No Curl? No problem

Development
1

I’m trying to reduce the number of apk adds I use. I found by searching online there were no real solutions for clean NetCat use. I wanted it clean, and I wanted to use built-in’s only. This is a script which can replace curl. It may be slow, but for my needs it doesn’t need to be fast. This will run in hassio terminal.

echo $(nc -i 1 hassio 80 <<<unix2dos<<EOF
GET /core/api/events HTTP/1.1
Host: supervisor
User-Agent: curl/7.69.1
Accept: */*
Authorization: Bearer ${SUPERVISOR_TOKEN}
Content-Type: application/json

EOF
)|sed -e 's/.*\x0d\x20\x0d//1'

Breakdown:

echo $(nc -i 1 (HOST NAME OR IP ADDRESS) 80<<<unix2dos<<EOF
(HTTP METHOD) (API ENDPOINT) HTTP/1.1
Host: supervisor
User-Agent: curl/7.69.1
Accept: */*
Authorization: Bearer ${SUPERVISOR_TOKEN}
Content-Type: application/json

(REQUEST BODY GOES HERE FOR POST REQUESTS)

EOF
)|sed -e 's/.*\x0d\x20\x0d//1'

example of getting number of startup listeners from the supervisor into a variable called “listeners”

listeners=$(echo $(nc -i 1 hassio 80 <<<unix2dos<<EOF
GET /core/api/events HTTP/1.1
Host: supervisor
User-Agent: curl/7.69.1
Accept: */*
Authorization: Bearer ${SUPERVISOR_TOKEN}
Content-Type: application/json

EOF
)|sed -e 's/.*\x0d\x20\x0d//1'|jq '.[]|select(.event=="homeassistant_start").listener_count')
1 Like
2

Hacky … I love it.

So what’s the purpose of creating the variable listeners?
Is this intended to be used in a bash script or something?

Also what’s the point of running a unix2dos on the reply?
I assume this is a Linux host which would be happy with the existing line-endings on the reply

1 Like
3

Yes! Exactly. The variable is for a BASH script. When starting an Addon you are in BASH. Launching python would require an additional apk add the overhead of installation, and running a script in that environment. BASH is already running. So instead of launching python, I’ve been writing Add-ons that use BASH.

Http request require /r/n. Linux uses /n. unix2dos converts the heredocument into http format. This is required because the included busybox nc isn’t smart in formatting your request, and the Home Assistant server isn’t forgiving.

4

Didn’t know about that nuance. Guess most applications take care of that for the user!

Thanks for sharing; definitely has me thinking about a similar use case :slight_smile:

1 Like
5

Yeah. I’m going to create/update a sensor from my addon, and it only needs to occur once every couple of minutes on a different process from the main, so this is perfect.