Handle Accept activities in the outbox

inc/activities/accept.php

@@ -2,6 +2,7 @@
 namespace activities\accept;
 
 require_once plugin_dir_path( __FILE__ ) . '/../following.php';
+require_once plugin_dir_path( __FILE__ ) . '/../followers.php';
 require_once plugin_dir_path( __FILE__ ) . '/../objects.php';
 require_once plugin_dir_path( __FILE__ ) . '/../actors.php';
 
@@ -37,4 +38,27 @@ function handle_inbox( $actor_slug, $activity ) {
     }
     return $activity;
 }
+
+function handle_outbox( $actor_slug, $activity ) {
+    if ( !array_key_exists( 'object', $activity ) ) {
+        return new \WP_Error(
+            'invalid_activity',
+            __( 'Activity must have an "object" field', 'pterotype' ),
+            array( 'status' => 400 )
+        );
+    }
+    $object = $activity['object'];
+    if ( array_key_exists( 'type', $object ) ) {
+        switch ( $object['type'] ) {
+        case 'Follow':
+            if ( !array_key_exists( 'actor', $object ) ) {
+                break;
+            }
+            $follower = $object['actor'];
+            \followers\add_follower( $actor_slug, $follower );
+            break;
+        }
+    }
+    return $activity;
+}
 ?>

inc/activities/follow.php

@@ -28,17 +28,51 @@ function handle_inbox( $actor_slug, $activity ) {
     // For now, always Accept follow requests
     // in the future, implement a UI to either accept or reject
     // (or automatically accept if the user chooses to enable that setting)
-    $accept = make_accept( $actor_slug, $activity );
-    if ( is_wp_error( $accept ) ) {
-        return $accept;
-    }
-    $res = \outbox\handle_activity( $actor_slug, $accept );
-    if ( is_wp_error( $res ) ) {
-        return $res;
+    if ( actor_is_object( $actor_slug, $activity ) ) {
+        if ( !array_key_exists( 'actor', $activity ) ) {
+            return new \WP_Error(
+                'invalid_activity',
+                __( 'Activity must have an "actor" field', 'pterotype' ),
+                array( 'status' => 400 )
+            );
+        }
+        $follower = $activity['actor'];
+        \objects\upsert_object( $follower );
+        $accept = make_accept( $actor_slug, $activity );
+        if ( is_wp_error( $accept ) ) {
+            return $accept;
+        }
+        $res = \outbox\handle_activity( $actor_slug, $accept );
+        if ( is_wp_error( $res ) ) {
+            return $res;
+        }
     }
     return $activity;
 }
 
+/*
+Return true if the actor denoted by $actor_slug is the object of $activity
+*/
+function actor_is_object( $actor_slug, $activity ) {
+    if ( !array_key_exists( 'object', $activity ) ) {
+        return false;
+    }
+    $actor = \actors\get_actor_by_slug( $actor_slug );
+    if ( is_wp_error( $actor ) ) {
+        return false;
+    }
+    $object = $activity['object'];
+    if ( !array_key_exists( 'type', $object ) ) {
+        return false;
+    }
+    switch ( $object['type'] ) {
+    case 'Link':
+        return array_key_exists( 'href', $object ) && $object['href'] === $actor['id'];
+    default:
+        return array_key_exists( 'id', $object ) && $object['id'] === $actor['id'];
+    }
+}
+
 function make_accept( $actor_slug, $follow ) {
     if ( !array_key_exists( 'actor', $follow ) ) {
         return new \WP_Error(

inc/actors.php

@@ -25,6 +25,11 @@ function get_actor_id( $slug ) {
 }
 
 function get_actor_from_row( $row ) {
+    if ( !$row ) {
+        return new \WP_Error(
+            'not_found', __( 'Actor not found', 'pterotype' ), array( 'status' => 404 )
+        );
+    }
     switch ( $row->type ) {
     case "user":
         $user = get_user_by( 'slug', $row->slug );

inc/followers.php

@@ -0,0 +1,37 @@
+<?php
+namespace followers;
+
+require_once plugin_dir_path( __FILE__ ) . '/actors.php';
+require_once plugin_dir_path( __FILE__ ) . '/objects.php';
+
+function add_follower( $actor_slug, $follower ) {
+    global $wpdb;
+    $actor_id = \actors\get_actor_id( $actor_slug ); 
+    if ( !$actor_id ) {
+        return new \WP_Error(
+            'not_found',
+            __( 'Actor not found', 'pterotype' ),
+            array( 'status' => 404 )
+        );
+    }
+    if ( !array_key_exists( 'id', $follower ) ) {
+        return new \WP_Error(
+            'invalid_object',
+            __( 'Object must have an "id" field', 'pterotype' ),
+            array( 'status' => 400 )
+        );
+    }
+    $object_id = \objects\get_object_id( $follower['id'] );
+    if ( !$object_id ) {
+        $row = \objects\upsert_object( $follower );
+        $object_id = $row->id;
+    }
+    $wpdb->insert(
+        'pterotype_followers',
+        array(
+            'actor_id' => $actor_id,
+            'object_id' = $object_id,
+        );
+    );
+}
+?>

inc/migrations.php

@@ -22,6 +22,7 @@ function run_migrations() {
     }
     apply_migration( '0.0.1', 'migration_0_0_1' );
     apply_migration( '0.0.2', 'migration_0_0_2' );
+    apply_migration( '0.0.3', 'migration_0_0_3' );
     update_option( 'pterotype_previously_migrated_version', PTEROTYPE_VERSION );
 }
 
@@ -159,4 +160,22 @@ function migration_0_0_2() {
         "
     );
 }
+
+function migration_0_0_3() {
+    global $wpdb;
+    $wpdb->query(
+        "
+        CREATE TABLE pterotype_followers(
+            actor_id INT UNSIGNED NOT NULL,
+            object_id INT UNSIGNED NOT NULL,
+            PRIMARY KEY (actor_id, object_id),
+            FOREIGN KEY following_actor_fk(actor_id)
+                REFERENCES pterotype_actors(id),
+            FOREIGN KEY following_object_fk(object_id)
+                REFERENCES pterotype_objects(id)
+        )
+        ENGINE=InnoDB DEFAULT CHARSET=utf8;
+       "
+    );
+}
 ?>

inc/objects.php

@@ -170,6 +170,13 @@ function get_object_by_activitypub_id( $activitypub_id ) {
     return json_decode( $object_json, true );
 }
 
+function get_object_id( $activitypub_id ) {
+    global $wpdb;
+    return $wpdb->get_var( $wpdb->prepare(
+        'SELECT id FROM pterotype_objects WHERE activitypub_id = %s', $activitypub_id
+    ) );
+}
+
 function delete_object( $object ) {
     global $wpdb;
     if ( !array_key_exists( 'id', $object ) ) {

inc/outbox.php

@@ -71,6 +71,9 @@ function handle_activity( $actor_slug, $activity ) {
             array( 'status' => 501 )
         );
         break;
+    case 'Accept':
+        $activity = \activities\accept\handle_inbox( $actor_slug, $activity );
+        break;
     default:
         $create_activity = wrap_object_in_create( $activity );
         if ( is_wp_error( $create_activity ) ) {

pterotype.php

@@ -4,7 +4,7 @@ Plugin Name: Pterotype
 */
 require_once plugin_dir_path( __FILE__ ) . 'inc/init.php';
 
-define( 'PTEROTYPE_VERSION', '0.0.2' );
+define( 'PTEROTYPE_VERSION', '0.0.3' );
 
 function pterotype_init() {
     do_action( 'pterotype_init' );