Basic Emoji suppport (#157)

33 files changed, 670 insertions, 42 deletions

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index d31e946..42057c1 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -46,4 +46,4 @@ repos:
     rev: v0.991
     hooks:
       - id: mypy
-        additional_dependencies: [types-pyopenssl, types-bleach, types-mock]
+        additional_dependencies: [types-pyopenssl, types-bleach, types-mock, types-cachetools]
diff --git a/activities/admin.py b/activities/admin.py
index edc7365..6b0c8a9 100644
--- a/activities/admin.py
+++ b/activities/admin.py
@@ -1,8 +1,10 @@
 from asgiref.sync import async_to_sync
 from django.contrib import admin
+from django.utils.safestring import mark_safe
 from django.utils.translation import gettext_lazy as _
 
 from activities.models import (
+    Emoji,
     FanOut,
     Hashtag,
     Post,
@@ -50,6 +52,46 @@ class HashtagAdmin(admin.ModelAdmin):
             instance.transition_perform("outdated")
 
 
+@admin.register(Emoji)
+class EmojiAdmin(admin.ModelAdmin):
+    list_display = (
+        "shortcode",
+        "preview",
+        "local",
+        "domain",
+        "public",
+        "state",
+        "created",
+    )
+    list_filter = ("local", "public", "state")
+    search_fields = ("shortcode",)
+
+    readonly_fields = ("preview", "created", "updated")
+
+    actions = ["force_execution", "approve_emoji", "reject_emoji"]
+
+    @admin.action(description="Force Execution")
+    def force_execution(self, request, queryset):
+        for instance in queryset:
+            instance.transition_perform("outdated")
+
+    @admin.action(description="Approve Emoji")
+    def approve_emoji(self, request, queryset):
+        queryset.update(public=True)
+
+    @admin.action(description="Reject Emoji")
+    def reject_emoji(self, request, queryset):
+        queryset.update(public=False)
+
+    @admin.display(description="Emoji Preview")
+    def preview(self, instance):
+        if instance.public is False:
+            return mark_safe(f'<a href="{instance.full_url().relative}">Preview</a>')
+        return mark_safe(
+            f'<img src="{instance.full_url().relative}" style="height: 22px">'
+        )
+
+
 @admin.register(PostAttachment)
 class PostAttachmentAdmin(admin.ModelAdmin):
     list_display = ["id", "post", "created"]
diff --git a/activities/middleware.py b/activities/middleware.py
new file mode 100644
index 0000000..1ed2219
--- /dev/null
+++ b/activities/middleware.py
@@ -0,0 +1,27 @@
+from time import time
+
+from activities.models import Emoji
+
+
+class EmojiDefaultsLoadingMiddleware:
+    """
+    Caches the default Emoji
+    """
+
+    refresh_interval: float = 30.0
+
+    def __init__(self, get_response):
+        self.get_response = get_response
+        self.loaded_ts: float = 0.0
+
+    def __call__(self, request):
+        # Allow test fixtures to force and lock the Emojis
+        if not getattr(Emoji, "__forced__", False):
+            if (
+                not getattr(Emoji, "locals", None)
+                or (time() - self.loaded_ts) >= self.refresh_interval
+            ):
+                Emoji.locals = Emoji.load_locals()
+                self.loaded_ts = time()
+        response = self.get_response(request)
+        return response
diff --git a/activities/migrations/0004_emoji_post_emojis.py b/activities/migrations/0004_emoji_post_emojis.py
new file mode 100644
index 0000000..89bc825
--- /dev/null
+++ b/activities/migrations/0004_emoji_post_emojis.py
@@ -0,0 +1,91 @@
+# Generated by Django 4.1.4 on 2022-12-14 23:49
+
+import functools
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+import activities.models.emoji
+import core.uploads
+import stator.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("users", "0003_identity_followers_etc"),
+        ("activities", "0003_postattachment_null_thumb"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="Emoji",
+            fields=[
+                (
+                    "id",
+                    models.BigAutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                ("state_ready", models.BooleanField(default=True)),
+                ("state_changed", models.DateTimeField(auto_now_add=True)),
+                ("state_attempted", models.DateTimeField(blank=True, null=True)),
+                ("state_locked_until", models.DateTimeField(blank=True, null=True)),
+                ("shortcode", models.SlugField(max_length=100)),
+                ("local", models.BooleanField(default=True)),
+                ("public", models.BooleanField(null=True)),
+                (
+                    "object_uri",
+                    models.CharField(
+                        blank=True, max_length=500, null=True, unique=True
+                    ),
+                ),
+                ("mimetype", models.CharField(max_length=200)),
+                (
+                    "file",
+                    models.ImageField(
+                        blank=True,
+                        null=True,
+                        upload_to=functools.partial(
+                            core.uploads.upload_emoji_namer, *("emoji",), **{}
+                        ),
+                    ),
+                ),
+                ("remote_url", models.CharField(blank=True, max_length=500, null=True)),
+                ("category", models.CharField(blank=True, max_length=100, null=True)),
+                (
+                    "state",
+                    stator.models.StateField(
+                        choices=[("outdated", "outdated"), ("updated", "updated")],
+                        default="outdated",
+                        graph=activities.models.emoji.EmojiStates,
+                        max_length=100,
+                    ),
+                ),
+                ("created", models.DateTimeField(auto_now_add=True)),
+                ("updated", models.DateTimeField(auto_now=True)),
+                (
+                    "domain",
+                    models.ForeignKey(
+                        blank=True,
+                        null=True,
+                        on_delete=django.db.models.deletion.CASCADE,
+                        to="users.domain",
+                    ),
+                ),
+            ],
+            options={
+                "unique_together": {("domain", "shortcode")},
+            },
+        ),
+        migrations.AddField(
+            model_name="post",
+            name="emojis",
+            field=models.ManyToManyField(
+                blank=True, related_name="posts_using_emoji", to="activities.emoji"
+            ),
+        ),
+    ]
diff --git a/activities/models/__init__.py b/activities/models/__init__.py
index aa34c0f..15a08a2 100644
--- a/activities/models/__init__.py
+++ b/activities/models/__init__.py
@@ -1,3 +1,4 @@
+from .emoji import Emoji, EmojiStates  # noqa
 from .fan_out import FanOut, FanOutStates  # noqa
 from .hashtag import Hashtag, HashtagStates  # noqa
 from .post import Post, PostStates  # noqa
diff --git a/activities/models/emoji.py b/activities/models/emoji.py
new file mode 100644
index 0000000..00f6e67
--- /dev/null
+++ b/activities/models/emoji.py
@@ -0,0 +1,261 @@
+import re
+from functools import partial
+from typing import ClassVar, cast
+
+import urlman
+from asgiref.sync import sync_to_async
+from django.conf import settings
+from django.core.exceptions import ValidationError
+from django.db import models
+from django.utils.safestring import mark_safe
+
+from core.files import get_remote_file
+from core.html import strip_html
+from core.models import Config
+from core.uploads import upload_emoji_namer
+from core.uris import AutoAbsoluteUrl, RelativeAbsoluteUrl, StaticAbsoluteUrl
+from stator.models import State, StateField, StateGraph, StatorModel
+from users.models import Domain
+
+
+class EmojiStates(StateGraph):
+    outdated = State(try_interval=300, force_initial=True)
+    updated = State()
+
+    outdated.transitions_to(updated)
+
+    @classmethod
+    async def handle_outdated(cls, instance: "Emoji"):
+        """
+        Fetches remote emoji and uploads to file for local caching
+        """
+        if instance.remote_url and not instance.file:
+            file, mimetype = await get_remote_file(
+                instance.remote_url,
+                timeout=settings.SETUP.REMOTE_TIMEOUT,
+                max_size=settings.SETUP.EMOJI_MAX_IMAGE_FILESIZE_KB * 1024,
+            )
+            if file:
+                instance.file = file
+                instance.mimetype = mimetype
+                await sync_to_async(instance.save)()
+
+        return cls.updated
+
+
+class EmojiQuerySet(models.QuerySet):
+    def usable(self, domain: Domain | None = None):
+        public_q = models.Q(public=True)
+        if Config.system.emoji_unreviewed_are_public:
+            public_q |= models.Q(public__isnull=True)
+
+        qs = self.filter(public_q)
+        if domain:
+            if domain.local:
+                qs = qs.filter(local=True)
+            else:
+                qs = qs.filter(domain=domain)
+        return qs
+
+
+class EmojiManager(models.Manager):
+    def get_queryset(self):
+        return EmojiQuerySet(self.model, using=self._db)
+
+    def usable(self, domain: Domain | None = None):
+        return self.get_queryset().usable(domain)
+
+
+class Emoji(StatorModel):
+
+    # Normalized Emoji without the ':'
+    shortcode = models.SlugField(max_length=100, db_index=True)
+
+    domain = models.ForeignKey(
+        "users.Domain", null=True, blank=True, on_delete=models.CASCADE
+    )
+    local = models.BooleanField(default=True)
+
+    # Should this be shown in the public UI?
+    public = models.BooleanField(null=True)
+
+    object_uri = models.CharField(max_length=500, blank=True, null=True, unique=True)
+
+    mimetype = models.CharField(max_length=200)
+
+    # Files may not be populated if it's remote and not cached on our side yet
+    file = models.ImageField(
+        upload_to=partial(upload_emoji_namer, "emoji"),
+        null=True,
+        blank=True,
+    )
+
+    # A link to the custom emoji
+    remote_url = models.CharField(max_length=500, blank=True, null=True)
+
+    # Used for sorting custom emoji in the picker
+    category = models.CharField(max_length=100, blank=True, null=True)
+
+    # State of this Emoji
+    state = StateField(EmojiStates)
+
+    created = models.DateTimeField(auto_now_add=True)
+    updated = models.DateTimeField(auto_now=True)
+
+    objects = EmojiManager()
+
+    # Cache of the local emojis {shortcode: Emoji}
+    locals: ClassVar["dict[str, Emoji]"]
+
+    class Meta:
+        unique_together = ("domain", "shortcode")
+
+    class urls(urlman.Urls):
+        root = "/admin/emoji/"
+        create = "{root}/create/"
+        edit = "{root}{self.Emoji}/"
+        delete = "{edit}delete/"
+
+    emoji_regex = re.compile(r"\B:([a-zA-Z0-9(_)-]+):\B")
+
+    def clean(self):
+        super().clean()
+        if self.local ^ (self.domain is None):
+            raise ValidationError("Must be local or have a domain")
+
+    def __str__(self):
+        return f"{self.id}-{self.shortcode}"
+
+    @classmethod
+    def load_locals(cls) -> dict[str, "Emoji"]:
+        return {x.shortcode: x for x in Emoji.objects.usable().filter(local=True)}
+
+    @property
+    def fullcode(self):
+        return f":{self.shortcode}:"
+
+    @property
+    def is_usable(self) -> bool:
+        """
+        Return True if this Emoji is usable.
+        """
+        return self.public or (
+            self.public is None and Config.system.emoji_unreviewed_are_public
+        )
+
+    def full_url(self) -> RelativeAbsoluteUrl:
+        if self.is_usable:
+            if self.file:
+                return AutoAbsoluteUrl(self.file.url)
+            elif self.remote_url:
+                return AutoAbsoluteUrl(f"/proxy/emoji/{self.pk}/")
+        return StaticAbsoluteUrl("img/blank-emoji-128.png")
+
+    def as_html(self):
+        if self.is_usable:
+            return mark_safe(
+                f'<img src="{self.full_url().relative}" class="emoji" alt="Emoji {self.shortcode}">'
+            )
+        return self.fullcode
+
+    @classmethod
+    def imageify_emojis(
+        cls,
+        content: str,
+        *,
+        emojis: list["Emoji"] | EmojiQuerySet | None = None,
+        include_local: bool = True,
+    ):
+        """
+        Find :emoji: in content and convert to <img>. If include_local is True,
+        the local emoji will be used as a fallback for any shortcodes not defined
+        by emojis.
+        """
+        emoji_set = (
+            cast(list[Emoji], list(cls.locals.values())) if include_local else []
+        )
+
+        if emojis:
+            if isinstance(emojis, (EmojiQuerySet, list)):
+                emoji_set.extend(list(emojis))
+            else:
+                raise TypeError("Unsupported type for emojis")
+
+        possible_matches = {
+            emoji.shortcode: emoji.as_html() for emoji in emoji_set if emoji.is_usable
+        }
+
+        def replacer(match):
+            fullcode = match.group(1).lower()
+            if fullcode in possible_matches:
+                return possible_matches[fullcode]
+            return match.group()
+
+        return mark_safe(Emoji.emoji_regex.sub(replacer, content))
+
+    @classmethod
+    def emojis_from_content(cls, content: str, domain: Domain) -> list[str]:
+        """
+        Return a parsed and sanitized of emoji found in content without
+        the surrounding ':'.
+        """
+        emoji_hits = cls.emoji_regex.findall(strip_html(content))
+        emojis = sorted({emoji.lower() for emoji in emoji_hits})
+        return list(
+            cls.objects.filter(local=domain is None)
+            .usable(domain)
+            .filter(shortcode__in=emojis)
+        )
+
+    def to_ap_tag(self):
+        """
+        Return this Emoji as an ActivityPub Tag
+        http://joinmastodon.org/ns#Emoji
+        """
+        return {
+            "id": self.object_uri,
+            "type": "Emoji",
+            "name": self.shortcode,
+            "icon": {
+                "type": "Image",
+                "mediaType": self.mimetype,
+                "url": self.full_url().absolute,
+            },
+        }
+
+    @classmethod
+    def by_ap_tag(cls, domain: Domain, data: dict, create: bool = False):
+        """ """
+        try:
+            return cls.objects.get(object_uri=data["id"])
+        except cls.DoesNotExist:
+            if not create:
+                raise KeyError(f"No emoji with ID {data['id']}", data)
+
+        # create
+        shortcode = data["name"].lower().strip(":")
+        icon = data["icon"]
+        category = (icon.get("category") or "")[:100]
+        emoji = cls.objects.create(
+            shortcode=shortcode,
+            domain=None if domain.local else domain,
+            local=domain.local,
+            object_uri=data["id"],
+            mimetype=icon["mediaType"],
+            category=category,
+            remote_url=icon["url"],
+        )
+        return emoji
+
+    ### Mastodon API ###
+
+    def to_mastodon_json(self):
+        url = self.full_url().absolute
+        data = {
+            "shortcode": self.shortcode,
+            "url": url,
+            "static_url": self.remote_url or url,
+            "visible_in_picker": self.public,
+            "category": self.category or "",
+        }
+        return data
diff --git a/activities/models/fan_out.py b/activities/models/fan_out.py
index 8f4f342..fd52acd 100644
--- a/activities/models/fan_out.py
+++ b/activities/models/fan_out.py
@@ -184,8 +184,14 @@ class FanOut(StatorModel):
         """
         Returns a version of the object with all relations pre-loaded
         """
-        return await FanOut.objects.select_related(
-            "identity",
-            "subject_post",
-            "subject_post_interaction",
-        ).aget(pk=self.pk)
+        return (
+            await FanOut.objects.select_related(
+                "identity",
+                "subject_post",
+                "subject_post_interaction",
+            )
+            .prefetch_related(
+                "subject_post__emojis",
+            )
+            .aget(pk=self.pk)
+        )
diff --git a/activities/models/post.py b/activities/models/post.py
index 8e355bf..2b0a7c2 100644
--- a/activities/models/post.py
+++ b/activities/models/post.py
@@ -12,8 +12,10 @@ from django.template.defaultfilters import linebreaks_filter
 from django.utils import timezone
 from django.utils.safestring import mark_safe
 
+from activities.models.emoji import Emoji
 from activities.models.fan_out import FanOut
 from activities.models.hashtag import Hashtag
+from activities.templatetags.emoji_tags import imageify_emojis
 from core.html import sanitize_post, strip_html
 from core.ld import canonicalise, format_ld_date, get_list, parse_ld_date
 from stator.models import State, StateField, StateGraph, StatorModel
@@ -218,6 +220,12 @@ class Post(StatorModel):
     # Hashtags in the post
     hashtags = models.JSONField(blank=True, null=True)
 
+    emojis = models.ManyToManyField(
+        "activities.Emoji",
+        related_name="posts_using_emoji",
+        blank=True,
+    )
+
     # When the post was originally created (as opposed to when we received it)
     published = models.DateTimeField(default=timezone.now)
 
@@ -328,8 +336,11 @@ class Post(StatorModel):
         """
         Returns the content formatted for local display
         """
-        return Hashtag.linkify_hashtags(
-            self.linkify_mentions(sanitize_post(self.content), local=True)
+        return imageify_emojis(
+            Hashtag.linkify_hashtags(
+                self.linkify_mentions(sanitize_post(self.content), local=True)
+            ),
+            self.author.domain,
         )
 
     def safe_content_remote(self):
@@ -379,6 +390,8 @@ class Post(StatorModel):
                     visibility = reply_to.Visibilities.local_only
             # Find hashtags in this post
             hashtags = Hashtag.hashtags_from_content(content) or None
+            # Find emoji in this post
+            emojis = Emoji.emojis_from_content(content, author.domain)
             # Strip all HTML and apply linebreaks filter
             content = linebreaks_filter(strip_html(content))
             # Make the Post object
@@ -395,6 +408,7 @@ class Post(StatorModel):
             post.object_uri = post.urls.object_uri
             post.url = post.absolute_object_uri()
             post.mentions.set(mentions)
+            post.emojis.set(emojis)
             if attachments:
                 post.attachments.set(attachments)
             post.save()
@@ -416,6 +430,7 @@ class Post(StatorModel):
             self.edited = timezone.now()
             self.hashtags = Hashtag.hashtags_from_content(content) or None
             self.mentions.set(self.mentions_from_content(content, self.author))
+            self.emojis.set(Emoji.emojis_from_content(content, self.author.domain))
             self.attachments.set(attachments or [])
             self.save()
 
@@ -520,14 +535,11 @@ class Post(StatorModel):
             value["updated"] = format_ld_date(self.edited)
         # Mentions
         for mention in self.mentions.all():
-            value["tag"].append(
-                {
-                    "href": mention.actor_uri,
-                    "name": "@" + mention.handle,
-                    "type": "Mention",
-                }
-            )
+            value["tag"].append(mention.to_ap_tag())
             value["cc"].append(mention.actor_uri)
+        # Emoji
+        for emoji in self.emojis.all():
+            value["tag"].append(emoji.to_ap_tag())
         # Attachments
         for attachment in self.attachments.all():
             value["attachment"].append(attachment.to_ap())
@@ -616,7 +628,9 @@ class Post(StatorModel):
         # Do we have one with the right ID?
         created = False
         try:
-            post = cls.objects.get(object_uri=data["id"])
+            post = cls.objects.select_related("author__domain").get(
+                object_uri=data["id"]
+            )
         except cls.DoesNotExist:
             if create:
                 # Resolve the author
@@ -645,10 +659,10 @@ class Post(StatorModel):
                     mention_identity = Identity.by_actor_uri(tag["href"], create=True)
                     post.mentions.add(mention_identity)
                 elif tag["type"].lower() == "as:hashtag":
-                    post.hashtags.append(tag["name"].lstrip("#"))
+                    post.hashtags.append(tag["name"].lower().lstrip("#"))
                 elif tag["type"].lower() == "http://joinmastodon.org/ns#emoji":
-                    # TODO: Handle incoming emoji
-                    pass
+                    emoji = Emoji.by_ap_tag(post.author.domain, tag, create=True)
+                    post.emojis.add(emoji)
                 else:
                     raise ValueError(f"Unknown tag type {tag['type']}")
             # Visibility and to
@@ -818,7 +832,7 @@ class Post(StatorModel):
                 if self.hashtags
                 else []
             ),
-            "emojis": [],
+            "emojis": [emoji.to_mastodon_json() for emoji in self.emojis.usable()],
             "reblogs_count": self.interactions.filter(type="boost").count(),
             "favourites_count": self.interactions.filter(type="like").count(),
             "replies_count": 0,
diff --git a/activities/templatetags/emoji_tags.py b/activities/templatetags/emoji_tags.py
new file mode 100644
index 0000000..ad221db
--- /dev/null
+++ b/activities/templatetags/emoji_tags.py
@@ -0,0 +1,27 @@
+from cachetools import TTLCache, cached
+from django import template
+
+from activities.models import Emoji
+from users.models import Domain
+
+register = template.Library()
+
+
+@cached(cache=TTLCache(maxsize=1000, ttl=60))
+def emoji_from_domain(domain: Domain | None) -> list[Emoji]:
+    if not domain:
+        return list(Emoji.locals.values())
+    return list(Emoji.objects.usable(domain))
+
+
+@register.filter
+def imageify_emojis(value: str, arg: Domain | None = None):
+    """
+    Convert hashtags in content in to /tags/<hashtag>/ links.
+    """
+    if not value:
+        return ""
+
+    emojis = emoji_from_domain(arg)
+
+    return Emoji.imageify_emojis(value, emojis=emojis)
diff --git a/activities/views/posts.py b/activities/views/posts.py
index e285c7e..1b8676d 100644
--- a/activities/views/posts.py
+++ b/activities/views/posts.py
@@ -67,6 +67,8 @@ class Individual(TemplateView):
                 in_reply_to=self.post_obj.object_uri,
             )
             .distinct()
+            .select_related("author__domain")
+            .prefetch_related("emojis")
             .order_by("published", "created"),
         }
 
diff --git a/activities/views/timelines.py b/activities/views/timelines.py
index 0c1b693..f55e331 100644
--- a/activities/views/timelines.py
+++ b/activities/views/timelines.py
@@ -98,8 +98,8 @@ class Local(ListView):
     def get_queryset(self):
         return (
             Post.objects.local_public()
-            .select_related("author")
-            .prefetch_related("attachments", "mentions")
+            .select_related("author", "author__domain")
+            .prefetch_related("attachments", "mentions", "emojis")
             .order_by("-created")[:50]
         )
 
@@ -126,8 +126,8 @@ class Federated(ListView):
             Post.objects.filter(
                 visibility=Post.Visibilities.public, in_reply_to__isnull=True
             )
-            .select_related("author")
-            .prefetch_related("attachments", "mentions")
+            .select_related("author", "author__domain")
+            .prefetch_related("attachments", "mentions", "emojis")
             .order_by("-created")[:50]
         )
 
@@ -173,7 +173,13 @@ class Notifications(ListView):
         return (
             TimelineEvent.objects.filter(identity=self.request.identity, type__in=types)
             .order_by("-created")[:50]
-            .select_related("subject_post", "subject_post__author", "subject_identity")
+            .select_related(
+                "subject_post",
+                "subject_post__author",
+                "subject_post__author__domain",
+                "subject_identity",
+            )
+            .prefetch_related("subject_post__emojis")
         )
 
     def get_context_data(self, **kwargs):
diff --git a/core/files.py b/core/files.py
index a04cef9..3ef79aa 100644
--- a/core/files.py
+++ b/core/files.py
@@ -1,7 +1,10 @@
 import io
 
 import blurhash
+import httpx
+from django.conf import settings
 from django.core.files import File
+from django.core.files.base import ContentFile
 from PIL import Image, ImageOps
 
 
@@ -37,3 +40,28 @@ def blurhash_image(file) -> str:
     Returns the blurhash for an image
     """
     return blurhash.encode(file, 4, 4)
+
+
+async def get_remote_file(
+    url: str,
+    *,
+    timeout: float = settings.SETUP.REMOTE_TIMEOUT,
+    max_size: int | None = None,
+) -> tuple[File | None, str | None]:
+    """
+    Download a URL and return the File and content-type.
+    """
+    async with httpx.AsyncClient() as client:
+        async with client.stream("GET", url, timeout=timeout) as stream:
+            allow_download = max_size is None
+            if max_size:
+                try:
+                    content_length = int(stream.headers["content-length"])
+                    allow_download = content_length <= max_size
+                except TypeError:
+                    pass
+            if allow_download:
+                file = ContentFile(await stream.aread(), name=url)
+                return file, stream.headers["content-type"]
+
+    return None, None
diff --git a/core/models/config.py b/core/models/config.py
index 8f5dc31..9670c11 100644
--- a/core/models/config.py
+++ b/core/models/config.py
@@ -224,6 +224,8 @@ class Config(models.Model):
         hashtag_unreviewed_are_public: bool = True
         hashtag_stats_max_age: int = 60 * 60
 
+        emoji_unreviewed_are_public: bool = False
+
         cache_timeout_page_default: int = 60
         cache_timeout_page_timeline: int = 60 * 3
         cache_timeout_page_post: int = 60 * 2
diff --git a/core/uploads.py b/core/uploads.py
index 41b6e94..f6c0e89 100644
--- a/core/uploads.py
+++ b/core/uploads.py
@@ -1,10 +1,14 @@
 import os
 import secrets
+from typing import TYPE_CHECKING
 
 from django.utils import timezone
 from storages.backends.gcloud import GoogleCloudStorage
 from storages.backends.s3boto3 import S3Boto3Storage
 
+if TYPE_CHECKING:
+    from activities.models import Emoji
+
 
 def upload_namer(prefix, instance, filename):
     """
@@ -16,6 +20,18 @@ def upload_namer(prefix, instance, filename):
     return f"{prefix}/{now.year}/{now.month}/{now.day}/{new_filename}{old_extension}"
 
 
+def upload_emoji_namer(prefix, instance: "Emoji", filename):
+    """
+    Names uploaded emoji per domain
+    """
+    _, old_extension = os.path.splitext(filename)
+    if instance.domain is None:
+        domain = "_default"
+    else:
+        domain = instance.domain.domain
+    return f"{prefix}/{domain}/{instance.shortcode}{old_extension}"
+
+
 class TakaheS3Storage(S3Boto3Storage):
     """
     Custom override backend that makes webp files store correctly
diff --git a/mediaproxy/views.py b/mediaproxy/views.py
index 57257f3..4fc09b1 100644
--- a/mediaproxy/views.py
+++ b/mediaproxy/views.py
@@ -5,7 +5,7 @@ from django.http import Http404, HttpResponse
 from django.shortcuts import get_object_or_404
 from django.views.generic import View
 
-from activities.models import PostAttachment
+from activities.models import Emoji, PostAttachment
 from users.models import Identity
 
 
@@ -57,6 +57,21 @@ class BaseCacheView(View):
         raise NotImplementedError()
 
 
+class EmojiCacheView(BaseCacheView):
+    """
+    Caches Emoji
+    """
+
+    item_timeout = 86400 * 7  # One week
+
+    def get_remote_url(self):
+        self.emoji = get_object_or_404(Emoji, pk=self.kwargs["emoji_id"])
+
+        if not self.emoji.remote_url:
+            raise Http404()
+        return self.emoji.remote_url
+
+
 class IdentityIconCacheView(BaseCacheView):
     """
     Caches identity icons (avatars)
diff --git a/requirements.txt b/requirements.txt
index d24b45d..628b19a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,6 @@
 bleach~=5.0.1
 blurhash-python~=1.1.3
+cachetools~=5.2.0
 cryptography~=38.0
 dj_database_url~=1.0.0
 django-cache-url~=3.4.2
diff --git a/static/css/style.css b/static/css/style.css
index ce01793..9b509b8 100644
--- a/static/css/style.css
+++ b/static/css/style.css
@@ -358,6 +358,10 @@ nav a i {
     width: auto;
 }
 
+.icon-menu .option img.emoji {
+    height: 22px;
+}
+
 .icon-menu .option i {
     display: inline-block;
     text-align: center;
@@ -740,6 +744,10 @@ h1.identity .icon {
     margin: 0 20px 0 0;
 }
 
+h1.identity .emoji {
+    height: 22px;
+}
+
 h1.identity small {
     display: block;
     font-size: 60%;
@@ -752,6 +760,10 @@ h1.identity small {
     margin: 0 0 20px 0;
 }
 
+.bio .emoji {
+    height: 22px;
+}
+
 .system-note {
     background: var(--color-bg-menu);
     color: var(--color-text-dull);
@@ -789,6 +801,10 @@ table.metadata td.name {
     gap: 1em;
 }
 
+table.metadata td .emoji {
+    height: 22px;
+}
+
 /* Timelines */
 
 .left-column .timeline-name {
@@ -857,6 +873,10 @@ table.metadata td.name {
     float: left;
 }
 
+.post .emoji {
+    height: 22px;
+}
+
 .post .handle {
     display: block;
     padding: 7px 0 0 64px;
@@ -1014,6 +1034,13 @@ table.metadata td.name {
     padding: 0 0 3px 5px;
 }
 
+.boost-banner .emoji,
+.mention-banner .emoji,
+.follow-banner .emoji,
+.like-banner .emoji {
+    height: 22px;
+}
+
 .boost-banner a,
 .mention-banner a,
 .follow-banner a,
diff --git a/static/img/blank-emoji-128.png b/static/img/blank-emoji-128.png
new file mode 100644
index 0000000..e1bc56c
--- /dev/null
+++ b/static/img/blank-emoji-128.png
diff --git a/takahe/settings.py b/takahe/settings.py
index 91bfe7b..98bc9dd 100644
--- a/takahe/settings.py
+++ b/takahe/settings.py
@@ -107,6 +107,11 @@ class Settings(BaseSettings):
     #: is necessary for compatibility with Mastodon’s image proxy.
     MEDIA_MAX_IMAGE_FILESIZE_MB: int = 10
 
+    #: Maximum filesize for Emoji. Attempting to upload Local Emoji larger than this size will be
+    #: blocked. Remote Emoji larger than this size will not be fetched and served from media, but
+    #: served through the image proxy.
+    EMOJI_MAX_IMAGE_FILESIZE_KB: int = 200
+
     #: Request timeouts to use when talking to other servers Either
     #: float or tuple of floats for (connect, read, write, pool)
     REMOTE_TIMEOUT: float | tuple[float, float, float, float] = 5.0
@@ -194,6 +199,7 @@ MIDDLEWARE = [
     "core.middleware.ConfigLoadingMiddleware",
     "api.middleware.ApiTokenMiddleware",
     "users.middleware.IdentityMiddleware",
+    "activities.middleware.EmojiDefaultsLoadingMiddleware",
 ]
 
 ROOT_URLCONF = "takahe.urls"
diff --git a/takahe/urls.py b/takahe/urls.py
index e8aa359..d6d893f 100644
--- a/takahe/urls.py
+++ b/takahe/urls.py
@@ -194,6 +194,11 @@ urlpatterns = [
         mediaproxy.PostAttachmentCacheView.as_view(),
         name="proxy_post_attachment",
     ),
+    path(
+        "proxy/emoji/<emoji_id>/",
+        mediaproxy.EmojiCacheView.as_view(),
+        name="proxy_emoji",
+    ),
     # Well-known endpoints and system actor
     path(".well-known/webfinger", activitypub.Webfinger.as_view()),
     path(".well-known/host-meta", activitypub.HostMeta.as_view()),
diff --git a/templates/activities/_event.html b/templates/activities/_event.html
index 0c94aad..10d1ce4 100644
--- a/templates/activities/_event.html
+++ b/templates/activities/_event.html
@@ -3,14 +3,14 @@
 {% if event.type == "followed" %}
     <div class="follow-banner">
         <a href="{{ event.subject_identity.urls.view }}">
-            {{ event.subject_identity.name_or_handle }}
+            {{ event.subject_identity.html_name_or_handle }}
         </a> followed you
     </div>
     {% include "activities/_identity.html" with identity=event.subject_identity created=event.created %}
 {% elif event.type == "liked" %}
     <div class="like-banner">
         <a href="{{ event.subject_identity.urls.view }}">
-            {{ event.subject_identity.name_or_handle }}
+            {{ event.subject_identity.html_name_or_handle }}
         </a> liked your post
     </div>
     {% if not event.collapsed %}
@@ -19,7 +19,7 @@
 {% elif event.type == "mentioned" %}
     <div class="mention-banner">
         <a href="{{ event.subject_identity.urls.view }}">
-            {{ event.subject_identity.name_or_handle }}
+            {{ event.subject_identity.html_name_or_handle }}
         </a> mentioned you
     </div>
     {% if not event.collapsed %}
@@ -28,7 +28,7 @@
 {% elif event.type == "boosted" %}
     <div class="boost-banner">
         <a href="{{ event.subject_identity.urls.view }}">
-            {{ event.subject_identity.name_or_handle }}
+            {{ event.subject_identity.html_name_or_handle }}
         </a> boosted your post
     </div>
     {% if not event.collapsed %}
diff --git a/templates/activities/_identity.html b/templates/activities/_identity.html
index feb3178..791f05f 100644
--- a/templates/activities/_identity.html
+++ b/templates/activities/_identity.html
@@ -12,6 +12,6 @@
     {% endif %}
 
     <a href="{{ identity.urls.view }}" class="handle">
-        {{ identity.name_or_handle }} <small>@{{ identity.handle }}</small>
+        {{ identity.html_name_or_handle }} <small>@{{ identity.handle }}</small>
     </a>
 </div>
diff --git a/templates/activities/_mini_post.html b/templates/activities/_mini_post.html
index 9f83333..335a8a4 100644
--- a/templates/activities/_mini_post.html
+++ b/templates/activities/_mini_post.html
@@ -7,7 +7,7 @@
     </a>
 
     <a href="{{ post.author.urls.view }}" class="handle">
-        {{ post.author.name_or_handle }}
+        {{ post.author.html_name_or_handle }}
     </a>
 
     <div class="content">
diff --git a/templates/activities/_post.html b/templates/activities/_post.html
index 5802acd..5d75b78 100644
--- a/templates/activities/_post.html
+++ b/templates/activities/_post.html
@@ -59,7 +59,7 @@
     {% endif %}
 
     <a href="{{ post.author.urls.view }}" class="handle">
-        {{ post.author.name_or_handle }} <small>@{{ post.author.handle }}</small>
+        {{ post.author.html_name_or_handle }} <small>@{{ post.author.handle }}</small>
     </a>
 
     {% if post.summary %}
diff --git a/templates/activities/follows.html b/templates/activities/follows.html
index 27a13d3..18c7811 100644
--- a/templates/activities/follows.html
+++ b/templates/activities/follows.html
@@ -8,7 +8,7 @@
             <a class="option" href="{{ identity.urls.view }}">
                 <img src="{{ identity.local_icon_url.relative }}">
                 <span class="handle">
-                    {{ identity.name_or_handle }}
+                    {{ identity.html_name_or_handle }}
                     <small>@{{ identity.handle }}</small>
                 </span>
                 {% if details.outbound %}
diff --git a/templates/activities/home.html b/templates/activities/home.html
index d574e2a..546da0d 100644
--- a/templates/activities/home.html
+++ b/templates/activities/home.html
@@ -10,7 +10,7 @@
         {% elif event.type == "boost" %}
             <div class="boost-banner">
                 <a href="{{ event.subject_identity.urls.view }}">
-                    {{ event.subject_identity.name_or_handle }}
+                    {{ event.subject_identity.html_name_or_handle }}
                 </a> boosted
                 <time>
                     {{ event.subject_post_interaction.published | timedeltashort }} ago
diff --git a/templates/activities/post.html b/templates/activities/post.html
index fd717ad..6205064 100644
--- a/templates/activities/post.html
+++ b/templates/activities/post.html
@@ -1,6 +1,6 @@
 {% extends "base.html" %}
 
-{% block title %}Post by {{ post.author.name_or_handle }}{% endblock %}
+{% block title %}Post by {{ post.author.html_name_or_handle }}{% endblock %}
 
 {% block content %}
     {% if parent %}
diff --git a/templates/identity/select.html b/templates/identity/select.html
index b3fc41d..5f73464 100644
--- a/templates/identity/select.html
+++ b/templates/identity/select.html
@@ -8,7 +8,7 @@
             <a class="option" href="{{ identity.urls.activate }}">
                 <img src="{{ identity.local_icon_url.relative }}">
                 <span class="handle">
-                    {{ identity.name_or_handle }}
+                    {{ identity.html_name_or_handle }}
                     <small>@{{ identity.handle }}</small>
                 </span>
             </a>
diff --git a/templates/identity/view.html b/templates/identity/view.html
index 7e2c8d4..145a0ef 100644
--- a/templates/identity/view.html
+++ b/templates/identity/view.html
@@ -1,4 +1,5 @@
 {% extends "base.html" %}
+{% load emoji_tags %}
 
 {% block title %}{{ identity }}{% endblock %}
 
@@ -40,7 +41,7 @@
             {% endif %}
         {% endif %}
 
-        {{ identity.name_or_handle }}
+        {{ identity.html_name_or_handle }}
         <small>
             @{{ identity.handle }}
             <a title="Copy handle"
diff --git a/tests/activities/models/test_post.py b/tests/activities/models/test_post.py
index a5f2f79..ff74a9e 100644
--- a/tests/activities/models/test_post.py
+++ b/tests/activities/models/test_post.py
@@ -100,7 +100,9 @@ def test_linkify_mentions_remote(
 
 
 @pytest.mark.django_db
-def test_linkify_mentions_local(identity, identity2, remote_identity):
+def test_linkify_mentions_local(
+    config_system, emoji_locals, identity, identity2, remote_identity
+):
     """
     Tests that we can linkify post mentions properly for local use
     """
diff --git a/tests/conftest.py b/tests/conftest.py
index f2b9d64..4466130 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -2,6 +2,7 @@ import time
 
 import pytest
 
+from activities.models import Emoji
 from api.models import Application, Token
 from core.models import Config
 from stator.runner import StatorModel, StatorRunner
@@ -69,6 +70,16 @@ def config_system(keypair):
 
 @pytest.fixture
 @pytest.mark.django_db
+def emoji_locals():
+    Emoji.locals = Emoji.load_locals()
+    Emoji.__forced__ = True
+    yield Emoji.locals
+    Emoji.__forced__ = False
+    del Emoji.locals
+
+
+@pytest.fixture
+@pytest.mark.django_db
 def user() -> User:
     return User.objects.create(email="test@example.com")
 
diff --git a/users/models/identity.py b/users/models/identity.py
index 1239ca1..7898b4a 100644
--- a/users/models/identity.py
+++ b/users/models/identity.py
@@ -169,16 +169,20 @@ class Identity(StatorModel):
 
     @property
     def safe_summary(self):
-        return sanitize_post(self.summary)
+        from activities.templatetags.emoji_tags import imageify_emojis
+
+        return imageify_emojis(sanitize_post(self.summary), self.domain)
 
     @property
     def safe_metadata(self):
+        from activities.templatetags.emoji_tags import imageify_emojis
+
         if not self.metadata:
             return []
         return [
             {
                 "name": data["name"],
-                "value": strip_html(data["value"]),
+                "value": imageify_emojis(strip_html(data["value"]), self.domain),
             }
             for data in self.metadata
         ]
@@ -240,6 +244,15 @@ class Identity(StatorModel):
     def name_or_handle(self):
         return self.name or self.handle
 
+    @cached_property
+    def html_name_or_handle(self):
+        """
+        Return the name_or_handle with any HTML substitutions made
+        """
+        from activities.templatetags.emoji_tags import imageify_emojis
+
+        return imageify_emojis(self.name_or_handle, self.domain)
+
     @property
     def handle(self):
         if self.username is None:
@@ -303,6 +316,17 @@ class Identity(StatorModel):
             }
         return response
 
+    def to_ap_tag(self):
+        """
+        Return this Identity as an ActivityPub Tag
+        http://joinmastodon.org/ns#Mention
+        """
+        return {
+            "href": self.actor_uri,
+            "name": "@" + self.handle,
+            "type": "Mention",
+        }
+
     ### ActivityPub (inbound) ###
 
     @classmethod
@@ -470,7 +494,15 @@ class Identity(StatorModel):
     ### Mastodon Client API ###
 
     def to_mastodon_json(self):
+        from activities.models import Emoji
+
         header_image = self.local_image_url()
+        metadata_value_text = (
+            " ".join([m["value"] for m in self.metadata]) if self.metadata else ""
+        )
+        emojis = Emoji.emojis_from_content(
+            f"{self.name} {self.summary} {metadata_value_text}", self.domain
+        )
         return {
             "id": self.pk,
             "username": self.username,
@@ -491,7 +523,7 @@ class Identity(StatorModel):
                 if self.metadata
                 else []
             ),
-            "emojis": [],
+            "emojis": [emoji.to_mastodon_json() for emoji in emojis],
             "bot": False,
             "group": False,
             "discoverable": self.discoverable,
diff --git a/users/views/admin/settings.py b/users/views/admin/settings.py
index a4e0190..b9e2543 100644
--- a/users/views/admin/settings.py
+++ b/users/views/admin/settings.py
@@ -85,6 +85,10 @@ class BasicSettings(AdminSettingsPage):
             "title": "Unreviewed Hashtags Are Public",
             "help_text": "Public Hashtags may appear in Trending and have a Tags timeline",
         },
+        "emoji_unreviewed_are_public": {
+            "title": "Unreviewed Emoji Are Public",
+            "help_text": "Public Emoji may appear as images, instead of shortcodes",
+        },
     }
 
     layout = {
@@ -100,6 +104,7 @@ class BasicSettings(AdminSettingsPage):
             "post_length",
             "content_warning_text",
             "hashtag_unreviewed_are_public",
+            "emoji_unreviewed_are_public",
         ],
         "Identities": [
             "identity_max_per_user",