How to convert an XML document to a JSON text string with PHP language?

Currently, there is no built-in function or any standard extension that you can use to convert an XML document to a JSON text string.

But you can use the following PHP example, xml_to_json_converter.php, to convert an XML document to a JSON text string:

<?php
# xml_to_json_converter.php
# Copyright (c) FYIcenter.com 

   $dom = new DOMDocument('1.0');
   $dom->preserveWhiteSpace = false;
   $dom->load($argv[1]) or die("Unable to open json file!");

   $root = $dom->documentElement;
   $tag = $root->tagName;

   $obj = new stdClass();
   $obj->{$tag} = buildJSON($root);
   print(json_encode($obj,JSON_PRETTY_PRINT));

function buildJSON($element) {
   $val = null;
   $att = buildAttributes($element);
   $txt = buildText($element);
   $sub = buildElements($element);
   
   if ($att!=null) {
    if ($val==null) $val = new stdClass();
      foreach ($att as $k => $v) {
       $val->{$k} = $v;
      }
   }
   if ($sub!=null) {
    if ($val==null) $val = new stdClass();
      foreach ($sub as $k => $v) {
       $val->{$k} = $v;
      }
   }
   if ($txt!=null) {
    if (($val==null) && is_scalar($txt)) {
         $val = $txt;
    } else {
     if ($val==null) $val = new stdClass();
       $val->{"#text"} = $txt;
    }
   }

   return $val;
}

function buildAttributes($element) {
   $val = null;
   if ($element->hasAttributes()) {
      $val = new stdClass();
    foreach ($element->attributes as $att) {
         $v = $att->value;
     if ($v=="") $v = null;
         $val->{"@".$att->name} = $v;
      }
   }
   return $val;
}

function buildText($element) {
   $arr = array();
   if ($element->hasChildNodes()) {
    foreach ($element->childNodes as $node) {
     if ($node->nodeType==XML_TEXT_NODE || $node->nodeType==XML_CDATA_SECTION_NODE) {
      array_push($arr,$node->nodeValue);
     }
      }
   }
   if (count($arr)==1) return $arr[0];
   else if (count($arr)>1) return $arr;
   else return null;
}

function buildElements($element) {
   $val = new stdClass();
   if ($element->hasChildNodes()) {
    foreach ($element->childNodes as $node) {
     if ($node->nodeType==XML_ELEMENT_NODE) {
      if (!property_exists($val,$node->nodeName)) {
               $val->{$node->nodeName} = buildJSON($node);
      } else {
         $cur = $val->{$node->nodeName};
         if (is_array($cur)) {
           array_push($cur,buildJSON($node));
         } else {
           $val->{$node->nodeName} = array($cur,buildJSON($node));
         }
      }
     }
      }
   }
   if (count((array)$val)>0) return $val;
   else return null;
}
?>

To try the above PHP example, you can enter the following XML file, xml_sample.xml:

<profile id="10001">
   <name>John<mid>M</mid>Smith</name>
   <age>25</age>
   <address>
      <street>21 2nd Street</street>
      <city>New York</city>
   </address>
   <phone type="home">212 555-1234</phone>
   <phone type="office">646 555-4567</phone>
   <children/>
</profile>

Then run the above PHP example through the PHP engine with the XML file provided in the command line:

>\fyicenter\php\php.exe xml_to_json_converter.php xml_sample.xml
{
    "profile": {
        "@id": "10001",
        "name": {
            "mid": "M",
            "#text": [
                "John",
                "Smith"
            ]
        },
        "age": "25",
        "address": {
            "street": "21 2nd Street",
            "city": "New York"
        },
        "phone": [
            {
                "@type": "home",
                "#text": "212 555-1234"
            },
            {
                "@type": "office",
                "#text": "646 555-4567"
            }
        ],
        "children": null
    }
}

⇒ XML to JSON Conversion at fyicenter.com

⇐ Mapping XML Elements with Mixed Contents to JSON Values

⇑ XML to JSON Conversion

⇑⇑ JSON Tutorials