From 93efeb004068d1f47f5fb03752aa61a7cf829f38 Mon Sep 17 00:00:00 2001
From: Kuba Suder <jakub.suder@gmail.com>
Date: Mon, 20 May 2024 01:54:07 +0200
Subject: [PATCH] reworked authentication to call user's actual PDS

---
 api.js       |  2 +-
 minisky.js   | 56 +++++++++++++++++++++++++++++++++++++++++++++++++---
 skythread.js | 29 +++++++++++++++++++++++----
 3 files changed, 79 insertions(+), 8 deletions(-)

diff --git a/api.js b/api.js
index 19722cb..8167d9b 100644
--- a/api.js
+++ b/api.js
@@ -84,7 +84,7 @@ class LocalStorageConfig {
 
 class BlueskyAPI extends Minisky {
 
-  /** @param {string} host, @param {boolean} useAuthentication */
+  /** @param {string | undefined} host, @param {boolean} useAuthentication */
   constructor(host, useAuthentication) {
     super(host, useAuthentication ? new LocalStorageConfig() : undefined);
 
diff --git a/minisky.js b/minisky.js
index b8c1d7f..8124f0d 100644
--- a/minisky.js
+++ b/minisky.js
@@ -20,24 +20,61 @@ class APIError extends Error {
 class AuthError extends Error {}
 
 
+/**
+ * Thrown when DID or DID document is invalid.
+ */
+
+class DIDError extends Error {}
+
+
 /**
  * Base API client for connecting to an ATProto XRPC API.
  */
 
 class Minisky {
 
+  /** @param {string} did, @returns {Promise<string>} */
+
+  static async pdsEndpointForDid(did) {
+    let url;
+
+    if (did.startsWith('did:plc:')) {
+      url = new URL(`https://plc.directory/${did}`);
+    } else if (did.startsWith('did:web:')) {
+      let host = did.replace(/^did:web:/, '');
+      url = new URL(`https://${host}/.well-known/did.json`);
+    } else {
+      throw new DIDError("Unknown DID type: " + did);
+    }
+
+    let response = await fetch(url);
+    let text = await response.text();
+    let json = text.trim().length > 0 ? JSON.parse(text) : undefined;
+
+    if (response.status == 200) {
+      let service = (json.service || []).find(s => s.id == '#atproto_pds');
+      if (service) {
+        return service.serviceEndpoint;
+      } else {
+        throw new DIDError("Missing #atproto_pds service definition");
+      }
+    } else {
+      throw new APIError(response.status, json);
+    }
+  }
+
   /**
    * @typedef {object} MiniskyOptions
    * @prop {boolean} [sendAuthHeaders]
    * @prop {boolean} [autoManageTokens]
    *
-   * @param {string} host, @param {object} config, @param {MiniskyOptions} [options]
+   * @param {string | undefined} host, @param {object} config, @param {MiniskyOptions} [options]
    */
+
   constructor(host, config, options) {
     this.host = host;
     this.config = config;
     this.user = config?.user;
-    this.baseURL = (host.includes('://') ? host : `https://${host}`) + '/xrpc';
 
     this.sendAuthHeaders = !!this.user;
     this.autoManageTokens = !!this.user;
@@ -47,10 +84,21 @@ class Minisky {
     }
   }
 
+  /** @returns {string} */
+
+  get baseURL() {
+    if (this.host) {
+      let host = (this.host.includes('://')) ? this.host : `https://${this.host}`;
+      return host + '/xrpc';
+    } else {
+      throw new AuthError('Hostname not set');
+    }
+  }
+
   /** @returns {boolean} */
 
   get isLoggedIn() {
-    return !!(this.user && this.user.accessToken && this.user.refreshToken && this.user.did);
+    return !!(this.user && this.user.accessToken && this.user.refreshToken && this.user.did && this.user.pdsEndpoint);
   }
 
   /**
@@ -210,6 +258,7 @@ class Minisky {
     this.user.accessToken = json['accessJwt'];
     this.user.refreshToken = json['refreshJwt'];
     this.user.did = json['did'];
+    this.user.pdsEndpoint = json['didDoc']['service'].find(s => s.id == '#atproto_pds')['serviceEndpoint'];
     this.config.save();
   }
 
@@ -217,6 +266,7 @@ class Minisky {
     delete this.user.accessToken;
     delete this.user.refreshToken;
     delete this.user.did;
+    delete this.user.pdsEndpoint;
     this.config.save();
   }
 }
diff --git a/skythread.js b/skythread.js
index d26fafc..40d508b 100644
--- a/skythread.js
+++ b/skythread.js
@@ -68,13 +68,15 @@ function init() {
 
   window.appView = new BlueskyAPI('api.bsky.app', false);
   window.blueAPI = new BlueskyAPI('blue.mackuba.eu', false);
-  window.accountAPI = new BlueskyAPI('bsky.social', true);
+  window.accountAPI = new BlueskyAPI(undefined, true);
 
   if (accountAPI.isLoggedIn && !isIncognito) {
     window.api = accountAPI;
+    accountAPI.host = accountAPI.user.pdsEndpoint;
     showLoggedInStatus(true, api.user.avatar);
   } else if (accountAPI.isLoggedIn && isIncognito) {
     window.api = appView;
+    accountAPI.host = accountAPI.user.pdsEndpoint;
     showLoggedInStatus('incognito');
     document.querySelector('#account_menu a[data-action=incognito]').innerText = '✓ Incognito mode';
   } else {
@@ -213,15 +215,13 @@ function submitLogin() {
 
   if (submit.style.display == 'none') { return }
 
-  let pds = new BlueskyAPI('bsky.social', true);
-
   handle.blur();
   password.blur();
 
   submit.style.display = 'none';
   cloudy.style.display = 'inline-block';
 
-  pds.logIn(handle.value, password.value).then(() => {
+  logIn(handle.value, password.value).then((pds) => {
     window.api = pds;
 
     hideLogin();
@@ -239,6 +239,27 @@ function submitLogin() {
   });
 }
 
+/** @param {string} identifier, @param {string} password, @returns {Promise<BlueskyAPI>} */
+
+async function logIn(identifier, password) {
+  let pdsEndpoint;
+
+  if (identifier.match(/^did:/)) {
+    pdsEndpoint = await Minisky.pdsEndpointForDid(identifier);
+  } else if (identifier.match(/^[^@]+@[^@]+$/)) {
+    pdsEndpoint = 'bsky.social';
+  } else if (identifier.match(/^[\w\-]+(\.[\w\-]+)+$/)) {
+    let did = await appView.resolveHandle(identifier);
+    pdsEndpoint = await Minisky.pdsEndpointForDid(did);
+  } else {
+    throw 'Please enter your handle or DID';
+  }
+
+  let pds = new BlueskyAPI(pdsEndpoint, true);
+  await pds.logIn(identifier, password);
+  return pds;
+}
+
 function loadCurrentUserAvatar() {
   api.loadCurrentUserAvatar().then(data => {
     if (data) {
-- 
2.51.2