JSON - getting data from an HTTP-response

[peterbos]

Hi,

If I do a call to

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https://apps.hvcgroep.nl/rest/adressen/1562BP-1

I get this response:

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[{"bagId":"0479200000033698","postcode":"1562BP","huisnummer":1,"huisletter":"","huisnummerToevoeging":"","openbareRuimteNaam":"Glennstraat","woonplaatsNaam":"Krommenie","latitude":52.50839,"longitude":4.755153,"woonplaatsId":1880,"gemeenteId":479}]

I searched the forum and the rest of the internet but can't find how to retrieve the values of the fields as strings (frankly, I miss a manual how to use json in dzVents). Can someone point me in the right direction?

Peter

[roblom]

Not a direct answer to your question, but there is a plugin you can use for that.

https://github.com/Xorfor/Domoticz-Afvalwijzer-Plugin

[waltervl]

And there is also a garbage calender lua script for almost the whole netherlands: https://github.com/jvanderzande/GarbageCalendar

For example scripts with json search for keyword "isJSON" in this forum: search.php?keywords=isjson
The parsing of json depends on its structure. As dzvents is lua you can also search outside this forum for lua and json.

[rwblinn]

Please find a dzVents example triggered by a switch (hardware dummy virtual sensor):

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-- Domoticz IDX of the switch triggering HTTP request
local IDX_SWITCH  = 16
local URL_SERVER = "https://apps.hvcgroep.nl/rest/adressen/1562BP-1"
local RES_HTTP = "RES_1562BP"
local LOG_MARKER = "LOG_1562BP"

return {
	on = { 
           devices = { IDX_SWITCH }, 
           httpResponses = { RES_HTTP } 
	},
	logging = {
	  level = domoticz.LOG_INFO, marker = LOG_MARKER,	
	},
	execute = function(domoticz, item)
           if (item.isDevice) then
             domoticz.openURL({ url = URL_SERVER, method = 'GET', callback = RES_HTTP, }) 
          end
          if (item.isHTTPResponse) then
            if (item.statusCode == 200) then
                if (item.isJSON) then
                   -- Get the data which is a JSON array with one element
                    local data = item.json[1]
                    domoticz.log(string.format('lon=%s, lat=%s', tostring(data["longitude"]), tostring(data["latitude"])))
                    -- lon=4.755153, lat=52.50839. Instead data["key"] can also use data.key:
                    -- domoticz.log(string.format('lon=%s, lat=%s', tostring(data.longitude), tostring(data.latitude))) 
                end
            else
                -- Error like 7 false; ERROR 7:Couldn't connect to server 
                domoticz.log(string.format("ERROR %d:%s", item.statusCode, item.statusText))
            end
        end		
      end
}

[willemd]

If you create a new DZvents script and choose the template for http request, you can then fill in your api call and modify the assignment of someValue slightly and you will get the example below.

I guess your problem was how to get a certain value out of the long string and I have included in the example the extraction of the postal code. Documentation on this is indeed very poor and in previous scripts I developed I have spent days of trial and error.

In this case the following works:

local someValue = item.json[1].postcode

The important thing is to look closely to the buildup of your response, i.e. the square brackets, the curled brackets, the field identifiers etc.

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return {
	on = {
		timer = {
			'every 1 minutes' -- just an example to trigger the request
		},
		httpResponses = {
			'trigger' -- must match with the callback passed to the openURL command
		}
	},
	logging = {
		level = domoticz.LOG_INFO,
		marker = 'template',
	},
	execute = function(domoticz, item)

		if (item.isTimer) then
			domoticz.openURL({
				url = 'https://apps.hvcgroep.nl/rest/adressen/1562BP-1',
				method = 'GET',
				callback = 'trigger', -- see httpResponses above.
			})
		end

		if (item.isHTTPResponse) then

			if (item.ok) then
				if (item.isJSON) then

                    
					local someValue = item.json[1].postcode -- just an example

					-- update some device in Domoticz
					domoticz.log('myTextDevice '.. someValue, domoticz.LOG_INFO)
				end
			else
				domoticz.log('There was a problem handling the request', domoticz.LOG_ERROR)
				domoticz.log(item, domoticz.LOG_ERROR)
			end

		end

	end
}

[peterbos]

Thanks all,

It was the [1] that did the trick. That is not in the template for a http request.

Peter

[willemd]

Also note there is no dot before the [1]

basically you use a number between brackets, without a dot, in order to get the part between curly brackets

and you use the name, with a dot before it, of a name/value pair to get the value

and this can be nested in many ways

Once you get that logic is becomes easy ...