If we had an upvote button on this forum I'd click it. Really really hard. (…thanks Raul. This is getting copied to where I can find it again in a couple more years.)
On Thu, 1 Jul 2021 at 20:03, Raul Miller <rauldmil...@gmail.com> wrote: > You need to understand internet protocols a bit more, before that can work. > > Here's a brief overview. > > Computers hooked to the internet use a software/hardware stack which > looks something like this: > > application layer (supplies/consumes data) > transport layer (organizes access to the internet) > internet layer (identifies addresses and protocol, makes best effort to > deliver) > network layer (where all the messy communications happen) > electrical layer (computers, wires, antenna, all powered on) > physical layer (the hardware itself) > > https://www.w3.org/People/Frystyk/thesis/TcpIp.html > > Anyways... host addresses are something for the internet layer. With a > host address, you can send packets of information and know that they > will usually but not always reach their destination. (And there will > be a return address for responses that identifies your machine.) > > Also, the socket library gives you direct access to the "transport > layer". You will almost certainly be using tcp here (which does some > carefully engineered work to make it appear that you are sending an > arbitrary lengthy sequence of data and receiving an arbitrary length > sequence of data -- which is often called a "stream"). > > For something like stream.data.alpaca.markets/v2/sip you also have a > protocol that you will need to be specific about. It's probably http, > but might be https or ftp. > > Once you know the protocol (which in this case would also identify the > transport layer "port" that you need to connect to. That would be 80 > for http, 443 for https and 21 for ftp), you can look up the details > of how that protocol works. > > And, the protocol is where the path part of that address -- the > /v2/sip part -- is used. > > Anyways, there's a lot of details here. If you want to understand > them... some people are capable of picking up the necessary details > through self study. But there's also classes which teach this kind of > thing. (Nowadays, you'll probably also hear a lot of people saying > it's too complicated to learn, and you should use a prepackaged > implementation. Whether or not you follow their footsteps or dive in > and do it yourself is up to you. That said, it's probably also worth > noting that most of the unnecessary complicated stuff falls into > disuse after a few years because it's too complicated to learn.) > > Good luck, > > -- > Raul > > On Thu, Jul 1, 2021 at 2:44 PM Ed Gottsman <edward.j.gotts...@gmail.com> > wrote: > > > > Hello. I've begun working with the socket library. I can use it to > resolve host names: > > > > sdgethostbyname 'stream.data.alpaca.markets' > > > > ┌─┬─┬────────────┐ > > │0│2│38.122.35.99│ > > └─┴─┴────────────┘ > > > > Unfortunately, both the code (to the extent that I've been able to > understand it) and the documentation suggest that only a "raw" host can be > used to identify an endpoint. So, for example, there seems to be no way to > connect to > > > > 'stream.data.alpaca.markets/v2/sip' or '38.122.35.99/v2/sip' > > > > ...which is what I'd like to do. > > > > I've mucked around trying to hit the DLL more directly--just passing it > a url--but it's a pretty desperate approach and unlikely to succeed. I'd > very much appreciate any ideas the community might have. > > > > Btw: I checked the nabble archive for an answer and all the emails’ > contents read, “…the author has deleted this message.” So while the nabble > search engine did turn up a lot of socket traffic (which is encouraging), > it wasn’t of much help. > > > > Thank you. > > > > Ed > > > > Sent from my iPad > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
