How to parse a JSON http response ?

What specifically happens when you call a!fromJson on the above json string?  Any chance you can post it here as text instead of as a picture?

Hello, 

Here is the json string as text: 

{"coord":{"lon":-3.7,"lat":40.42},"weather":[{"id":801,"main":"Clouds","description":"few clouds","icon":"02d"}],"base":"stations","main":{"temp":297.85,"feels_like":296.53,"temp_min":296.15,"temp_max":299.15,"pressure":1026,"humidity":44},"visibility":10000,"wind":{"speed":2.6,"deg":120},"clouds":{"all":20},"dt":1590499496,"sys":{"type":1,"id":6443,"country":"ES","sunrise":1590468593,"sunset":1590521653},"timezone":7200,"id":3117735,"name":"Madrid","cod":200}

If I want to post in a read-only interface the "temp" and "pressure" value only for example, what expression/function should I use?   

Calling a!fromJson on that string does return a valid dictionary of data.  You should be able to refer to individual elements of the dictionary via standard dot notation in this case.  In this case if you stored the result of the fromJson call in local!jsonDictionary, then you could get "temp" just by calling local!jsonDictionary.main.temp

Thank you very much for your answer Mike. And if I want to show various values? not only the "temp"? 

You should be able to access any of the properties in the dictionary using dot notation in the same syntax.

a!fromJSON will return an "Object" with no specific type. From there, you can access the values via dot notation or via index.

Assuming local!weatherData is your variable that holds the response.

with (
   /* ASSUMING RESPONSE BODY IS JSON STRING */
   local!weatherData: a!fromJson(ri!httpResponseBody),
   local!temperature: index(local!weatherData, "main", "temp", null),
   local!pressure: index(local!weatherData, "main", "pressure", null),
   /* RETURNS BOTH TEMPERATURE AND PRESSURE */
   {
     temperature: local!temperature,
     pressure: local!pressure
  }
)

I hope this helps.

You can also convert the response to Appian value on the integration object