C / C++ / MFC

Simle question about HTTP...

15-Jun-02 1:20

There is a nice implementation using the C in the www.wdj.com magazine. Search the site, if you cannot find it, email me I think I downloaded the sources - I will search my hard disk!

Best regards,
Paul.

Paul Selormey, Bsc (Elect Eng), MSc (Mobile Communication) is currently Windows open source developer in Japan.

Empty class

14-Jun-02 23:58

Hi all,

When do we need an empty class like?

class Foo{};

thanks in advance
regards
/rsasalm

Re: Empty class

Christian Graus15-Jun-02 0:44

Christian Graus

15-Jun-02 0:44

Never, except in examples where we need a dummy class to show it's use, or visibility.

Christian

I am completely intolerant of stupidity. Stupidity is, of course, anything that doesn't conform to my way of thinking. - Jamie Hale - 29/05/2002

Half the reason people switch away from VB is to find out what actually goes on.. and then like me they find out that they weren't quite as good as they thought - they've been nannied. - Alex, 13 June 2002

Re: Empty class

Rama Krishna Vavilala15-Jun-02 1:09

Rama Krishna Vavilala

15-Jun-02 1:09

Christian Graus wrote:
Never, except in examples where we need a dummy class to show it's use, or visibility

Sometimes in defining exceptions they are useful.

Re: Empty class

Joaquín M López Muñoz15-Jun-02 1:42

Joaquín M López Muñoz

15-Jun-02 1:42

They have a role sometimes:

To define exceptions, as Rama pointed out.
To provide alternate constructors. Consider this example:
```
struct chess_king{
  struct white{};
  struct black{};
  chess_king(const white&); //construct a white king
  chess_king(const black&); //construct a black king
  ...
}
```
We could have used bool to indicate wheter the piece is white or black, but defining the constructors with the empty classes white and black allow the compiler to optimize them away in release mode, which matters if you're writting highly speed critical code (this is not an academic example, I've actually used it for writing a game engine in the past.)

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Artem Moroz14-Jun-02 23:10

Artem Moroz

14-Jun-02 23:10

How to determine whether the new request header is coming from client in HTTP/1.1 Keep-alive Connections ?

Mike Nordell16-Jun-02 5:56

16-Jun-02 5:56

Looking at the header and check for "Keep-Alive:" ?

Artem Moroz16-Jun-02 6:04

Artem Moroz

16-Jun-02 6:04

How to check whether this is a NEW http-header ?
Do I have to check EVERY message or just the first ones?

Mike Nordell16-Jun-02 6:55

16-Jun-02 6:55

M A V wrote:
How to check whether this is a NEW http-header ?

As opposed to what? An OLD HTTP-header?

Of course you have to parse every request the server gets.

If your question is instead "How do I know if it's a 1.1 or 1.0" request: Well, read the header. It's all there, in plain-text format. It's either "HTTP/1.0" or "HTTP/1.1".

Maybe a trip to this place can clear things up? Especially this page might prove useful.

Artem Moroz16-Jun-02 10:48

Artem Moroz

16-Jun-02 10:48

How can I determine whether the data that was just received, is a HTTP-header?
I am writing HTTP proxy server application,it works ok with HTTP/1.0 and fails with HTTP/1.1...
For example, when the page contains some data wich needs to be loaded from other server this data is not displayed.
I think that browser, when configured to use HTTP/1.1 sends it's requests one after another without breaking the connection.

My code looks like:

Thread1(started on every connect from client):
recv(...);
// parse header get URL_to_connect

_beginthread(Thread2);
// wait here for Event..

while(!Thread1done && !Thread2Done)
{
recv(...); //from client
send(...); //to server
}
closesocket();

//Thread2

connect(server_ip);
// fire the Event...
while(!Thread1Done && !Thread2Done)
{
recv(); //from server
send(); //to client
}
closesocket();

I've read RFC, but found nothing concrete about this...

Mike Nordell17-Jun-02 17:53

Detect code page/encoding of a text...

17-Jun-02 17:53

AFAIK you can't just recv() + send() to pass on any data to any server. You need to parse every request sent from the client to see f.ex. what server to pass on the request to.

Paul Selormey14-Jun-02 21:00

14-Jun-02 21:00

Can anyone help me to detect the code pages of text strings?
I wish to know so that I could convert to and from!

Best regards,
Paul.

Paul Selormey, Bsc (Elect Eng), MSc (Mobile Communication) is currently Windows open source developer in Japan.

Mike Nordell14-Jun-02 23:38

14-Jun-02 23:38

If the only information you have is the strings themselves, you are out of luck. There is no way, short of reading the text, understanding what language it is and then start guessing what codepage for that language it uses.

Paul Selormey15-Jun-02 1:17

15-Jun-02 1:17

How about if I have the text file?

Best regards,
Paul.

Paul Selormey, Bsc (Elect Eng), MSc (Mobile Communication) is currently Windows open source developer in Japan.

Mike Nordell16-Jun-02 6:00

16-Jun-02 6:00

You still only have the characters (the "text"). You can't possibly know anything about what language and code-page was used to produce that file without some kind of meta content, wether in the text itself or as an alternate stream for the file or whatever).

Paul Selormey16-Jun-02 14:05

16-Jun-02 14:05

The "Advanced Save As..." dialog in the VS.NET seems to indicate the correct codepage. What is the magic here?

Best regards,
Paul.

Paul Selormey, Bsc (Elect Eng), MSc (Mobile Communication) is currently Windows open source developer in Japan.

Mike Nordell17-Jun-02 17:54

17-Jun-02 17:54

For a plain text file? I haven't got a clue. Named NTFS streams?

Michael Dunn15-Jun-02 6:07

Michael Dunn

15-Jun-02 6:07

A code page is simply a mapping of a byte value to a glyph. Only a person can tell if text is being mapped using the right codepage - they have to look at the output and decide if it looks correct. To the computer it's all just bytes.

--Mike--
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Paul Selormey15-Jun-02 16:52