Add PostgreSQL backend

[leso-kn]

This PR adds experimental PostgreSQL support.

Based upon the work of @dxtr, extended and adapted to the latest version of Baikal.

✅ The following features were tested:

• Baikal setup procedure / UI (with Postgres)
• Creating / deleting / editing a user
• Creating / deleting / editing a calendar
• Listing contacts
• Logging in / creating / deleting an event through the webui (User login)
• Subscribing to a calendar / adding / deleting an event through a DAV client
  • Thunderbird
  • DAVx⁵ for Android

[leso-kn]

ref #122

[2Belette]

since one ! does this PR would make it into new release ?

[comrada]

Looking forward to Postgresql support!! I keep MySQL on the server just for the sake of Baikal.

[ndruba]

I use Baikal with this patch for my personal use during half year from clean install and don't have any troubles.

The following features were tested:

Baikal setup procedure / UI (with Postgres)
Creating a user
Creating / editing a calendar (with Todos and Tasks)
Creating / editing Address Book
Logging in, listing an event and contacts through the webui (dav.php)
Subscribing to a calendar and address book / adding / deleting an event and contacts through a DAV client
Thunderbird
Carddav-sync/Caldav-sync

[Terrance]

I've just had a go at setting this up locally (I have a lot of calendars so SQLite is probably not a great choice, and I'm not interested in setting up MySQL just for this when I already have other software talking to PostgreSQL) and it seems to work, but with a couple of snags during the initial setup.

Baikal/Core/Frameworks/Baikal/Core/Tools.php

Lines 46 to 50 in 3ca9b4f

	# Asserting PDO::SQLite or PDO::MySQL
	$aPDODrivers = \PDO::getAvailableDrivers();
	if (!in_array('sqlite', $aPDODrivers, true) && !in_array('mysql', $aPDODrivers, true)) {
	exit('<strong>Baikal Fatal Error</strong>: Both <strong>PDO::sqlite</strong> and <strong>PDO::mysql</strong> are unavailable. One of them at least is required by Baikal.');
	}

This check needs updating to also include PDO::pgsql as a valid option.

[Terrance]

One more hiccup with the settings page (/admin/?/settings/database/):

Baikal/Core/Frameworks/BaikalAdmin/Controller/Settings/Database.php

Line 87 in 3ca9b4f

if ($bMySQL === true) {

Baikal/Core/Frameworks/BaikalAdmin/Controller/Settings/Database.php

Line 101 in 3ca9b4f

if (intval($oForm->modelInstance()->get("mysql")) === 1) {

These will need similar updates to the installation's database page to check for PostgreSQL too (currently the page falls through to SQLite).

[leso-kn]

@Terrance Done! Sorry for the late reply, the updates described in your previous comment are now included in 54ebfe0

[dewey]

Great to see this, any idea what would be needed to get this merged?

[Terrance]

I've not seen any other issues. 👍

[Ornias1993]

Combined with CloudNative-PG this finally gives an easy route to enterprise-grade hosted baikal, nice!

[nileshtrivedi]

Looking forward to this being merged that would finally fix #122