Piping stdout to websockets

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1

I was thinking of ways to stream pipes through ipc, and came across this which redirects stdin/out through websockets. Maybe some of you find it interesting.

https://github.com/joewalnes/websocketd

$ ./websocketd --port 8080 curl “http://stream-sandbox.oanda.com/v1/prices?accountId=12345&instruments=AUD_CAD%2CAUD_CHF%2CGBP_USD%2CUSD_EUR” -N  

Fri, 10 Oct 2014 21:07:02 +0200 | INFO   | server     |  | Serving using application   : /usr/bin/curl http://stream-sandbox.oanda.com/v1/prices?accountId=12345&instruments=AUD_CAD%2CAUD_CHF%2CGBP_USD%2CUSD_EUR -N

Fri, 10 Oct 2014 21:07:02 +0200 | INFO   | server     |  | Starting WebSocket server   : ws://:8080/

Fri, 10 Oct 2014 21:07:08 +0200 | ACCESS | session    | url:‘http://host:port/’ id:‘1412968028000414119’ remote:‘localhost’ command:‘/usr/bin/curl’ origin:‘file://’ | CONNECT

Fri, 10 Oct 2014 21:07:08 +0200 | ERROR  | stderr     | url:‘http://host:port/’ id:‘1412968028000414119’ remote:‘localhost’ command:‘/usr/bin/curl’ origin:‘file://’ pid:‘35749’ |   % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current

Fri, 10 Oct 2014 21:07:08 +0200 | ERROR  | stderr     | url:‘http://host:port/’ id:‘1412968028000414119’ remote:‘localhost’ command:‘/usr/bin/curl’ origin:‘file://’ pid:‘35749’ |                                  Dload  Upload   Total   Spent    Left  Speed

Fri, 10 Oct 2014 21:07:12 +0200 | ACCESS | session    | url:‘http://host:port/’ id:‘1412968028000414119’ remote:‘localhost’ command:‘/usr/bin/curl’ origin:‘file://’ pid:‘35749’ | DISCONNECT

and then in kdb+

q).z.ws:{0N!x;} / just print incoming

q)r:(`$“:ws://127.0.0.1:8080”)“GET / HTTP/1.1\r\nHost: host:port\r\n\r\n”

q) / updates printed below

“{"tick":{"instrument":"AUD_CAD","time":"2014-10-10T19:07:40.359506Z","bid":0.93824,"ask":0.93875}}”

“{"tick":{"instrument":"AUD_CHF","time":"2014-10-10T19:07:38.362939Z","bid":0.97566,"ask":0.97603}}”

“{"tick":{"instrument":"GBP_USD","time":"2014-10-10T19:07:37.750485Z","bid":1.4758,"ask":1.47598}}”

“{"tick":{"instrument":"USD_EUR","time":"2014-10-10T19:07:39.219876Z","bid":0.79621,"ask":0.79627}}”

“{"tick":{"instrument":"AUD_CAD","time":"2014-10-10T19:07:41.062111Z","bid":0.9383,"ask":0.93881}}”

“{"tick":{"instrument":"USD_EUR","time":"2014-10-10T19:07:41.660565Z","bid":0.79624,"ask":0.7963}}”

“{"tick":{"instrument":"AUD_CHF","time":"2014-10-10T19:07:41.901723Z","bid":0.9757,"ask":0.97607}}”

“{"tick":{"instrument":"USD_EUR","time":"2014-10-10T19:07:41.964353Z","bid":0.79626,"ask":0.79632}}”

2

very interesting idea!
is current free 32-bit version supporting websocket client feature?

3

yes

4

Can we connect to KDB(secured by password) through websockets?

As in the following c.js section of article wslogin page, there is a login button, but i am not sure if it is used for login in kdb. It though demonstrates serialize/deserialize.

http://code.kx.com/wiki/Cookbook/Websocket

5

That example is indeed misleading - it’s relying on a custom authentication via submission to .z.ws.

A websocket connection is an upgrade of an http connection; hence the authentication is part of the http protocol (basic authentication, as comes into force when using the -u/U cmd line option of kdb+). Chrome currently has some issues with this, although firefox is fine. The issue appears to be fixed in the latest release of Chrome ‘Canary’.

6

Thanks Charles. Authentication works fine in firefox.