Another sockets problem

[pepribal]

I'm getting a full file from a server, doing:

flags=fcntl(socknum,F_GETFL,NULL);
flags|=O_NONBLOCK;
fcntl(socknum,F_SETFL,flags);

while(read(socknum,&buffer,1)>0)
cout << (int)buffer << " - " << buffer << endl;

If I don't set the O_NONBLOCK flag this works fine, except that after the last character has been read, the next read() blocks, and I want it to exit the while(). But if I set the nonblocking flag, then it doesn't read a single character.

What am I missing?

Thanks.

[Bookar]

1)The problem here is that you don't mark end of data that should be read. To tell the client program that no more data will be sent through this socket you should call close(socknum) function on the server side which will close connection. After connection is closed next read() call you make on the client side will return 0 so you can get out of loop. (didn't check this but it will probably work)

If you want some way to tell the client that server sent whole file but you don't want to close connection it is more complicated - you could for example send size of the file you want to send first, and then send contents of the file.
Another method involves using one special character (for example '^') as a marker of end of transmission/file/package (whatever you need). But the major drawback of this method is that this character cannot be present in transmitted data.

2) When you set socket to nonblocking it will never wait for incoming data. It will read only data which is available at certain moment. If no data is available read function will return -1 and errno global variable will contain EAGAIN value (didn't check it either).

[pepribal]

The problem is that I have no control over the server. It is a simple text file accessed via HTTP 1.1 protocol. In this case, how should this be handled?

[pepribal]

Solved! I've just seen the length info the HTTP 1.1 protocol sends before the actual file.

[ibbo]

pepribal

What is it your attempting to do?

Ibbo

[pepribal]

ibbo, just retrieving a plain text file from a server via HTTP protocol. It's solved anyway. Thanks!