Thank you so much for your instant reply. I guess I need much more time to process the information. You are so helpful.
Best, Hanks 2012/3/25 Glyph <gl...@twistedmatrix.com>: > > On Mar 26, 2012, at 2:21 AM, hz hanks wrote: > > Hi, all > > I'm writing a program to transfer files over Internet. Sometimes the > files would be very big. Therefore, I'm not sure whether I could read > a large block of data and send them via one time > internet.protocol.transport.write(). On the other hand, does the > function internet.protocol.transport.write() have any buffer scheme? > If so, I could just read one line of the file each time and call that > function. Or if you have any advice on how to transfer large amount of > data, please let me know. Really appreciated. > > > First, you want to read this > <http://twistedmatrix.com/documents/current/core/howto/producers.html>. > > Second, you should understand that transport.write() will always buffer; it > will never raise an error. The rationale for this behavior is that if > you've already got the data as a Python string (as you must, if you're > calling write() with it), you have already paid the not-inconsiderable cost > of pulling that data into your process, allocating memory for it, and > slinging it around in Python, which probably means you've already copied it > a few times by splitting it up, moving it around, etc. The transport > implementations will endeavor to not copy it around too much more (they > generally keep a list of strings around as a buffer rather than a string > they keep concatenating to), but they will hold on to it until they're able > to write it. > > If you want to know about the state of the buffer you need to subscribe to > it using registerProducer() - so see the above document for how to do that. > > -glyph > > > _______________________________________________ > Twisted-Python mailing list > Twisted-Python@twistedmatrix.com > http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python > _______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
