IoT Platform:Function list

Expression

Description

convert2HotStorageData(fields, time)

Transforms the fields data into a standardized format suitable for storage.

• fields: The data record in Map or JSON format to be stored, structured as follows:

  {
      "key1": value1,
      "key2": value2
  }

  • key1 and key2 are identifiers for the fields to be stored, representing the names of the data.

  • value1 and value2 are the values assigned to the respective fields from the device data.

  Important

  The fields parameter may include a maximum of 500 key.

• time: The timestamp in milliseconds corresponding to the data, expressed as a numeric value.

  The timestamp() function can be used to obtain the current system timestamp, or you can specify a custom time.

  This timestamp is assigned to the fields data for all fields as time.

{
    "key1": {
        "value": value1,
        "time": timestamp()
    },
    "key2": {
        "value": value2,
        "time": timestamp()
    }
}

writeHotStorage(params)

Stores data in the standardized format params into the IoT Platform's time series data storage.

{
    "key1": {
        "value": value1,
        "time": 1626948134319
    },
    "key2": {
        "value": value2,
        "time": 1626948134000
    }
}

Function

Description

toBoolean(Object)

Converts the Object parameter into a Boolean value. The parameter supports the following data types:

• Boolean: The function returns the same value as the parameter.

• Number: If the parameter is set to 0, the function returns false. Otherwise, the function returns true.

• String: If the parameter is set to "true", the function returns true. Otherwise, the function returns false.

• If the parameter is set to NULL, the function returns false.

toNumber(Object)

Converts the value of the Object parameter into a number. The parameter supports the following data types:

• Boolean: If the parameter is set to true, the function returns 1. If the parameter is set to false, the function returns 0.

• Number: The function returns the same value as the parameter.

• String: The function parses the string to a number.

• If the parameter is set to NULL, the function returns 0.

toString(Object)

Converts the value of the Object parameter into a string.

If the parameter is set to a value other than NULL, the function returns the value as a string. If the parameter is set to NULL, the function returns an empty string.

If the parameter is of the binary type, the function returns a UTF-8 decoded value.

toMap(Object)

Converts the value of the Object parameter into a map. The parameter supports the following data types:

• Map: The function returns the same value as the parameter.

• String: The function parses the string to a map in the JSON format.

• If the parameter is set to NULL, the function returns an empty map.

toArray(Object)

Converts the value of the Object parameter into an array. The parameter supports the following data types:

• Array: The function returns the same value as the parameter.

• String: The function parses the string to an array in the JSON format.

• If the parameter is set to NULL, the function returns an empty array.

toBinary(Object)

Converts the value of the Object parameter into a binary value. The parameter supports the following data types:

• Binary: The function returns the same value as the parameter.

• String: The function returns a UTF-8 encoded value.

• If the parameter is set to NULL, the function returns an empty binary value.

Function

Description

format_date(timestamp, patten, timeZone)

Converts a timestamp in milliseconds into a time value in a specified format. A string is returned.

• timestamp: the timestamp in milliseconds.

• patten: the required time format. Example: yyyy-MM-dd HH:mm:ss.

• timeZone: the time zone. Examples: GMT, UTC, and CST. We recommend that you specify a time zone. If you do not configure the timeZone parameter, the function returns a time value in GMT+8.

to_timestamp(dateString, patten, timeZone)

Converts a time value in a specified format into a timestamp in milliseconds. A numeric value is returned.

• dateString: the time string.

• patten: the time format. Example: yyyy-MM-dd HH:mm:ss.

• timeZone: the time zone. Examples: GMT, UTC, and CST. We recommend that you specify a time zone. If you do not configure the timeZone parameter, the function returns a timestamp in GMT+8.

Function

Description

endWith(input, suffix)

Checks whether the input string ends with a specified suffix.

A Boolean value is returned.

productKey()

Returns the ProductKey of the current product.

getDeviceTag(key)

Returns the device tag value of a tag key. If the tag that contains the specified key is not attached to a device, no tag value is returned.

getOrNull(data, "items", ......)

Returns the value of a specified field in the JSON-formatted data parameter.

You can configure one or more fields in the function. Multiple fields must be configured based on levels. The function returns the value of the last field. If the last field does not exist or the field is empty, the function returns null.

Example of data:

"items": {
    "Humidity": {
        "value": 25,
        "time": 1626948134319
    }
}

Examples:

• getOrNull(data, "items"): returns the value of the items field "Humidity": {"value": 25,"time": 1626948134319}.

• getOrNull(data, "items", "Humidity", "value"): returns the value of the value field 25.

• getOrNull(data, "items", "Temperature"): returns the value null if the Temperature field does not exist.

payload(textEncoding)

Encodes the message payload that is sent by a device. The textEncoding parameter specifies an encoding scheme.

• If you do not configure the parameter, the message payload is converted into a UTF-8 encoded string. payload() is equivalent to payload('utf-8').

• If you set the parameter to 'json', the message payload is converted into a map. If the payload is not in the JSON format, an error occurs.

• If you set the parameter to 'binary', the message payload is converted into pass-through binary data.

parseNumber(numberString, radix)

Converts a string specified by the numberString parameter into a number based on a number system specified by the radix parameter.

// A device submits data. 
var content = '0xFF';
// The function obtains the string FF to be converted.
var x = content.substring(2);
// The function converts the string FF into a hexadecimal number. 
var value = parseNumber(x, 16);