Using PHP to convert XML to CSV but with a twist - php

Question

I'm trying to convert some XML files I have to CSV using PHP SimpleXML class. However, I'm unable to achieve the result I want, because one parent could have several child elements with the same name. My current XML file is as follows:
<?xml version="1.0" encoding="UTF-8"?>
<root>
<club>
<name>Green Riders</name>
<membership>Free</membership>
<boardMember>
<name>James F.</name>
<position>CEO</position>
</boardMember>
<boardMember>
<name>Helen D.</name>
<position>Associate Director</position>
</boardMember>
</club>
<club>
<name>Broken Dice</name>
<membership>Paid</membership>
<boardMember>
<name>Patrick B.</name>
<position>CEO</position>
</boardMember>
</club>
</root>
The CSV output I was hoping to achieve is as such:
club,name,membership,boardMember>Name,boardMember>position
Green Riders,Free,James F.,CEO
Green Riders,Free,Helen D., Associate Director
Broken Dice,Paid,Patrick B., CEO
Is there anyway to achieve this without hard-coding the element names into the script (i.e. make it work on any generic XML file)?
I'm really hoping this is possible, given that I'll be having more than 25 XML variants; so would really be inefficient to write a dedicated script for each.
Thanks!

Answer 1

Since every child node's data need to be a row in the csv including the root root data, First you can capture & store the root data, then traverse the children and print their data with the root's data preceding them.
Please check the following code:
$xml = simplexml_load_file("your_xml_file.xml") or die("Error: Cannot create object");
$csv_delimeter = ",";
$csv_new_line = "\n";
foreach($xml->children() as $n) {
$club_data = array();
$club_data[] = $n->name;
$club_data[] = $n->membership;
if (isset($n->boardMember)) {
foreach ($n->boardMember as $boardMember) {
$boardMember_data = $club_data;
$boardMember_data[] = $boardMember->name;
$boardMember_data[] = $boardMember->position;
echo implode($csv_delimeter, $boardMember_data).$csv_new_line;
}
}
else {
echo implode($csv_delimeter, $club_data).$csv_new_line;
}
}
After testing with the example xml data, it generated the following type of output:
Green Riders,Free,James F.,CEO
Green Riders,Free,Helen D., Associate Director
Broken Dice,Paid,Patrick B., CEO
You can set different values based on your scenario for:
$csv_delimeter = ",";
$csv_new_line = "\n";
As there are no strict rules in csv output - like delimeter can be ",", ",", ";" or "|" and also new line can be "\n\r"
The codes prints csv rows one-by-one on the fly, but if you are to save csv data in a file, then instead of writing rows one-by-one, better approach would be create the entire array and write it once(as disk access is costly) unless the xml data is large. You will get plenty of simple php array-to-csv function examples in the net.

Answer 2

It is not really possible. XML is a nested structure and you miss the information. You can define some default mapping for XML structures, but that gets really complex really fast. So it is far easier (and less time consuming) to define the mapping by hand.
A Reusable Conversion
function readXMLAsRecords(string $xml, array $map) {
// load the xml
$document = new DOMDocument();
$document->loadXml($xml);
$xpath = new DOMXpath($document);
// iterate the elements defining the rows
foreach ($xpath->evaluate($map['row']) as $row) {
$line = [];
// get the field values from the current $row
foreach ($map['columns'] as $name => $expression) {
$line[$name] = $xpath->evaluate($expression, $row);
}
// return a line
yield $line;
}
}
The Mapping
With DOMXpath::evaluate() Xpath expressions can return strings. So we need one expression that returns the boardMember nodes and a list of expressions for the fields.
$map = [
'row' => '/root/club/boardMember',
'columns' => [
'club_name' => 'string(parent::club/name)',
'club_membership' => 'string(parent::club/membership)',
'board_member_name' => 'string(name)',
'board_member_position' => 'string(position)'
]
];
To CSV
readXMLAsRecords() returns a generator, you can use foreach on it:
$csv = fopen('php://stdout', 'w');
fputcsv($csv, array_keys($map['columns']));
foreach (readXMLAsRecords($xml, $map) as $record) {
fputcsv($csv, $record);
}
Output:
club_name,club_membership,board_member_name,board_member_position
"Green Riders",Free,"James F.",CEO
"Green Riders",Free,"Helen D.","Associate Director"
"Broken Dice",Paid,"Patrick B.",CEO