From 4de5612b8c3a842c53aea1c74d5a9ebae515449c Mon Sep 17 00:00:00 2001
From: Jeremy Dormitzer <jeremy.dormitzer@gmail.com>
Date: Tue, 4 Sep 2018 00:01:34 -0600
Subject: [PATCH] Implement Follow (outbox) activity

---
 following.php             | 29 +++++++++++++++++++++++++++++
 inc/activities/follow.php | 23 +++++++++++++++++++++++
 inc/init.php              |  2 ++
 inc/outbox.php            |  2 ++
 4 files changed, 56 insertions(+)
 create mode 100644 following.php
 create mode 100644 inc/activities/follow.php

diff --git a/following.php b/following.php
new file mode 100644
index 0000000..ce688aa
--- /dev/null
+++ b/following.php
@@ -0,0 +1,29 @@
+<?php
+namespace following;
+
+$PENDING = 'PENDING';
+$FOLLOWING = 'FOLLOWING';
+
+function request_follow( $actor_id, $object ) {
+    global $wpdb;
+    return $wpdb->insert(
+        'activitypub_following',
+        array( 'actor_id' => $actor_id, 'object' => wp_json_encode( $object ) )
+    );
+}
+
+function create_following_table() {
+    global $wpdb;
+    $wpdb->query(
+        "
+        CREATE TABLE IF NOT EXISTS activitypub_following(
+            actor_id INT UNSIGNED NOT NULL,
+            object TEXT NOT NULL,
+            state VARCHAR(64) NOT NULL,
+            FOREIGN KEY actor_fk(actor_id)
+            REFERENCES activitypub_actors(id)
+        );
+        "
+    );
+}
+?>
diff --git a/inc/activities/follow.php b/inc/activities/follow.php
new file mode 100644
index 0000000..8d276eb
--- /dev/null
+++ b/inc/activities/follow.php
@@ -0,0 +1,23 @@
+<?php
+namespace activities\follow;
+
+require_once plugin_dir_path( __FILE__ ) . '/../following.php';
+require_once plugin_dir_path( __FILE__ ) . '/../actors.php';
+
+function handle( $actor, $activity ) {
+    if ( !array_key_exists( 'object', $activity ) ) {
+        return new \WP_Error(
+            'invalid_activity',
+            __( 'Expected an object', 'activitypub' ),
+            array( 'status' => 400 )
+        );
+    }
+    $object = $activity['object'];
+    $actor_id = \actors\get_actor_id( $actor );
+    $res = \following\request_follow( $actor_id, $object );
+    if ( is_wp_error( $res ) ) {
+        return $res;
+    }
+    return $activity;
+}
+?>
diff --git a/inc/init.php b/inc/init.php
index 9acf95c..5283d97 100644
--- a/inc/init.php
+++ b/inc/init.php
@@ -7,6 +7,7 @@ require_once plugin_dir_path( __FILE__ ) . '/objects.php';
 require_once plugin_dir_path( __FILE__ ) . '/activities.php';
 require_once plugin_dir_path( __FILE__ ) . '/actors.php';
 require_once plugin_dir_path( __FILE__ ) . '/likes.php';
+require_once plugin_dir_path( __FILE__ ) . '/following.php';
 
 add_action( 'rest_api_init', function() {
     \api\register_routes();
@@ -24,5 +25,6 @@ add_action( 'activitypub_init', function() {
     \actors\create_actors_table();
     \actors\initialize_user_actors();
     \likes\create_likes_table();
+    \following\create_following_table();
 } );
 ?>
diff --git a/inc/outbox.php b/inc/outbox.php
index dc112aa..69b5814 100644
--- a/inc/outbox.php
+++ b/inc/outbox.php
@@ -17,6 +17,7 @@ require_once plugin_dir_path( __FILE__ ) . '/activities/create.php';
 require_once plugin_dir_path( __FILE__ ) . '/activities/update.php';
 require_once plugin_dir_path( __FILE__ ) . '/activities/delete.php';
 require_once plugin_dir_path( __FILE__ ) . '/activities/like.php';
+require_once plugin_dir_path( __FILE__ ) . '/activities/follow.php';
 
 function handle_activity( $actor, $activity ) {
     // TODO handle authentication/authorization
@@ -38,6 +39,7 @@ function handle_activity( $actor, $activity ) {
         $activity = \activities\delete\handle( $actor, $activity );
         break;
     case 'Follow':
+        $activity = \activities\follow\handle( $actor, $activity );
         break;
     case 'Add':
         break;