How to read an XML file with an undefined namespace with XMLReader? - php

Question

I'm relatively new to parsing XML files and am attempting to read a large XML file with XMLReader.
<?xml version="1.0" encoding="UTF-8"?>
<ShowVehicleRemarketing environment="Production" lang="en-CA" release="8.1-Lite" xsi:schemaLocation="http://www.starstandards.org/STAR /STAR/Rev4.2.4/BODs/Standalone/ShowVehicleRemarketing.xsd">
<ApplicationArea>
<Sender>
<Component>Component</Component>
<Task>Task</Task>
<ReferenceId>w5/cron</ReferenceId>
<CreatorNameCode>CreatorNameCode</CreatorNameCode>
<SenderNameCode>SenderNameCode</SenderNameCode>
<SenderURI>http://www.example.com</SenderURI>
<Language>en-CA</Language>
<ServiceId>ServiceId</ServiceId>
</Sender>
<CreationDateTime>CreationDateTime</CreationDateTime>
<Destination>
<DestinationNameCode>example</DestinationNameCode>
</Destination>
</ApplicationArea>
...
I am recieving the following error
ErrorException [ Warning ]: XMLReader::read() [xmlreader.read]: compress.zlib://D:/WebDev/example/local/public/../upload/example.xml.gz:2: namespace error : Namespace prefix xsi for schemaLocation on ShowVehicleRemarketing is not defined
I've searched around and can't find much useful information on using XMLReader to read XML files with namespaces -- How would I go about defining a namespace, if that is in fact what I need to do.. little help? links to pertinent resources?

Answer 1

There needs to be a definition of the xsi namespace. E.g.
<ShowVehicleRemarketing
environment="Production"
lang="en-CA"
release="8.1-Lite"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.starstandards.org/STAR/STAR/Rev4.2.4/BODs/Standalone/ShowVehicleRemarketing.xsd"
>
Update: You could write a user defined filter and then let the XMLReader use that filter, something like:
stream_filter_register('darn', 'DarnFilter');
$src = 'php://filter/read=darn/resource=compress.zlib://something.xml.gz';
$reader->open($src);
The contents read by the compress.zlib wrapper is then "routed" through the DarnFilter which has to find the (first) location where it can insert the xmlns:xsi declaration. But this is quite messy and will take some afford to do it right (e.g. theoretically bucket A could contain xs, bucket B i:schem and bucket C aLocation=")
Update 2: here's an ad-hoc example of a filter in php that inserts the xsi namespace declaration. Mostly untested (worked with the one test I ran ;-) ) and undocumented. Take it as a proof-of-concept not production-code.
<?php
stream_filter_register('darn', 'DarnFilter');
$src = 'php://filter/read=darn/resource=compress.zlib://d:/test.xml.gz';
$r = new XMLReader;
$r->open($src);
while($r->read()) {
echo '.';
}
class DarnFilter extends php_user_filter {
protected $buffer='';
protected $status = PSFS_FEED_ME;
public function filter($in, $out, &$consumed, $closing)
{
while ( $bucket = stream_bucket_make_writeable($in) ) {
$consumed += $bucket->datalen;
if ( PSFS_PASS_ON == $this->status ) {
// we're already done, just copy the content
stream_bucket_append($out, $bucket);
}
else {
$this->buffer .= $bucket->data;
if ( $this->foo() ) {
// first element found
// send the current buffer
$bucket->data = $this->buffer;
$bucket->datalen = strlen($bucket->data);
stream_bucket_append($out, $bucket);
$this->buffer = null;
// no need for further processing
$this->status = PSFS_PASS_ON;
}
}
}
return $this->status;
}
/* looks for the first (root) element in $this->buffer
* if it doesn't contain a xsi namespace decl inserts it
*/
protected function foo() {
$rc = false;
if ( preg_match('!<([^?>\s]+)\s?([^>]*)>!', $this->buffer, $m, PREG_OFFSET_CAPTURE) ) {
$rc = true;
if ( false===strpos($m[2][0], 'xmlns:xsi') ) {
echo ' inserting xsi decl ';
$in = '<'.$m[1][0]
. ' xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" '
. $m[2][0] . '>';
$this->buffer = substr($this->buffer, 0, $m[0][1])
. $in
. substr($this->buffer, $m[0][1] + strlen($m[0][0]));
}
}
return $rc;
}
}
Update 3: And here's an ad-hoc solution written in C#
XmlNamespaceManager nsmgr = new XmlNamespaceManager(new NameTable());
// prime the XMLReader with the xsi namespace
nsmgr.AddNamespace("xsi", "http://www.w3.org/2001/XMLSchema-instance");
using ( XmlReader reader = XmlTextReader.Create(
new GZipStream(new FileStream(#"\test.xml.gz", FileMode.Open, FileAccess.Read), CompressionMode.Decompress),
new XmlReaderSettings(),
new XmlParserContext(null, nsmgr, null, XmlSpace.None)
)) {
while (reader.Read())
{
System.Console.Write('.');
}
}

Answer 2

You can file_get_contents and str_replace the XML before passing it to XMLReader.
Either insert the required namespace declararation for the xsi prefix:
$reader = new XMLReader;
$reader->xml(str_replace(
'<ShowVehicleRemarketing',
'<ShowVehicleRemarketing xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"',
file_get_contents('http://example.com/data.xml')));
Another option would be to remove the schemaLocation attribute:
$reader->xml(str_replace(
'xsi:schemaLocation="http://www.starstandards.org/STAR /STAR/Rev4.2.4/BODs/Standalone/ShowVehicleRemarketing.xsd"',
'',
file_get_contents('http://example.com/data.xml')));
However, if there is more prefixes in the document, you will have to replace all of them.

Answer 3

Either fix whatever's writing out malformed XML, or write a separate tool to perform the fix later. (It doesn't have to read it all into memory at the same time, necessarily - stream the data in/out, perhaps reading and writing a line at a time.)
That way your reading code doesn't need to worry about trying to do something useful with the data and fixing it up at the same time.

Answer 4

The xsi namespace is normally reserved for use with Schema Instance Namespace:
xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'
if it isn't, your XML file is not XML+NS compliant and cannot be parsed. So you should solve that in the source document.
A note on xsi: it is even more vital than some possible other namespaces, because it directs a validating parser to the correct schema locations for the schema of your XML.