IoT Platform:PHP sample script

Script template

You can write a PHP script to parse data based on the following PHP template:

<?php
/**
 * Convert the data that is sent by a device to a custom topic to JSON data when the device submits data to IoT Platform. 
 * $topic: the input parameter that specifies the topic to which the device sends messages. The value is a string. 
 * $rawData: the input parameter. The value is an array of integers. 
 * $jsonObj: an output parameter. The value is a JSON object that indicates an association array. The value of each key must be a string that is not a numeric string such as "10". Key values cannot be empty. 
 */
function transformPayload($topic, $rawData)
{
    $jsonObj = array();
    return $jsonObj;
}
?>

Notes for script writing

• Do not use global variables or static variables. Otherwise, results may be inconsistent.
• In the script, process data by using the two's complement operation. The complement range for values in the range of [-128,127] is [0,255]. For example, the complement of -1 is 255 in decimal.
• The input parameter of the transformPayload function is an array of integers. Use 0xFF for the bitwise AND operation to obtain the complement. The return result is an association array. Each key value must contain non-array characters. For example, if a key value is "10", the PHP array retrieves the integer 10.
• The PHP runtime environment is significantly strict with exception handling. If an error occurs, an exception is thrown and subsequent code is not run. To ensure code robustness, you need to capture and process exceptions.

Sample script

<?php
/*
  Sample data
  Use the following custom topic to submit data:
     /user/update. 
  Input:
     topic: /${productKey}/${deviceName}/user/update
     bytes: 0x000000000100320100000000 
  Output:
  {
     "prop_float": 0,
     "prop_int16": 50,
     "prop_bool": 1,
     "topic": "/${productKey}/${deviceName}/user/update"
   }
 */
function transformPayload($topic, $bytes)
{
    $data = array();
    $length = count($bytes);
    for ($i = 0; $i < $length; $i++) {
        $data[$i] = $bytes[$i] & 0xff;
    }

    $jsonMap = array();

    if (strpos($topic, '/user/update/error') !== false) {
        $jsonMap['topic'] = $topic;
        $jsonMap['errorCode'] = getInt8($data, 0);
    } else if (strpos($topic, '/user/update') !== false) {
        $jsonMap['topic'] = $topic;
        $jsonMap['prop_int16'] = getInt16($data, 5);
        $jsonMap['prop_bool'] = $data[7];
    }

    return $jsonMap;
}

function getInt32($bytes, $index)
{
    $array = array($bytes[$index], $bytes[$index + 1], $bytes[$index + 2], $bytes[$index + 3]);

    return hexdec(byteArrayToHexString($array));
}

function getInt16($bytes, $index)
{
    $array = array($bytes[$index], $bytes[$index + 1]);

    return hexdec(byteArrayToHexString($array));
}

function getInt8($bytes, $index)
{
    $array = array($bytes[$index]);
    return hexdec(byteArrayToHexString($array));
}

function byteArrayToHexString($data)
{
    $hexStr = '';
    for ($i = 0; $i < count($data); $i++) {
        $hexValue = dechex($data[$i]);

        $tempHexStr = strval($hexValue);

        if (strlen($tempHexStr) === 1) {
            $hexStr = $hexStr . '0' . $tempHexStr;
        } else {
            $hexStr = $hexStr . $tempHexStr;
        }
    }

    return $hexStr;
}

function hexStringToByteArray($hex)
{
    $result = array();
    $index = 0;
    for ($i = 0; $i < strlen($hex) - 1; $i += 2) {
        $result[$index++] = hexdec($hex[$i] . $hex[$i + 1]);
    }
    return $result;
}


function concat($array, $data)
{
    return array_merge($array, $data);
}

function toHex($data)
{
    $var = dechex($data);
    $length = strlen($var);
    if ($length % 2 == 1) {
        $var = '0' . $var;
    }
    return $var;
}