Download a file using C++?

[GamesSmash]

Hello,

I have searched, but haven't found it, so I will ask.
How can I download a file from the internet using C++?
For example, it would be good if I could download a file like this:

int code = Download("codeguru.com/file.zip", "c:\\file.zip");

Thanks in advance.

RESOLVED:
You can use this code to download a file:

#include <tchar.h>
#include <urlmon.h>
#pragma comment(lib, "urlmon.lib")
int main()
{
	HRESULT hr = URLDownloadToFile ( NULL, _T("your web page"), _T("c:/web_page.html"), 0, NULL );
	return 0;
}

[TheCPUWizard]

Hello,

I have searched, but haven't found it, so I will ask.
How can I download a file from the internet using C++?
For example, it would be good if I could download a file like this:

int code = Download("codeguru.com/file.zip", "c:\\file.zip");

Thanks in advance.

Amazing Google displays samples right on the first page....

[GamesSmash]

I found some, but they require windows.h.
Windows.h doesn't work from my visual C++ 2005 express compiler.
Is there code that doesn't require windows.h available?

[S_M_A]

Another option is to goto MS and download the SDK. Make sure you follow every single step of the installation instructions.

[GamesSmash]

Okay, I am following steps at http://forums.microsoft.com/MSDN/Sho...95837&SiteID=1 to make my compiler work with windows.h.

But seriously, why can't I just download a zipped file with windows.h libraries (even if it comes from Dev C++)?

[Lindley]

Because C++ isn't *that* high-level a language. It'll give you access to the socket layer (TCP), not to the HTTP or FTP (application-layer) protocols typically used to download files. You can write some pretty quick code to handle that level yourself though.

The Boost libraries might have something to help with this.

[Peter_APIIT]

Boost has asio headr file that does socket connection but i don't know there are suck API or SDK that help us to write downloader.

[GamesSmash]

I've gotten windows.h installed.
Well I don't want to download random libraries yet. I am just looking to simply download a file.
I searched some more and found this:

"HRESULT hr = URLDownloadToFile ( NULL, "http://www.codeguru.com/index.htm", "C:\\codguru.htm", 0, NULL );"

However, it doesn't work.
I get the errors

'URLDownloadToFileW' : cannot convert parameter 2 from 'char *' to 'LPCWSTR'

Anybody know why it isn't working?

[TheCPUWizard]

I've gotten windows.h installed.
Well I don't want to download random libraries yet. I am just looking to simply download a file.
I searched some more and found this:

"HRESULT hr = URLDownloadToFile ( NULL, "http://www.codeguru.com/index.htm", "C:\\codguru.htm", 0, NULL );"

However, it doesn't work.
I get the errors

'URLDownloadToFileW' : cannot convert parameter 2 from 'char *' to 'LPCWSTR'

Anybody know why it isn't working?

Because you are using a "char *" where an LPCWSTR is required.

You are basically attempting to mix Unicode and 8 bit ASCII.....

[GamesSmash]

So.... I don't get it.
Does that mean I need to insert some random japanese character in the string to make it work?
I just tried it, it doesn't work.
What should I do?

[TheCPUWizard]

So.... I don't get it.
Does that mean I need to insert some random japanese character in the string to make it work?
I just tried it, it doesn't work.
What should I do?

Did you do a search here on CodeGuru or on Google for "C++ Unicode Literal"???

Both reveal multiple solutions to your problem.

[GamesSmash]

I searched for LPCWSTR on Google but found some weird stuff like this "FAQ": http://www.codeguru.com/forum/showthread.php?t=231165
I tried its thing, but my code still doesn't work:

int main()
{
	char *ansistr = "http://www.google.com/index.htm";
	int a = lstrlenA(ansistr);
	BSTR unicodestr = SysAllocStringLen(NULL, a);
	::MultiByteToWideChar(CP_ACP, 0, ansistr, a, unicodestr, a);

	char *ansistr2 = "C:\\file.html";
	a = lstrlenA(ansistr2);
	BSTR unicodestr2 = SysAllocStringLen(NULL, a);
	::MultiByteToWideChar(CP_ACP, 0, ansistr2, a, unicodestr2, a);
	
	HRESULT hr = URLDownloadToFile ( NULL, unicodestr, unicodestr2, 0, NULL );

	//... when done, free the BSTR
	::SysFreeString(unicodestr);
	return 0;
}

Any ideas?

[TheCPUWizard]

I searched for LPCWSTR on Google but found some weird stuff like this "FAQ": [<snip>
Any ideas?

I specifically suggested "C++ Unicode Literal" NOT LPCWSTR....

If you enter that in Google your first hit contains:

Handle literal strings properly.

The Visual C++ compiler interprets a literal string coded as:

L"this is a literal string"

to mean a string of Unicode characters. You can use the same prefix for literal characters. Use the _T macro to code literal strings generically, so they compile as Unicode strings under Unicode or as ANSI strings (including MBCS) without Unicode. For example, instead of:

pWnd->SetWindowText( "Hello" );

use:

pWnd->SetWindowText( _T("Hello") );

With _UNICODE defined, _T translates the literal string to the L-prefixed form; otherwise, _T translates the string without the L prefix.


The _T macro is identical to the _TEXT macro.

So simply "decorating" your literals (which should always be done for every string literal in ANY C++ program that is targeted towards VC++) with _T() will solve your problem.

[GamesSmash]

I tried that, but I get this error:

"error C3861: '_T': identifier not found"

[TheCPUWizard]

I tried that, but I get this error:

"error C3861: '_T': identifier not found"

Did you even bother to read the link that I just gave you??????

Tchar.h supplies portable data types and the _T macro for translating literal strings and characters. For more information, see Generic-Text Mappings in Tchar.h.