$url = "http://192.168.8.1/api/monitoring/traffic-statistics";
$data = file_get_contents($url);
$xml = new SimpleXmlElement($data);

$variables = array(
        "CurrentConnectTime",
        "CurrentUpload",
        "CurrentDownload",
        "CurrentDownloadRate",
        "CurrentUploadRate",
        "TotalUpload",
        "TotalDownload",
        "TotalConnectTime",
//      "showtraffic",           // this doesn't seem to change from '1' so I just ignore it
        "MaxUploadRate",
        "MaxDownloadRate");

// this outputs the current download rate (in bytes/second) as reported by the device:
// echo $xml->CurrentDownloadRate;

// I build a single line payload for my influx database
$payload = "huawei ";

foreach($variables as $var) {
        $payload .= "$var=".$xml->$var.",";
}

$payload = trim($payload,",");

// That looks something like this (timestamp is automatically appended):
// huawei CurrentConnectTime=92016,CurrentUpload=5832119940,CurrentDownload=32772130236,CurrentDownloadRate=895,CurrentUploadRate=1539,TotalUpload=824477229102,TotalDownload=5553380109187,TotalConnectTime=15820842,MaxUploadRate=8737338,MaxDownloadRate=41668223

// Then post it to my influx database:
$url = "https://yourinfluxserver/write?db=huawei";
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $payload);
$response = curl_exec($ch);