WinHttpWrappers v1.02 A set of MFC classes to encapsulate WinHttp

Welcome to WinHttpWrappers, a set of MFC classes to encapsulate WinHttp and especially its asynchronous support. The classes are based on the MSDN Magazine article about WinHttp by Kenny Kerr at http://msdn.microsoft.com/en-gb/magazine/cc716528.aspx. You should read this article to get a better understanding on how to properly use WinHttp (especially when in asynchronous mode). Coming back to my classes then should make more sense<gg>.

The classes provided are: CWinHttpHandle, CWinHttpSession, CWinHttpConnection, CWinHttpRequest, CAsyncWinHttpDownloader & CSyncWinHttpDownloader.

CWinHttpHandle provides a class based encapsulation of a HINTERNET handle and various WinHttp methods which work on any HINTERNET type handle. It also provides a prebuilt virtual callback method called "OnCallback" which derived classes can customize.

CWinHttpSession provides encapsulation of a WinHttp session HINTERNET handle. It provides an "Initialize" method which encapsulates the WinHttpOpen API.

CWinHttpConnection provides encapsulation of a WinHttp connection HINTERNET handle. It provides an "Initialize" method which encapsulates the WinHttpConnect API.

CWinHttpRequest provides encapsulation of a WinHttp request HINTERNET handle. It provides an "Initialize" method which encapsulates the WinHttpOpenRequest API. It also encapsulates all the WinHttp API calls which take a request handle such as WinHttpAddRequestHeaders, WinHttpQueryHeaders, WinHttpReadData, WinHttpQueryAuthSchemes etc etc.

CAsyncWinHttpDownloader which derives from CWinHttpRequest which provides for a high level wrapping of an asynchronous WinHttp request. It supports sending request bodies from a file or from an in-memory array. It also supports downloading to a file or to an in-memory array. Internally this class looks after a memory buffer and file for downloading the request into. It also supports various authentication schemes and bandwidth throttling. It also implements proper thread protection of these values to ensure correct operation when WinHttp is used in asynchronous mode. It also provides a number of virtual methods, including OnReadData, OnWriteData, GetHeaders, GetContentLength, DoAuthentication, ChooseAuthScheme, On407Response, On401Response and OnCallbackComplete which provide various notifications during the lifetime of a WinHttp download request.

Finally CSyncWinHttpDownloader which derives from CAsyncWinHttpDownloader is provided. This class provides a high level wrapping of a synchronous WinHttp request.

Features

• Provides a simple MFC Header only module to easily encapsulate WinHttp.
• Supports both WinHttp synchronous and asynchronous modes.
• Provides a complete wrapping for all the WinHttp functionality.
• Provides a version of a asynchronous callback method which dumps all the status to the debugger output window when in debug mode. This helps provides a good understanding of the various callbacks which WinHttp can provide.

The enclosed zip file contains the WinHttpWrappers source code and a simple VC 2008 dialog based application which demonstrates the classes using a simply asynchronous download of a HTTP page to a local file using the "CDownloadFileWinHttpRequest" class. It also demonstrates cancelling of pending requests as well as reporting the various callbacks which occur during the download.

Copyright

• You are allowed to include the source code in any product (commercial, shareware, freeware or otherwise) when your product is released in binary form.
• You are allowed to modify the source code in any way you want except you cannot modify the copyright details at the top of each module.
• If you want to distribute source code with your application, then you are only allowed to distribute versions released by the author. This is to maintain a single distribution point for the source code.

Updates

V1.0 (29 May 2011)

• Initial public release.

V1.01 (30 May 2011)

• All tracing in CWinHttpHandle::OnCallback has been moved into a new TraceCallback method which client code is free to call. Also all tracing in CWinHttpHandle:: OnCallbackComplete has been moved into a new TraceCallbackComplete method. Also all tracing in CDownloadFileWinHttpRequest::OnCallbackComplete has been moved into a new TraceCallbackComplete method.
• Moved cleanup of resources from CDownloadFileWinHttpRequest::OnCallbackComplete to a new public method called ReleaseResources()

V1.02 (1 August 2011)

• CDownloadFileWinHttpRequest class is now called CAsyncWinHttpDownloader
• Major rework of the CAsyncWinHttpDownloader to now support HTTP and Proxy authentication, pre-authentication, resumed downloads, file uploads, in-memory arrays and bandwidth throttling.
• Fixed an issue in TraceCallback where WINHTTP_CALLBACK_STATUS_SECURE_FAILURE would be reported incorrectly by TRACE statements
• Addition of a new CSyncWinHttpDownloader class which provides for synchronous WinHTTP downloads.
• Updated the sample app to allow all of the new configuration settings of CAsyncWinHttpDownloader and CSyncWinHttpDownloader classes to be exercised.
• Fixed a bug in CWinHttpRequest::WriteData() where buffer parameter was incorrectly set as a LPVOID instead of a LPCVOID.