Write Slide Value

can anyone help me with this one?
i have a DDC controller, i can write value with this request:

http://192.168.1.240/root?resource=WriteProperty&jsoncode={"index"%3A335938824%2C"property"%3A85%2C"value"%3A45}&callback=_jqjsp&_1548966493485=

the value Writing is now 45. now i want to use the slider to change the value and send it.
i tried to use the http request node like this:
http://192.168.1.240/root?resource=WriteProperty&jsoncode={"index"%3A335938824%2C"property"%3A85%2C"value"%3A{msg.payload}}&callback=_jqjsp&_1548966493485=

but it doesn't work. does anyone has an idea?

thanks..

try building the url in a function node and passing that to the http request node.

That way you can also use a debug to see what you have defined and where you might be going wrong.

thanks for your feedback,

I have tried to write the function node but do not get it working. tried several things. I think it should look like this:

[{"id":"52da13b5.537f4c","type":"ui_slider","z":"912a3768.44dad8","name":"","label":"slider","tooltip":"","group":"369ad7fb.53ec58","order":0,"width":"6","height":"1","passthru":true,"outs":"all","topic":"","min":"35","max":"45","step":"1","x":490,"y":160,"wires":[["818cb14b.c0e95"]]},{"id":"818cb14b.c0e95","type":"function","z":"912a3768.44dad8","name":"Slider into HTTP request","func":"var msg = {\n    method: 'get',\n    url: 'http://192.168.1.240/root?resource=WriteProperty&jsoncode={%22index%22%3A335938824%2C%22property%22%3A85%2C%22value%22%3A :msg.payload }}&callback=_jqjsp&_1548966493485='\n};\nreturn msg;\n","outputs":1,"noerr":0,"x":730,"y":160,"wires":[["3b5a97d0.dd5ea8"]]},{"id":"3b5a97d0.dd5ea8","type":"http request","z":"912a3768.44dad8","name":"","method":"use","ret":"txt","url":"","tls":"","x":990,"y":160,"wires":[[]]},{"id":"369ad7fb.53ec58","type":"ui_group","z":"","name":"Woonkamer","tab":"856afc2a.9be24","disp":true,"width":"6","collapse":false},{"id":"856afc2a.9be24","type":"ui_tab","z":"","name":"Woonkamer","icon":"dashboard","order":2,"disabled":false,"hidden":false}]

what am I doing wrong??

If you look at the result in a debug node does it look correct?
Also your flow is not importable, you need to edit the previous post as described in How to share code or flow json

That’s not how you concatenate strings in javascript
see

http://2ality.com/2011/10/string-concatenation.html