How to post JSON data from Arduino?

Question

I want to post data that I'm getting from the sensor every 5 seconds to my application in JSON format. Initially, I'm getting data as int and converting into String.

For example:

if data=15, it is converting into string.

String st=String(data);

Now I want to post st every 5 seconds.

 int S2 = http.sendRequest("PUT", "{\"itemId\":\"64006A962B71A1E7B3A0428637DA997C.327681\",\"item\":{\"Properties\":{\"AssetSensorDistance\":\"+st+\"}},\"operationType\":\"Update\",\"originalItem\":{\"Work_Order\":{\"ItemId\":\"64006A962B71A1E7B3A0428637DA997C.327681\"},\"Properties\":{\"AssetSensorDistance\":\"+st1+\"}}}");
 Serial.print("Sensor Status: ");
 Serial.println(S2);

st1 is the previous value, it is printing httpcode -2(invalid Syntax).

Can anyone help me with this issue?

Thanks in advance.

• Majenko: I take it, at some other point in your program, you are telling it where to post the data to?
• Anne Lingesh: To My Application
• jsotola: please provide detailed information in your question about what you are observing. ... there appears to be a contradiction in your statements

Answer 1

The string

"{\"AssetSensorDistance\":\"+st+\"}"

contains a literal "+st+". If you want to do string concatenation, you should terminate the string with a double quote character, then add st, then use another double quote to start the second part of the string:

"{\"AssetSensorDistance\":\""+st+"\"}"

• Anne Lingesh: it displaying as +st+ in my application instead of value
• Edgar Bonet: @AnneLingesh: That's what I wrote in my answer: you have a literal "+st+" in your string.
• Anne Lingesh: I didn't understand @Edgar Bonet 2
• jsotola: it displaying as +st+ in my application instead of value ... your post says that it does not work, that you are getting invalid Syntax ... which is it? you are either getting some data to your application, or you are not getting data to your application. .... update your question with more information
• Anne Lingesh: Getting data but which I'm not expected, I want to display value in my application not st(text)