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WebResourceProvider

, 23 Mar 2007
A framework to allow public web services to be used as objects in your application.
#include "StdAfx.h"
#include "AmHttpSocket.h"
#include <atlbase.h>
#include <limits.h>

#define AgentName _T("Nimo Software HTTP Retriever 1.0")

//case insensitive search functions...
#ifdef UNICODE
#define _tcsustr wcsustr
#else
#define _tcsustr strustr
#endif
char* strustr(char *source, char *s);
wchar_t* wcsustr(wchar_t *source, wchar_t *s);

char* strustr(char *source, char *s)
{
	//make an uppercase copy af source and s
	char *csource = strdup(source);
	char *cs = strdup(s);
	strupr(csource);
	strupr(cs);
	//find cs in csource...
	char *result = strstr(csource, cs);
	if (result != NULL)
	{
		//cs is somewhere in csource
		int pos = result - csource;
		result = source;
		result += pos;
	}
	//clean up
	free(csource);
	free(cs);
	return result;
}

wchar_t* wcsustr(wchar_t *source, wchar_t *s)
{
	//make an uppercase copy af source and s
	wchar_t *csource = wcsdup(source);
	wchar_t *cs = wcsdup(s);
	wcsupr(csource);
	wcsupr(cs);
	//find cs in csource...
	wchar_t *result = wcsstr(csource, cs);
	if (result != NULL)
	{
		//cs is somewhere in csource
		int pos = result - csource;
		result = source;
		result += pos;
	}
	//clean up
	free(csource);
	free(cs);
	return result;
}

CAmHttpSocket::CAmHttpSocket()
{
	LastError = 0;
	ReceivedData = NULL;
	Headers = NULL;
	hIO = NULL;
	hIS = NULL;
	hCO = NULL;
	hIO = InternetOpen(m_strAgentName, INTERNET_OPEN_TYPE_DIRECT, NULL, NULL, 0);
  m_strAgentName = AgentName;
}

CAmHttpSocket::~CAmHttpSocket()
{
	if (ReceivedData != NULL) free(ReceivedData);
	if (Headers != NULL) free(Headers);
	if (hIO != NULL) InternetCloseHandle(hIO);
	if (hIS != NULL) InternetCloseHandle(hIS);
	if (hCO != NULL) InternetCloseHandle(hCO);
}

bool CAmHttpSocket::OpenUrl(const TCHAR *url)
{
	if (hIS != NULL) InternetCloseHandle(hIS);
	hIS = InternetOpenUrl(hIO, url, NULL, 0, HTTP_QUERY_DATE, 0);
	if (hIS != NULL) return true;
	else
	{
		LastError = GetLastError();
		return false;
	}
}

bool CAmHttpSocket::PostUrl(const TCHAR *url, const char *PostData, int PostDataLength)
{
	//check length of postdata
	if (PostDataLength == -1)
		PostDataLength = strlen(PostData);
	//some variable that we need...
	URL_COMPONENTS uc;
	//let's split the url...
	uc.dwStructSize = sizeof(uc);
	uc.lpszScheme = NULL;
	uc.dwSchemeLength = 0;
	uc.lpszHostName = NULL;
	uc.dwHostNameLength = 1;
	uc.nPort = 0;
	uc.lpszUserName = NULL;
	uc.dwUserNameLength = 0;
	uc.lpszPassword = NULL;
	uc.dwPasswordLength = 0;
	uc.lpszUrlPath = NULL;
	uc.dwUrlPathLength = 1;
	uc.lpszExtraInfo = NULL;
	uc.dwExtraInfoLength = 0;
	InternetCrackUrl(url, _tcslen(url), 0, &uc);
	//post the data...
	if (hCO != NULL) InternetCloseHandle(hCO);
	TCHAR *HostName = _tcsdup(uc.lpszHostName);
	HostName[uc.dwHostNameLength] = '\0';
	TCHAR *FileName = _tcsdup(uc.lpszUrlPath);
	FileName[uc.dwUrlPathLength] = '\0';
	if (hIS != NULL) InternetCloseHandle(hIS); //if open, close the handle to the connection
	DWORD flags;
	if (uc.nPort == 80)
	{
		//we are talking plain http
		flags = INTERNET_FLAG_NO_CACHE_WRITE;
	}
	else
	{
		//we are talking secure https
		flags = INTERNET_FLAG_NO_CACHE_WRITE | INTERNET_FLAG_SECURE |
			INTERNET_FLAG_IGNORE_CERT_CN_INVALID | INTERNET_FLAG_IGNORE_CERT_DATE_INVALID;
	}
	TCHAR headers[] = _T("Content-Type: application/x-www-form-urlencoded"); //content type for post...
	TCHAR szAccept[] = _T("*/*"); //we accept everything...
	LPTSTR AcceptTypes[2]={0};
	AcceptTypes[0]=szAccept;
	hCO = InternetConnect(hIO, HostName, uc.nPort, _T(""), _T(""), INTERNET_SERVICE_HTTP, INTERNET_FLAG_NO_CACHE_WRITE, 0);
	hIS = HttpOpenRequest(hCO, _T("POST"), FileName, NULL, NULL, (LPCTSTR*)AcceptTypes, flags, 0);
	if (!HttpSendRequest(hIS, headers, _tcslen(headers), (TCHAR*)PostData, PostDataLength))
	{
		LastError = GetLastError();
		free(HostName);
		free(FileName);

    // View error message
    LPVOID lpMsgBuf;
    FormatMessage( 
        FORMAT_MESSAGE_ALLOCATE_BUFFER | 
        FORMAT_MESSAGE_FROM_SYSTEM | 
        FORMAT_MESSAGE_IGNORE_INSERTS,
        NULL,
        GetLastError(),
        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
        (LPTSTR) &lpMsgBuf,
        0,
        NULL);
    TRACE ("CAmHttpSocket error: %s\n", (LPCTSTR) lpMsgBuf);
    LocalFree (lpMsgBuf);
    // End: View error message

		return false;
	}
	free(HostName);
	free(FileName);
	return true;
}

TCHAR* CAmHttpSocket::GetHeaders(const TCHAR *url)
{
	//did we get an url?
	if (url == NULL)
	{
		LastError = -1;
		return NULL;
	}
	//open the url...
	OpenUrl(url);
	//delete old headers...
	if (Headers != NULL) free(Headers);
	Headers = (TCHAR*)calloc(1, sizeof(TCHAR));
	//get the size headers
	DWORD d = 1, d2 = 0;
	int i = HttpQueryInfo(hIS, HTTP_QUERY_RAW_HEADERS, Headers, &d, &d2);
	//alloc some space for the headers
	Headers = (TCHAR*)realloc(Headers, d * sizeof(TCHAR));
	if (!HttpQueryInfo(hIS, HTTP_QUERY_RAW_HEADERS, Headers, &d, &d2)) return NULL;
	return Headers;
}

char* CAmHttpSocket::GetPage(const TCHAR *url, bool Post, const char *PostData, int PostDataLength)
{
	//did we get an url?
	if (url == NULL)
	{
		LastError = -1;
		return NULL;
	}
	//get the page and store it in ReceivedData...
	if (Post)
	{
		//use http post...
		if (!PostUrl(url, PostData, PostDataLength)) return NULL;
	}
	else
	{
		//use http get
		if (!OpenUrl(url)) return NULL;
	}
	const int rdsize = 8192;
	char mr[rdsize];
	DWORD rd;
	int curpos = 0;
	if (ReceivedData != NULL) free(ReceivedData);
	ReceivedData = (char*)calloc(rdsize + 1, sizeof(char));
	while (InternetReadFile(hIS, mr, rdsize - 1, &rd))
	{
		if (rd == 0) break;
		mr[rd] = '\0';
		curpos += rd;
		ReceivedData[curpos] = '\0';
		strcat(ReceivedData, mr);
		ReceivedData = (char*)realloc(ReceivedData, curpos + rdsize);
		}
	return ReceivedData;
}

TCHAR* CAmHttpSocket::GetHeaderLine(TCHAR *s)
{
	//find a line in the headers that contains s, and return a pointer to the line...
	if (Headers == NULL) return NULL;
	TCHAR *ts = Headers;
	if (_tcsustr(ts, s) != NULL) return ts;
	while (1)
	{
		if (*ts == '\0' && ts[1] == '\0') break;
		if (*ts == '\0')
		{
			ts++;
			if (_tcsustr(ts, s) != NULL) return ts;
		}
		else ts++;
	}
	return NULL;
}

int CAmHttpSocket::GetPageStatusCode()
{
	//get the correct header line
	TCHAR *s = GetHeaderLine(_T("http"));
	if (s == NULL) return 0; //no headers
	//find the 3 digit code...
	if (_tcslen(s) < 3) return 0; //some error,  the string is too short...
	while (!(isdigit(s[0]) && isdigit(s[1]) && isdigit(s[2])))
	{
		if (s[3] == '\0') return 0; //we have reached the end of the string, without finding the number...
		s++;
	}
	//make a copy of s, and return the code
	TCHAR *code = _tcsdup(s);
	code[3] = '\0'; //remove all text after the 3 digit response code
	int result = _ttoi(code);
	free(code);
	return result;
}

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About the Author

Ravi Bhavnani
Technical Lead
Canada Canada
Ravi Bhavnani is an ardent fan of Microsoft technologies who loves building Windows apps, especially PIMs, system utilities, and things that go bump on the Internet. During his career, Ravi has developed expert systems, desktop imaging apps, marketing automation software, EDA tools, a platform to help people find, analyze and understand information, trading software for institutional investors and advanced data visualization solutions. He currently works for a company that provides enterprise workforce management solutions to large clients.
 
His interests include the .NET framework, reasoning systems, financial analysis and algorithmic trading, NLP, HCI and UI design. Ravi holds a BS in Physics and Math and an MS in Computer Science and was a Microsoft MVP (C++ and C# in 2006 and 2007). He is also the co-inventor of 2 patents on software security and generating data visualization dashboards. His claim to fame is that he crafted CodeProject's "joke" forum post icon.
 
Ravi's biggest fear is that one day he might actually get a life, although the chances of that happening seem extremely remote.
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Web04 | 2.8.140916.1 | Last Updated 23 Mar 2007
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