C++/MFC Read Product Example

This example code is a simple example showing how the MFC classes can be used to wrapper the HTTP API calls and retrieve product information. This example is retrieving a single product and displaying rudimentary details. Calling the API in this way has no dependencies on libraries.

If you do not program using C++/MFC this example still shows the overall logic that would be applicable to most languages

This code is deliberately simple and would need enhancing before use in production level code

• The code uses the returned XML string without using an XML parser
• The network call is made on the main thread and will block screen updates while waiting for a response on the network
• Network errors are displayed in technical form to the user

Code

Download Visual Studio Project (37Kb)

// Read user interface, [not shown here, download full source]
long thePid = ???; // Value from User Interface

// Build the URL we want
CString Url;

// For this example we request Named XML format
Url.Format("/gnap/M/buck?3=retailmax.elink.products&9=f100=%ld", thePid);

// Other formats are possible...
// Numeric XML
// Url.Format("/gnap/buck?3=retailmax.elink.products&9=f100=%ld", thePid);

// Named JSON
// Url.Format("/gnap/J/buck?3=retailmax.elink.products&9=f100=%ld", thePid);

// Numeric JSON
// Url.Format("/gnap/j/buck?3=retailmax.elink.products&9=f100=%ld", thePid);


CString gError;
CString ReplyString;

try {
	CInternetSession sess("MFC_ReadProduct " __DATE__ " " __TIME__);

	CHttpConnection* pHttp = sess.GetHttpConnection(m_ServerAddress, (INTERNET_PORT) port);
	if (pHttp) {
		const char* Accept[2] = { "*/*", NULL };
		CHttpFile* pHFile = pHttp->OpenRequest("GET", Url, NULL, 1, (const char**) Accept);
		if (pHFile) {
			pHFile->SendRequest();
			DWORD Status = 0;
			pHFile->QueryInfoStatusCode(Status);
			if ((Status >= 200) && (Status <= 299)) {
				{
					char bb[4096];
					int readlen = pHFile->Read(bb, sizeof(bb));
					while (readlen > 0) {
						ReplyString += CString(bb, readlen);
						readlen = pHFile->Read(bb, sizeof(bb));
					}
				}
			} else {
				switch (Status) {
				case	404:
					gError += "URL or file not found";
					break;
				default:
					CString w;
					w.Format("Request to server failed with error=%ld.  Read failed", Status);
					gError += w;
				}
			}

			delete pHFile;
		}

		delete pHttp;
	}


} catch (CInternetException*pI) {
	char bb[4096];
	pI->GetErrorMessage(bb, sizeof(bb));
	gError += "Network level error:\n\n";
	gError += bb;
	pI->Delete();
}

if (! gError.IsEmpty()) {
	AfxMessageBox(gError, MB_ICONSTOP);
	return;
}

// Display raw response string   AfxMessageBox(ReplyString);

// Decode and display response. [not shown here, download full source]