Update README.md

Update activitypub.extend.php

README.md

@@ -1,11 +1,14 @@
 # gnuboard5-activitypub
-ActivityPub implementation for GNUBOARD 5
+GNUBOARD5-ActivityPub: ActivityPub (Fediverse) implementation for GNUBOARD5
+
+* https://sir.kr/g5_plugin/10381
+* https://codeberg.org/fediverse/delightful-activitypub-development
 
 ## 사용 전 설정
   * `apstreams` 게시판 추가
   * `apstreams` 사용자 추가
 
-## 작업진행
+## 지원현황
 - [x] WebFinger
 - [x] User
 - [x] Inbox
@@ -13,22 +16,24 @@ ActivityPub implementation for GNUBOARD 5
 - [x] Followers
 - [x] Following
 - [x] Liked
-- [x] Shares
+- [ ] ~~Shares~~ (Altered to inbound/outbound)
-- [x] Geolocation (IP2Location, Naver Cloud)
+- [x] Geolocation
 - [x] File attachment
-- [ ] File attachment -> Auto sharing (Download/Upload)
+- [ ] File attachment - Automatically download a remote file to the local server
+- [x] Digest/Signature - Outbound
+- [ ] ~~Digest/Signature - Inbound~~ (No required)
+- [x] w3id.org (e.g. the `publicKey` field of an actor)
+- [ ] OAuth 2.0
+- [ ] Message Queue Compatible (e.g. Redis, RebbitMQ, Kafka)
 
 ## 부가기능 (옵션)
 - [x] 아바타 (gravatar.com)
 - [x] 날씨 (openweathermap.org)
 - [x] 환율 (koreaexim.go.kr)
+- [x] 국내 Geolocation (Naver Cloud)
+- [x] 국외 Geolocation (IP2Location)
 
-## 향후 지원 예정
+## 전문(메시지) 예시
-- [ ] OAuth 2.0
-- [ ] w3id.org (`publicKey` 필드) 지원
-- [ ] 메시지 큐(Redis, RebbitMQ, Kafka 등) 지원
-
-## 전문 예시
 
 ```json
 {
@@ -116,6 +121,11 @@ ActivityPub implementation for GNUBOARD 5
 * https://socialhub.activitypub.rocks/t/posting-to-pleroma-inbox/1184
 * https://github.com/broidHQ/integrations/tree/master/broid-schemas#readme
 * https://github.com/autogestion/pubgate-telegram
+* https://docs.joinmastodon.org/spec/security/
+* https://chat.openai.com/share/4fda7974-cc0b-439a-b0f2-dc828f8acfef
+* https://codeberg.org/mro/activitypub/src/commit/4b1319d5363f4a836f23c784ef780b81bc674013/like.sh#L101
+* https://socialhub.activitypub.rocks/t/problems-posting-to-mastodon-inbox/801/10
 
 ## 문의
 * abuse@catswords.net
+* ActivityPub [@gnh1201@catswords.social](https://catswords.social/@gnh1201)

extend/activitypub.extend.php

@@ -1,11 +1,12 @@
 <?php
 if (!defined('_GNUBOARD_')) exit; // 개별 페이지 접근 불가
 
-// ActivityPub implementation for GNUBOARD 5
+// Description: ActivityPub implementation for GNUBOARD 5
-// Go Namhyeon <abuse@catswords.net>
+// Author: Go Namhyeon (Catswords Research) <abuse@catswords.net>
-// MIT License
+// ActivityPub: @gnh1201@catswords.social
-// 2023-02-16 (version 0.1.14)
+// License: MIT
-
+// Date: 2023-08-08
+// Version: 0.1.18
 // References:
 //   * https://www.w3.org/TR/activitypub/
 //   * https://www.w3.org/TR/activitystreams-core/
@@ -17,17 +18,24 @@ if (!defined('_GNUBOARD_')) exit; // 개별 페이지 접근 불가
 //   * https://github.com/broidHQ/integrations/tree/master/broid-schemas#readme
 //   * https://github.com/autogestion/pubgate-telegram
 //   * https://blog.joinmastodon.org/2018/06/how-to-implement-a-basic-activitypub-server/
+//   * https://chat.openai.com/share/4fda7974-cc0b-439a-b0f2-dc828f8acfef
+//   * https://codeberg.org/mro/activitypub/src/commit/4b1319d5363f4a836f23c784ef780b81bc674013/like.sh#L101
+//   * https://socialhub.activitypub.rocks/t/problems-posting-to-mastodon-inbox/801/10
 
 define("ACTIVITYPUB_INSTANCE_ID", md5_file(G5_DATA_PATH . "/dbconfig.php"));
-define("ACTIVITYPUB_INSTANCE_VERSION", "0.1.14-dev");
+define("ACTIVITYPUB_INSTANCE_VERSION", "0.1.18");
+define("ACTIVITYPUB_DEFAULT_SCHEME", "https");    // 외부 통신용 스킴 (SSL 사용이 기본)
+define("ACTIVITYPUB_INSECURE_SCHEME", "http");    // 그누보드5 ActivityPub 통신용 스킴 (SSL 사용을 하지 않을 수도 있음을 고려)
 define("ACTIVITYPUB_HOST", (empty(G5_DOMAIN) ? $_SERVER['HTTP_HOST'] : G5_DOMAIN));
-define("ACTIVITYPUB_URL", (empty(G5_URL) ? "http://" . ACTIVITYPUB_INSTANCE_ID . ".local" : G5_URL));
+define("ACTIVITYPUB_URL", (empty(G5_URL) ? ACTIVITYPUB_INSECURE_SCHEME . "://" . ACTIVITYPUB_INSTANCE_ID . ".local" : G5_URL));
 define("ACTIVITYPUB_DATA_URL", ACTIVITYPUB_URL . '/' . G5_DATA_DIR);
 define("ACTIVITYPUB_G5_BOARDNAME", "apstreams");
 define("ACTIVITYPUB_G5_TABLENAME", $g5['write_prefix'] . ACTIVITYPUB_G5_BOARDNAME);
 define("ACTIVITYPUB_G5_USERNAME", "apstreams");
-define("ACTIVITYPUB_G5_NEW_DAYS", (empty($config['cf_new_del']) ? 30 : $config['cf_new_del']));
+define("ACTIVITYPUB_G5_OUTDATED_DAYS", (empty($config['cf_new_del']) ? 30 : $config['cf_new_del']));
+define("ACTIVITYPUB_G5_EXPIRED_DAYS", (empty($config['cf_memo_del']) ? 180 : $config['cf_memo_del']));
 define("ACTIVITYPUB_ACCESS_TOKEN", "server1.example.org=YOUR_ACCESS_TOKEN; server2.example.org=YOUR_ACCESS_TOKEN;");
+define("ACTIVITYPUB_CERTIFICATE_RETRY", 10);    // 최대 인증서 생성 시도 횟수
 define("ACTIVITYPUB_CERTIFICATE_DATAFIELD", "mb_9");    // 회원별 인증서(공개키, 개인키)를 저장할 필드 (기본: mb_9)
 define("OAUTH2_GRANT_DATAFIELD", "mb_10");    // 회원별 인증 정보를 저장할 필드 (기본: mb_10)
 define("DEFAULT_HTML_ENTITY_FLAGS", ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401);
@@ -66,6 +74,17 @@ function activitypub_load_library($name, $callback) {
     ));
 }
 
+// ActivityPub 표준 문서에서는 단수형, 실제 어플리케이션에선 복수형으로 표현되는 것을 모두 대응함
+function activitypub_cast_to_array($s) {
+    $d = array();
+    if (is_array($s)) {
+        $d = $s;
+    } else if (isset($s)) {
+        $d[] = $s;
+    }
+    return $d;
+}
+
 function activitypub_create_keypair() {
     $keypair = array('', '');
 
@@ -95,37 +114,44 @@ function activitypub_get_stored_keypair($mb) {
 
     $private_key = '';
     $public_key = '';
-    
-    // 인증서 정보 불러오기
-    if ($mb != null && !empty($mb['mb_id'])) {
-        $certificate_data = activitypub_parse_stored_data($mb[ACTIVITYPUB_CERTIFICATE_DATAFIELD]);  
-        $private_key = activitypub_get_memo($certificate_data['PrivateKeyId']);    // 개인키(Private Key)
-        $public_key = activitypub_get_memo($certificate_data['PublicKeyId']);     // 공개키(Public Key)
-    }
 
-    // 인증서 정보가 없으면 생성
+    // 인증서 생성
-    if (!$mb[ACTIVITYPUB_CERTIFICATE_DATAFIELD] || empty($private_key) || empty($public_key)) {
+    $k = 0;
-        $keypair = activitypub_create_keypair();   // 인증서(공개키, 개인키) 생성
+    while ($k < ACTIVITYPUB_CERTIFICATE_RETRY && (empty($private_key) || empty($public_key))) {
-        $private_key_id = activitypub_add_memo(ACTIVITYPUB_G5_USERNAME, $mb['mb_id'], $keypair[0]);   // 개인키(Private Key)
+        // 인증서 정보 불러오기
-        $public_key_id = activitypub_add_memo(ACTIVITYPUB_G5_USERNAME, $mb['mb_id'], $keypair[1]);    // 공개키(Public Key)
+        if ($mb != null && !empty($mb['mb_id'])) {
-
+            $certificate_data = activitypub_parse_stored_data($mb[ACTIVITYPUB_CERTIFICATE_DATAFIELD]);  
-        // 회원 정보에 등록
+            $private_key = activitypub_get_memo($certificate_data['PrivateKeyId']);    // 개인키(Private Key)
-        if ($private_key_id > 0 && $public_key_id > 0) {
+            $public_key = activitypub_get_memo($certificate_data['PublicKeyId']);     // 공개키(Public Key)
-            $stored_certificate_data = activitypub_build_stored_data(array(
-                "PrivateKeyId" => $private_key_id,
-                "PublicKeyId" => $public_key_id
-            ));
-            $sql = " update {$g5['member_table']} set " . ACTIVITYPUB_CERTIFICATE_DATAFIELD . " = '{$stored_certificate_data}' where mb_id = '{$mb['mb_id']}' ";
-            sql_query($sql);
         }
 
-        // 인증서 정보 불러오기
+        // 인증서 정보가 없으면 생성
-        $certificate_data = activitypub_parse_stored_data($mb[ACTIVITYPUB_CERTIFICATE_DATAFIELD]);  
+        if (!$mb[ACTIVITYPUB_CERTIFICATE_DATAFIELD] || empty($private_key) || empty($public_key)) {
-        $private_key = activitypub_get_memo($certificate_data['PrivateKeyId']);    // 개인키(Private Key)
+            $keypair = activitypub_create_keypair();   // 인증서(공개키, 개인키) 생성
-        $public_key = activitypub_get_memo($certificate_data['PublicKeyId']);     // 공개키(Public Key)
+            $private_key_id = activitypub_add_memo(ACTIVITYPUB_G5_USERNAME, $mb['mb_id'], $keypair[0]);   // 개인키(Private Key)
+            $public_key_id = activitypub_add_memo(ACTIVITYPUB_G5_USERNAME, $mb['mb_id'], $keypair[1]);    // 공개키(Public Key)
 
-        // 회원에게 알림
+            // 회원 정보에 등록
-        activitypub_add_memo(ACTIVITYPUB_G5_USERNAME, $mb['mb_id'], "외부 서버와 통신하기 위한 인증서가 발급되었습니다. 발급된 인증서는 두가지(개인키, 공개키)입니다. 인증서를 삭제하거나 타인과 공유하지 마세요. A certificate has been issued to communicate with an external server. There are two certificates issued (private key, public key). Do not delete the certificate or share it with others.");
+            if ($private_key_id > 0 && $public_key_id > 0) {
+                $stored_certificate_data = activitypub_build_stored_data(array(
+                    "PrivateKeyId" => $private_key_id,
+                    "PublicKeyId" => $public_key_id
+                ));
+                $sql = " update {$g5['member_table']} set " . ACTIVITYPUB_CERTIFICATE_DATAFIELD . " = '{$stored_certificate_data}' where mb_id = '{$mb['mb_id']}' ";
+                sql_query($sql);
+            }
+
+            // 회원에게 알림
+            $messsge1 = "[시스템] 외부 서버와 통신하기 위한 인증서(개인키, 공개키)가 발급되었습니다. 인증서를 타인과 공유하지 마세요. 인증서는 " . ACTIVITYPUB_G5_EXPIRED_DAYS . "일 후 만료됩니다.";
+            $message2 = "[System] The certificate (Private key, Public key) has been issued to communicate with an external server. Do not share it with others. The certificate will expire in " . ACTIVITYPUB_G5_EXPIRED_DAYS . " days.";
+            activitypub_add_memo(ACTIVITYPUB_G5_USERNAME, $mb['mb_id'], $messsge1 . ' ' . $message2);
+
+            // 회원정보 다시 불러오기
+            $mb = get_member($mb['mb_id']);
+
+            // 시도 횟수 증가
+            $k++;
+        }
     }
 
     return array($private_key, $public_key);
@@ -150,8 +176,8 @@ function activitypub_json_encode($arr) {
     return json_encode($arr);
 }
 
-function activitypub_json_decode($arr) {
+function activitypub_json_decode($str) {
-    return json_decode($arr, true);
+    return json_decode($str, true);
 }
 
 function activitypub_parse_stored_data($s) {
@@ -204,7 +230,13 @@ function activitypub_get_icon($mb) {
         $icon_file_url = "https://www.gravatar.com/avatar/" . md5($mb['mb_email']);
     }
 
-    return $icon_file_url;
+    $icon_ctx = array(
+        "type" => "Image",
+        "mediaType" => "image/png",
+        "url" => $icon_file_url
+    );
+
+    return $icon_ctx;
 }
 
 function activitypub_get_user_interactions() {
@@ -318,14 +350,69 @@ function activitypub_build_http_headers($headers) {
     return $lines;
 }
 
+function activitypub_build_datetime($s='now') {
+    // e.g. 18 Dec 2019 10:08:46 GMT
+    $format = "D, d M Y H:i:s e";
+    $dt = ($s == "now" ? new DateTime('now', new DateTimeZone("GMT")) : DateTime::createFromFormat($format, $s));
+    return $dt->format($format);
+}
+
+function activitypub_build_digest($body) {
+    $digest = hash('sha256', $body, true);
+    $digest = base64_encode($digest);
+    $digest = 'sha-256=' . $digest;
+    return $digest;
+}
+
+function activitypub_build_signature($url, $date, $digest, $mb, $method="post") {
+    // get a certificate
+    list($private_key, $public_key) = activitypub_get_stored_keypair($mb);
+    
+    // get host and path from URL
+    list($host, $path) = array(parse_url($url, PHP_URL_HOST), parse_url($url, PHP_URL_PATH));
+
+    // build a key id
+    $activitypub_user_id = activitypub_get_url("user", array("mb_id" => $mb['mb_id']));
+    $keyId = $activitypub_user_id . "#main-key";
+
+    // build a target data to get signature
+    /*
+    $signature = $method . ' ' . $path . "\n" .
+        'HOST: ' . $host . "\n" .
+        'Date: ' . $date . "\n" .
+        'Digest: ' . $digest;
+    */
+    // Ref: https://codeberg.org/mro/activitypub/src/commit/4b1319d5363f4a836f23c784ef780b81bc674013/like.sh#L101
+    $signature = sprintf(
+        "%s: %s\n%s: %s\n%s: %s\n%s: %s",
+        "(request-target)",
+        "{$method} {$path}",
+        "host", $host,
+        "date", $date,
+        "digest", $digest
+    );
+
+    // create a signature
+    openssl_sign($signature, $signature, $private_key, OPENSSL_ALGO_SHA256);
+    $signature = base64_encode($signature);
+
+    // create a signature header
+    return 'keyId="' . $keyId . '",headers="(request-target) host date digest",signature="' . $signature . '"';
+}
+
 function activitypub_http_get($url, $access_token = '') {
-    // make HTTP header
+    // build the header
-    $headers = array("Accept" => "application/ld+json; profile=\"" . NAMESPACE_ACTIVITYSTREAMS . "\"");
+    $headers = array(
+        "Date" => activitypub_build_datetime('now'),
+        "Accept" => "application/activity+json; profile=\"" . NAMESPACE_ACTIVITYSTREAMS . "\""
+    );
+
+    // set access token
     if (!empty($access_token)) {
         $headers["Authorization"] = "Bearer " . $access_token;
     }
 
-    // do HTTP request
+    // request
     $ch = curl_init();
     curl_setopt_array($ch, array(
         CURLOPT_URL => $url,
@@ -358,17 +445,28 @@ function activitypub_get_attachments($bo_table, $wr_id) {
     return $attachments;
 }
 
-function activitypub_http_post($url, $raw_data, $access_token = '', $mb = null) {
+function activitypub_http_post($url, $rawdata, $mb, $access_token = '') {
-    // make HTTP header
+    // get digest
-    $headers = array("Accept" => "application/ld+json; profile=\"" . NAMESPACE_ACTIVITYSTREAMS . "\"");
+    $date = activitypub_build_datetime('now');
+    $digest = activitypub_build_digest($rawdata);
+
+    // build the headers
+    $headers = array(
+        "Date" => $date,
+        "Digest" => $digest,
+        "Content-Type" => "application/activity+json; profile=\"" . NAMESPACE_ACTIVITYSTREAMS . "\"",
+    );
+
+    // build the signature
+    $signature = activitypub_build_signature($url, $date, $digest, $mb);
+    $headers["Signature"] = $signature;
+
+    // set access token
     if (!empty($access_token)) {
         $headers["Authorization"] = "Bearer " . $access_token;
     }
-    list($private_key, $public_key) = activitypub_get_stored_keypair($mb);
 
-    // TODO: make Signature header
+    // request
-
-    // do HTTP request
     $ch = curl_init();
     curl_setopt_array($ch, array(
         CURLOPT_URL => $url,
@@ -376,12 +474,18 @@ function activitypub_http_post($url, $raw_data, $access_token = '', $mb = null)
         CURLOPT_SSL_VERIFYPEER => false,
         CURLOPT_CONNECTTIMEOUT => 10,
         CURLOPT_RETURNTRANSFER => true,
-        CURLOPT_POSTFIELDS => $raw_data,
+        CURLOPT_POSTFIELDS => $rawdata,
         CURLOPT_POST => true
     ));
     $response = curl_exec($ch);
+    $errno = curl_errno($ch);
     curl_close($ch);
 
+    // 전송 오류가 있었을 시 쪽지로 알림
+    if ($errno) {
+        activitypub_add_memo(ACTIVITYPUB_G5_USERNAME, $mb['mb_id'], "[경고] 메시지 전송 중 오류가 발생함. 오류 번호: " . $errno);
+    }
+
     return activitypub_json_decode($response, true);
 }
 
@@ -477,6 +581,9 @@ function koreaexim_get_exchange_data() {
 }
 
 function activitypub_publish_content($content, $object_id, $mb, $_added_object = array(), $_added_to = array()) {
+    // 액티비티 관리용 계정의 글 전송 차단
+    if ($mb['mb_id'] == ACTIVITYPUB_G5_USERNAME) return;
+
     // 위치정보를 사용하는 경우 모듈 로드
     $location_ctx = array();
     if (ACTIVITYPUB_ENABLED_GEOLOCATION) {
@@ -564,7 +671,10 @@ function activitypub_publish_content($content, $object_id, $mb, $_added_object =
     $terms = activitypub_parse_content($content);
 
     // 수신자/내용 생성
-    $to = array_merge(array(NAMESPACE_ACTIVITYSTREAMS_PUBLIC), $_added_to);
+    $to = array_merge(activitypub_cast_to_array(NAMESPACE_ACTIVITYSTREAMS_PUBLIC), $_added_to);
+    $cc = array();  // 참조자
+    $tag = array();  // 태그
+    $endpoints = array();
     $content = "";
     foreach($terms as $term_ctx) {
         switch ($term_ctx['type']) {
@@ -573,23 +683,45 @@ function activitypub_publish_content($content, $object_id, $mb, $_added_object =
                 $account = substr($term_ctx['value'], 1);
                 $account_terms = explode('@', $account);
                 $account_ctx = array("username" => $account_terms[0], "host" => $account_terms[1]);
+                $webfigner_ctx = array("subject" => "");
                 if (!empty($account_ctx['host'])) {
-                    // 공통 WebFinger에 연결
+                    $counter = 2;    // WebFinger에 연결하는 경우의 수 정의 (=N-1)
-                    $webfigner_ctx = activitypub_http_get("http://" . $account_ctx['host'] . "/.well-known/webfinger?resource=acct:" . $account);
+                    while ($counter > -1 && $webfigner_ctx['subject'] != ("acct:" . $account)) {
+                        switch($counter) {
+                            case 0:    // 공통 WebFinger에 연결
+                                $webfigner_ctx = activitypub_http_get(ACTIVITYPUB_DEFAULT_SCHEME . "://" . $account_ctx['host'] . "/.well-known/webfinger?resource=acct:" . $account);
+                                break;
+                            case 1:    // 실패시, 그누보드5용 WebFinger에 연결
+                                $webfigner_ctx = activitypub_http_get(ACTIVITYPUB_DEFAULT_SCHEME . "://" . $account_ctx['host'] . "/?route=webfinger&resource=acct:" . $account);
+                                break;
+                            case 2:    // 실패시, 그누보드5용 WebFinger에 연결 + 보안통신 해제
+                                $webfigner_ctx = activitypub_http_get(ACTIVITYPUB_INSECURE_SCHEME . "://" . $account_ctx['host'] . "/?route=webfinger&resource=acct:" . $account);
+                                break;
+                            default:
+                                $counter = -1;
+                        }
 
-                    // 실패시, 그누5 전용 WebFinger에 연결
+                        $counter--;   // 시도 횟수 차감
-                    if ($webfigner_ctx['subject'] != ("acct:" . $account)) {
-                        $webfigner_ctx = activitypub_http_get("http://" . $account_ctx['host'] . "/?route=webfinger&resource=acct:" . $account);
                     }
 
-                    // 한번 더 확인
+                    // WebFinger 정보 수신을 못한 경우, 쪽지로 알리고 아무 작업도 하지 않음
-                    if ($webfigner_ctx['subject'] != ("acct:" . $account)) break;
+                    if (empty($webfigner_ctx['subject'])) {
+                        activitypub_add_memo(ACTIVITYPUB_G5_USERNAME, $mb['mb_id'], "[발송실패] 수신자를 찾을 수 없음: @" . $account);
+                        break;
+                    }
 
                     // 받은 요청으로 처리
                     $webfigner_links = $webfigner_ctx['links'];
                     foreach($webfigner_links as $link) {
                         if ($link['rel'] == "self" && $link['type'] == "application/activity+json") {
-                            array_push($to, $link['href']);  // 수신자에 반영
+                            // 태그 목록에 추가
+                            array_push($tag, array(
+                                "type" => "Mention",
+                                "href" => $link['href'],
+                                "name" => '@' . $account
+                            ));
+                            array_push($cc, $link['href']);  // 참조자 목록에 추가
+                            array_push($endpoints, $link['href']);  // 글을 전송할 엔드포인트(URL)에 반영
                         }
                     }
                 }
@@ -603,48 +735,57 @@ function activitypub_publish_content($content, $object_id, $mb, $_added_object =
 
     // 위치정보가 활성화되어 있으면
     if (ACTIVITYPUB_ENABLED_GEOLOCATION) {
-        $object = array_merge($_added_object, array(
+        $_added_object = array_merge($_added_object, array(
             "location" => $location_ctx
         ));
     }
 
+    // 태그 추가
+    $_added_object = array_merge($_added_object, array(
+        "tag" => $tag
+    ));
+
     // 전문 생성
     $object = activitypub_build_note($content, $object_id, $mb, $_added_object);
 
     // 외부로 보낼 전문 생성
     $data = array(
-        "@context" => NAMESPACE_ACTIVITYSTREAMS,
+        "@context" => activitypub_cast_to_array(NAMESPACE_ACTIVITYSTREAMS),
         "type" => "Create",
         "id" => G5_BBS_URL . "/board.php?bo_table=" . ACTIVITYPUB_G5_BOARDNAME . "#Draft",
         "to" => $to,
+        "cc" => $cc,
         "actor" => $object['attributedTo'],
         "object" => $object
     );
 
     // 초안(Draft) 작성
-    $activity_wr_id = activitypub_update_activity("outbox", $data, $mb, "draft");
+    $activity_id = activitypub_update_activity("outbox", $data, $mb, "draft");
-    $data['id'] = G5_BBS_URL . "/board.php?bo_table=" . ACTIVITYPUB_G5_BOARDNAME . "&wr_id=" . $activity_wr_id;
+    $data['object']['id'] = G5_BBS_URL . "/board.php?bo_table=" . ACTIVITYPUB_G5_BOARDNAME . "&wr_id=" . $activity_id;
+    $data['id'] = activitypub_get_url("activity", array("id" => $activity_id));
+
+    // 현재 시간 반영
+    $now_utc_tz = str_replace('+00:00', 'Z', gmdate('c'));
+    $data['published'] = $now_utc_tz;
+    $data['updated'] = $now_utc_tz;
 
     // 보낼 전문을 인코딩
     $rawdata = activitypub_json_encode($data);
 
-    // 수신자 작업
+    // 수신자 엔드포인트(URL) 작업
-    foreach($to as $_to) {
+    foreach($endpoints as $endpoint) {
-        // 공개 네임스페이스인 경우 건너뛰기
-        if ($_to == NAMESPACE_ACTIVITYSTREAMS_PUBLIC) continue;
-
         // 수신자 정보 조회
-        $remote_user_ctx = activitypub_http_get($_to);
+        $remote_account_ctx = activitypub_http_get($endpoint);
 
         // inbox 주소 찾기
-        $remote_inbox_url = $remote_user_ctx['inbox'];
+        $remote_inbox_url = $remote_account_ctx['inbox'];
         if (empty($remote_inbox_url)) {
-            $remote_inbox_url = $remote_user_ctx['endpoints']['sharedInbox'];
+            $remote_inbox_url = $remote_account_ctx['endpoints']['sharedInbox'];
         }
 
         // inbox 주소가 없으면 건너뛰기
         if (empty($remote_inbox_url)) {
-            activitypub_add_memo(ACTIVITYPUB_G5_USERNAME, $mb['mb_id'], "Could not find the inbox of " . $_to);
+            activitypub_add_memo(ACTIVITYPUB_G5_USERNAME, $mb['mb_id'], "이 사용자 또는 서버는 메시지를 수신할 수 없는 상태임: " . $_to);
             continue;
         }
 
@@ -659,7 +800,7 @@ function activitypub_publish_content($content, $object_id, $mb, $_added_object =
         }
 
         // inbox로 데이터 전송
-        $response = activitypub_http_post($remote_inbox_url, $rawdata, $access_token);
+        activitypub_http_post($remote_inbox_url, $rawdata, $mb, $access_token);
     }
 
     // 발행됨(Published)으로 상태 업데이트
@@ -674,12 +815,13 @@ function activitypub_parse_content($content) {
     $pos = -1;
     $get_next_position = function ($pos) use ($content) {
         try {
-            return min(array_filter(array(
+            $positions = array_filter(array(
                 strpos($content, '@', $pos + 1),
                 strpos($content, '#', $pos + 1),
                 strpos($content, 'http://', $pos + 1),
                 strpos($content, 'https://', $pos + 1)
-            ), "is_numeric"));
+            ), "is_numeric");
+            return (count($positions) > 0 ? min($positions) : false);
         } catch (ValueError $e) {
             return false;
         }
@@ -736,9 +878,9 @@ function activitypub_update_activity($inbox = "inbox", $data, $mb = array("mb_id
         $wr_num = get_next_num($write_table);
         $wr_reply = '';
         $ca_name = $inbox;    // Inbox/Outbox
-        $wr_subject = mb_substr($content, 0, 50);
+        $wr_subject = mb_substr(strip_tags($content), 0, 50);
-        $wr_seo_title = $content;
+        $wr_seo_title = strip_tags($content);
-        $wr_content = $content . "\r\n\r\n[외부에서 전송된 글입니다.]";
+        $wr_content = strip_tags($content) . "\r\n\r\n[외부에서 전송된 글입니다.]";
         $wr_link1 = $data['actor'];
         $wr_link2 = '';
         $wr_homepage = $data['actor'];
@@ -809,8 +951,8 @@ function activitypub_update_activity($inbox = "inbox", $data, $mb = array("mb_id
     if ($status == "published") {
         // 저장 전 데이터 처리
         $now_utc_tz = str_replace('+00:00', 'Z', gmdate('c'));
-        $data['published'] = $now_utc_tz;
+        $data['published'] = empty($data['published']) ? $now_utc_tz : $data['published'];
-        $data['updated'] = $now_utc_tz;
+        $data['updated'] = empty($data['updated']) ? $now_utc_tz : $data['updated'];
 
         // 요청 전문은 파일로 저장
         $raw_context = activitypub_json_encode($data);
@@ -852,50 +994,37 @@ function activitypub_update_activity($inbox = "inbox", $data, $mb = array("mb_id
     return $wr_id;
 }
 
-function activitypub_get_objects($inbox = "inbox", $mb_id = '') {
+function activitypub_get_activity_by_id($activity_id) {
     global $g5;
 
-    $items = array();
+    // 액티비티 전문
+    $activity_ctx = array();
 
-    // 정보 불러오기
+    // 해당 액티비티 찾고 없으면 빈 정보 반환
-    $sql = "";
+    $write_table = $g5['write_prefix'] . ACTIVITYPUB_G5_BOARDNAME;
-    if(empty($mb_id)) {
+    $wr = get_write($write_table, $activity_id);
-        $sql = "select wr_id from " . ACTIVITYPUB_G5_TABLENAME . "
+    if (empty($wr['wr_id'])) return $activity_ctx;
-            where ca_name = '$inbox'
+
-                and DATE(wr_datetime) BETWEEN CURDATE() - INTERVAL " . ACTIVITYPUB_G5_NEW_DAYS . " DAY AND CURDATE()
+    // 액티비티 조회
-        ";
+    $sql = "select * from {$g5['board_file_table']}
-    } else {
+        where bo_table = '" . ACTIVITYPUB_G5_BOARDNAME . "' and wr_id = '{$wr['wr_id']}' and bf_content = 'application/activity+json'";
-        $sql = "select wr_id from " . ACTIVITYPUB_G5_TABLENAME . "
-            where ca_name = '$inbox'
-                and FIND_IN_SET('$mb_id', wr_7) > 0
-                and DATE(wr_datetime) BETWEEN CURDATE() - INTERVAL " . ACTIVITYPUB_G5_NEW_DAYS . " DAY AND CURDATE()
-        ";
-    }
     $result = sql_query($sql);
-
-    // 정보 조회 후 처리
     while ($row = sql_fetch_array($result)) {
-        $sql2 = "select * from {$g5['board_file_table']}
+        $filename = $row['bf_file'];
-            where bo_table = '" . ACTIVITYPUB_G5_BOARDNAME . "' and wr_id = '{$row['wr_id']}' and bf_content = 'application/activity+json'";
+        $filepath = G5_DATA_PATH . "/file/" . ACTIVITYPUB_G5_BOARDNAME . "/" . $filename;
-        $result2 = sql_query($sql2);
+        if (file_exists($filepath)) {
-        while ($row2 = sql_fetch_array($result2)) {
+            $activity_ctx = activitypub_json_decode(@file_get_contents($filepath))['object'];
-            $filename = $row2['bf_file'];
-            $filepath = G5_DATA_PATH . "/file/" . ACTIVITYPUB_G5_BOARDNAME . "/" . $filename;
-            if(file_exists($filepath)) {
-                array_push($items, activitypub_json_decode(file_get_contents($filepath))['object']);
-            }
         }
     }
 
-    // 전문 만들기
+    return $activity_ctx;
-    return activitypub_build_collection($items);
 }
 
 // Object type: Note
 function activitypub_build_note($content, $object_id, $mb, $_added_object = array()) {
     return array_merge(array(
         "type" => "Note",
-        "generator" => "GNUBOARD5-ActivityPub/" . ACTIVITYPUB_INSTANCE_VERSION . " (" . ACTIVITYPUB_INSTANCE_ID . ")",
+        "generator" => "G5.ActivityPub/" . ACTIVITYPUB_INSTANCE_VERSION . " (GNUBOARD " . G5_GNUBOARD_VER . "; " . ACTIVITYPUB_INSTANCE_ID . ")",
         "id" => $object_id,
         "attributedTo" => activitypub_get_url("user", array("mb_id" => $mb['mb_id'])),
         "content" => $content,
@@ -907,7 +1036,7 @@ function activitypub_build_note($content, $object_id, $mb, $_added_object = arra
 function activitypub_build_collection($items, $summary = '') {
     return array(
         "@context" => NAMESPACE_ACTIVITYSTREAMS,
-        "generator" => "GNUBOARD5-ActivityPub/" . ACTIVITYPUB_INSTANCE_VERSION . " (" . ACTIVITYPUB_INSTANCE_ID . ")",
+        "generator" => "G5.ActivityPub/" . ACTIVITYPUB_INSTANCE_VERSION . " (GNUBOARD " . G5_GNUBOARD_VER . "; " . ACTIVITYPUB_INSTANCE_ID . ")",
         "summary" => $summary,
         "type" => "Collection",
         "totalItems" => count($items),
@@ -918,7 +1047,7 @@ function activitypub_build_collection($items, $summary = '') {
 
 class _GNUBOARD_ActivityPub {
     public static function open() {
-        header("Content-Type: application/ld+json; profile=\"" . NAMESPACE_ACTIVITYSTREAMS . "\"");
+        header("Content-Type: application/activity+json; profile=\"" . NAMESPACE_ACTIVITYSTREAMS . "\"");
     }
 
     public static function webfinger() {
@@ -1014,17 +1143,15 @@ class _GNUBOARD_ActivityPub {
             "@context" => array(NAMESPACE_ACTIVITYSTREAMS, NAMESPACE_W3ID_SECURITY_V1, array("@language" => "ko")),
             "type" => "Person",
             "id" => $activitypub_user_id,
-            "name" => $mb['mb_name'],
+            "name" => $mb['mb_nick'],   // display name
-            "preferredUsername" => $mb['mb_nick'],
+            "preferredUsername" => $mb['mb_id'],    // real ID
             "summary" => $mb['mb_profile'],
             "inbox" => activitypub_get_url("inbox", array("mb_id" => $mb['mb_id'])),
             "outbox" => activitypub_get_url("outbox", array("mb_id" => $mb['mb_id'])),
             "followers" => activitypub_get_url("followers", array("mb_id" => $mb['mb_id'])),
             "following" => activitypub_get_url("following", array("mb_id" => $mb['mb_id'])),
             "liked" => activitypub_get_url("liked", array("mb_id" => $mb['mb_id'])),
-            "icon" => array(
+            "icon" => activitypub_get_icon($mb),
-                activitypub_get_icon($mb)
-            ),
             "endpoints" => array(
                 "sharedInbox" => activitypub_get_url("inbox")
             ),
@@ -1032,11 +1159,24 @@ class _GNUBOARD_ActivityPub {
                 "id" => $activitypub_user_id . "#main-key",
                 "owner" => $activitypub_user_id,
                 "publicKeyPem" => $public_key
-            )
+            ),
+            "summary" => strip_tags($mb['mb_signature']),
+            "discoverable" => true,
         );
 
         return activitypub_json_encode($context);
     }
+    
+    public static function activity() {
+        // HTTP 요청 유형에 따라 작업
+        switch ($_SERVER['REQUEST_METHOD']) {
+            case "POST":
+                return activitypub_json_encode(array("message" => "Disallowed method"));
+
+            case "GET":
+                return activitypub_get_activity_by_id($_GET['id']);
+        }
+    }
 
     public static function inbox() {
         // HTTP 요청 유형에 따라 작업
@@ -1046,14 +1186,14 @@ class _GNUBOARD_ActivityPub {
                 // 공개(Public) 설정한 메시지는 ACTIVITYPUB_G5_TABLENAME에 저장
                 $data = activitypub_json_decode(file_get_contents("php://input"), true);
 
-                if (empty($data['@context'])) {
+                // @context의 네임스페이스는 단수형(string으로 표현) 또는 복수형(array로 표현)될 수 있음
-                    return activitypub_json_encode(array("message" => "This is a broken context"));
+                $namespaces = activitypub_cast_to_array($data['@context']);
-                }
+
-                
+                // ActivityStream 네임스페이스가 존재하지 않는 경우 요청 거절
-                if ($data['@context'] != NAMESPACE_ACTIVITYSTREAMS) {
+                if (!in_array(NAMESPACE_ACTIVITYSTREAMS, $namespaces)) {
                     return activitypub_json_encode(array("message" => "This is not an ActivityStreams request"));
                 }
-                
+
                 // 컨텐츠 변수 정의
                 $content = '';
 
@@ -1062,8 +1202,11 @@ class _GNUBOARD_ActivityPub {
                     // 정보 불러오기 
                     $mb = get_member(ACTIVITYPUB_G5_USERNAME);
 
-                    // 수신자 확인
+                    // 수신자 (참조자 포함) 확인
-                    $to = $data['to'];
+                    $to = array_merge(
+                        activitypub_cast_to_array($data['to']),
+                        activitypub_cast_to_array($data['cc'])
+                    );
 
                     // 원글 정보 확인
                     $object = $data['object'];
@@ -1084,7 +1227,12 @@ class _GNUBOARD_ActivityPub {
 
                             // 컨텐츠 설정
                             $bo = get_board_db(ACTIVITYPUB_G5_BOARDNAME, true);
-                            $content = sprintf("%s\r\n\r\n[외부에서 전송된 글입니다. 자세한 내용은 %s#%s 글을 확인하세요.]", $object['content'], $bo['bo_subject'], $activity_wr_id);
+                            $content = sprintf(
+                                "%s\r\n\r\n[외부에서 전송된 글입니다. 자세한 내용은 %s#%s 글을 확인하세요.]",
+                                strip_tags($object['content']),
+                                $bo['bo_subject'],
+                                $activity_wr_id
+                            );
 
                             // 답글인지 확인
                             if (!empty($object['inReplyTo'])) {
@@ -1273,8 +1421,7 @@ class _GNUBOARD_ActivityPub {
                 return activitypub_json_encode(array("message" => "Success"));
 
             case "GET":
-                $mb = get_member($_GET['mb_id']);
+                return activitypub_json_encode(array("message" => "Disallowed method"));
-                return activitypub_json_encode(activitypub_get_activities("inbox", $mb['mb_id']));
 
             default:
                 return activitypub_json_encode(array("message" => "Not supported method"));
@@ -1293,7 +1440,7 @@ class _GNUBOARD_ActivityPub {
             // 가장 최근의 활동을 가져옴
             case "GET":
                 $mb = get_member($_GET['mb_id']);
-                return activitypub_json_encode(activitypub_get_activities("outbox", $mb['mb_id']));
+                return activitypub_json_encode(activitypub_get_objects($mb, "outbox"));
         }
     }
 
@@ -1313,67 +1460,21 @@ class _GNUBOARD_ActivityPub {
     
     public static function shares() {
         global $g5;
-        
-        // 게시판인 경우
-        if (array_key_exists("bo_table", $_GET)) {
-            $bo = get_board_db($_GET['bo_table'], true);
 
-            if (!empty($bo['bo_table'])) {
+        $items = array();  // 항목을 담을 배열
-                switch($bo['bo_table']) {
-                    case ACTIVITYPUB_G5_BOARDNAME:
-                        return self::inbox();   // 액티비티를 저장하는 테이블인 경우 inbox와 동일하게 취급
 
-                    default:
+        // 최근 활동에서 추출
-                        $items = array();  // 항목을 담을 배열
+        $sql = "select * from " . $g5['board_new_table']; 
-
+        $result = sql_query($sql);
-                        // 조회할 페이지 수 불러오기
+        while ($row = sql_fetch_array($result)) {
-                        $page = intval($_GET['page']);
+            $write_table = $g5['write_prefix'] . $row['bo_table'];
-                        if ($page < 1) {
+            $sql2 = "select wr_id, mb_id, wr_content, wr_datetime from {$write_table} where wr_id = '{$row['wr_id']}' and FIND_IN_SET('secret', wr_option) = 0 ";
-                            $page = 1;
+            $row2 = sql_fetch($sql2);
-                        }
+            if ($row2['wr_id']) {
-
+                $object_id = G5_BBS_URL . "/board.php?bo_table={$row['bo_table']}&wr_id={$row2['wr_id']}";
-                        // 페이지 당 표시할 게시물 수 불러오기
+                $mb = get_member($row2['mb_id']);
-                        $page_rows = 0;
+                $content = $row2['wr_content'];
-                        if (!empty($bo['bo_mobile_page_rows'])) {
+                array_push($items, activitypub_build_note($content, $object_id, $mb));
-                            $page_rows = intval($bo['bo_mobile_page_rows']);
-                        } else if (!empty($bo['bo_page_rows'])) {
-                            $page_rows = intval($bo['bo_page_rows']);
-                        }
-
-                        // 페이지 당 표시할 게시물 수가 1보다 작으면 기본값(15)로 설정
-                        if ($pages_rows < 1) {
-                            $page_rows = 15;
-                        }
-                        
-                        // SQL 작성
-                        $write_table = $g5['write_prefix'] . $bo['bo_table'];
-                        $offset = ($page - 1) * $page_rows;
-                        $sql = "select wr_id, mb_id, wr_content, wr_datetime from {$write_table} where FIND_IN_SET('secret', wr_option) = 0 order by wr_datetime desc limit {$offset}, {$page_rows} ";
-
-                        // SQL 실행
-                        $result = sql_query($sql);
-                        while ($row = sql_fetch_array($result)) {
-                            $object_id = G5_BBS_URL . "/board.php?bo_table={$bo['bo_table']}&wr_id={$row['wr_id']}";
-                            $mb = get_member($row['mb_id']);
-                            $content = $row['wr_content'];
-                            array_push($items, activitypub_build_note($content, $object_id, $mb));
-                        }
-                }
-            }
-        } else {   // 게시판이 아닌 경우
-            // 최근 활동에서 추출
-            $sql = "select * from " . $g5['board_new_table']; 
-            $result = sql_query($sql);
-            while ($row = sql_fetch_array($result)) {
-                $write_table = $g5['write_prefix'] . $row['bo_table'];
-                $sql2 = "select wr_id, mb_id, wr_content, wr_datetime from {$write_table} where wr_id = '{$row['wr_id']}' and FIND_IN_SET('secret', wr_option) = 0 ";
-                $row2 = sql_fetch($sql2);
-                if ($row2['wr_id']) {
-                    $object_id = G5_BBS_URL . "/board.php?bo_table={$row['bo_table']}&wr_id={$row2['wr_id']}";
-                    $mb = get_member($row2['mb_id']);
-                    $content = $row2['wr_content'];
-                    array_push($items, activitypub_build_note($content, $object_id, $mb));
-                }
             }
         }
 
@@ -1386,15 +1487,15 @@ class _GNUBOARD_ActivityPub {
 
         switch ($grant_type) {
             case "authorization_code":
-                return activitypub_json_encode(array("message" => "Sorry. This grant type does not supported yet"));
+                return activitypub_json_encode(array("message" => "Not implemented"));
                 break;
 
             case "password":
-                return activitypub_json_encode(array("message" => "Sorry. This grant type does not supported yet"));
+                return activitypub_json_encode(array("message" => "Not implemented"));
                 break;
 
             case "client_credentials":
-                return activitypub_json_encode(array("message" => "Sorry. This grant type does not supported yet"));
+                return activitypub_json_encode(array("message" => "Not implemented"));
                 break;
         }
     }
@@ -1411,13 +1512,13 @@ function _activitypub_memo_form_update_after($member_list, $str_nick_list, $redi
     // 'apstreams' 계정이 있는지 확인
     if (!in_array(ACTIVITYPUB_G5_USERNAME, $member_list['id'])) return;
 
-    // 현재 로그인되어 있으면, 로그인된 계정의 정보를 따름
+    // 글을 생성한 회원 정보
     $mb = (isset($member['mb_id']) ? $member : get_member(ACTIVITYPUB_G5_USERNAME));
 
     // 글 전송하기
     if (!empty($mb['mb_id'])) {
         // 글 전송하기
-        $data = activitypub_publish_content(
+        activitypub_publish_content(
             $me_memo,
             activitypub_get_url("user", array("mb_id" => $mb['mb_id'])),
             $mb
@@ -1428,12 +1529,12 @@ function _activitypub_memo_form_update_after($member_list, $str_nick_list, $redi
 function _activitypub_write_update_after($board, $wr_id, $w, $qstr, $redirect_url) {
     global $g5, $member;
 
-    // 본문 가져오기
+    // 본문 가져오기 (본문이 없는 경우 중단)
     $sql = "select wr_id, wr_content from {$g5['write_prefix']}{$board['bo_table']} where wr_id = '{$wr_id}'";
     $row = sql_fetch($sql);
     if (empty($row['wr_id'])) return;
-    
+
-    // 현재 로그인되어 있으면, 로그인된 계정의 정보를 따름
+    // 글을 생성한 회원 정보
     $mb = (isset($member['mb_id']) ? $member : get_member(ACTIVITYPUB_G5_USERNAME));
 
     // 추가할 오브젝트 속성
@@ -1447,7 +1548,7 @@ function _activitypub_write_update_after($board, $wr_id, $w, $qstr, $redirect_ur
 
     // 글 전송하기
     if (!empty($mb['mb_id'])) {
-        $data = activitypub_publish_content(
+        activitypub_publish_content(
             $row['wr_content'],
             G5_BBS_URL . "/board.php?bo_table={$board['bo_table']}&wr_id={$row['wr_id']}",
             $mb,
@@ -1459,12 +1560,12 @@ function _activitypub_write_update_after($board, $wr_id, $w, $qstr, $redirect_ur
 function _activitypub_comment_update_after($board, $wr_id, $w, $qstr, $redirect_url, $comment_id, $reply_array) {
     global $g5, $member;
 
-    // 본문(댓글) 가져오기
+    // 본문(댓글) 가져오기 (본문이 없는 경우 중단)
     $sql = "select wr_id, wr_content from {$g5['write_prefix']}{$board['bo_table']} where wr_id = '{$wr_id}'";
     $row = sql_fetch($sql);
     if (empty($row['wr_id'])) return;
-    
+
-    // 현재 로그인되어 있으면, 로그인된 계정의 정보를 따름
+    // 글을 생성한 회원 정보
     $mb = (isset($member['mb_id']) ? $member : get_member(ACTIVITYPUB_G5_USERNAME));
 
     // 추가할 오브젝트 속성
@@ -1480,7 +1581,7 @@ function _activitypub_comment_update_after($board, $wr_id, $w, $qstr, $redirect_
 
     // 글 전송하기
     if (!empty($mb['mb_id'])) {
-        $data = activitypub_publish_content(
+        activitypub_publish_content(
             $row['wr_content'],
             G5_BBS_URL . "/board.php?bo_table={$board['bo_table']}&wr_id={$row['wr_parent']}&c_id=" . $comment_id,
             $mb,
@@ -1504,17 +1605,15 @@ while ($entry = $tmp->read()) {
 $route = array_key_exists("route", $_GET) ? $_GET['route'] : "";
 
 switch ($route) {
-    // 액펍(ActivityPub)과 웹핑거(WebFinger)는 다른 개념이지만, 여기서는 액펍(ActivityPub) 전용으로 사용한다.
+    // 일부 소프트웨어는 통신을 하기 위해 아래와 같이 설정을 해야할 수 있습니다. (선택사항)
-    // 액펍(ActivityPub)에서 사용자를 조회하기 전단계에서 이뤄지는 요청이다.
+    // .htaccess에 추가
-    //
-    // .htaccess에 추가 (추가해야만 그누보드 외 다른 플랫폼과 통신 가능, 그누보드 사이에서만 연결할 경우 필수사항 아님)
     //
     //     <IfModule mod_rewrite.c>
     //         RewriteEngine on
     //         RewriteRule ^\.well-known/webfinger /?route=webfinger [QSA,L]
     //     </IfModule>
     //
-    // Reference: https://wordpress.org/support/topic/htaccess-conflict/
+    // 참고: https://wordpress.org/support/topic/htaccess-conflict/
     //
     case "webfinger":
         _GNUBOARD_ActivityPub::open();
@@ -1528,6 +1627,12 @@ switch ($route) {
         _GNUBOARD_ActivityPub::close();
         break;
 
+    case "activitypub.activity":
+        _GNUBOARD_ActivityPub::open();
+        echo _GNUBOARD_ActivityPub::activity();
+        _GNUBOARD_ActivityPub::close();
+        break;
+
     case "activitypub.inbox":
         _GNUBOARD_ActivityPub::open();
         echo _GNUBOARD_ActivityPub::inbox();
@@ -1564,9 +1669,10 @@ switch ($route) {
         _GNUBOARD_ActivityPub::close();
         break;
         
-    case "oauth2.authorize":  // TODO
+    case "oauth2.authorize":  // Not implemented
         _GNUBOARD_ActivityPub::open();
         echo _GNUBOARD_ActivityPub::authorize();
         _GNUBOARD_ActivityPub::close();
         break;
 }
+

lib/chatgpt.activitypub.lib.php

@@ -0,0 +1,112 @@
+<?php
+// GhatGPT-ActivityPub implementation for GNUBOARD 5
+// Go Namhyeon <abuse@catswords.net>
+// MIT License
+// 2023-02-16
+
+if (!defined('_GNUBOARD_') || !defined("ACTIVITYPUB_INSTANCE_ID")) exit; // 개별 페이지 접근 불가
+
+// ChatGPT API 키 발급: https://platform.openai.com/account/api-keys
+define("CHATGPT_API_KEY", "YOUR_API_KEY");   // API 키 입력
+define("CHATGPT_API_URL", "https://api.openai.com/v1/completions");    // GhatGPT API 주소 입력
+define("LINGVA_API_URL", "https://lingva.ml/api/v1");   // Lingva Translate (구글 번역기 프론트엔드) API 주소 입력
+
+function lingva_translate($content, $source = 'ko', $target = 'en') {
+    $handle = curl_init();
+    curl_setopt($handle, CURLOPT_URL, LINGVA_API_URL . '/' . $source . '/' . $target . '/' . urlencode($content));
+    curl_setopt($handle, CURLOPT_RETURNTRANSFER, 1);
+    curl_setopt($handle, CURLOPT_SSL_VERIFYPEER, false);
+    $response = json_decode(curl_exec($handle), true);
+    curl_close($handle);
+    return $response['translation'];
+}
+
+function lingva_ko2en($content) {
+    return lingva_translate($content, 'ko', 'en');
+}
+
+function lingva_en2ko($content) {
+    return lingva_translate($content, 'en', 'ko');
+}
+
+function chatgpt_request($content, $mb) {
+    // "What is the capital of France?"
+    $prompt = lingva_ko2en(filter_var($content, FILTER_SANITIZE_STRING));
+    $prompt = filter_var($content, FILTER_SANITIZE_STRING);
+
+    $data = array(
+        "model" => "text-davinci-003",
+        "prompt" => $prompt,
+        "max_tokens" => 3000,
+        "temperature" => 0.5,
+    );
+
+    $data_string = json_encode($data);
+
+    $ch = curl_init();
+    curl_setopt($ch, CURLOPT_URL, CHATGPT_API_URL);
+    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
+    curl_setopt($ch, CURLOPT_POST, true);
+    curl_setopt($ch, CURLOPT_POSTFIELDS, $data_string);
+    curl_setopt($ch, CURLOPT_HTTPHEADER, array(
+        "Content-Type: application/json",
+        "Authorization: Bearer " . CHATGPT_API_KEY,
+        "Content-Length: " . strlen($data_string))
+    );
+
+    $output = curl_exec($ch);
+    curl_close($ch);
+    // print_r($output);
+
+    $output_json = json_decode($output, true);
+    $response = $output_json["choices"][0]["text"];
+    // echo $response;
+    
+    return lingva_en2ko($response);
+}
+
+function chatgpt_send_conversation($content) {
+    global $member;
+    
+    // 로그인 상태인 경우 해당 회원, 아닌 경우 ActivityPub 공통 계정
+    $mb = isset($member['mb_id']) ? $member : get_member(ACTIVITYPUB_G5_USERNAME);
+
+    // 수신자 목록
+    $to = array();
+
+    // 참고: 아래에 기술된 역할은 외부 프로그램이 담당하게 할 수도 있음 (service:chatgpt)
+    if (!empty(CHATGPT_API_KEY)) {
+        $response = chatgpt_request($content, $mb);
+        $to[] = "service:chatgpt";
+    }
+
+    // Activity 발행 (발신: 그누보드5 -> ChatGPT)
+    activitypub_publish_content(
+        $content,
+        activitypub_get_url("user", array("mb_id" => $mb['mb_id'])),
+        get_member(ACTIVITYPUB_G5_USERNAME),
+        array(),
+        $to
+    );
+
+    // Activity 발행 (수신: ChatGPT -> 그누보드5)
+    activitypub_publish_content(
+        $response,
+        "service:chatgpt",
+        get_member(ACTIVITYPUB_G5_USERNAME),
+        array(),
+        array(
+            activitypub_get_url("user", array("mb_id" => $mb['mb_id']))
+        )
+    );
+}
+
+function _chatgpt_memo_form_update_after($member_list, $str_nick_list, $redirect_url, $me_memo) {
+    // 수신자에 'apstreams' 계정이 있는지 확인
+    if (!in_array(ACTIVITYPUB_G5_USERNAME, $member_list['id'])) return;
+
+    // ChatGPT에게 대화 걸기
+    chatgpt_send_conversation($me_memo);
+}
+
+add_event("memo_form_update_after", "_chatgpt_memo_form_update_after", 1, 4);