how to fix XML with <0> tags

Question

i am generating an XML file FROM Json FIle

  $array = file_get_contents('Invoice.json');
  $json = json_decode($array, true);
  $token =  $json['invoice']; 

function array_to_xml( $data, &$xml_data ) {
    foreach( $data as $key => $value ) {
        if( is_array($value) ) {
            if( is_numeric($key) ){
                $key = 'item'.$key; //dealing with <0/>..<n/> issues
                $key2 = 'contact_persons'.$key;
           
            }
            $subnode = $xml_data->addChild($key);
            array_to_xml($value, $subnode);
        } else {
            $xml_data->addChild("$key",htmlspecialchars("$value"));
        }
     }
}
  
$xml_data = new SimpleXMLElement('<?xml version="1.0" encoding="UTF-8"?><data></data>');

// function call to convert array to xml
array_to_xml($token,$xml_data);

//saving generated xml file; 
$result = $xml_data->asXML('Invoice.xml');

inside the XML I have this Error

<contact_persons><0>122396000000033035</0></contact_persons>

and All of my XML data is in one line how can I Fix This Error and Create the XML to Show in multi-lines? thank U! ---EDIT-- this is the Json :

{"invoice":{"can_send_in_mail":false,"zcrm_potential_id":"","is_client_review_settings_enabled":false,"discount":0,"taxes":[],"billing_address":{"zip":"","country":"","address":"","city":"","phone":"","attention":"","street2":"","state":"","fax":""},"line_items":[{"bcy_rate":50,"item_total_formatted":"\u20ac50,00","salesorder_item_id":"","line_item_id":"122396000000033067","rate_formatted":"\u20ac50,00","header_id":"","documents":[],"item_type":"","item_type_formatted":"","purchase_rate":"","description":"asdfasdfasdf","discount":0,"item_order":0,"project_id":"","rate":50,"markup_amount":0,"pricebook_id":"","bcy_rate_formatted":"\u20ac50,00","quantity":1,"image_document_id":"","item_id":"","expense_receipt_name":"","tax_name":"INPS","item_total":50,"header_name":"","item_custom_fields":[],"tax_id":"122396000000032221","purchase_rate_formatted":"","unit":"","tax_type":"tax","time_entry_ids":[],"name":"","tax_percentage":4,"markup_amount_formatted":"\u20ac0,00","expense_id":""},{"bcy_rate":200,"item_total_formatted":"\u20ac200,00","salesorder_item_id":"","line_item_id":"122396000000033441","rate_formatted":"\u20ac200,00","header_id":"","documents":[],"item_type":"","item_type_formatted":"","purchase_rate":"","description":"3334 asdf","discount":0,"item_order":1,"project_id":"","rate":200,"markup_amount":0,"pricebook_id":"","bcy_rate_formatted":"\u20ac200,00","quantity":1,"image_document_id":"","item_id":"","expense_receipt_name":"","tax_name":"INPS","item_total":200,"header_name":"","item_custom_fields":[],"tax_id":"122396000000032221","purchase_rate_formatted":"","unit":"","tax_type":"tax","time_entry_ids":[],"name":"","tax_percentage":4,"markup_amount_formatted":"\u20ac0,00","expense_id":""}],"payment_expected_date_formatted":"","balance":267,"terms":"asdf fgsdfg sdfg ","credits_applied":0,"credits_applied_formatted":"\u20ac0,00","invoice_number":"INV-000001","payment_options":{"payment_gateways":[]},"stop_reminder_until_payment_expected_date":false,"customer_default_billing_address":{"zip":"","country":"","address":"","city":"","phone":"","street2":"","state":"","fax":"","state_code":""},"sub_total_inclusive_of_tax":0,"inprocess_transaction_present":false,"exchange_rate":1,"approver_id":"","estimate_id":"","submitted_date_formatted":"","sales_channel":"direct_sales","merchant_name":"","shipping_charge_formatted":"\u20ac3,00","status_formatted":"Draft","reference_number":"ככגעכ","shipping_charge_tax_id":"","ecomm_operator_name":"","is_autobill_enabled":false,"discount_percent":0,"shipping_charge_tax_name":"","page_height":"11.69in","status":"draft","reader_offline_payment_initiated":false,"schedule_time_formatted":"","discount_total":0,"tax_total":0,"is_viewed_by_client":false,"adjustment_formatted":"\u20ac4,00","balance_formatted":"\u20ac267,00","write_off_amount":0,"salesorder_id":"","currency_code":"EUR","page_width":"8.27in","sub_statuses":[],"bcy_total":267,"last_reminder_sent_date_formatted":"","date_formatted":"14/06/2020","client_viewed_time_formatted":"","salesorders":[],"adjustment_description":"Adjustment","last_modified_time":"2020-06-14T21:15:18+0200","currency_symbol":"\u20ac","ach_supported":false,"shipping_bills":[],"discount_type":"entity_level","transaction_rounding_type":"no_rounding","contact_persons_details":[],"roundoff_value":0,"template_name":"","schedule_time":"","deliverychallans":[],"salesorder_number":"","template_id":"122396000000000103","customer_name":"Thest Compan","customer_id":"122396000000033033","roundoff_value_formatted":"\u20ac0,00","unused_retainer_payments_formatted":"\u20ac0,00","total_formatted":"\u20ac267,00","discount_total_formatted":"\u20ac0,00","payment_terms_label":"Due on Receipt","show_no_of_copies":true,"date":"2020-06-14","submitted_date":"","notes":"Thanks for your business.","template_type_formatted":"","late_fee":{"amount":0,"rate_formatted":"\u20ac0,00","rate":0,"name":"","amount_formatted":"\u20ac0,00","frequency_type":"month","type":"percentage"},"documents":[],"client_viewed_time":"","discount_amount":0,"ecomm_operator_id":"","shipping_charge_inclusive_of_tax":3,"last_modified_by_id":"122396000000032001","write_off_amount_formatted":"\u20ac0,00","payment_discount_formatted":"\u20ac0,00","invoice_id":"122396000000033059","contact_category":"","template_type":"","recurring_invoice_id":"","color_code":"","contact_persons":["122396000000033035"],"can_send_invoice_sms":true,"shipping_charge_tax":"","bcy_tax_total":10,"created_time":"2020-06-14T18:33:43+0200","created_date_formatted":"14/06/2020","last_payment_date_formatted":"","is_inclusive_tax":false,"custom_fields":[],"last_payment_date":"","discount_applied_on_amount_formatted":"\u20ac0,00","price_precision":2,"sub_total_inclusive_of_tax_formatted":"\u20ac0,00","current_sub_status_formatted":"Draft","payment_discount":0,"approvers_list":[],"shipping_charge_tax_percentage":"","zcrm_potential_name":"","adjustment":4,"created_by_id":"122396000000032001","is_backorder":"","current_sub_status":"draft","discount_amount_formatted":"\u20ac0,00","due_date_formatted":"14/06/2020","is_discount_before_tax":true,"shipping_charge_inclusive_of_tax_formatted":"\u20ac3,00","attachment_name":"","ach_payment_initiated":false,"last_reminder_sent_date":"","merchant_id":"","payment_terms":0,"shipping_charge_exclusive_of_tax":3,"total":267,"shipping_charge_exclusive_of_tax_formatted":"\u20ac3,00","tax_total_formatted":"\u20ac0,00","current_sub_status_id":"","sub_total_formatted":"\u20ac250,00","tax_amount_withheld":0,"tax_amount_withheld_formatted":"\u20ac0,00","custom_field_hash":{},"bcy_shipping_charge":3,"shipping_address":{"zip":"","country":"","address":"","city":"","phone":"","attention":"","street2":"","state":"","fax":""},"next_reminder_date_formatted":"","shipping_charge_tax_formatted":"","bcy_discount_total":0,"shipping_charge_tax_type":"","orientation":"portrait","discount_applied_on_amount":0,"due_date":"2020-06-14","no_of_copies":1,"submitter_id":"","submitted_by":"","subject_content":"This is The Subject","payment_made_formatted":"\u20ac0,00","payment_expected_date":"","unused_retainer_payments":0,"bcy_sub_total":250,"is_emailed":false,"reminders_sent":0,"salesperson_name":"","salesperson_id":"","shipping_charge":3,"payment_made":0,"bcy_adjustment":4,"sub_total":250,"allow_partial_payments":false,"created_date":"2020-06-14","currency_id":"122396000000000071","invoice_url":"https://zohosecurepay.eu/invoice/otwsrl/secure?CInvoiceID=2-6ca32e7b078791fcdcc5ead77dbc52a7b54cc4d3c1c1bb6d49d351c9232255b05582a0db903a6955a054be84c7c26eeb73482b971d9cd4781af23344c636f0a15ff36ce7c9675220 ","payment_reminder_enabled":true}}

Answer 1

The problem comes from when you have something which isn't an array which has a key of 0. So what I've done here is to move the check for a numeric key outside the if and so it gets applied to either time you add the key into the structure...

function array_to_xml( $data, &$xml_data ) {
    foreach( $data as $key => $value ) {
        if( is_numeric($key) ){
            $key = 'item'.$key; //dealing with <0/>..<n/> issues
        }
        if( is_array($value) ) {
            $subnode = $xml_data->addChild($key);
            array_to_xml($value, $subnode);
        } else {
            $xml_data->addChild("$key",htmlspecialchars("$value"));
        }
    }
}