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Diffstat (limited to 'pydis_site/apps/home/signals.py')
| -rw-r--r-- | pydis_site/apps/home/signals.py | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/pydis_site/apps/home/signals.py b/pydis_site/apps/home/signals.py new file mode 100644 index 00000000..687a99fe --- /dev/null +++ b/pydis_site/apps/home/signals.py @@ -0,0 +1,156 @@ +from typing import List, Optional, Type + +from allauth.account.signals import user_logged_in +from allauth.socialaccount.models import SocialAccount, SocialLogin +from allauth.socialaccount.providers.base import Provider +from allauth.socialaccount.providers.discord.provider import DiscordProvider +from allauth.socialaccount.signals import ( + pre_social_login, social_account_added, social_account_removed, + social_account_updated) +from django.contrib.auth.models import Group, User as DjangoUser +from django.db.models.signals import post_save + +from pydis_site.apps.api.models import User as DiscordUser +from pydis_site.apps.staff.models import RoleMapping + + +class SignalListener: + """ + Listens to and processes events via the Django Signals system. + + Django Signals is basically an event dispatcher. It consists of Signals (which are the events) + and Receivers, which listen for and handle those events. Signals are triggered by Senders, + which are essentially just any class at all, and Receivers can filter the Signals they listen + for by choosing a Sender, if required. + + Signals themselves define a set of arguments that they will provide to Receivers when the + Signal is sent. They are always keyword arguments, and Django recommends that all Receiver + functions accept them as `**kwargs` (and will supposedly error if you don't do this), + supposedly because Signals can change in the future and your receivers should still work. + + Signals do provide a list of their arguments when they're initially constructed, but this + is purely for documentation purposes only and Django does not enforce it. + + The Django Signals docs are here: https://docs.djangoproject.com/en/2.2/topics/signals/ + """ + + def __init__(self): + post_save.connect(self.model_updated, sender=DiscordUser) + + pre_social_login.connect(self.social_account_updated) + social_account_added.connect(self.social_account_updated) + social_account_updated.connect(self.social_account_updated) + social_account_removed.connect(self.social_account_removed) + + user_logged_in.connect(self.user_logged_in) + + def user_logged_in(self, sender: Type[DjangoUser], **kwargs) -> None: + """Handles signals relating to Allauth logins.""" + user: DjangoUser = kwargs["user"] + + try: + account: SocialAccount = SocialAccount.objects.get( + user=user, provider=DiscordProvider.id + ) + except SocialAccount.DoesNotExist: + return # User's never linked a Discord account + try: + discord_user: DiscordUser = DiscordUser.objects.get(id=int(account.uid)) + except DiscordUser.DoesNotExist: + return + + self._apply_groups(discord_user, account) + + def social_account_updated(self, sender: Type[SocialLogin], **kwargs) -> None: + """Handle signals relating to new/existing social accounts.""" + social_login: SocialLogin = kwargs["sociallogin"] + + account: SocialAccount = social_login.account + provider: Provider = account.get_provider() + + if not isinstance(provider, DiscordProvider): + return + + try: + user: DiscordUser = DiscordUser.objects.get(id=int(account.uid)) + except DiscordUser.DoesNotExist: + return + + self._apply_groups(user, account) + + def social_account_removed(self, sender: Type[SocialLogin], **kwargs) -> None: + """Handle signals relating to removal of social accounts.""" + account: SocialAccount = kwargs["socialaccount"] + provider: Provider = account.get_provider() + + if not isinstance(provider, DiscordProvider): + return + + try: + user: DiscordUser = DiscordUser.objects.get(id=int(account.uid)) + except DiscordUser.DoesNotExist: + return + + self._apply_groups(user, account, True) + + def model_updated(self, sender: Type[DiscordUser], **kwargs) -> None: + """Handle signals related to the updating of Discord User model entries.""" + instance: DiscordUser = kwargs["instance"] + raw: bool = kwargs["raw"] + + # `update_fields` could be used for checking changes, but it's None here due to how the + # model is saved without using that argument - so we can't use it. + + if raw: + # Fixtures are being loaded, so don't touch anything + return + + try: + account: SocialAccount = SocialAccount.objects.get(uid=str(instance.id)) + except SocialAccount.DoesNotExist: + return # User has never logged in with Discord on the site + + self._apply_groups(instance, account) + + def _apply_groups( + self, user: DiscordUser, account: Optional[SocialAccount], deletion: bool = False + ) -> None: + mappings = RoleMapping.objects.all() + + try: + current_groups: List[Group] = list(account.user.groups.all()) + except SocialAccount.user.RelatedObjectDoesNotExist: + return # There's no user account yet, this will be handled by another receiver + + if not user.in_guild: + deletion = True + + if deletion: + # They've unlinked Discord or left the server, so we have to remove their groups + + if not current_groups: + return # They have no groups anyway, no point in processing + + account.user.groups.remove( + *(mapping.group for mapping in mappings) + ) + else: + new_groups = [] + + for role in user.roles.all(): + try: + new_groups.append(mappings.get(role=role).group) + except RoleMapping.DoesNotExist: + continue # No mapping exists + + remove_groups = [ + mapping.group for mapping in mappings if mapping.group not in new_groups + ] + + add_groups = [group for group in new_groups if group not in current_groups] + + if remove_groups: + account.user.groups.remove(*remove_groups) + + if add_groups: + account.user.groups.add(*add_groups) |