Re: Lightwight socket IO wrapper

"Dennis Lee Bieber" wrote in message news:mailman.12.1442794762.28679.python-l...@python.org... On Sun, 20 Sep 2015 23:36:30 +0100, "James Harris" declaimed the following: There are a few things and more crop up as time goes on. For example,

Re: Lightwight socket IO wrapper

"Marko Rauhamaa" wrote in message news:8737y6cgp6@elektro.pacujo.net... "James Harris" : I agree with what you say. A zero-length UDP datagram should be possible and not indicate end of input but is that guaranteed and portable? The

Re: Lightwight socket IO wrapper

Random832 wrote: Isn't this technically the same problem as pressing ctrl-d at a terminal - it's not _really_ the end of the input (you can continue reading after), but it sends the program something it will interpret as such? Yes. There's no concept of "closing the connection" with UDP,

Re: Lightwight socket IO wrapper

"Akira Li" <4kir4...@gmail.com> wrote in message news:mailman.18.1442804862.28679.python-l...@python.org... "James Harris" writes: ... There are a few things and more crop up as time goes on. For example, over TCP it would be helpful to have a function to receive a

Re: Lightwight socket IO wrapper

"James Harris" : > I agree with what you say. A zero-length UDP datagram should be > possible and not indicate end of input but is that guaranteed and > portable? The zero-length payload size shouldn't be an issue, but UDP doesn't make any guarantees about delivering

Re: Lightwight socket IO wrapper

On Tue, Sep 22, 2015, at 15:45, James Harris wrote: > "Dennis Lee Bieber" wrote in message > news:mailman.12.1442794762.28679.python-l...@python.org... > > On Sun, 20 Sep 2015 23:36:30 +0100, "James Harris" > > declaimed the following: >

Re: Lightwight socket IO wrapper

On Mon, 2015-09-21, Cameron Simpson wrote: > On 21Sep2015 10:34, Chris Angelico wrote: >>If you're going to add sequencing and acknowledgements to UDP, >>wouldn't it be easier to use TCP and simply prefix every message with >>a two-byte length? > > Frankly, often yes. That's

Re: Lightwight socket IO wrapper

On Mon, 2015-09-21, Chris Angelico wrote: > On Mon, Sep 21, 2015 at 6:38 PM, Marko Rauhamaa wrote: >> Chris Angelico : >> >>> On Mon, Sep 21, 2015 at 5:59 PM, Marko Rauhamaa wrote: You can read a full buffer even if you have a

Re: Lightwight socket IO wrapper

On 21Sep2015 12:40, Chris Angelico wrote: On Mon, Sep 21, 2015 at 11:55 AM, Cameron Simpson wrote: On 21Sep2015 10:34, Chris Angelico wrote: If you're going to add sequencing and acknowledgements to UDP, wouldn't it be easier to use TCP

Re: Lightwight socket IO wrapper

Marko Rauhamaa wrote: > I recommend using socket.TCP_CORK with socket.TCP_NODELAY where they are > available (Linux). If these options are not available are both option constants also not available? Or does the implementation have to look into sys.platform? Ciao, Michael. --

Re: Lightwight socket IO wrapper

Chris Angelico : > On Mon, Sep 21, 2015 at 4:27 PM, Cameron Simpson wrote: >> For sizes below 128, one byte of length. For sizes 128-16383, two bytes. And >> so on. Compact yet unbounded. > > [...] > > It's generally a lot faster to do a read(2) than a loop

Re: Lightwight socket IO wrapper

Michael Ströder : > Marko Rauhamaa wrote: >> I recommend using socket.TCP_CORK with socket.TCP_NODELAY where they >> are available (Linux). > > If these options are not available are both option constants also not > available? Or does the implementation have to look into

Re: Lightwight socket IO wrapper

On Mon, Sep 21, 2015 at 5:59 PM, Marko Rauhamaa wrote: > Chris Angelico : > >> On Mon, Sep 21, 2015 at 4:27 PM, Cameron Simpson wrote: >>> For sizes below 128, one byte of length. For sizes 128-16383, two bytes. And >>> so on. Compact yet

Re: Lightwight socket IO wrapper

Chris Angelico : > On Mon, Sep 21, 2015 at 2:39 PM, Marko Rauhamaa wrote: >> Chris Angelico : >> >>> If you write a packet of data, then write another one, and another, >>> and another, and another, without waiting for responses, Nagling >>>

Re: Lightwight socket IO wrapper

On Mon, Sep 21, 2015 at 4:27 PM, Cameron Simpson wrote: > I don't like embedding arbitrary size limits in protocols or data formats if > I can easily avoid it. So (for my home grown binary protocols) I encode > unsigned integers as big endian octets with the top bit meaning

Re: Lightwight socket IO wrapper

On 2015-09-21 09:47, Marko Rauhamaa wrote: Michael Ströder : Marko Rauhamaa wrote: Michael Ströder : Marko Rauhamaa wrote: I recommend using socket.TCP_CORK with socket.TCP_NODELAY where they are available (Linux). If these options are not

Re: Lightwight socket IO wrapper

On Mon, 2015-09-21, Dennis Lee Bieber wrote: > On Sun, 20 Sep 2015 23:36:30 +0100, "James Harris" > declaimed the following: ... >>I thought UDP would deliver (or drop) a whole datagram but cannot find >>anything in the Python documentaiton to guarantee that. In fact

Re: Lightwight socket IO wrapper

On 21Sep2015 18:07, Chris Angelico wrote: On Mon, Sep 21, 2015 at 5:59 PM, Marko Rauhamaa wrote: Chris Angelico : On Mon, Sep 21, 2015 at 4:27 PM, Cameron Simpson wrote: For sizes below 128, one byte of length. For

Re: Lightwight socket IO wrapper

Chris Angelico : > On Mon, Sep 21, 2015 at 5:59 PM, Marko Rauhamaa wrote: >> You can read a full buffer even if you have a variable-length length >> encoding. > > Not sure what you mean there. Unless you can absolutely guarantee that > you didn't read too

Re: Lightwight socket IO wrapper

On Mon, Sep 21, 2015 at 6:38 PM, Marko Rauhamaa wrote: > Chris Angelico : > >> On Mon, Sep 21, 2015 at 5:59 PM, Marko Rauhamaa wrote: >>> You can read a full buffer even if you have a variable-length length >>> encoding. >> >> Not sure what

Re: Lightwight socket IO wrapper

Chris Angelico : > On Mon, Sep 21, 2015 at 6:38 PM, Marko Rauhamaa wrote: >> Only one reader can read a socket safely at any given time so mutual >> exclusion is needed. >> >> If you read "too much," the excess can be put in the application's read >> buffer

Re: Lightwight socket IO wrapper

Marko Rauhamaa wrote: > Michael Ströder : > >> Marko Rauhamaa wrote: >>> I recommend using socket.TCP_CORK with socket.TCP_NODELAY where they >>> are available (Linux). >> >> If these options are not available are both option constants also not >> available? Or does the

Re: Lightwight socket IO wrapper

Michael Ströder : > Marko Rauhamaa wrote: >> Michael Ströder : >> >>> Marko Rauhamaa wrote: I recommend using socket.TCP_CORK with socket.TCP_NODELAY where they are available (Linux). >>> >>> If these options are not available are both option

Re: Lightwight socket IO wrapper

Marko Rauhamaa : > Chris Angelico : > >> On Mon, Sep 21, 2015 at 6:38 PM, Marko Rauhamaa wrote: >>> Only one reader can read a socket safely at any given time so mutual >>> exclusion is needed. >>> >>> If you read "too much," the excess can

Re: Lightwight socket IO wrapper

On Mon, Sep 21, 2015 at 6:38 PM, Marko Rauhamaa wrote: > Chris Angelico : > >> On Mon, Sep 21, 2015 at 5:59 PM, Marko Rauhamaa wrote: >>> You can read a full buffer even if you have a variable-length length >>> encoding. >> >> Not sure what

Lightwight socket IO wrapper

I guess there have been many attempts to make socket IO easier to handle and a good number of those have been in Python. The trouble with trying to improve something which is already well designed (and conciously left as is) is that the so-called improvement can become much more complex and

Re: Lightwight socket IO wrapper

"Akira Li" <4kir4...@gmail.com> wrote in message news:mailman.37.1442754893.21674.python-l...@python.org... "James Harris" writes: I guess there have been many attempts to make socket IO easier to handle and a good number of those have been in Python. The trouble

Re: Lightwight socket IO wrapper

On Mon, Sep 21, 2015 at 10:19 AM, Dennis Lee Bieber wrote: > Even if the IP layer has to fragment a UDP packet to meet limits of > the > transport media, it should put them back together on the other end before > passing it up to the UDP layer. To my knowledge, UDP

Re: Lightwight socket IO wrapper

"James Harris" writes: > I guess there have been many attempts to make socket IO easier to > handle and a good number of those have been in Python. > > The trouble with trying to improve something which is already well > designed (and conciously left as is) is that the

Re: Lightwight socket IO wrapper

On 21Sep2015 10:34, Chris Angelico wrote: If you're going to add sequencing and acknowledgements to UDP, wouldn't it be easier to use TCP and simply prefix every message with a two-byte length? Frankly, often yes. That's what I do. (different length encoding, but

Re: Lightwight socket IO wrapper

"James Harris" writes: ... > There are a few things and more crop up as time goes on. For example, > over TCP it would be helpful to have a function to receive a specific > number of bytes or one to read bytes until reaching a certain > delimiter such as newline or zero

Re: Lightwight socket IO wrapper

Dennis Lee Bieber wrote: worst case: each TCP packet is broken up to fit Hollerith cards; Or printed on strips of paper and tied to pigeons: https://en.wikipedia.org/wiki/IP_over_Avian_Carriers -- Greg -- https://mail.python.org/mailman/listinfo/python-list

Re: Lightwight socket IO wrapper

On Mon, Sep 21, 2015 at 11:55 AM, Cameron Simpson wrote: > On 21Sep2015 10:34, Chris Angelico wrote: >> >> If you're going to add sequencing and acknowledgements to UDP, >> wouldn't it be easier to use TCP and simply prefix every message with >> a two-byte

Re: Lightwight socket IO wrapper

Chris Angelico : > On Mon, Sep 21, 2015 at 11:55 AM, Cameron Simpson wrote: >> Another nice thing about TCP is that wil a little effort you get to >> pack multiple data packets (or partial data packets) into a network >> packet, etc. > > Emphatically - a little

Re: Lightwight socket IO wrapper

On Mon, Sep 21, 2015 at 2:39 PM, Marko Rauhamaa wrote: > Chris Angelico : > >> On Mon, Sep 21, 2015 at 11:55 AM, Cameron Simpson wrote: >>> Another nice thing about TCP is that wil a little effort you get to >>> pack multiple data packets (or