4 files changed, 112 insertions, 5 deletions
diff --git a/Digitigrade/Model/Actor.php b/Digitigrade/Model/Actor.php
index 4f3aab2..fa08463 100644
--- a/Digitigrade/Model/Actor.php
+++ b/Digitigrade/Model/Actor.php
@@ -1,7 +1,10 @@
 <?php
 namespace Digitigrade\Model;
 
-class Actor extends PushableModel {
+use Digitigrade\RpcException;
+use Digitigrade\RpcReceiver;
+
+class Actor extends PushableModel implements RpcReceiver {
     public ?int $id;
     public string $uri;
     public bool $isLocal = false;
@@ -83,6 +86,64 @@ class Actor extends PushableModel {
         return ActorWebfinger::findByAcct($acct, $autoSave, $forceRefetch)->actor;
     }
 
+    public static function findByRequestHeaders(): ?self {
+        $instance = Instance::findByRequestHeaders();
+        if ($instance == null || !isset($_SERVER['HTTP_X_PAWPUB_ACTOR']))
+            return null;
+        $uri = $_SERVER['HTTP_X_PAWPUB_ACTOR'];
+        if (hostname_from_uri($uri) != $instance->domain)
+            return null;
+        return self::findByUri($uri);
+    }
+
+    protected function rpcCall(string $method, array $args) {
+        switch ($method) {
+            case 'follow': // $this is the target, $args[0] is the initiator
+                $status = $this->requestToFollow ? FollowRelationStatus::PENDING : FollowRelationStatus::ACTIVE;
+                if (!$this->isLocal) {
+                    $endpoint = $this->endpoints->follow ?? null;
+                    if (!isset($endpoint, $this->endpoints->unfollow)) {
+                        throw new RpcException("Actor `$this->uri` has no (un)follow endpoint");
+                    }
+                    $result = send_request_authenticated($endpoint, method: 'POST', actingAs: $args[0]);
+                    if (!str_contains($result->headers[0], ' 20')) {
+                        throw new RpcException('remote call did not indicate success: ' . $result->headers[0]);
+                    }
+                }
+                FollowRelation::create($args[0], $this, $status);
+                return $status;
+
+            case 'unfollow':
+                if (!$this->isLocal) {
+                    $endpoint = $this->endpoints->unfollow ?? null;
+                    if (!isset($endpoint, $this->endpoints->follow)) {
+                        throw new RpcException("Actor `$this->uri` has no (un)follow endpoint");
+                    }
+                    $result = send_request_authenticated($endpoint, method: 'POST', actingAs: $args[0]);
+                    if (!str_contains($result->headers[0], ' 20')) {
+                        throw new RpcException('remote call did not indicate success: ' . $result->headers[0]);
+                    }
+                }
+                FollowRelation::findByActors($args[0], $this)->remove();
+
+            default:
+                throw new \RuntimeException("Actor rpc method $method not (yet?) implemented");
+        }
+    }
+
+    /**
+     * Tries to follow (or send a follow request to) another actor
+     * @param Actor $target the actor to follow
+     * @return FollowRelationStatus PENDING if a request was sent or ACTIVE if the follow went through immediately
+     */
+    public function follow(self $target): FollowRelationStatus {
+        return $target->rpcCall('follow', [$this]);
+    }
+
+    public function unfollow(self $target) {
+        $target->rpcCall('unfollow', [$this]);
+    }
+
     public function jsonSerialize(): array {
         return [
             'type' => 'actor',
@@ -97,7 +158,9 @@ class Actor extends PushableModel {
             'automated' => $this->automated,
             'endpoints' => [
                 'basicFeed' => path_to_uri("/user/$this->handle/basicFeed"),
-                'fullFeed' => path_to_uri("/user/$this->handle/fullFeed")
+                'fullFeed' => path_to_uri("/user/$this->handle/fullFeed"),
+                'follow' => path_to_uri("/user/$this->handle/follow"),
+                'unfollow' => path_to_uri("/user/$this->handle/unfollow"),
             ]
         ];
     }
diff --git a/Digitigrade/Model/FetchableModel.php b/Digitigrade/Model/FetchableModel.php
index 1120823..5e4d1e8 100644
--- a/Digitigrade/Model/FetchableModel.php
+++ b/Digitigrade/Model/FetchableModel.php
@@ -55,10 +55,10 @@ abstract class FetchableModel extends Model implements RemoteFetchable {
     protected static function fetchFromRemote(string $uri, bool $autoSave): ?static {
         // fetch the object
         // janky hack: if this is an Instance then avoid recursively fetching itself
-        $data = @get_remote_object_authenticated($uri, static::class == Instance::class);
-        if ($data === false)
+        $result = @send_request_authenticated($uri, static::class == Instance::class);
+        if (!str_contains($result->headers[0], '200'))
             return null;
-        $data = json_decode($data);
+        $data = json_decode($result->body);
         if ($data === null)
             return null;
 
diff --git a/Digitigrade/Model/FollowRelation.php b/Digitigrade/Model/FollowRelation.php
new file mode 100644
index 0000000..fc43a6f
--- /dev/null
+++ b/Digitigrade/Model/FollowRelation.php
@@ -0,0 +1,37 @@
+<?php
+namespace Digitigrade\Model;
+
+use Digitigrade\Model;
+
+class FollowRelation extends Model {
+    public Actor $subject;
+    public Actor $object;
+    public FollowRelationStatus $status;
+
+    /**
+     * Creates and saves a new follower/following relationship
+     * @param Actor $subject the follower
+     * @param Actor $object the followee
+     * @param FollowRelationStatus $status whether the relationship is pending or active
+     * @return FollowRelation
+     */
+    public static function create(Actor $subject, Actor $object, FollowRelationStatus $status): self {
+        $rel = new self();
+        $rel->subject = $subject;
+        $rel->object = $object;
+        $rel->status = $status;
+        $rel->save();
+        return $rel;
+    }
+
+    protected function getUpdateWhereClause(\PDO $db): ?string {
+        if (self::findWhere('subject = ? and object = ?', [$this->subject->id, $this->object->id]) != null) {
+            return 'subject = ' . $this->subject->id . ' and object = ' . $this->object->id;
+        }
+        return null;
+    }
+
+    public static function findByActors(Actor $subject, Actor $object): ?self {
+        return self::findWhere('subject = ? and object = ?', [$subject->id, $object->id]);
+    }
+}
+\ No newline at end of file
diff --git a/Digitigrade/Model/FollowRelationStatus.php b/Digitigrade/Model/FollowRelationStatus.php
new file mode 100644
index 0000000..24ba34b
--- /dev/null
+++ b/Digitigrade/Model/FollowRelationStatus.php
@@ -0,0 +1,7 @@
+<?php
+namespace Digitigrade\Model;
+
+enum FollowRelationStatus: string {
+    case PENDING = 'pending';
+    case ACTIVE = 'active';
+}
+\ No newline at end of file