Generating XML from SQL using Mysqli - php

Question

I'm trying to pull all the data from my users table and display it in XML format. The connection works fine and everything as I have a login and registration set up fine, but I can't seem to get this to display anything other than a white screen.
I've found lots of different tutorials on how to do it with mysql but not mysqli. what am i missing?
generatexml.php
<?php
include 'connection.php';
$xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>";
$root_element = $config['users'];
$xml .= "<$root_element>";
if ($result = $mysqli->query("SELECT * FROM users", MYSQLI_USE_RESULT)) {
while($row = $result->fetch_assoc())
{
$xml .= "<".$config['users'].">";
//loop through each key,value pair in row
foreach($result_array as $key => $value)
{
//$key holds the table column name
$xml .= "<$key>";
//embed the SQL data in a CDATA element to avoid XML entity issues
$xml .= "<![CDATA[$value]]>";
//and close the element
$xml .= "</$key>";
}
$xml.="</".$config['users'].">";
echo $xml;
}
}
?>

Answer 1

I struggle a lot to find out this solution in mysqli format but nowhere i found the solution. Below is the solution i figured. Run this demo and map it your requirement, surely it will help.
<?php
//Create file name to save
$filename = "export_xml_".date("Y-m-d_H-i",time()).".xml";
$mysql = new Mysqli('server', 'user', 'pass', 'database');
if ($mysql->connect_errno) {
throw new Exception(sprintf("Mysqli: (%d): %s", $mysql->connect_errno, $mysql->connect_error));
}
//Extract data to export to XML
$sqlQuery = 'SELECT * FROM t1';
if (!$result = $mysql->query($sqlQuery)) {
throw new Exception(sprintf('Mysqli: (%d): %s', $mysql->errno, $mysql->error));
}
//Create new document
$dom = new DOMDocument;
$dom->preserveWhiteSpace = FALSE;
//add table in document
$table = $dom->appendChild($dom->createElement('table'));
//add row in document
foreach($result as $row) {
$data = $dom->createElement('row');
$table->appendChild($data);
//add column in document
foreach($row as $name => $value) {
$col = $dom->createElement('column', $value);
$data->appendChild($col);
$colattribute = $dom->createAttribute('name');
// Value for the created attribute
$colattribute->value = $name;
$col->appendChild($colattribute);
}
}
/*
** insert more nodes
*/
$dom->formatOutput = true; // set the formatOutput attribute of domDocument to true
// save XML as string or file
$test1 = $dom->saveXML(); // put string in test1
$dom->save($filename); // save as file
$dom->save('xml/'.$filename);
?>

Answer 2

If you have access to the mysql CLI, here's my quick hack for achieving this:
$sql = "SELECT * FROM dockcomm WHERE listname = 'roortoor'
and status IN ('P','E') and comm_type IN ('W','O')
and comm_period NOT IN ('1','2','3','4') order by comment_num";
$cmd = "/usr/bin/mysql -u<person> -h<host> -p<password> <database> --xml -e \"$sql\";";
$res = system($cmd ,$resval);
echo $res;

Answer 3

Here is a solution using php only. You where close to getting it right. This was the key part of the code that I changed "$row as $key => $data" used $row instead of $result_array, ie. iterate through row not the result_array (this contains the entire dataset). Hope this helps someone.
if ($result->num_rows > 0) {
// output data of each row
while($row = $result->fetch_assoc()) {
$value .="<record>\r\n";
//loop through each key,value pair in row
foreach($row as $key => $data)
{
//$key holds the table column name
$vals = "\t" . "<". $key . ">" . "<![CDATA[" . $data . "]]>" . "</" . $key . ">" . "\r\n";
$value = $value . $vals;
//echo $value;
}
$value .="</record>\r\n";
$count++;
}
} else {
// echo "0 results";
}
$conn->close();

Answer 4

One possible issue could be this line:
if ($result = $mysqli->query("SELECT * FROM users", MYSQLI_USE_RESULT)) {
Try the procedural approach instead of the object oriented approach. I do not know if $mysqli is defined in connection.php, but it is possible that you mixed it up.
if ($result = mysqli_query('SELECT * FROM users', MYSQLI_USE_RESULT)) {
This could resolve the white screen error.
I noticed two other things:
(1) One tiny effectiveness issue:
$xml = '<?xml version="1.0" encoding="UTF-8"?>';
So you do not need to escape every single quotation mark.
(2) One serious XML issue: The root element needs to be closed before you echo your $xml.
$xml .= "</$root_element>";
echo $xml;
Generally, for your purpose, it would be safer to use PHP's XMLWriter extension, as already proposed.