7 files changed, 121 insertions, 3 deletions
diff --git a/Digitigrade/Job/PushObject.php b/Digitigrade/Job/PushObject.php
index c3d7210..0278eb5 100644
--- a/Digitigrade/Job/PushObject.php
+++ b/Digitigrade/Job/PushObject.php
@@ -3,6 +3,7 @@ namespace Digitigrade\Job;
 
 use Digitigrade\Exception\AuthException;
 use Digitigrade\Exception\EndpointMissingException;
+use Digitigrade\HttpResponseStatus\PolicyRejected;
 use Digitigrade\Job;
 use Digitigrade\Logger;
 use Digitigrade\Model\Instance;
@@ -38,6 +39,9 @@ class PushObject extends Job {
             // start auth now and hopefully by the next retry we'll be able to
             $instance->beginOutboundAuth();
             throw $e;
+        } catch (PolicyRejected $e) {
+            $log->warning("can't push to $instance->domain because a policy rejected it. giving up");
+            // and don't throw again, pretty much same reasoning as above
         }
     }
 }
 \ No newline at end of file
diff --git a/Digitigrade/Model/Instance.php b/Digitigrade/Model/Instance.php
index 5545849..eecc6ff 100644
--- a/Digitigrade/Model/Instance.php
+++ b/Digitigrade/Model/Instance.php
@@ -6,6 +6,7 @@ use Digitigrade\Exception\EndpointMissingException;
 use Digitigrade\GlobalConfig;
 use Digitigrade\HttpResponseStatus\Unauthorized;
 use Digitigrade\Job\RefreshOutboundAuthToken;
+use Digitigrade\PolicyManager;
 
 class Instance extends FetchableModel {
     public ?int $id;
@@ -208,6 +209,7 @@ class Instance extends FetchableModel {
         if (!$this->auth->outboundPushEnabled) {
             throw new \RuntimeException("won't push to $this->domain because it hasn't subscribed to us");
         }
+        PolicyManager::getInstance()->checkFederationOrThrow($obj, $this);
         $context = stream_context_create(['http' => [
             'method' => 'POST',
             'header' => "Content-Type: application/json\nAuthorization: Bearer " . $this->auth->outboundToken,
diff --git a/Digitigrade/Policy.php b/Digitigrade/Policy.php
index 56fbdb0..973c229 100644
--- a/Digitigrade/Policy.php
+++ b/Digitigrade/Policy.php
@@ -2,6 +2,7 @@
 namespace Digitigrade;
 
 use Digitigrade\Model\Actor;
+use Digitigrade\Model\Instance;
 use Digitigrade\Model\Interaction;
 use Digitigrade\Model\Note;
 
@@ -34,4 +35,39 @@ abstract class Policy {
     }
 
     // TODO: public function checkExtension()
+
+    /**
+     * Checks if an Actor is allowed to be federated to a certain Instance,
+     * and possibly alters it.
+     * @param Actor $actor the actor to check (may be modified in-place)
+     * @param ?Instance $instance the instance that is receiving this (may be null if unknown)
+     * @return bool true if allowed, false if the request should be cancelled
+     */
+    public function checkActorFederation(Actor $actor, ?Instance $instance): bool {
+        return true;
+    }
+
+    /**
+     * Checks if an Interaction is allowed to be federated to a certain Instance,
+     * and possibly alters it.
+     * @param Interaction $interaction the interaction to check (may be modified in-place)
+     * @param ?Instance $instance the instance that is receiving this (may be null if unknown)
+     * @return bool true if allowed, false if the request should be cancelled
+     */
+    public function checkInteractionFederation(Interaction $interaction, ?Instance $instance): bool {
+        return true;
+    }
+
+    /**
+     * Checks if an Note is allowed to be federated to a certain Instance,
+     * and possibly alters it.
+     * @param Note $note the note to check (may be modified in-place)
+     * @param ?Instance $instance the instance that is receiving this (may be null if unknown)
+     * @return bool true if allowed, false if the request should be cancelled
+     */
+    public function checkNoteFederation(Note $note, ?Instance $instance): bool {
+        return true;
+    }
+
+    // TODO: public function checkExtensionFederation()
 }
 \ No newline at end of file
diff --git a/Digitigrade/Policy/BlockInstance.php b/Digitigrade/Policy/BlockInstance.php
index 5f902f2..053418c 100644
--- a/Digitigrade/Policy/BlockInstance.php
+++ b/Digitigrade/Policy/BlockInstance.php
@@ -2,6 +2,7 @@
 namespace Digitigrade\Policy;
 
 use Digitigrade\Model\Actor;
+use Digitigrade\Model\Instance;
 use Digitigrade\Model\Interaction;
 use Digitigrade\Model\Note;
 use Digitigrade\Model\PushableModel;
@@ -15,8 +16,11 @@ class BlockInstance extends Policy {
         $this->blockedHosts = $hosts;
     }
 
-    private function isBlocked(PushableModel $obj): bool {
-        $objHost = hostname_from_uri($obj->uri);
+    private function isBlocked(PushableModel|Instance|null $obj): bool {
+        if ($obj == null) {
+            return false;
+        }
+        $objHost = hostname_from_uri($obj instanceof Instance ? $obj->domain : $obj->uri);
         foreach ($this->blockedHosts as $host) {
             if (str_ends_with($objHost, $host)) {
                 return true;
@@ -34,4 +38,14 @@ class BlockInstance extends Policy {
     public function checkNote(Note $note): bool {
         return !$this->isBlocked($note);
     }
+
+    public function checkActorFederation(Actor $actor, ?Instance $instance): bool {
+        return !$this->isBlocked($instance);
+    }
+    public function checkInteractionFederation(Interaction $interaction, ?Instance $instance): bool {
+        return !$this->isBlocked($instance);
+    }
+    public function checkNoteFederation(Note $note, ?Instance $instance): bool {
+        return !$this->isBlocked($instance);
+    }
 }
 \ No newline at end of file
diff --git a/Digitigrade/Policy/RemoteInstanceInfoSubstitution.php b/Digitigrade/Policy/RemoteInstanceInfoSubstitution.php
new file mode 100644
index 0000000..cbcecfc
--- /dev/null
+++ b/Digitigrade/Policy/RemoteInstanceInfoSubstitution.php
@@ -0,0 +1,33 @@
+<?php
+namespace Digitigrade\Policy;
+
+use Digitigrade\Model\Instance;
+use Digitigrade\Model\Note;
+use Digitigrade\Policy;
+
+class RemoteInstanceInfoSubstitution extends Policy {
+    public function checkNoteFederation(Note $note, ?Instance $instance): bool {
+        if ($instance == null) {
+            return true;
+        }
+
+        $infos = [
+            '%Instance.domain' => $instance->domain,
+            '%Instance.name' => $instance->name,
+            '%Instance.description' => $instance->description ?? '',
+            '%Instance.softwareName' => $instance->softwareName,
+            '%Instance.softwareDescription' => $instance->softwareDescription ?? '',
+            '%Instance.softwareHomepage' => $instance->softwareHomepage ?? '',
+            '%Instance.softwareVersion' => $instance->softwareVersion ?? ''
+        ];
+
+        foreach ($infos as $needle => $replacement) {
+            $note->plainContent = str_replace($needle, $replacement, $note->plainContent);
+            foreach ($note->formattedContent as $type => $content) {
+                $note->formattedContent[$type] = str_replace($needle, $replacement, $content);
+            }
+        }
+
+        return true;
+    }
+}
+\ No newline at end of file
diff --git a/Digitigrade/PolicyManager.php b/Digitigrade/PolicyManager.php
index 24c2c7f..69e2ab0 100644
--- a/Digitigrade/PolicyManager.php
+++ b/Digitigrade/PolicyManager.php
@@ -1,8 +1,10 @@
 <?php
 namespace Digitigrade;
 
+use Digitigrade\HttpResponseStatus\PolicyRejected;
 use Digitigrade\Model\Actor;
 use Digitigrade\Model\FetchableModel;
+use Digitigrade\Model\Instance;
 use Digitigrade\Model\Interaction;
 use Digitigrade\Model\Note;
 
@@ -34,6 +36,34 @@ class PolicyManager extends Singleton {
         };
     }
 
+    public function checkOrThrow(FetchableModel $object) {
+        if (!$this->check($object)) {
+            throw new PolicyRejected();
+        }
+    }
+
+    /**
+     * Checks if an object is allowed to be sent to a certain Instance by all
+     * policies, and possibly alters it.
+     * @param FetchableModel $object the object to check (may be modified in-place)
+     * @param ?Instance $instance the instance it's being sent to (may be null if unknown)
+     * @return bool true if allowed, false if the request should be cancelled
+     */
+    public function checkFederation(FetchableModel $object, ?Instance $instance): bool {
+        return match ($object::class) {
+            Actor::class => self::arrayAll($this->policies, fn(Policy $p) => $p->checkActorFederation($object, $instance)),
+            Interaction::class => self::arrayAll($this->policies, fn(Policy $p) => $p->checkInteractionFederation($object, $instance)),
+            Note::class => self::arrayAll($this->policies, fn(Policy $p) => $p->checkNoteFederation($object, $instance)),
+            default => true
+        };
+    }
+
+    public function checkFederationOrThrow(FetchableModel $object, ?Instance $instance) {
+        if (!$this->checkFederation($object, $instance)) {
+            throw new PolicyRejected();
+        }
+    }
+
     private static function arrayAll(array $arr, callable $test): bool {
         // i would use array_all but that's php 8.4+ only which i don't have lol
         foreach ($arr as $item) {
diff --git a/Digitigrade/Singleton.php b/Digitigrade/Singleton.php
index 23b2e78..a90bb4a 100644
--- a/Digitigrade/Singleton.php
+++ b/Digitigrade/Singleton.php
@@ -10,7 +10,6 @@ abstract class Singleton {
      */
     public static function getInstance() {
         if (!isset(self::$instances[static::class])) {
-            //error_log('making a new ' . static::class);
             self::$instances[static::class] = new static();
         }
         return self::$instances[static::class];