Implement inbound account migration

static/css/style.css

@@ -432,6 +432,17 @@ section h1.above {
     margin-bottom: -20px;
 }
 
+section h2.above {
+    position: relative;
+    top: -35px;
+    left: -15px;
+    font-weight: bold;
+    font-size: 100%;
+    text-transform: uppercase;
+    color: var(--color-text-dull);
+    margin-bottom: -20px;
+}
+
 section p {
     margin: 5px 0 10px 0;
 }
@@ -983,6 +994,7 @@ button,
     background-color: var(--color-highlight);
     color: var(--color-text-in-highlight);
     display: inline-block;
+    text-decoration: none;
 }
 
 button.delete,

takahe/urls.py

@@ -65,6 +65,11 @@ urlpatterns = [
         settings.CsvFollowers.as_view(),
         name="settings_export_followers_csv",
     ),
+    path(
+        "@<handle>/settings/migrate_in/",
+        settings.MigrateInPage.as_view(),
+        name="settings_migrate_in",
+    ),
     path(
         "@<handle>/settings/tokens/",
         settings.TokensRoot.as_view(),

templates/settings/_menu.html

@@ -14,6 +14,10 @@
             <i class="fa-solid fa-cloud-arrow-up"></i>
             <span>Import/Export</span>
         </a>
+        <a href="{% url "settings_migrate_in" handle=identity.handle %}" {% if section == "migrate_in" %}class="selected"{% endif %} title="Interface">
+            <i class="fa-solid fa-door-open"></i>
+            <span>Migrate Inbound</span>
+        </a>
         <a href="{% url "settings_tokens" handle=identity.handle %}" {% if section == "tokens" %}class="selected"{% endif %} title="Authorized Apps">
             <i class="fa-solid fa-window-restore"></i>
             <span>Authorized Apps</span>

templates/settings/migrate_in.html

@@ -0,0 +1,36 @@
+{% extends "settings/base.html" %}
+
+{% block subtitle %}Migrate Here{% endblock %}
+
+{% block settings_content %}
+    <form action="." method="POST">
+        {% csrf_token %}
+
+
+        <fieldset>
+            <legend>Add New Alias</legend>
+            <p>
+                To move another account to this one, first add it as an alias here,
+                and then go to the server where it is hosted and initiate the move.
+            </p>
+            {% include "forms/_field.html" with field=form.alias %}
+        </fieldset>
+
+        <div class="buttons">
+            <button>Add</button>
+        </div>
+
+    </form>
+
+    <section>
+        <h2 class="above">Current Aliases</h2>
+        <table>
+            {% for alias in aliases %}
+                <tr><td>{{ alias.handle }} <a href=".?remove_alias={{ alias.actor_uri|urlencode }}" class="button danger">Remove Alias</button></td></tr>
+            {% empty %}
+                <tr><td class="empty">You have no aliases.</td></tr>
+            {% endfor %}
+        </table>
+    </section>
+
+{% endblock %}

users/migrations/0021_identity_aliases.py

@@ -0,0 +1,18 @@
+# Generated by Django 4.2.1 on 2023-07-22 17:07
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("users", "0020_alter_identity_local"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="identity",
+            name="aliases",
+            field=models.JSONField(blank=True, null=True),
+        ),
+    ]

users/models/identity.py

@@ -1,6 +1,6 @@
 import ssl
 from functools import cached_property, partial
-from typing import Literal
+from typing import Literal, Optional
 from urllib.parse import urlparse
 
 import httpx
@@ -201,6 +201,10 @@ class Identity(StatorModel):
     # Should be a list of object URIs (we don't want a full M2M here)
     pinned = models.JSONField(blank=True, null=True)
 
+    # A list of other actor URIs - if this account was moved, should contain
+    # the one URI it was moved to.
+    aliases = models.JSONField(blank=True, null=True)
+
     # Admin-only moderation fields
     sensitive = models.BooleanField(default=False)
     restriction = models.IntegerField(
@@ -330,8 +334,21 @@ class Identity(StatorModel):
             self.following_uri = self.actor_uri + "following/"
             self.shared_inbox_uri = f"https://{self.domain.uri_domain}/inbox/"
 
+    def add_alias(self, actor_uri: str):
+        self.aliases = (self.aliases or []) + [actor_uri]
+        self.save()
+
+    def remove_alias(self, actor_uri: str):
+        self.aliases = [x for x in (self.aliases or []) if x != actor_uri]
+        self.save()
+
     ### Alternate constructors/fetchers ###
 
+    @classmethod
+    def by_handle(cls, handle, fetch: bool = False) -> Optional["Identity"]:
+        username, domain = handle.lstrip("@").split("@", 1)
+        return cls.by_username_and_domain(username=username, domain=domain, fetch=fetch)
+
     @classmethod
     def by_username_and_domain(
         cls,
@@ -339,7 +356,7 @@ class Identity(StatorModel):
         domain: str | Domain,
         fetch: bool = False,
         local: bool = False,
-    ):
+    ) -> Optional["Identity"]:
         """
         Get an Identity by username and domain.
 
@@ -543,6 +560,8 @@ class Identity(StatorModel):
                 }
                 for item in self.metadata
             ]
+        if self.aliases:
+            response["alsoKnownAs"] = self.aliases
         # Emoji
         emojis = Emoji.emojis_from_content(
             (self.name or "") + " " + (self.summary or ""), None

users/views/settings/__init__.py

@@ -11,6 +11,7 @@ from users.views.settings.import_export import (  # noqa
     ImportExportPage,
 )
 from users.views.settings.interface import InterfacePage  # noqa
+from users.views.settings.migration import MigrateInPage  # noqa
 from users.views.settings.posting import PostingPage  # noqa
 from users.views.settings.profile import ProfilePage  # noqa
 from users.views.settings.security import SecurityPage  # noqa

users/views/settings/migration.py

@@ -0,0 +1,49 @@
+from django import forms
+from django.contrib import messages
+from django.contrib.auth.decorators import login_required
+from django.shortcuts import redirect
+from django.utils.decorators import method_decorator
+from django.views.generic import FormView
+
+from users.models import Identity
+from users.views.base import IdentityViewMixin
+
+
+@method_decorator(login_required, name="dispatch")
+class MigrateInPage(IdentityViewMixin, FormView):
+    """
+    Lets the identity's profile be migrated in or out.
+    """
+
+    template_name = "settings/migrate_in.html"
+    extra_context = {"section": "migrate_in"}
+
+    class form_class(forms.Form):
+        alias = forms.CharField(
+            help_text="The @account@example.com username you want to move here"
+        )
+
+        def clean_alias(self):
+            self.alias_identity = Identity.by_handle(
+                self.cleaned_data["alias"], fetch=True
+            )
+            if self.alias_identity is None:
+                raise forms.ValidationError("Cannot find that account.")
+            return self.alias_identity.actor_uri
+
+    def form_valid(self, form):
+        self.identity.add_alias(form.cleaned_data["alias"])
+        messages.info(self.request, f"Alias to {form.alias_identity.handle} added")
+        return redirect(".")
+
+    def get_context_data(self, **kwargs):
+        context = super().get_context_data(**kwargs)
+        # If they asked for an alias deletion, do it here
+        if "remove_alias" in self.request.GET:
+            self.identity.remove_alias(self.request.GET["remove_alias"])
+        context["aliases"] = []
+        if self.identity.aliases:
+            context["aliases"] = [
+                Identity.by_actor_uri(uri) for uri in self.identity.aliases
+            ]
+        return context