MFCを利用してHTTPアクセスをするクラス。
GETメソッドしか使えないけど、
ヘッダ情報とコンテンツぐらいは取得可能。

// Http.h: interface for the CHttp class.
//
//////////////////////////////////////////////////////////////////////

#if !defined(AFX_HTTP_H__A1198C8D_2219_4E9E_A135_1C189078CD3D__INCLUDED_)
#define AFX_HTTP_H__A1198C8D_2219_4E9E_A135_1C189078CD3D__INCLUDED_

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

class CHttp  
{

// Attributes:
private:
	CString m_strHeaders;
	CString m_strContent;

// Construction/Destruction:
public:
	CHttp();
	virtual ~CHttp();

// Internal Opreations:
private:
	void Clear();

// Opreations:
public:
	void DoGet(CString strURL);
	CString GetHeaders();
	CString GetContent();

};

#endif // !defined(AFX_HTTP_H__A1198C8D_2219_4E9E_A135_1C189078CD3D__INCLUDED_)

>>2 のつづき。

// Http.cpp: implementation of the CHttp class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include <afxinet.h>
#include "Http.h"

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

//////////////////////////////////////////////////////////////////////
// Internal Constant
//////////////////////////////////////////////////////////////////////

static CString LINE_SEPARATOR = "\n";

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

CHttp::CHttp()
{

}

CHttp::~CHttp()
{

}

CString CHttp::GetContent()
{
	return m_strContent;
}

CString CHttp::GetHeaders()
{
	return m_strHeaders;
}

void CHttp::Clear()
{
	m_strHeaders = "";
	m_strContent = "";
}

>>3 のつづき。

void CHttp::DoGet(CString strURL)
{
	Clear();

	DWORD dwServiceType;
	CString server;
	CString file; 
	CString referer;
	INTERNET_PORT nPort;

	if(!AfxParseURL(strURL, dwServiceType, server, file, nPort)){
		::MessageBox(NULL, "Filed to parse URL.", "Error", MB_OK);
		return;
	}

	CInternetSession session;
	CHttpConnection* pCon =
		session.GetHttpConnection(
			server,
			CHttpConnection::HTTP_VERB_GET,
			nPort,
			NULL,
			NULL);
	CHttpFile* pFile =
		pCon->OpenRequest(
			// CHttpConnection::HTTP_VERB_HEAD, // for head method
			CHttpConnection::HTTP_VERB_GET,
			file,
			NULL,
			1,
			NULL,
			NULL,
			INTERNET_FLAG_RELOAD | INTERNET_FLAG_DONT_CACHE);
	pFile->SendRequest();

	// for debug
	//::MessageBox(NULL, pFile->GetFileURL(), "URL", MB_OK);

	// get headers
	CString strHeaders;
	{
		DWORD dwIndex = 0;
		CString buf;

		while(true){

			BOOL bResult =
				pFile->QueryInfo(
					HTTP_QUERY_RAW_HEADERS_CRLF,
					buf,
					&dwIndex);

			if(!bResult){
				break;
			}

			strHeaders = strHeaders + buf;
			strHeaders = strHeaders + LINE_SEPARATOR;
			dwIndex++;
		}
	}
	m_strHeaders = strHeaders; // set to member variable

	// get content
	CString strContent;
	{
		CString buf;
		while(pFile->ReadString(buf)){
			strContent = strContent + buf;
			strContent = strContent + LINE_SEPARATOR;
		}
	}
	m_strContent = strContent; // set to member variable

	pFile->Close();
	session.Close();
}

>>4 の 使用例

CString strURL = "http://www.nilab.info/";
CHttp http;
http.DoGet(strURL);
CString strHeaders = http.GetHeaders();
CString strContent = http.GetContent();