[RFC|Merged] General Hook Architecture of phpBB3.1

[Oleg]

https://gist.github.com/576ef0aa6a455ade7393

[rxu]

Oleg
Could you please provide an extended description of your alternative ("version 2") hooks architecture?
That probably would help to contribute in developing it.

[Oleg]

The problem is I don't really have a design even so much as some rough ideas about going about getting it designed.

I believe last time I looked into hooks I got the template insertion working.

Also, some of my earlier posts in this topic have been superseded by the extensions.

I still need answers for viewtopic.php?f=84&t=32805&start=30#p231831 so you can possibly help with that or poke Nils.

[rxu]

so you can possibly help with that or poke Nils.

Well, all the Dev team should participate, I just can through my own opinion here:

Extension ordering. Which order does extension finder return files in? Looks like this is not documented, and possibly not even defined.

Currently, extensions info is stored in the special table:

Code: Select all

# Table: 'phpbb_ext'
CREATE TABLE phpbb_ext (
   ext_name varchar(255) DEFAULT '' NOT NULL,
   ext_active tinyint(1) UNSIGNED DEFAULT '0' NOT NULL,
   ext_state text NOT NULL,
   UNIQUE ext_name (ext_name)
) CHARACTER SET `utf8` COLLATE `utf8_bin`;

As we can see, it does not have ext_id column. I'd suggest to create that to be able to sort extensions by id. Why is it needed? Imagine you have 2 or more extensions which exploit the same hook. Having id, we can 1) state what extension would overwrite previous ones results if needed, and 2) the order of extensions were installed (for example, for debugging purposes/etc). Probably, there're some more pros with the id.
So, generally, my suggestion is to sort by id. As for the order id is assigned, I assume it's the same PHP reads files from directory, that means "The entries are returned in the order in which they are stored by the filesystem."

Some template hooks are style-specific, some are not (i.e. they should be invoked for all styles, they are providing sitewide markup). Specifying style name over and over in hooks is suboptimal, but currently the template engine does not know which style it is rendering.

Personally, I think (and it seems to be apparent thing) template hooks are style-unique. You can invoke template hook for all styles, but it should be a user choice. Generally speaking, one template hook, being invoked for some custom/modified/etc-non-default style, can break the page layout completely.
As for inheritance, I think it should be user configured as well if the hook should be inherited by every style.
Speaking about implementation, I'm not sure to be honest. Probably, it's depending on the answer for the question #3:

Should we compile extensions' templates when core templates are compiled, or when templates are executed?

For my taste, it could be the latter way, it looks like it should let to control things dynamically.

Please note that my comments can be irrelevant in some parts since even you

don't really have a design even so much as some rough ideas about going about getting it designed.

[igorw]

As we can see, it does not have ext_id column. I'd suggest to create that to be able to sort extensions by id. Why is it needed? Imagine you have 2 or more extensions which exploit the same hook. Having id, we can 1) state what extension would overwrite previous ones results if needed, and 2) the order of extensions were installed (for example, for debugging purposes/etc). Probably, there're some more pros with the id.
So, generally, my suggestion is to sort by id. As for the order id is assigned, I assume it's the same PHP reads files from directory, that means "The entries are returned in the order in which they are stored by the filesystem."

I don't think this is a good idea. We already have the unique ext name, it's probably best to sort by that. Installing the same N MODs should always have the same result in terms of hook execution order. Hooks should be able to define their own priority, higher priority hooks get executed first.

[sajaki]

What about mod dependencies, say mod C requires mod A & B to be installed, can hooks manage that order ?
if not I'd like to be able to sort by install timestamp, id and name.
Automod has had this same problem, and there was even a sorting mod developed for it.

[Oleg]

I was making good progress today until php ruined everything, as it tends to do.

First, I like https://github.com/phpbb/phpbb3/pull/529. I rebased my work on top of event dispatcher and replaced run_hooks calls with event dispatcher stuff.

At this point https://github.com/p/phpbb3-ext-overall-header-addition dropped in the phpbb directory produced a good-looking (?) yellow background everywhere.

Procedure to reproduce:

1. QI-install phpbb.
2. rsync https://github.com/p/phpbb3/compare/dev ... 2Fledges-2 over the install and run database updater.
3. rsync https://github.com/p/phpbb3-ext-overall-header-addition over the install.
4. enable the extension (currently needs to be done by creating an appropriate entry in the ext table?)
5. view the board.

To make #4 more reasonable I did https://github.com/phpbb/phpbb3/pull/546 but when I got to enabling and disabling of extensions php decided to rear its ugly head, which is where I stopped. Someone fix that script please.

[igorw]

Thank you. Everything is in feature/ledges-2? No PR for this?

[Oleg]

https://github.com/phpbb/phpbb3/pull/551

Pull requests are messy because of all the different branches that are going on.

[naderman]

It would be great if we can resolve extensions at compile time and at runtime based on maybe a define in config.php. Projects like debian, run multiple boards with a single code base, they rely on the template cache being usable by all boards. If extensions are compiled into templates, this will no longer be the case. However compiling them in might be faster. So having them resolved at compile time would be the default, but a define would allow moving all extension related calculations to runtime.