArray,pVarResult);
}

bool CWebPage::CallJScript(const CString strFunc,const CString strArg1,
						   CComVariant* pVarResult)
{
	CStringArray paramArray;
	paramArray.Add(strArg1);
	return CallJScript(strFunc,paramArray,pVarResult);
}

bool CWebPage::CallJScript(const CString strFunc,const CString strArg1,
						   const CString strArg2,CComVariant* pVarResult)
{
	CStringArray paramArray;
	paramArray.Add(strArg1);
	paramArray.Add(strArg2);
	return CallJScript(strFunc,paramArray,pVarResult);
}

bool CWebPage::CallJScript(const CString strFunc,const CString strArg1,
						   const CString strArg2,const CString strArg3,
						   CComVariant* pVarResult)
{
	CStringArray paramArray;
	paramArray.Add(strArg1);
	paramArray.Add(strArg2);
	paramArray.Add(strArg3);
	return CallJScript(strFunc,paramArray,pVarResult);
}

bool CWebPage::CallJScript(const CString strFunc,
						   const CStringArray& paramArray,
						   CComVariant* pVarResult)
{
	CComPtr<IDispatch> spScript;
	if(!GetJScript(spScript))
	{
		ShowError("Cannot GetScript");
		return false;
	}
	CComBSTR bstrMember(strFunc);
	DISPID dispid = NULL;
	HRESULT hr = spScript->GetIDsOfNames(IID_NULL,&bstrMember,1,
					LOCALE_SYSTEM_DEFAULT,&dispid);
	if(FAILED(hr))
	{
		ShowError(GetSystemErrorMessage(hr));
		return false;
	}

	const int arraySize = paramArray.GetSize();

	DISPPARAMS dispparams;
	memset(&dispparams, 0, sizeof dispparams);
	dispparams.cArgs = arraySize;
	dispparams.rgvarg = new VARIANT[dispparams.cArgs];
	
	for( int i = 0; i < arraySize; i++)
	{
		CComBSTR bstr = paramArray.GetAt(arraySize - 1 - i); // back reading
		bstr.CopyTo(&dispparams.rgvarg[i].bstrVal);
		dispparams.rgvarg[i].vt = VT_BSTR;
	}
	dispparams.cNamedArgs = 0;

	EXCEPINFO excepInfo;
	memset(&excepInfo, 0, sizeof excepInfo);
   	CComVariant vaResult;
	UINT nArgErr = (UINT)-1;  // initialize to invalid arg
         
	hr = spScript->Invoke(dispid,IID_NULL,0,
							DISPATCH_METHOD,&dispparams,&vaResult,
							&excepInfo,&nArgErr);

	delete [] dispparams.rgvarg;
	if(FAILED(hr))
	{
		ShowError(GetSystemErrorMessage(hr));
		return false;
	}
	
	if(pVarResult)
	{
		*pVarResult = vaResult;
	}
	return true;
}

// returned java script function name, input string is truncating
CString CWebPage::ScanJScript(CString& strAText, CStringArray& args)
{
	args.RemoveAll();
	CString strDelim(" \n\r\t"),strSrc(strAText);
	bool bFound = false;
	while(!strSrc.IsEmpty())
	{
		CString strStart = GetNextToken(strSrc,strDelim);
		if(strStart == "function")
		{
			bFound = true;
			break;
		}
		if(strStart == "/*")
		{
			// Skip comments
			while(!strSrc.IsEmpty())
			{
				CString strStop = GetNextToken(strSrc,strDelim);
				if(strStop == "*/")
				{
					break;
				}
			}
		}
	}

	if(!bFound)
		return "";
	
	CString strFunc = GetNextToken(strSrc,"(",true);
	CString strArgs = GetNextToken(strSrc,")",true);

	// Parse arguments
	CString strArg;
	while(!(strArg = GetNextToken(strArgs,",")).IsEmpty())
		args.Add(strArg);

	strAText= strSrc;
	return strFunc;
}