[ale] Python regex (Now: readline())

[Alex LeDonne]

On 9/10/06, Christopher Fowler <cfowler at outpostsentinel.com> wrote:
> Is there a readline method in a class that can turn a socket into
> buffered I/O?  I'm writing a class to interface with a server on an
> embedded device and I need to interact by line.
>
> I simply added it to my class since my class is the client to the server
> --------[ Cut Here ] ---------------------------------------------------
>   def readline(self):
>     buffer = None
>     if self.socket is None: return None
>
>     data = self.socket.recv(1)
>
>     while data is not None:
>       if buffer is None:
>         buffer = str(data)
>       else:
>         buffer = buffer + str(data)
>
>       if data.startswith("\n"):
>         return buffer
>
>       # No NL yet.  Read again
>       data = self.socket.recv(1)
>
>     # If we get here then we've encountered
>     # an EOF condition.  Return the buffer. The
>     # next call to readline will cause None
>     # to be sent to caller
>     return buffer
>
> --------[ Cut Here ] ---------------------------------------------------
> Not sure if that is the best way?  But it works.
>

This seems... inefficient. I think you should safely be able to read a
much larger chunk at a time, say data = self.socket.recv(1024). If
there's a newline, then len(data) < 1024. The only thing you have to
check is if len(data) == 1024, whether data.endswith("\n").

By the way, you'll want to test data against '' (empty string) -
that's what recv will return if the socket disconnects.

-A