feat: Support unfollowing

README.md

@@ -73,7 +73,7 @@
 ## Protocol Support
 
 - [x] Check that signature header (digest) matches digest of body contents
-- [ ] Check the domain of the public key against the domain of the object being CRUDed
+- [x] Check the domain of the public key against the domain of the object being CRUDed
 
 ## Testing
 

lib/activity_pub.ex

@@ -38,9 +38,12 @@ defmodule ActivityPub do
       |> Req.Request.put_header("accept", "application/json")
 
     case Req.get(request) do
-      {:ok, result} ->
+      {:ok, %{status: 200} = result} ->
         {:ok, result.body}
 
+      {:ok, %{status: 404}} ->
+        nil
+
       error ->
         error
     end

lib/activity_pub/headers.ex

@@ -77,6 +77,9 @@ defmodule ActivityPub.Headers do
         {:ok, public_key} ->
           :public_key.verify(to_verify, :sha256, signature, public_key)
 
+        nil ->
+          false
+
         error ->
           error
       end

lib/postland/actors.ex

@@ -6,9 +6,13 @@ defmodule Postland.Actors do
   def actor(actor_id) do
     result =
       Cachex.fetch(:main_cache, "actor:#{actor_id}", fn _key ->
-        {:ok, actor} = ActivityPub.fetch_actor(actor_id)
+        case ActivityPub.fetch_actor(actor_id) do
+          {:ok, actor} ->
+            {:commit, actor, expire: :timer.seconds(300)}
 
-        {:commit, actor, expire: :timer.seconds(300)}
+          nil ->
+            {:commit, nil, expire: :timer.seconds(300)}
+        end
       end)
 
     case result do

lib/postland/follows.ex

@@ -52,14 +52,30 @@ defmodule Postland.Follows do
   def record_and_send_withdrawl(request) do
     Multi.new()
     |> Multi.delete(:delete, request)
-    |> Multi.run(:send_acceptance, fn _data, _repo ->
+    |> Multi.run(:send_withdrawl, fn _data, _repo ->
       send_withdrawl(request)
     end)
     |> Repo.transaction()
   end
 
+  def record_and_unfollow(follow) do
+    Multi.new()
+    |> Multi.delete(:delete, follow)
+    |> Multi.run(:send_delete_follow, fn _data, _repo ->
+      send_delete_follow(follow)
+    end)
+    |> Repo.transaction()
+  end
+
   def send_withdrawl(request) do
-    {:ok, actor} = ActivityPub.fetch_actor(request.followee)
+    request.followee
+    |> ActivityPub.fetch_actor()
+    |> do_send_withdrawl(request)
+  end
+
+  defp do_send_withdrawl(nil, _), do: {:ok, nil}
+
+  defp do_send_withdrawl({:ok, actor}, request) do
     inbox = Map.get(actor, "inbox")
 
     body =
@@ -84,7 +100,14 @@ defmodule Postland.Follows do
   end
 
   def send_acceptance(request) do
-    {:ok, actor} = ActivityPub.fetch_actor(request.follower)
+    request.follower
+    |> ActivityPub.fetch_actor()
+    |> do_send_acceptance(request)
+  end
+
+  defp do_send_acceptance(nil, _), do: {:ok, nil}
+
+  defp do_send_acceptance({:ok, actor}, request) do
     inbox = Map.get(actor, "inbox")
 
     case get_follow_activity(request.follower) do
@@ -180,6 +203,34 @@ defmodule Postland.Follows do
     Req.post(inbox, headers: headers, body: follow_request)
   end
 
+  def send_delete_follow(follow) do
+    encoded_followee = Base.url_encode64(follow.followee, padding: false)
+    encoded_follower = Base.url_encode64(follow.follower, padding: false)
+
+    {:ok, actor} = ActivityPub.fetch_actor(follow.followee)
+    inbox = Map.get(actor, "inbox")
+
+    follow_request =
+      %{
+        "@context" => "https://www.w3.org/ns/activitystreams",
+        "type" => "Delete",
+        "actor" => Postland.my_actor_id(),
+        "object" => url(~p"/follows/#{encoded_followee}/#{encoded_follower}")
+      }
+      |> Jason.encode!()
+
+    headers =
+      Headers.signing_headers(
+        "POST",
+        inbox,
+        follow_request,
+        Postland.my_actor_id(),
+        Accounts.solo_user().private_key
+      )
+
+    Req.post(inbox, headers: headers, body: follow_request)
+  end
+
   def get(follower, followee) do
     from(f in Follow, where: f.followee == ^followee, where: f.follower == ^follower)
     |> Repo.one()

lib/postland_web/components/core_components.ex

@@ -60,6 +60,14 @@ defmodule PostlandWeb.CoreComponents do
           >
             Withdraw Request
           </.button>
+          <.button
+            :if={@status == :following_confirmed}
+            phx-click="unfollow"
+            phx-value-dom-id={@dom_id}
+            phx-value-id={@account["id"]}
+          >
+            Unfollow
+          </.button>
         </div>
       </div>
     </div>
@@ -177,7 +185,7 @@ defmodule PostlandWeb.CoreComponents do
   end
 
   def post_card(assigns) do
-    author = Postland.Timeline.attribution(assigns.post) || %{}
+    author = Postland.Timeline.attribution(assigns.post)
 
     %{host: host} =
       case author do
@@ -201,7 +209,7 @@ defmodule PostlandWeb.CoreComponents do
       |> Map.put(:cw, cw)
 
     ~H"""
-    <div class="flex items-start space-x-4 w-full">
+    <div :if={@author} class="flex items-start space-x-4 w-full">
       <div class="flex-shrink-0">
         <img
           class="inline-block h-16 w-16 rounded-full drop-shadow-lg"

lib/postland_web/live/followers_live.ex

@@ -36,6 +36,7 @@ defmodule PostlandWeb.FollowersLive do
           account: Actors.actor(follow.follower)
         }
       end)
+      |> Enum.reject(&is_nil(&1.account))
 
     account_count = Enum.count(followers)
 

lib/postland_web/live/following_live.ex

@@ -33,6 +33,7 @@ defmodule PostlandWeb.FollowingLive do
           account: Actors.actor(follow.followee)
         }
       end)
+      |> Enum.reject(&is_nil(&1.account))
 
     account_count = Enum.count(follows)
 
@@ -60,4 +61,21 @@ defmodule PostlandWeb.FollowingLive do
 
     {:noreply, socket}
   end
+
+  def handle_event("unfollow", %{"id" => id, "dom-id" => dom_id}, socket) do
+    request = Follows.get(Postland.my_actor_id(), id)
+
+    socket =
+      case Follows.record_and_unfollow(request) do
+        {:ok, _} ->
+          socket
+          |> stream_delete_by_dom_id(:accounts, dom_id)
+          |> assign(:count, socket.assigns.count - 1)
+
+        _ ->
+          put_flash(socket, :error, "An unexpected error occurred.")
+      end
+
+    {:noreply, socket}
+  end
 end