Incorrect assumption about Flarum XML

[JoshyPHP]

This is about that part:

nitro-porter/src/Parser/Flarum/QuoteEmbed.php

Lines 83 to 88 in 193b0fd

	// Carefully mimic the TextFormatter output for quote replies.
	// Omits 'p' tags that wrap <POSTMENTION> thru {body} normally because we don't know if the body has 'p' tags.
	$this->wrapElement('<QUOTE><i>&gt; </i>' .
	// Postscript will fill in blank attributes BUT THEY MUST BE IN THIS ORDER.
	'<POSTMENTION id="{postid}" discussionid="{discussionid}" number="" displayname="{author}">' .
	'@"{author}"#p{postid}</POSTMENTION> {body}</QUOTE>', ['author', 'postid', 'body', 'discussionid']);

Without delving into Flarum's internal, it should be impossible to create XML attributes in this order. TextFormatter always sort them in lexicographical order. For instance:

$configurator = new s9e\TextFormatter\Configurator;
$configurator->BBCodes->addCustom(
	'[POSTMENTION id={NUMBER} discussionid={NUMBER} number={NUMBER} displayname={NUMBER}/]',
	'<hr title="{@id} {@discussionid} {@number} {@displayname}"/>'
);

extract($configurator->finalize());

$text = '[POSTMENTION id=0 discussionid=1 number=2 displayname=3]';
$xml  = $parser->parse($text);
$html = $renderer->render($xml);

die("$text\n$xml\n$html");

[POSTMENTION id=0 discussionid=1 number=2 displayname=3]
<r><POSTMENTION discussionid="1" displayname="3" id="0" number="2">[POSTMENTION id=0 discussionid=1 number=2 displayname=3]</POSTMENTION></r>
<hr title="0 1 2 3">

Save for bugs and unforeseen circumstances, all utilities in the s9e\TextFormatter library preserve this order, that's why I strongly advise against modifying its XML with string functions. The library itself transforms XML to HTML via two different renderer, either the XSLT renderer based on PHP's own ext/xsl extension, or the library's own PHP renderer which is compiled from the XSL template. The PHP renderer itself has two different modes: one where it loads the XML input in a DOM document and transforms the XML using DOM functions, in which the attribute order doesn't matter at all, and another mode togglable via $enableQuickRenderer which uses string functions rather than DOM methods, which makes it more efficient but has the downside of being sensitive to attribute order.

[linc]

Thanks for the heads up! I'll get it adjusted for this case. I would assume I did not chose that order arbitrarily & used actual Flarum output as a template, but I don't have my work documented to that level to be sure.

My core challenges with finding a broader solution are:

• This particular Vanilla formatter (Quill library) stores its data in its own bespoke data format.
• I am using Vanilla's db schema as my intermediary (in part because of its permissiveness to avoid double-processing) which means Quill is a valid intermediary right now.
• Converting out of Quill requires using the Quill parser, which has no knowledge of TextFormatter or Flarum.
• The Flarum format requires data that is usually not in the markup of other forums.

It seems like my only path out of this being an ongoing issue is to use an intermediary format consistently (like TextFormatter's XML). However, that would be double-converting formatting for many forums, which is usually the most expensive part of the migration already. I am not convinced that level of consistency is worth worse performance to that degree.

Open to suggestions here, I just don't see a great path out of bespoke bits like this with the current architecture.

[JoshyPHP]

If you post a few rows of Vanilla's data somewhere (in your test suite for future use?) I'll take a look at it. XML files would be nice

[JoshyPHP]

I noticed there was another assumption about the XML, that a post always starts with <t> or <r>. That's not always the case and some plugins may declare namespaces there. If you manipulate/transform the XML with string functions, you risk corrupting it.

There's a tool in the library that facilitates a number of manipulations. It also sorts out attributes IIRC and generally tidies up the markup. It's the best way to manipulate the XML safely:

$dom = s9e\TextFormatter\Utils\ParsedDOM::loadXML(
	'<r><POSTMENTION id="{postid}" discussionid="{discussionid}" number="" displayname="{author}">..</POSTMENTION></r>'
);

$dom->firstOf('//POSTMENTION')->setMarkupStart('@user#123');

echo (string) $dom;

<r><POSTMENTION discussionid="{discussionid}" number="" displayname="{author}" id="{postid}"><s>@user#123</s>..</POSTMENTION></r>

https://s9e.github.io/TextFormatter/api/s9e/TextFormatter/Utils/ParsedDOM/Element.html