From ff2858b6ea8f586daa95e51ae21315f86cc5ded5 Mon Sep 17 00:00:00 2001
From: Arno Richter <oelna@oelna.de>
Date: Fri, 13 Jan 2023 17:47:09 +0100
Subject: first draft of activitypub support

---
 lib/activitypub-actor.php     | 56 +++++++++++++++++++++++++++++++++++++++++++
 lib/activitypub-webfinger.php | 22 +++++++++++++++++
 2 files changed, 78 insertions(+)
 create mode 100644 lib/activitypub-actor.php
 create mode 100644 lib/activitypub-webfinger.php

(limited to 'lib')

diff --git a/lib/activitypub-actor.php b/lib/activitypub-actor.php
new file mode 100644
index 0000000..705955b
--- /dev/null
+++ b/lib/activitypub-actor.php
@@ -0,0 +1,56 @@
+<?php
+
+	if(!file_exists(ROOT.DS.'keys'.DS.'id_rsa')) {
+		if(!is_dir(ROOT.DS.'keys')) {
+			mkdir(ROOT.DS.'keys');
+		}
+
+		// generate a key pair, if neccessary
+
+		$rsa = openssl_pkey_new([ 
+			'digest_alg' => 'sha512',
+			'private_key_bits' => 4096,
+			'private_key_type' => OPENSSL_KEYTYPE_RSA,
+		]);
+		openssl_pkey_export($rsa, $private_key);
+		$public_key = openssl_pkey_get_details($rsa)['key'];
+
+		file_put_contents(ROOT.DS.'keys'.DS.'id_rsa', $private_key);
+		file_put_contents(ROOT.DS.'keys'.DS.'id_rsa.pub', $public_key);
+	} else {
+		$public_key = file_get_contents(ROOT.DS.'keys'.DS.'id_rsa.pub');
+	}
+
+	
+
+	/*
+
+	$data = [
+		'subject' => 'acct:'.$actor.'@'.$domain,
+		'links' => [
+			'rel' => 'self',
+			'type' => 'application/activity+json',
+			'href' => $config['url'].'/actor'
+		]
+	];
+	*/
+
+	header('Content-Type: application/ld+json');
+	// echo(json_encode($data, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES));
+?>{
+	"@context": [
+		"https://www.w3.org/ns/activitystreams",
+		"https://w3id.org/security/v1"
+	],
+
+	"id": "<?= $config['url'] ?>/actor",
+	"type": "Person",
+	"preferredUsername": "<?= ltrim($config['microblog_account'], '@') ?>",
+	"inbox": "<?= $config['url'] ?>/inbox",
+
+	"publicKey": {
+		"id": "<?= $config['url'] ?>/actor#main-key",
+		"owner": "<?= $config['url'] ?>/actor",
+		"publicKeyPem": "<?= preg_replace('/\n/', '\n', $public_key) ?>"
+	}
+}
diff --git a/lib/activitypub-webfinger.php b/lib/activitypub-webfinger.php
new file mode 100644
index 0000000..2ad44fb
--- /dev/null
+++ b/lib/activitypub-webfinger.php
@@ -0,0 +1,22 @@
+<?php
+
+	// todo: handle empty usernames
+
+	$actor = ltrim($config['microblog_account'], '@');
+	$url = parse_url($config['url']);
+	$domain = $url['host'];
+	if(!empty($url['path'])) $domain .= rtrim($url['path'], '/');
+
+	$data = [
+		'subject' => 'acct:'.$actor.'@'.$domain,
+		'links' => [
+			[
+				'rel' => 'self',
+				'type' => 'application/activity+json',
+				'href' => $config['url'].'/actor'
+			]
+		]
+	];
+
+	header('Content-Type: application/ld+json');
+	echo(json_encode($data, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES));
-- 
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