On Feb 19, 6:58 pm, GiBo <[EMAIL PROTECTED]> wrote: > Hi! > > Classic situation - I have to process an input stream of unknown length > until a I reach its end (EOF, End Of File). How do I check for EOF? The > input stream can be anything from opened file through sys.stdin to a > network socket. And it's binary and potentially huge (gigabytes), thus > "for line in stream.readlines()" isn't really a way to go.
Could you use xreadlines()? It's a lazily-evaluated stream reader. > For now I have roughly: > > stream = sys.stdin > while True: > data = stream.read(1024) > process_data(data) > if len(data) < 1024: ## (*) > break > > I smell a fragile point at (*) because as far as I know e.g. network > sockets streams may return less data than requested even when the socket > is still open. Well it depends on a lot of things. Is the stream blocking or non- blocking (on sockets and some other sorts of streams, you can pick this yourself)? What are the underlying semantics (reliable-and- blocking TCP or dropping-and-unordered-UDP)? Unfortunately, you really need to just know what you're working with (and there's really no better solution; trying to hide the underlying semantics under a proscribed overlaid set of semantics can only lead to badness in the long run). > I'd better like something like: > > while not stream.eof(): > ... > > but there is not eof() method :-( > > This is probably a trivial problem but I haven't found a decent solution. For your case, it's not so hard: http://pyref.infogami.com/EOFError says "read() and readline() methods of file objects return an empty string when they hit EOF." so you should assume that if something is claiming to be a file-like object that it will work this way. > Any hints? So: stream = sys.stdin while True: data = stream.read(1024) if data=="": break process_data(data) -- http://mail.python.org/mailman/listinfo/python-list
