CWebGrab
is a simple class that allows you to quickly and easily download files from the net. The class is merely a light wrapper for the MFC internet classes, and as such supports any protocol that the MFC classes support.
The class is extremely simple to use and has only one main function that you need to call: CWebGrab::GetFile
. The syntax is:
BOOL GetFile(LPCTSTR szURL, CString& strBuffer,
LPCTSTR szAgentName = NULL, CWnd* pWnd = NULL);
Downloads a file from the given URL
szURL
is the URL
strBuffer
is a CString
buffer that will hold the contents of the downloaded file
szAgentName
is the agent name you want to send to the website (may be NULL)
pWnd
is a status window. Status updates will be sent to this window using SetWindowText()
BOOL GetFileInfo(LPCTSTR szURL, CString& strLastModified, DWORD& dwSize,
DWORD& dwServerError, LPCTSTR szAgentName = NULL,
CWnd* pWnd = NULL);
(Added by Ravi Bhavnani) Retrieves the information about a file from the given URL
szURL
is the URL
strLastModified
is a CString
buffer that will hold the last modified date of the file
dwServerError
will return any error codes that were raised.
szAgentName
is the agent name you want to send to the website (may be NULL)
pWnd
is a status window. Status updates will be sent to this window using SetWindowText()
Bryce Burrows kindly updated the code to include the following functions:
void SetUseProxy(bool use);
Sets whether or not to use a proxy
void SetProxyServer(LPCSTR server);
Sets the proxy server
void SetProxyPort(UINT port);
Sets the proxy port
void SetProxy(LPCSTR proxy, WORD port, bool use=true);
Sets the proxy information in one call
void SetForceReload (bool bForceReload)
Sets whether or not to force a reload when downloading a document. If a force reload is set the the document will not be a cached version.
void GetForceReload()
Gets whether or not to force a reload when downloading a document.
void SetTimeOut(DWORD timeOut);
Sets the timeout for the operation
double GetRate();
Retrieves the download rate in Kb/sec
SHORT GetErrorCode();
CString GetErrorMessage();
Get the error code and message (if any)
Example of use
#include "webgrab.h"
void CWebGrabberDlg::OnDownload()
{
CString strBuffer;
CWebGrab grab;
if (grab.GetFile("http://www.mysite.com/index.htm",
strBuffer,
_T("WebGrab demo"),
GetDlgItem(IDC_STATUS)))
{
TRACE0("everything went OK\n")
}
}
History
26 Jan 2002 - Bryce Burrows kindly added the proxy code.
16 Feb 2002 - Bryce Burrows source code update.
2 Mar 2002 - Ravi Bhavnani added a "force reload" option to ensure that the downloaded data is not read from the cache, plus Get/SetForceReload()
functions.
17 Apr 2002 - Ravi Bhavnani added a GetFileInfo
Chris Maunder is the co-founder of
CodeProject, DeveloperMedia and ContentLab, and has been a prominent figure in the software development community for nearly 30 years. Hailing from Australia, Chris has a background in Mathematics, Astrophysics, Environmental Engineering and Defence Research. His programming endeavours span everything from FORTRAN on Super Computers, C++/MFC on Windows, through to to high-load .NET web applications and Python AI applications on everything from macOS to a Raspberry Pi. Chris is a full-stack developer who is as comfortable with SQL as he is with CSS.
In the late 1990s, he and his business partner David Cunningham recognized the need for a platform that would facilitate knowledge-sharing among developers, leading to the establishment of CodeProject.com in 1999. Chris's expertise in programming and his passion for fostering a collaborative environment have played a pivotal role in the success of CodeProject.com. Over the years, the website has grown into a vibrant community where programmers worldwide can connect, exchange ideas, and find solutions to coding challenges. Chris is a prolific contributor to the developer community through his articles and tutorials, and his latest passion project,
CodeProject.AI.
In addition to his work with CodeProject.com, Chris co-founded ContentLab and DeveloperMedia, two projects focussed on helping companies make their Software Projects a success. While at CodeProject, Chris' roles included Architecture and coding, Product Development, Content Creation, Community Growth, Client Satisfaction and Systems Automation, and many, many sales meetings. All while keeping his sense of humour.