HTTP_PROXY

Community Support
1

Hi,

I’m a bit confused as to how the HTTP_PROXY in system settings is picked up. I’ve set it to http://127.0.0.1:8888 to see requests and responses in Fiddler. 

I can see the following two requests are sent to the proxy: 

.Q.hg`:https://www.example.com/ 

.Q.hp[`:https://www.example.com/;“Custom-Type”]“”

How can I ensure that a request like this is picked up by the proxy, as I’d like to see websocket requests in Fiddler?

r:(`$“:ws://echo.websocket.org:80”)“GET / HTTP/1.1\r\nHost: echo.websocket.org:80\r\n\r\n”;

Thanks in advance for any help. 

2

Hi Student,

.Q.hg and .Q.hp both use the underlying .Q.hmb function which has the proxy support in them (written in q). Essentially they check two env variables; HTTP_PROXY and NO_PROXY; if HTTP_PROXY is set & the URL being requested is not in NO_PROXY, they will use the proxy, which effectively means doing something like

`:https://127.0.0.1:8888 “GET https://www.example.com HTTP/1.1\r\nHost:example.com\r\n\r\n”

as opposed to 

`:https://www.example.com “GET / HTTP/1.1\r\nHost:example.com\r\n\r\n”

You would need to try the following to ensure it is picked up by the proxy:

r:`:ws://127.0.0.1:8888 “GET ws://echo.websocket.org:80 HTTP/1.1\r\nHost:echo.websocket.org\r\n\r\n”

This method of seeing the websocket request is quite manual. If you would like to do this automatically, by reading from HTTP_PROXY if it is set, I would highly recommend using the following websockets library that a colleague of mine wrote: https://github.com/jonathonmcmurray/ws.q

Once cloning this repo, you can access this by entering the following:

~/ws.q$ q ws.q -verbose

q).echo.upd:show;.echo.h:.ws.open[“ws://echo.websocket.org”;`.echo.upd]

– REQUEST –

:ws://echo.websocket.org GET / HTTP/1.1

Host: echo.websocket.org

Origin: echo.websocket.org

– RESPONSE –

HTTP/1.1 101 Web Socket Protocol Handshake

Access-Control-Allow-Credentials: true

Access-Control-Allow-Headers: content-type

Access-Control-Allow-Headers: authorization

Access-Control-Allow-Headers: x-websocket-extensions

Access-Control-Allow-Headers: x-websocket-version

Access-Control-Allow-Headers: x-websocket-protocol

Access-Control-Allow-Origin: echo.websocket.org

Connection: Upgrade

Date: Tue, 31 Jul 2018 09:02:21 GMT

Sec-WebSocket-Accept: HSmrc0sMlYUkAGmm5OPpG2HaGWk=

Server: Kaazing Gateway

Upgrade: websocket

q).echo.h"hello"

q)“hello”

This can be run without the verbose flag, the purpose of this is to log the request and response to the console. 

I hope this helps,

Julia

3

I would like to highlight that HTTP_PROXY should be used in the ws.q example to show that the output is being sent to the proxy instead of directly to the server. For example,

$ echo $HTTP_PROXY 

http://127.0.0.1:33207