<?php
   //datos de factura RFC emisor, RFC receptor, Total, UUID
   //@toro https://tar.mx/archivo/2018/validar-folio-fiscal-cfdi-con-php-directo-del-sat-2018.html
   $emisor="";
   $receptor="";
   $total="";
   $uuid="";
   //
   $soap = sprintf('<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:tem="http://tempuri.org/"><soapenv:Header/><soapenv:Body><tem:Consulta><tem:expresionImpresa>?re=%s&amp;rr=%s&amp;tt=%s&amp;id=%s</tem:expresionImpresa></tem:Consulta></soapenv:Body></soapenv:Envelope>', $emisor,$receptor,$total,$uuid);
   //encabezados
   $headers = [
   'Content-Type: text/xml;charset=utf-8',
   'SOAPAction: http://tempuri.org/IConsultaCFDIService/Consulta',
   'Content-length: '.strlen($soap)
   ];

   $url = 'https://consultaqr.facturaelectronica.sat.gob.mx/ConsultaCFDIService.svc';
   $ch = curl_init();
   curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 1);
   curl_setopt($ch, CURLOPT_URL, $url);
   curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
   curl_setopt($ch, CURLOPT_POST, true);
   curl_setopt($ch, CURLOPT_POSTFIELDS, $soap);
   curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
   curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
   curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
   $res = curl_exec($ch);
   curl_close($ch);
   $xml = simplexml_load_string($res);
   $data = $xml->children('s', true)->children('', true)->children('', true);
   $data = json_encode($data->children('a', true), JSON_UNESCAPED_UNICODE);
   print_r(json_decode($data));