Experimental Physics and
Industrial Control System

Freddie Akeroyd - STFC UKRI via Tech-talk <tech-talk at aps.anl.gov> · Fri, 10 Jun 2022 13:30:57 +0000

Hi Chris,

I think I read somewhere that HTTP/1.1 defined CR LF as the end-of-line marker? So maybe

 	  outTerminator = CF LF;
 	  replyTimeout = 5000;
 	  out "GET
 http://<my_ip_address>:8001/REST/HTTP_CMD/?RDVAR/State HTTP/1.1";
                 out "";
 	  in "%#s";

Regards,

Freddie

> -----Original Message-----
> From: Tech-talk <tech-talk-bounces at aps.anl.gov> On Behalf Of Chris Gregory
> - STFC UKRI via Tech-talk
> Sent: 10 June 2022 14:10
> To: tech-talk at aps.anl.gov
> Subject: StreamDevice with a REST API
> 
> 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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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System