[Python-Dev] Patch to telnetlib.py (original) (raw)

Eric Smith eric at trueblade.com
Sat Mar 13 19:23:16 CET 2010

Can you create an issue on the bug tracker? Otherwise this will get lost.

Eric.

On 3/13/2010 12:24 PM, gregory dudek wrote:

The Telnet module telnetlib.py can be very slow -- unusably slow -- for large automated data transfers. There are typically done in raw mode.

The attached patch greatly increased the speed of telnet interactions in raw mode. I submitted this a couple of year ago, but it was for an older branch of python. There are 2 key things being done: 1) concatenations string with string.join instead of '+' (which is probably a minor issue) 2) wholesale appending the raw and processed buffers when the IAC character is not found. The should be examined carefully since I am not an expert in the Telnet protocol, but it seems to work very well giving me a 5x speedup.

--- installed/telnetlib.py 2010-02-02 22:57:58.000000000 -0500 +++ telnetlib.py 2010-03-13 12:17:02.000000000 -0500 @@ -30,6 +30,7 @@ - timeout should be intrinsic to the connection object instead of an option on one of the read calls only +Modified by G. Dudek for greater efficiency. """ @@ -420,6 +421,14 @@ """ buf = ['', ''] try: + if self.rawq: + if not IAC in self.rawq: + # speed hack, no IAC just grab whole queue. --Dudek + buf[self.sb] = "".join((buf[self.sb] , self.rawq)) + self.cookedq = "".join((self.cookedq , buf[0] )) + self.sbdataq = "".join((self.sbdataq , buf[1] )) + self.rawqflush() + return while self.rawq: c = self.rawqgetchar() if not self.iacseq: @@ -428,7 +437,7 @@ if c == "\021": continue if c != IAC: - buf[self.sb] = buf[self.sb] + c + buf[self.sb] = "".join((buf[self.sb] , c)) continue else: self.iacseq += c @@ -480,8 +489,14 @@ self.iacseq = '' # Reset on EOF self.sb = 0 pass - self.cookedq = self.cookedq + buf[0] - self.sbdataq = self.sbdataq + buf[1] + self.cookedq = "".join((self.cookedq , buf[0] )) + self.sbdataq = "".join((self.sbdataq , buf[1] )) + + + def rawqflush(self): + """ Set the queue to empty status """ + self.rawq = '' + self.irawq = 0 def rawqgetchar(self): """Get next char from raw queue. @@ -516,7 +531,7 @@ buf = self.sock.recv(50) self.msg("recv %r", buf) self.eof = (not buf) - self.rawq = self.rawq + buf + self.rawq = "".join((self.rawq,buf)) def sockavail(self): """Test whether data is available on the socket."""

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