Help with parsing UDP json response

Community Playground General Discussions
#1

I’m tyring to parse json response from a UDP request. Let’s say I want the value of the “method” item below. I have the sendUDP function in startupLua. The expected return is in the format:

{“method”:“getSystemConfig”,“env”:“pro”,“result”:{“mac”:“a8bb50891fbe”,“homeId”:654213,“roomId”:990480,“homeLock”:false,“pairingLock”:false,“typeId”:0,“moduleName”:“ESP01_SHTW1C_31”,“fwVersion”:“1.18.0”,“groupId”:0,“drvConf”:[20,1]}}

Here’s the code I’m using:
//code
local JSON = require(“dkjson”)

local WizInfo = (sendUDP(‘{“method”: “getPilot”, “params”:{}}’, “46”))
//
From there, I know I need to parse the json, but that’s where I fall down. I’ve done a lot of searching and reading, am unable to get the items I need. I thank you for your help.

#2

Are you sure of the use of UDP? In you example, you’re just sending out that packet through UDP, there will be no response on/from WizInfo. A TCP or HTTP request would make more sense here. What kind of device are you trying to talk to?

#3

Thanks for the reply. I’m working with Wiz Connected bulbs. Wiz API communicates via UDP and says sending {“method”: “getPilot”, “params”:{}} should get all current settings for given light. If I do sendUDP(‘{“method”: “setPilot”, “params”:{“state”:true}}’, “46”) it turns the light on.
Also, I’m not sure how to see response.

#4

In that case you need to read from an UDP connection, not use just sendUDP. See this example Lua UDP example · GitHub for a bit of code that sends data over UDP and reads from it.

Timeout setting is important, as the default is udp:settimeout(0), which basically means the connection is closed immediately after sending the data. The timeout indicates the connection to remain open for a specified time to be able to read from it.

Then reading should work by:

  data = udp:receive()

Once that is done, you should be able to decode the data using dkjson. This gives the json.decode option, probably something like:

-- set variables

local data
local wizdata = {}

-- receive the data from the bulb
data = udp:receive()

-- decode received data
local jsonresponse = JSON.decode(data)

-- read method field
wizdata.method = jsonresponse.method
wizdata.homelock = jsonresponse.result.homeLock
#5

OMG…thats great info and I totally understand it. I’ll give it a shot and report back. Thanks again, @jouked!!!

#6

@jouked…that worked perfectly. Thanks again.