Publishing using JSON?

[ridgerunnersjw]

I am doing a single JSON publish every 2 seconds four times over then wait and publish again 20 seconds later and so on. When I look at the console some of the publishes look as expected from your tutorial BUT some of them look like this (notice I don’t get the PRETTY or RAW buttons)…Can someone explain??

[ScruffR]

Only a blue rectangle?!?!?!
More context would be good.

[ridgerunnersjw]

I edited the post…should be able to see what I see

[ScruffR]

It seems your string is not terminated properly and that’s why you see these trailing characters after the place where the terminating '\0' should be.

Possibly a buffer overflow issue.

[ridgerunnersjw]

So for context and with hope that you can guide me thru this…I create an event every 20 seconds and that generates 4 publishes. After each of the publishes I delay for 2 seconds. 20 seconds later I wake up and do it again. And this occurs for a total of 3 cycles (ie 12 publishes). What I notice is the first two publishes always look like you see above (strange) but the 2nd two publishes are fine. I have shared the code which shows publishing…If I just publish to Particle without using JSON (the remarked out section of code in the state machine piece, I have no issues…works just fine. Can you comment a little more on what may be going on? (Sorry I am new to JSON ) From my perspective I just call this function and it is identical every time I call it and the particle.publish when unremarked uses the same datum and works fine.
Thanks

          case WEB_PUBLISH:
            for (current = 0; current < 4; current++){
              Serial.printlnf("Publishing to Particle CYCLE %d, CURRENT %0.1f mA", ((readCycle > 0) ? readCycle : 3), DAC_C[current]);
/*
              Particle.publish("Event/Cycle/Current/Vbias/SiPM/LED1/LED2/Tw/Tbd",String::format("%lu, %d, %0.1f, %0.2f, %0.2f, %0.2f, %0.2f, %0.1f, %0.1f",\
              events, ((readCycle > 0) ? readCycle : 3), DAC_C[current], SensorDataPerCyclePublish.Vbias[current], \
                SensorDataPerCyclePublish.SiPMCurrent[current], SensorDataPerCyclePublish.LED1Current[current], SensorDataPerCyclePublish.LED2Current[current], \
                SensorDataPerCyclePublish.w_temp[current],SensorDataPerCyclePublish.bd_temp[current]));
*/
              createEventPayload(events, ((readCycle > 0) ? readCycle : 3), SensorDataPerCyclePublish.Vbias[current], \
                SensorDataPerCyclePublish.SiPMCurrent[current], SensorDataPerCyclePublish.LED1Current[current], SensorDataPerCyclePublish.LED2Current[current], \
                SensorDataPerCyclePublish.w_temp[current],SensorDataPerCyclePublish.bd_temp[current]);
              delay(2000);
            }

void createEventPayload(unsigned long postNum, uint8_t cycle, float bias, float sipm, float led1, float led2, float t1, float t2){
  char buf[256];
  JSONBufferWriter jw(buf, sizeof(buf));

  jw.beginObject();
  jw.name("Identifier").value(postNum);
  jw.name("Cycle").value(cycle);
  jw.name("BiasVoltage").value(bias, 2);
  jw.name("SiPMVoltage").value(sipm, 2);
  jw.name("LED1Voltage").value(led1, 2);
  jw.name("LED2Voltage").value(led2, 2);
  jw.name("WaterTemp").value(t1, 1);
  jw.name("BoardTemp").value(t2, 1);
  jw.endObject();

  Particle.publish("Fluorimeter-Data", jw.buffer(), PRIVATE);
}

[ScruffR]

Can you try increase the size of your buffer and also clear it.

  char buf[320];
  memset(buf, 0, sizeof(buf));
  JSONBufferWriter jw(buf, sizeof(buf)-1);

That’s also what the doc’s samples suggest

Device OS API | Reference Documentation

[ridgerunnersjw]

Thank you that worked…
Not sure which line above fixed the issue but it now works…I thought the buffer max was 256??
Do you think I have to flush the buffer with memset?

[rickkas7]

Yes. JSONBufferWriter does not null terminate the buffer, so you either need to clear the buffer with memset or add null terminator. The docs show both ways:

JSONBufferWriter