Got up to incoming posts working

3 files changed, 248 insertions, 0 deletions

diff --git a/activities/models/__init__.py b/activities/models/__init__.py
new file mode 100644
index 0000000..b74075f
--- /dev/null
+++ b/activities/models/__init__.py
@@ -0,0 +1,2 @@
+from .post import Post  # noqa
+from .timeline_event import TimelineEvent  # noqa
diff --git a/activities/models/post.py b/activities/models/post.py
new file mode 100644
index 0000000..f4d159f
--- /dev/null
+++ b/activities/models/post.py
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+import urlman
+from django.db import models
+
+from activities.models.timeline_event import TimelineEvent
+from core.html import sanitize_post
+from stator.models import State, StateField, StateGraph, StatorModel
+from users.models.follow import Follow
+from users.models.identity import Identity
+
+
+class PostStates(StateGraph):
+    new = State(try_interval=300)
+    fanned_out = State()
+
+    new.transitions_to(fanned_out)
+
+    @classmethod
+    async def handle_new(cls, instance: "Post"):
+        """
+        Creates all needed fan-out objects for a new Post.
+        """
+        pass
+
+
+class Post(StatorModel):
+    """
+    A post (status, toot) that is either local or remote.
+    """
+
+    class Visibilities(models.IntegerChoices):
+        public = 0
+        unlisted = 1
+        followers = 2
+        mentioned = 3
+
+    # The author (attributedTo) of the post
+    author = models.ForeignKey(
+        "users.Identity",
+        on_delete=models.PROTECT,
+        related_name="posts",
+    )
+
+    # The state the post is in
+    state = StateField(PostStates)
+
+    # If it is our post or not
+    local = models.BooleanField()
+
+    # The canonical object ID
+    object_uri = models.CharField(max_length=500, blank=True, null=True)
+
+    # Who should be able to see this Post
+    visibility = models.IntegerField(
+        choices=Visibilities.choices,
+        default=Visibilities.public,
+    )
+
+    # The main (HTML) content
+    content = models.TextField()
+
+    # If the contents of the post are sensitive, and the summary (content
+    # warning) to show if it is
+    sensitive = models.BooleanField(default=False)
+    summary = models.TextField(blank=True, null=True)
+
+    # The public, web URL of this Post on the original server
+    url = models.CharField(max_length=500, blank=True, null=True)
+
+    # The Post it is replying to as an AP ID URI
+    # (as otherwise we'd have to pull entire threads to use IDs)
+    in_reply_to = models.CharField(max_length=500, blank=True, null=True)
+
+    # The identities the post is directly to (who can see it if not public)
+    to = models.ManyToManyField(
+        "users.Identity",
+        related_name="posts_to",
+        blank=True,
+    )
+
+    # The identities mentioned in the post
+    mentions = models.ManyToManyField(
+        "users.Identity",
+        related_name="posts_mentioning",
+        blank=True,
+    )
+
+    created = models.DateTimeField(auto_now_add=True)
+    updated = models.DateTimeField(auto_now=True)
+
+    class urls(urlman.Urls):
+        view = "{self.identity.urls.view}posts/{self.id}/"
+
+    def __str__(self):
+        return f"{self.author} #{self.id}"
+
+    @property
+    def safe_content(self):
+        return sanitize_post(self.content)
+
+    ### Local creation ###
+
+    @classmethod
+    def create_local(cls, author: Identity, content: str) -> "Post":
+        post = cls.objects.create(
+            author=author,
+            content=content,
+            local=True,
+        )
+        post.object_uri = post.author.actor_uri + f"posts/{post.id}/"
+        post.url = post.object_uri
+        post.save()
+        return post
+
+    ### ActivityPub (outgoing) ###
+
+    ### ActivityPub (incoming) ###
+
+    @classmethod
+    def by_ap(cls, data, create=False) -> "Post":
+        """
+        Retrieves a Post instance by its ActivityPub JSON object.
+
+        Optionally creates one if it's not present.
+        Raises KeyError if it's not found and create is False.
+        """
+        # Do we have one with the right ID?
+        try:
+            return cls.objects.get(object_uri=data["id"])
+        except cls.DoesNotExist:
+            if create:
+                # Resolve the author
+                author = Identity.by_actor_uri(data["attributedTo"], create=create)
+                return cls.objects.create(
+                    author=author,
+                    content=sanitize_post(data["content"]),
+                    summary=data.get("summary", None),
+                    sensitive=data.get("as:sensitive", False),
+                    url=data.get("url", None),
+                    local=False,
+                    # TODO: to
+                    # TODO: mentions
+                    # TODO: visibility
+                )
+            else:
+                raise KeyError(f"No post with ID {data['id']}", data)
+
+    @classmethod
+    def handle_create_ap(cls, data):
+        """
+        Handles an incoming create request
+        """
+        # Ensure the Create actor is the Post's attributedTo
+        if data["actor"] != data["object"]["attributedTo"]:
+            raise ValueError("Create actor does not match its Post object", data)
+        # Create it
+        post = cls.by_ap(data["object"], create=True)
+        # Make timeline events as appropriate
+        for follow in Follow.objects.filter(target=post.author, source__local=True):
+            TimelineEvent.add_post(follow.source, post)
+        # Force it into fanned_out as it's not ours
+        post.transition_perform(PostStates.fanned_out)
diff --git a/activities/models/timeline_event.py b/activities/models/timeline_event.py
new file mode 100644
index 0000000..43fc458
--- /dev/null
+++ b/activities/models/timeline_event.py
@@ -0,0 +1,85 @@
+from django.db import models
+
+
+class TimelineEvent(models.Model):
+    """
+    Something that has happened to an identity that we want them to see on one
+    or more timelines, like posts, likes and follows.
+    """
+
+    class Types(models.TextChoices):
+        post = "post"
+        mention = "mention"
+        like = "like"
+        follow = "follow"
+        boost = "boost"
+
+    # The user this event is for
+    identity = models.ForeignKey(
+        "users.Identity",
+        on_delete=models.CASCADE,
+        related_name="timeline_events",
+    )
+
+    # What type of event it is
+    type = models.CharField(max_length=100, choices=Types.choices)
+
+    # The subject of the event (which is used depends on the type)
+    subject_post = models.ForeignKey(
+        "activities.Post",
+        on_delete=models.CASCADE,
+        blank=True,
+        null=True,
+        related_name="timeline_events_about_us",
+    )
+    subject_identity = models.ForeignKey(
+        "users.Identity",
+        on_delete=models.CASCADE,
+        blank=True,
+        null=True,
+        related_name="timeline_events_about_us",
+    )
+
+    created = models.DateTimeField(auto_now_add=True)
+
+    class Meta:
+        index_together = [
+            # This relies on a DB that can use left subsets of indexes
+            ("identity", "type", "subject_post", "subject_identity"),
+            ("identity", "type", "subject_identity"),
+        ]
+
+    ### Alternate constructors ###
+
+    @classmethod
+    def add_follow(cls, identity, source_identity):
+        """
+        Adds a follow to the timeline if it's not there already
+        """
+        return cls.objects.get_or_create(
+            identity=identity,
+            type=cls.Types.follow,
+            subject_identity=source_identity,
+        )[0]
+
+    @classmethod
+    def add_post(cls, identity, post):
+        """
+        Adds a post to the timeline if it's not there already
+        """
+        return cls.objects.get_or_create(
+            identity=identity,
+            type=cls.Types.post,
+            subject_post=post,
+        )[0]
+
+    @classmethod
+    def add_like(cls, identity, post):
+        """
+        Adds a like to the timeline if it's not there already
+        """
+        return cls.objects.get_or_create(
+            identity=identity,
+            type=cls.Types.like,
+            subject_post=post,
+        )[0]