support outbox post

- we can now receive content into outbox (f.e. from contentnation) and post it into the outbox-user-logfile for now
- we now verify post-requests according to ActivityPub standard
- minor bugfix where user specified by passed user-parameter is possibly not included in postForUser-call

php/federator/api.php

@@ -192,6 +192,81 @@ class Api extends Main
         throw new $exception($message);
     }
 
+    /**
+     * check if the headers include a valid signature
+     *
+     * @param string[] $headers
+     *          permission(s) to check for
+     * @throws Exceptions\PermissionDenied
+     */
+    public function checkSignature($headers)
+    {
+        $signatureHeader = $headers['Signature'] ?? null;
+
+        if (!$signatureHeader) {
+            http_response_code(400);
+            throw new Exceptions\PermissionDenied("Missing Signature header");
+        }
+
+        // Parse Signature header
+        preg_match_all('/(\w+)=["\']?([^"\',]+)["\']?/', $signatureHeader, $matches);
+        $signatureParts = array_combine($matches[1], $matches[2]);
+
+        $signature = base64_decode($signatureParts['signature']);
+        $keyId = $signatureParts['keyId'];
+        $signedHeaders = explode(' ', $signatureParts['headers']);
+
+        // Fetch public key from `keyId` (usually actor URL + #main-key)
+        [$publicKeyData, $info] = \Federator\Main::getFromRemote($keyId, ['Accept: application/activity+json']);
+
+        if ($info['http_code'] !== 200) {
+            http_response_code(500);
+            throw new Exceptions\PermissionDenied("Failed to fetch public key from keyId: $keyId");
+        }
+
+        $actor = json_decode($publicKeyData, true);
+        error_log("actor: " . $publicKeyData);
+        $publicKeyPem = $actor['publicKey']['publicKeyPem'] ?? null;
+
+        error_log($publicKeyPem);
+        error_log(json_encode($headers));
+        if (!$publicKeyPem) {
+            http_response_code(500);
+            throw new Exceptions\PermissionDenied("Invalid public key format from actor with keyId: $keyId");
+        }
+
+        // Reconstruct the signed string
+        $signedString = '';
+        foreach ($signedHeaders as $header) {
+            $headerValue = '';
+
+            if ($header === '(request-target)') {
+                $method = strtolower($_SERVER['REQUEST_METHOD']);
+                $path = $_SERVER['REQUEST_URI'];
+                $headerValue = "$method $path";
+            } else {
+                $headerValue = $headers[ucwords($header, '-')] ?? '';
+            }
+
+            $signedString .= strtolower($header) . ": " . $headerValue . "\n";
+        }
+        $signedString = rtrim($signedString);
+
+        // Verify the signature
+        $pubkeyRes = openssl_pkey_get_public($publicKeyPem);
+        $verified = false;
+        if ($pubkeyRes) {
+            $verified = openssl_verify($signedString, $signature, $pubkeyRes, OPENSSL_ALGO_SHA256);
+        }
+        if ($verified !== 1) {
+            http_response_code(500);
+            throw new Exceptions\PermissionDenied("Signature verification failed for publicKey with keyId: $keyId");
+        }
+
+        // Signature is valid!
+        return "Signature verified from actor: " . $actor['id'];
+    }
+
     /**
      * remove unwanted elements from html input
      *

php/federator/api/fedusers/inbox.php

@@ -22,7 +22,7 @@ class Inbox implements \Federator\Api\FedUsers\FedUsersInterface
 
     /**
      * constructor
-     * @param \Federator\Main $main main instance
+     * @param \Federator\Api $main api main instance
      */
     public function __construct($main)
     {
@@ -51,6 +51,16 @@ class Inbox implements \Federator\Api\FedUsers\FedUsersInterface
         $inboxActivity = null;
         $_rawInput = file_get_contents('php://input');
 
+        $allHeaders = getallheaders();
+        try {
+            $result = $this->main->checkSignature($allHeaders);
+            error_log($result); // Signature verified
+        } catch (\Federator\Exceptions\PermissionDenied $e) {
+            error_log("Inbox::post Signature check failed: " . $e->getMessage());
+            http_response_code(403); // Or 401
+            exit("Access denied");
+        }
+
         $activity = json_decode($_rawInput, true);
         $host = $_SERVER['SERVER_NAME'];
 
@@ -124,6 +134,11 @@ class Inbox implements \Federator\Api\FedUsers\FedUsersInterface
                                 $apNote->addTag($tagObj);
                             }
                         }
+                        if (array_key_exists('cc', $obj)) {
+                            foreach ($obj['cc'] as $cc) {
+                                $apNote->addCC($cc);
+                            }
+                        }
                         
                         $create->setObject($apNote);
                         break;
@@ -176,6 +191,7 @@ class Inbox implements \Federator\Api\FedUsers\FedUsersInterface
                     case 'Note':
                         $note = new \Federator\Data\ActivityPub\Common\Note();
                         $note->setID($objData['id'])
+                            ->setSummary($objData['summary'])
                             ->setContent($objData['content'] ?? '')
                             ->setPublished(strtotime($objData['published'] ?? 'now'))
                             ->setURL($objData['url'] ?? $objData['id'])
@@ -290,7 +306,7 @@ class Inbox implements \Federator\Api\FedUsers\FedUsersInterface
                 $users = array_merge($users, $this->fetchAllFollowers($receiver, $host));
             }
         }
-        if ($_user !== false && in_array($_user, $users)) {
+        if ($_user !== false && !in_array($_user, $users)) {
             $users[] = $_user;
         }
         foreach ($users as $user) {
@@ -324,6 +340,7 @@ class Inbox implements \Federator\Api\FedUsers\FedUsersInterface
                 $cache
             );
             if ($user->id === null) {
+                error_log("Inbox::postForUser couldn't find user: $_user");
                 return false;
             }
         }

php/federator/api/fedusers/outbox.php

@@ -64,7 +64,7 @@ class Outbox implements \Federator\Api\FedUsers\FedUsersInterface
             $items = [];
         }
         $host = $_SERVER['SERVER_NAME'];
-        $id = 'https://' . $host .'/' . $_user . '/outbox';
+        $id = 'https://' . $host . '/' . $_user . '/outbox';
         $outbox->setPartOf($id);
         $outbox->setID($id);
         if ($page !== '') {
@@ -74,9 +74,9 @@ class Outbox implements \Federator\Api\FedUsers\FedUsersInterface
             $outbox->setFirst($id);
             $outbox->setLast($id . '&min=0');
         }
-        if (sizeof($items)>0) {
+        if (sizeof($items) > 0) {
             $newestId = $items[0]->getPublished();
-            $oldestId = $items[sizeof($items)-1]->getPublished();
+            $oldestId = $items[sizeof($items) - 1]->getPublished();
             $outbox->setNext($id . '&max=' . $newestId);
             $outbox->setPrev($id . '&min=' . $oldestId);
         }
@@ -87,11 +87,359 @@ class Outbox implements \Federator\Api\FedUsers\FedUsersInterface
     /**
      * handle post call
      *
-     * @param string $_user user to add data to outbox @unused-param
+     * @param string $_user user to add data to outbox
      * @return string|false response
      */
     public function post($_user)
     {
-        return false;
+        $outboxActivity = null;
+        $_rawInput = file_get_contents('php://input');
+
+        $allHeaders = getallheaders();
+        try {
+            $result = $this->main->checkSignature($allHeaders);
+            error_log($result); // Signature verified
+        } catch (\Federator\Exceptions\PermissionDenied $e) {
+            error_log("Outbox::post Signature check failed: " . $e->getMessage());
+            http_response_code(403); // Or 401
+            exit("Access denied");
+        }
+
+        $activity = json_decode($_rawInput, true);
+        $host = $_SERVER['SERVER_NAME'];
+
+        $sendTo = [];
+
+        switch ($activity['type']) {
+            case 'Create':
+                if (!isset($activity['object'])) {
+                    break;
+                }
+
+                $obj = $activity['object'];
+                $create = new \Federator\Data\ActivityPub\Common\Create();
+                $create->setID($activity['id'])
+                    ->setURL($activity['id'])
+                    ->setPublished(published: strtotime($activity['published'] ?? $obj['published'] ?? 'now'))
+                    ->setAActor($activity['actor']);
+
+                if (array_key_exists('cc', $activity)) {
+                    foreach ($activity['cc'] as $cc) {
+                        $create->addCC($cc);
+                    }
+                }
+
+                if (array_key_exists('to', $activity)) {
+                    foreach ($activity['to'] as $to) {
+                        $create->addTo($to);
+                    }
+                }
+
+                switch ($obj['type']) {
+                    case 'Note':
+                        $apNote = new \Federator\Data\ActivityPub\Common\Note();
+                        $apNote->setID($obj['id'])
+                            ->setPublished(strtotime($obj['published'] ?? 'now'))
+                            ->setContent($obj['content'] ?? '')
+                            ->setSummary($obj['summary'])
+                            ->setURL($obj['url'])
+                            ->setAttributedTo($obj['attributedTo'] ?? $activity['actor'])
+                            ->addTo("https://www.w3.org/ns/activitystreams#Public");
+
+                        if (!empty($obj['sensitive'])) {
+                            $apNote->setSensitive($obj['sensitive']);
+                        }
+                        if (!empty($obj['conversation'])) {
+                            $apNote->setConversation($obj['conversation']);
+                        }
+                        if (!empty($obj['inReplyTo'])) {
+                            $apNote->setInReplyTo($obj['inReplyTo']);
+                        }
+
+                        // Handle attachments
+                        if (!empty($obj['attachment']) && is_array($obj['attachment'])) {
+                            foreach ($obj['attachment'] as $media) {
+                                if (!isset($media['type'], $media['url']))
+                                    continue;
+                                $mediaObj = new \Federator\Data\ActivityPub\Common\APObject($media['type']);
+                                $mediaObj->setURL($media['url']);
+                                $apNote->addAttachment($mediaObj);
+                            }
+                        }
+
+                        if (array_key_exists('tag', $obj)) {
+                            foreach ($obj['tag'] as $tag) {
+                                $tagName = is_array($tag) && isset($tag['name']) ? $tag['name'] : (string) $tag;
+                                $cleanName = preg_replace('/\s+/', '', ltrim($tagName, '#')); // Remove space and leading #
+                                $tagObj = new \Federator\Data\ActivityPub\Common\Tag();
+                                $tagObj->setName('#' . $cleanName)
+                                    ->setHref("https://$host/tags/" . urlencode($cleanName))
+                                    ->setType('Hashtag');
+                                $apNote->addTag($tagObj);
+                            }
+                        }
+                        if (array_key_exists('cc', $obj)) {
+                            foreach ($obj['cc'] as $cc) {
+                                $apNote->addCC($cc);
+                            }
+                        }
+
+                        $create->setObject($apNote);
+                        break;
+                    default:
+                        error_log("Outbox::post we currently don't support the obj type " . $obj['type'] . "\n");
+                        break;
+                }
+
+                $outboxActivity = $create;
+
+                break;
+            case 'Announce':
+                if (!isset($activity['object'])) {
+                    break;
+                }
+
+                $objectURL = is_array($activity['object']) ? $activity['object']['id'] : $activity['object'];
+
+                // Fetch the original object (e.g. Note)
+                [$response, $info] = \Federator\Main::getFromRemote($objectURL, ['Accept: application/activity+json']);
+                if ($info['http_code'] != 200) {
+                    print_r($info);
+                    error_log("Outbox::post Failed to fetch original object for Announce: $objectURL\n");
+                    break;
+                }
+                $objData = json_decode($response, true);
+                if ($objData === false || $objData === null || !is_array($objData)) {
+                    break;
+                }
+
+                $announce = new \Federator\Data\ActivityPub\Common\Announce();
+                $announce->setID($activity['id'])
+                    ->setURL($activity['id'])
+                    ->setPublished(strtotime($activity['published'] ?? 'now'))
+                    ->setAActor($activity['actor']);
+
+                if (array_key_exists('cc', $activity)) {
+                    foreach ($activity['cc'] as $cc) {
+                        $announce->addCC($cc);
+                    }
+                }
+                if (array_key_exists('to', $activity)) {
+                    foreach ($activity['to'] as $to) {
+                        $announce->addTo($to);
+                    }
+                }
+
+                // Parse the shared object as a Note or something else
+                switch ($objData['type']) {
+                    case 'Note':
+                        $note = new \Federator\Data\ActivityPub\Common\Note();
+                        $note->setID($objData['id'])
+                            ->setSummary($objData['summary'])
+                            ->setContent($objData['content'] ?? '')
+                            ->setPublished(strtotime($objData['published'] ?? 'now'))
+                            ->setURL($objData['url'] ?? $objData['id'])
+                            ->setAttributedTo($objData['attributedTo'] ?? null)
+                            ->addTo("https://www.w3.org/ns/activitystreams#Public");
+
+                        if (array_key_exists('cc', $objData)) {
+                            foreach ($objData['cc'] as $cc) {
+                                $note->addCC($cc);
+                            }
+                        }
+                        $announce->setObject($note);
+                        break;
+                    default:
+                        // fallback object
+                        $fallback = new \Federator\Data\ActivityPub\Common\APObject($objData['type']);
+                        $fallback->setID($objData['id'] ?? $objectURL);
+                        $announce->setObject($fallback);
+                        break;
+                }
+
+                $outboxActivity = $announce;
+                break;
+            case 'Undo':
+                if (!isset($activity['object'])) {
+                    break;
+                }
+
+                $undo = new \Federator\Data\ActivityPub\Common\Undo();
+                $undo->setID($activity['id'] ?? "test")
+                    ->setURL($activity['url'] ?? $activity['id'])
+                    ->setActor($activity['actor'] ?? null);
+
+                if (array_key_exists('cc', $activity)) {
+                    foreach ($activity['cc'] as $cc) {
+                        $undo->addCC($cc);
+                    }
+                }
+                if (array_key_exists('to', $activity)) {
+                    foreach ($activity['to'] as $to) {
+                        $undo->addTo($to);
+                    }
+                }
+
+                // what was undone
+                $undone = $activity['object'];
+                if (is_array($undone) && isset($undone['type'])) {
+                    switch ($undone['type']) {
+                        case 'Announce':
+                            $announce = new \Federator\Data\ActivityPub\Common\Announce();
+                            $announce->setID($undone['id'] ?? null)
+                                ->setAActor($undone['actor'] ?? null)
+                                ->setURL($undone['url'] ?? $undone['id'])
+                                ->setPublished(strtotime($undone['published'] ?? 'now'));
+
+                            if (array_key_exists('cc', $undone)) {
+                                foreach ($undone['cc'] as $cc) {
+                                    $announce->addCC($cc);
+                                }
+                            }
+                            $undo->setObject($announce);
+                            break;
+                        case 'Follow':
+                            // Implement if needed
+                            break;
+                        default:
+                            // Fallback for unknown types
+                            $apObject = new \Federator\Data\ActivityPub\Common\APObject($undone['type']);
+                            $apObject->setID($undone['id'] ?? null);
+                            $undo->setObject($apObject);
+                            break;
+                    }
+                }
+
+                $outboxActivity = $undo;
+                break;
+            default:
+                error_log("Outbox::post we currently don't support the activity type " . $activity['type'] . "\n");
+                break;
+        }
+
+        $sendTo = $outboxActivity->getCC();
+        if ($outboxActivity->getType() === 'Undo') {
+            $sendTo = $outboxActivity->getObject()->getCC();
+        }
+
+        $users = [];
+
+        foreach ($sendTo as $receiver) {
+            if (!$receiver || !is_string($receiver)) {
+                continue;
+            }
+
+            if (str_ends_with($receiver, '/followers')) {
+                $users = array_merge($users, $this->fetchAllFollowers($receiver, $host));
+            }
+        }
+        if ($_user !== false && !in_array($_user, $users)) {
+            $users[] = $_user;
+        }
+        foreach ($users as $user) {
+            if (!$user)
+                continue;
+
+            $this->postForUser($user, $outboxActivity);
+        }
+        return json_encode($outboxActivity, JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT);
+    }
+
+    /**
+     * handle post call for specific user
+     *
+     * @param string $_user user to add data to outbox
+     * @param \Federator\Data\ActivityPub\Common\Activity $outboxActivity the activity that we received
+     * @return string|false response
+     */
+    private function postForUser($_user, $outboxActivity)
+    {
+        if ($_user) {
+            $dbh = $this->main->getDatabase();
+            $cache = $this->main->getCache();
+            $connector = $this->main->getConnector();
+
+            // get user
+            $user = \Federator\DIO\User::getUserByName(
+                $dbh,
+                $_user,
+                $connector,
+                $cache
+            );
+            if ($user->id === null) {
+                error_log("Outbox::postForUser couldn't find user: $_user");
+                return false;
+            }
+        }
+
+        $rootDir = $_SERVER['DOCUMENT_ROOT'] . '../';
+        // Save the raw input and parsed JSON to a file for inspection
+        file_put_contents(
+            $rootDir . 'logs/outbox_' . $_user . '.log',
+            date('Y-m-d H:i:s') . ": ==== POST " . $_user . " Outbox Activity ====\n" . json_encode($outboxActivity, JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT) . "\n\n",
+            FILE_APPEND
+        );
+
+        return true;
+    }
+
+    /**
+     * fetch all followers from url and return the ones that belong to our server
+     *
+     * @param string $collectionUrl The url of f.e. the posters followers
+     * @param string $host our current host-url
+     * @return array|false the names of the followers that are hosted on our server
+     */
+    private function fetchAllFollowers(string $collectionUrl, string $host): array
+    {
+        $users = [];
+
+        [$collectionResponse, $collectionInfo] = \Federator\Main::getFromRemote($collectionUrl, ['Accept: application/activity+json']);
+        if ($collectionInfo['http_code'] !== 200) {
+            error_log("Outbox::fetchAllFollowers Failed to fetch follower collection metadata from $collectionUrl");
+            return [];
+        }
+
+        $collectionData = json_decode($collectionResponse, true);
+        $nextPage = $collectionData['first'] ?? $collectionData['current'] ?? null;
+
+        if (!$nextPage) {
+            error_log("Outbox::fetchAllFollowers No 'first' or 'current' page in collection at $collectionUrl");
+            return [];
+        }
+
+        // Loop through all pages
+        while ($nextPage) {
+            [$pageResponse, $pageInfo] = \Federator\Main::getFromRemote($nextPage, ['Accept: application/activity+json']);
+            if ($pageInfo['http_code'] !== 200) {
+                error_log("Outbox::fetchAllFollowers Failed to fetch follower page at $nextPage");
+                break;
+            }
+
+            $pageData = json_decode($pageResponse, true);
+            $items = $pageData['orderedItems'] ?? $pageData['items'] ?? [];
+
+            foreach ($items as $followerUrl) {
+                $parts = parse_url($followerUrl);
+                if (!isset($parts['host']) || !str_ends_with($parts['host'], $host)) {
+                    continue;
+                }
+
+                [$actorResponse, $actorInfo] = \Federator\Main::getFromRemote($followerUrl, ['Accept: application/activity+json']);
+                if ($actorInfo['http_code'] !== 200) {
+                    error_log("Outbox::fetchAllFollowers Failed to fetch actor data for follower: $followerUrl");
+                    continue;
+                }
+
+                $actorData = json_decode($actorResponse, true);
+                if (isset($actorData['preferredUsername'])) {
+                    $users[] = $actorData['preferredUsername'];
+                }
+            }
+
+            $nextPage = $pageData['next'] ?? null;
+        }
+
+        return $users;
     }
 }