Add support for numeric-based URIs for local accounts

Actors would be served at `/ap/users/:user_id` and statuses at `/ap/statuses/:id`

app/controllers/accounts_controller.rb

@@ -71,6 +71,10 @@ class AccountsController < ApplicationController
     params[:username]
   end
 
+  def account_id_param
+    params[:id]
+  end
+
   def skip_temporary_suspension_response?
     request.format == :json
   end

app/controllers/concerns/account_owned_concern.rb

@@ -18,7 +18,11 @@ module AccountOwnedConcern
   end
 
   def set_account
-    @account = Account.find_local!(username_param)
+    @account = username_param.present? ? Account.find_local!(username_param) : Account.local.find(account_id_param)
+  end
+
+  def account_id_param
+    params[:numeric_account_id]
   end
 
   def username_param

app/lib/activitypub/tag_manager.rb

@@ -38,11 +38,23 @@ class ActivityPub::TagManager
 
     case target.object_type
     when :person
-      target.instance_actor? ? instance_actor_url : account_url(target)
+      if target.instance_actor?
+        instance_actor_url
+      elsif target.numeric_ap_id?
+        ap_account_url(target.id)
+      else
+        account_url(target)
+      end
     when :note, :comment, :activity
+      if target.account.numeric_ap_id?
+        return activity_ap_status_url(target.account, target) if target.reblog?
+
+        ap_status_url(target)
+      else
         return activity_account_status_url(target.account, target) if target.reblog?
 
         account_status_url(target.account, target)
+      end
     when :emoji
       emoji_url(target)
     when :flag
@@ -58,6 +70,10 @@ class ActivityPub::TagManager
     account_url(username: username)
   end
 
+  def uri_for_account_id(id)
+    ap_account_url(id: id)
+  end
+
   def generate_uri_for(_target)
     URI.join(root_url, 'payloads', SecureRandom.uuid)
   end
@@ -65,55 +81,67 @@ class ActivityPub::TagManager
   def activity_uri_for(target)
     raise ArgumentError, 'target must be a local activity' unless %i(note comment activity).include?(target.object_type) && target.local?
 
-    activity_account_status_url(target.account, target)
+    target.account.numeric_ap_id? ? activity_ap_status_url(target) : activity_account_status_url(target.account, target)
   end
 
   def replies_uri_for(target, page_params = nil)
     raise ArgumentError, 'target must be a local activity' unless %i(note comment activity).include?(target.object_type) && target.local?
 
-    account_status_replies_url(target.account, target, page_params)
+    target.account.numeric_ap_id? ? ap_status_replies_url(target, page_params) : account_status_replies_url(target.account, target, page_params)
   end
 
   def likes_uri_for(target)
     raise ArgumentError, 'target must be a local activity' unless %i(note comment activity).include?(target.object_type) && target.local?
 
-    account_status_likes_url(target.account, target)
+    target.account.numeric_ap_id? ? ap_status_likes_url(target) : account_status_likes_url(target.account, target)
   end
 
   def shares_uri_for(target)
     raise ArgumentError, 'target must be a local activity' unless %i(note comment activity).include?(target.object_type) && target.local?
 
-    account_status_shares_url(target.account, target)
+    target.account.numeric_ap_id? ? ap_status_shares_url(target) : account_status_shares_url(target.account, target)
   end
 
   def following_uri_for(target, ...)
     raise ArgumentError, 'target must be a local account' unless target.local?
 
-    account_following_index_url(target, ...)
+    target.numeric_ap_id? ? ap_account_following_index_url(target.id, ...) : account_following_index_url(target, ...)
   end
 
   def followers_uri_for(target, ...)
     return target.followers_url.presence unless target.local?
 
-    account_followers_url(target, ...)
+    target.numeric_ap_id? ? ap_account_followers_url(target.id, ...) : account_followers_url(target, ...)
   end
 
   def collection_uri_for(target, ...)
-    raise NotImplementedError unless target.local?
+    raise ArgumentError, 'target must be a local account' unless target.local?
 
-    account_collection_url(target, ...)
+    target.numeric_ap_id? ? ap_account_collection_url(target.id, ...) : account_collection_url(target, ...)
   end
 
   def inbox_uri_for(target)
-    raise NotImplementedError unless target.local?
+    raise ArgumentError, 'target must be a local account' unless target.local?
 
-    target.instance_actor? ? instance_actor_inbox_url : account_inbox_url(target)
+    if target.instance_actor?
+      instance_actor_inbox_url
+    elsif target.numeric_ap_id?
+      ap_account_inbox_url(target.id)
+    else
+      account_inbox_url(target)
+    end
   end
 
   def outbox_uri_for(target, ...)
-    raise NotImplementedError unless target.local?
+    raise ArgumentError, 'target must be a local account' unless target.local?
 
-    target.instance_actor? ? instance_actor_outbox_url(...) : account_outbox_url(target, ...)
+    if target.instance_actor?
+      instance_actor_outbox_url(...)
+    elsif target.numeric_ap_id?
+      ap_account_outbox_url(target.id, ...)
+    else
+      account_outbox_url(target, ...)
+    end
   end
 
   # Primary audience of a status

app/models/account.rb

@@ -182,6 +182,11 @@ class Account < ApplicationRecord
 
   update_index('accounts', :self)
 
+  def numeric_ap_id?
+    # TODO: this is a placeholder for now
+    false
+  end
+
   def local?
     domain.nil?
   end

app/models/concerns/account/interactions.rb

@@ -283,8 +283,10 @@ module Account::Interactions
   def local_followers_hash
     Rails.cache.fetch("followers_hash:#{id}:local") do
       digest = "\x00" * 32
-      followers.where(domain: nil).pluck_each(:username) do |username|
-        Xorcist.xor!(digest, Digest::SHA256.digest(ActivityPub::TagManager.instance.uri_for_username(username)))
+      # TODO
+      followers.where(domain: nil).pluck_each('false as numeric_ap_id', :id, :username) do |numeric_ap_id, id, username|
+        uri = numeric_ap_id ? ActivityPub::TagManager.instance.uri_for_account_id(id) : ActivityPub::TagManager.instance.uri_for_username(username)
+        Xorcist.xor!(digest, Digest::SHA256.digest(uri))
       end
       digest.unpack1('H*')
     end

config/routes.rb

@@ -94,7 +94,19 @@ Rails.application.routes.draw do
 
   get '/authorize_follow', to: redirect { |_, request| "/authorize_interaction?#{request.params.to_query}" }
 
-  resources :accounts, path: 'users', only: [:show], param: :username do
+  concern :account_resources do
+    resources :followers, only: [:index], controller: :follower_accounts
+    resources :following, only: [:index], controller: :following_accounts
+
+    scope module: :activitypub do
+      resource :outbox, only: [:show]
+      resource :inbox, only: [:create]
+      resources :collections, only: [:show]
+      resource :followers_synchronization, only: [:show]
+    end
+  end
+
+  resources :accounts, path: 'users', only: [:show], param: :username, concerns: :account_resources do
     resources :statuses, only: [:show] do
       member do
         get :activity
@@ -105,15 +117,19 @@ Rails.application.routes.draw do
       resources :likes, only: [:index], module: :activitypub
       resources :shares, only: [:index], module: :activitypub
     end
+  end
 
-    resources :followers, only: [:index], controller: :follower_accounts
-    resources :following, only: [:index], controller: :following_accounts
+  scope path: 'ap', as: 'ap' do
+    resources :accounts, path: 'users', only: [:show], param: :id, concerns: :account_resources
 
-    scope module: :activitypub do
-      resource :outbox, only: [:show]
-      resource :inbox, only: [:create]
-      resources :collections, only: [:show]
-      resource :followers_synchronization, only: [:show]
+    resources :statuses, module: :activitypub, only: [:show] do
+      member do
+        get :activity
+      end
+
+      resources :replies, only: [:index]
+      resources :likes, only: [:index]
+      resources :shares, only: [:index]
     end
   end
 

spec/requests/accounts_spec.rb

@@ -5,6 +5,14 @@ require 'rails_helper'
 RSpec.describe 'Accounts show response' do
   let(:account) { Fabricate(:account) }
 
+  context 'with numeric-based identifiers' do
+    it 'returns http success' do
+      get "/ap/users/#{account.id}"
+
+      expect(response).to have_http_status(200)
+    end
+  end
+
   context 'with an unapproved account' do
     before { account.user.update(approved: false) }