Sulu CMS: how to search/filter for content of a specific type with specific values for specifc attributes?

Short description of the situation:

We're running a forked version of Sulu 1.5.2, PHP 7.1, Windows server environment, db connection with PostgreSQL
We have a website structure/tree where we have house templates at the top level; each house has one house_rooms and one house_occupants template; each house_rooms template has N house_rooms_room templates, and each house_occupants template has N house_occupants_occupant templates. This represents an actual House that has N Rooms and N Occupants.

Now I'd like to know if there is a way to specifically get, for instance, all the house_occupants_occupant content that follows a certain pattern of attributes (for instance: their gender attribute having value 'female' and their date_of_birth parameter being >= 1990/01/01), without having to load each house, then find its house_occupantspage among the children, and then loop over that template's house_occupants_occupant children and filter the thus begotten content according to their gender and date of birth attributes.

I already found that there is a ContentRepository class that can ::findAll() and ::findByUuids(), but there doesn't seem to be a way to filter on specific attributes (like template type, template attributes, ...). So I took a roundabout way of creating my own "repository" that does direct PDO queries on the phpcr_nodes table in the database, to specifically scan the props attribute for the occurence of a certain template name:

$this->pdo->query("SELECT identifier, props FROM phpcr_nodes WHERE props LIKE '%>house_occupants_occupant<%'");

I can see that the propscontains a string value representing an XML document that somehow translates into the entire template with attribute-value pairs, however it is obscured regarding tag-levels and how certain attributes relate to certain values. So in theory I could use a specific XML parser to turn this into something human-readable, so that for my house_occupants_occupant data I could get something like:

// what I would get after putting the props through a certain XML parser:
$xmlHumanReadableData = [
    '<the_uuid_of_occupant_1>' => [
        ...
        'gender' => 'female',
        'date_of_birth' => '1992-05-18T00:00:00.000+00:00',
        ...
    ],
    ... //etcetera etcetera
];

When I would have that, I could filter the readable data to ascertain which content I want to keep, add the node-uuid to some $theUuids variable, and then retrieve the actual content using Sulu's ContentRepository::findByUuids($theUuids) method. That would "only" require 2 queries and some PHP array filtering in between, which is a great deal better than looping over all the children content starting from a certain parent and doing this until you've traversed all the parents and all their children... (Certainly, the overhead would increase if you'd want to search for, for instance, all house nodes where at least one of its house_occupants_occupant nodes represents a child less than 10 years old, since you'd need extra queries to "set up" the filterdata used in the final query. But still: a great deal better than looping everything... ;-) )

So my question is sort-of twofold:

What is the Sulu-specific XML parser I can use to turn the XML string value in this props column into something human-readable, with proper attribute-value pairs?
And/or, hopefully: is there a way I can avoid all this nonsense and just use a less low-level way of retrieving content of a specific template type with specific values for specific attributes ?

Solution

The ContentRepository you've found is already an abstraction to some of our requirements for pages. Your requirements are already quite specific, so you should write your own query using SQL-2, the query language for PHPCR.

This should enable you to write a query which matches your requirements.