How to publish a table using JSON format to MQTT server in DolphinDB

hz.wale Published at Dev

hz.wale

I want to publish a table using JSON format,the table is defined as below,

COLS_READINGS   = `time`device_id`battery_level`battery_status`battery_temperature`bssid`cpu_avg_1min`cpu_avg_5min`cpu_avg_15min`mem_free`mem_used`rssi`ssid
TYPES_READINGS  = `DATETIME`SYMBOL`INT`SYMBOL`DOUBLE`SYMBOL`DOUBLE`DOUBLE`DOUBLE`LONG`LONG`SHORT`SYMBOL
schema_readings = table(COLS_READINGS, TYPES_READINGS)

Then what should I do? Does dolphindb support mqtt publish，Or can I write a plugin myself with mosquitto?

smile qian

DolphinDB has a mqtt client plugin that can be downloaded from https://github.com/dolphindb/DolphinDBPlugin/tree/master/mqtt.

loadPlugin("PluginMQTTClient.txt"); 
use mqtt; 

//***************************publish a table****************************************//
MyFormat = take("", 5)
MyFormat[2] = "0.000"
f = createCsvFormatter(MyFormat, ',', ';')

//create a record for every device
def writeData(hardwareVector){
  hardwareNumber = size(hardwareVector)
  return table(take(hardwareVector,hardwareNumber) as hardwareId ,take(now(),
    hardwareNumber) as ts,rand(20..41,hardwareNumber) as temperature,
    rand(50,hardwareNumber) as humidity,rand(500..1000,
    hardwareNumber) as voltage)
 }
def publishTableData(server,topic,iterations,hardwareVector,interval,f){
 conn=connect(server,1883,0,f,100)
 for(i in 0:iterations){
   t=writeData(hardwareVector)
   publish(conn,topic,t)
   sleep(interval)
 }
 close(conn)

}
host="192.168.1.201"
submitJob("submit_pub1", "submit_p1", 
publishTableData{host,"sensor/s001",10,100..149,100,f})
publishTableData(host,"sensor/s001",100,0..99,100,f)

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