MICHAEL danieletto

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9 years, 8 months ago.  This question has been closed. Reason: Off Topic

JSON on mbed

hello, through a webservice I receive , after a get request , the json .

{"coord":{"lon":7.28,"lat":43.7},"sys":{"type":3,"id":61624,"message":0.2379,"country":"France","sunrise":1427433653,"sunset":1427478691},"weather":[{"id":800,"main":"Clear","description":"Sky is Clear","icon":"01d"}],"base":"cmc stations","main":{"temp":292.21,"humidity":67.44,"pressure":1005.96,"temp_min":289.84,"temp_max":295.37},"wind":{"speed":2.41,"deg":359.001},"rain":{"3h":0},"clouds":{"all":0},"dt":1427457594,"id":2990440,"name":"Nice","cod":200}

But the trouble is that I would recover for example only the value of Temp ... How could I do? thank you in advance.

the json is contained in a char variable

posted by MICHAEL danieletto 27 Mar 2015

2 Answers

Colin Meikle
9 years, 8 months ago.

I've used picoJSON and it worked great on a resent demo project, which is doing exactly what you are looking for

there is write up here http://www.element14.com/community/roadTestReviews/1984 and more detail here http://www.element14.com/community/people/colin_meikle%40mentor.com/blog/2015/03/23/k64f-mbed-part-2-weather-station and the code here http://developer.mbed.org/users/colinmeikle/code/weather/

From my experience the JSON libraries can be memory intensive, so you may have problems on some boards I'm using K64F I had previously used a K25Z and had problems with memory I suspect and resorted to string matching.

Accepted Answer

Thanks you very much ! my plan works perfectly !! You are the best :)

posted by MICHAEL danieletto 27 Mar 2015
Andy A
9 years, 8 months ago.

So you need a JSON parser? Try searching for JSON, there are a few already written.

Yes of course I tried this but I do not have a good result ..

void capture(void){ MbedJSONValue demo; double temp; parse(demo,json); temp=(demo["temp"].get<double>()); pc.printf("\n\rtempertature =%f\r\n",temp); }

json is the char variable contained my data

posted by MICHAEL danieletto 27 Mar 2015