Re: StreamDevice with a REST API

["Zimoch Dirk \(PSI\) via Tech-talk" <tech-talk at aps.anl.gov>]

Hi Chris

I did something similar here:
https://paulscherrerinstitute.github.io/StreamDevice/tipsandtricks.html#web

At a first glance, all you did looks just fine.

As the host is running on Windows, do you need CR LF CR LF? (I hope not.)

I am testing now now one of our REST APIs....

Dirk


On Fri, 2022-06-10 at 13:10 +0000, Chris Gregory - STFC UKRI via Tech-talk wrote:
> I'm writing an IOC for a device that has a REST API. Replies are simple and predictable so I'm hoping that I won't
> need anything more complex than StreamDevice. 
> 
> At the moment I can't get a reply from the device. In my dev setup I'm running the IOC under WSL2, with the device
> software running on the Windows host on port 8001. The port is open in the firewall. Would anyone have any pointers
> please? (I've subbed my real Windows host ip address with <my_ip_address> in the below but in the application I've got
> the full address written out.) 
> 
> 
> Protocol:
> 	read_variable{
> 	  outTerminator = LF LF;
> 	  replyTimeout = 5000;
> 	  out "GET http://<my_ip_address>:8001/REST/HTTP_CMD/?RDVAR/State HTTP/1.1";
> 	  in "%#s";
> 	}
> 
> Record:
> 	record (stringin, "RDV_TEST") {
>  	  field(DTYP, "stream")
>   	  field(INP, "@eksplaAPL038.proto read_variable() $(PORT)")
>  	  field(SCAN, "5 second")
> 	}
> 
> 
> PORT configuration in st.cmd:
> 	drvAsynIPPortConfigure("$(PORT)", "<my_ip_address>:8001 HTTP",0,0,0)
> 
> 
> When I run the IOC the asynTraceMask shows that I'm sending what I expect, but I don't get any reply. E.g.
> 	epics> 2022/06/10 13:40:59.703 <my_ip_address>:8001 HTTP write 67
> 	GET http://<my_ip_address>:8001/REST/HTTP_CMD/?RDVAR/State HTTP/1.1\n\n 
> 
> 
> Using telnet from WSL2 with the same ip:port the following both succeed and get the expected reply from the device:
> 	GET http://<my_ip_address>:8001/REST/HTTP_CMD/?RDVAR/State HTTP/1.1
> 	or
> 	GET /REST/HTTP_CMD/?RDVAR/State HTTP/1.1
> 
> 
> I've tried the following "out" commands in the protocol file. No reply in any case:
> 	out "GET http://<my_ip_address>:8001/REST/HTTP_CMD/?RDVAR/State HTTP/1.1";
> 	out "GET http://<my_ip_address>:8001/REST/HTTP_CMD/?RDVAR/State";
> 	out "GET /REST/HTTP_CMD/?RDVAR/State HTTP/1.1";
> 	out "GET /REST/HTTP_CMD/?RDVAR/State";
> 
> I'd be grateful for any help,
> Chris
> 
> 
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