Re: tcp socket programming


On Tue, 4 Oct 2005, Irmen de Jong wrote:

> Mohammed Smadi wrote:
> > hi;
> > If i have a tcp connection with a remote server, what is a good way to
> > read all the data into a buffer before starting to process the data?
> > I know that the data recieved will be 3 lines with CRLF between them.
> > However if I can sock.recv(1024) the output is not consistent all the
> > time, sometime i get one line and sometimes i get two. So I figures I
> > should read all the data first then work on it and I used the following
> > code:
> > result = []
> > while True:
> > got=s.recv(1024)
> > print got
> > if not got: break
> > result.append(got)
> > got = [] # i tried also taking this out
> > s.close()
> >
> > but this code just hangs in the loop and never quits
>
> ... because it doesn't 'know' when to stop reading.
> The socket recv() returns anything from 0 to 1024 bytes
> depending on the amount of data that is available at that time.
>
> You have to design your wire protocol a bit differently if you want
> to do this in a consistent, reliable way.
> For instance, you can decide on sending *one* byte first that
> signifies the amount of bytes to read after that. (limiting the
> size to 255 ofcourse).
>
> Or you will have to change your read-loop to read until it
> encountered the third CRLF occurrence (and no more!)
>
> The latter is actually quite easily done by not reading directly
> from the socket object, but first converting it to a file-like
> object:
>
> s=socket.socket(....)
> s.connect(...)
>
> fs=s.makefile()
> fs.readline()
> fs.readline()
> fs.readline()
>
>
> --Irmen.
>
that seems to have worked. I need to do more testing. Thanks

.

Relevant Pages

  • Re: tcp socket programming
    ... However if I can sock.recvthe output is not consistent all the time, sometime i get one line and sometimes i get two. ... The socket recv() returns anything from 0 to 1024 bytes depending on the amount of data that is available at that time. ... encountered the third CRLF occurrence ...
    (comp.lang.python)
  • Sat Sels
    ... furlong shouldn`t be a problem.The consistent but rarely winning IRISH WOLF ... Won with any amount in hand at Ayr beating the bottle job OONINPOHJA,and ... TRIMLESTOWN from Henry Candys honest yard is the most consistent of animals ... effect of the drawOn the other side of the draw EISTEDDFOD looks to be a ...
    (uk.sport.horseracing)
  • Re: Sat Sels
    ... furlong shouldn`t be a problem.The consistent but rarely winning IRISH ... Won with any amount in hand at Ayr beating the bottle job OONINPOHJA,and ... TRIMLESTOWN from Henry Candys honest yard is the most consistent of ... to the effect of the drawOn the other side of the draw EISTEDDFOD ...
    (uk.sport.horseracing)
  • Re: PATCH: README - Fix misleading pointer to the defconf directory
    ... Arnd Bergmann wrote: ... Darn, I used 'find' to ensure the structure is consistent, stupidly I didn't check wether the amount of fitting cases equals the amount of platforms at all, thus I did miss those who do not fit. ... I am going to resend the patch with your suggestions above soon. ...
    (Linux-Kernel)
Loading