PHP convert XML to JSON


Answers

Sorry for answering an old post, but this article outlines an approach that is relatively short, concise and easy to maintain. I tested it myself and works pretty well.

http://lostechies.com/seanbiefeld/2011/10/21/simple-xml-to-json-with-php/

<?php   
class XmlToJson {
    public function Parse ($url) {
        $fileContents= file_get_contents($url);
        $fileContents = str_replace(array("\n", "\r", "\t"), '', $fileContents);
        $fileContents = trim(str_replace('"', "'", $fileContents));
        $simpleXml = simplexml_load_string($fileContents);
        $json = json_encode($simpleXml);

        return $json;
    }
}
?>
Question

I am trying to convert xml to json in php. If I do a simple convert using simple xml and json_encode none of the attributes in the xml show.

$xml = simplexml_load_file("states.xml");
echo json_encode($xml);

So I am trying to manually parse it like this.

foreach($xml->children() as $state)
{
    $states[]= array('state' => $state->name); 
}       
echo json_encode($states);

and the output for state is {"state":{"0":"Alabama"}} rather than {"state":"Alabama"}

What am I doing wrong?

XML:

<?xml version="1.0" ?>
<states>
    <state id="AL">     
    <name>Alabama</name>
    </state>
    <state id="AK">
        <name>Alaska</name>
    </state>
</states>

Output:

[{"state":{"0":"Alabama"}},{"state":{"0":"Alaska"}

var dump:

object(SimpleXMLElement)#1 (1) {
["state"]=>
array(2) {
[0]=>
object(SimpleXMLElement)#3 (2) {
  ["@attributes"]=>
  array(1) {
    ["id"]=>
    string(2) "AL"
  }
  ["name"]=>
  string(7) "Alabama"
}
[1]=>
object(SimpleXMLElement)#2 (2) {
  ["@attributes"]=>
  array(1) {
    ["id"]=>
    string(2) "AK"
  }
  ["name"]=>
  string(6) "Alaska"
}
}
}



This is an improvement of the most upvoted solution by Antonio Max, which also works with XML that has namespaces (by replacing the colon with an underscore). It also has some extra options (and does parse <person my-attribute='name'>John</person> correctly).

function parse_xml_into_array($xml_string, $options = array()) {
    /*
    DESCRIPTION:
    - parse an XML string into an array
    INPUT:
    - $xml_string
    - $options : associative array with any of these keys:
        - 'flatten_cdata' : set to true to flatten CDATA elements
        - 'use_objects' : set to true to parse into objects instead of associative arrays
        - 'convert_booleans' : set to true to cast string values 'true' and 'false' into booleans
    OUTPUT:
    - associative array
    */

    // Remove namespaces by replacing ":" with "_"
    if (preg_match_all("|</([\\w\\-]+):([\\w\\-]+)>|", $xml_string, $matches, PREG_SET_ORDER)) {
        foreach ($matches as $match) {
            $xml_string = str_replace('<'. $match[1] .':'. $match[2], '<'. $match[1] .'_'. $match[2], $xml_string);
            $xml_string = str_replace('</'. $match[1] .':'. $match[2], '</'. $match[1] .'_'. $match[2], $xml_string);
        }
    }

    $output = json_decode(json_encode(@simplexml_load_string($xml_string, 'SimpleXMLElement', ($options['flatten_cdata'] ? LIBXML_NOCDATA : 0))), ($options['use_objects'] ? false : true));

    // Cast string values "true" and "false" to booleans
    if ($options['convert_booleans']) {
        $bool = function(&$item, $key) {
            if (in_array($item, array('true', 'TRUE', 'True'), true)) {
                $item = true;
            } elseif (in_array($item, array('false', 'FALSE', 'False'), true)) {
                $item = false;
            }
        };
        array_walk_recursive($output, $bool);
    }

    return $output;
}



Optimizing Antonio Max answer:

$xmlfile = 'yourfile.xml';
$xmlparser = xml_parser_create();

// open a file and read data
$fp = fopen($xmlfile, 'r');
//9999999 is the length which fread stops to read.
$xmldata = fread($fp, 9999999);

// converting to XML
$xml = simplexml_load_string($xmldata, "SimpleXMLElement", LIBXML_NOCDATA);

// converting to JSON
$json = json_encode($xml);
$array = json_decode($json,TRUE);



I guess I'm a bit late to the party but I have written a small function to accomplish this task. It also takes care of attributes, text content and even if multiple nodes with the same node-name are siblings.

Dislaimer: I'm not a PHP native, so please bear with simple mistakes.

function xml2js($xmlnode) {
    $root = (func_num_args() > 1 ? false : true);
    $jsnode = array();

    if (!$root) {
        if (count($xmlnode->attributes()) > 0){
            $jsnode["$"] = array();
            foreach($xmlnode->attributes() as $key => $value)
                $jsnode["$"][$key] = (string)$value;
        }

        $textcontent = trim((string)$xmlnode);
        if (count($textcontent) > 0)
            $jsnode["_"] = $textcontent;

        foreach ($xmlnode->children() as $childxmlnode) {
            $childname = $childxmlnode->getName();
            if (!array_key_exists($childname, $jsnode))
                $jsnode[$childname] = array();
            array_push($jsnode[$childname], xml2js($childxmlnode, true));
        }
        return $jsnode;
    } else {
        $nodename = $xmlnode->getName();
        $jsnode[$nodename] = array();
        array_push($jsnode[$nodename], xml2js($xmlnode, true));
        return json_encode($jsnode);
    }
}   

Usage example:

$xml = simplexml_load_file("myfile.xml");
echo xml2js($xml);

Example Input (myfile.xml):

<family name="Johnson">
    <child name="John" age="5">
        <toy status="old">Trooper</toy>
        <toy status="old">Ultrablock</toy>
        <toy status="new">Bike</toy>
    </child>
</family>

Example output:

{"family":[{"$":{"name":"Johnson"},"child":[{"$":{"name":"John","age":"5"},"toy":[{"$":{"status":"old"},"_":"Trooper"},{"$":{"status":"old"},"_":"Ultrablock"},{"$":{"status":"new"},"_":"Bike"}]}]}]}

Pretty printed:

{
    "family" : [{
            "$" : {
                "name" : "Johnson"
            },
            "child" : [{
                    "$" : {
                        "name" : "John",
                        "age" : "5"
                    },
                    "toy" : [{
                            "$" : {
                                "status" : "old"
                            },
                            "_" : "Trooper"
                        }, {
                            "$" : {
                                "status" : "old"
                            },
                            "_" : "Ultrablock"
                        }, {
                            "$" : {
                                "status" : "new"
                            },
                            "_" : "Bike"
                        }
                    ]
                }
            ]
        }
    ]
}

Quirks to keep in mind: Several tags with the same tagname can be siblings. Other solutions will most likely drop all but the last sibling. To avoid this each and every single node, even if it only has one child, is an array which hold an object for each instance of the tagname. (See multiple "" elements in example)

Even the root element, of which only one should exist in a valid XML document is stored as array with an object of the instance, just to have a consistent data structure.

To be able to distinguish between XML node content and XML attributes each objects attributes are stored in the "$" and the content in the "_" child.

Edit: I forgot to show the output for your example input data

{
    "states" : [{
            "state" : [{
                    "$" : {
                        "id" : "AL"
                    },
                    "name" : [{
                            "_" : "Alabama"
                        }
                    ]
                }, {
                    "$" : {
                        "id" : "AK"
                    },
                    "name" : [{
                            "_" : "Alaska"
                        }
                    ]
                }
            ]
        }
    ]
}



The question doesn't say it, but usually PHP is returning JSON to a web page.

I find it much easier to convert the XML to JSON in the browser/page via a JS lib, for example:

https://code.google.com/p/x2js/downloads/detail?name=x2js-v1.1.3.zip



$xml = simplexml_load_string($xml_string);
$json = json_encode($xml);
$array = json_decode($json,TRUE);

just add those three lines you will get the correct output:-)




A common pitfall is to forget that json_encode() does not respect elements with a textvalue and attribute(s). It will choose one of those, meaning dataloss. The function below solves that problem. If one decides to go for the json_encode/decode way, the following function is advised.

function json_prepare_xml($domNode) {
  foreach($domNode->childNodes as $node) {
    if($node->hasChildNodes()) {
      json_prepare_xml($node);
    } else {
      if($domNode->hasAttributes() && strlen($domNode->nodeValue)){
         $domNode->setAttribute("nodeValue", $node->textContent);
         $node->nodeValue = "";
      }
    }
  }
}

$dom = new DOMDocument();
$dom->loadXML( file_get_contents($xmlfile) );
json_prepare_xml($dom);
$sxml = simplexml_load_string( $dom->saveXML() );
$json = json_decode( json_encode( $sxml ) );

by doing so, <foo bar="3">Lorem</foo> will not end up as {"foo":"Lorem"} in your JSON.




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Tags

php php   xml   json json