From df897504016be607efce060373f66de584a493a7 Mon Sep 17 00:00:00 2001
From: Eric Eastwood <contact@ericeastwood.com>
Date: Tue, 18 Oct 2022 16:42:33 -0500
Subject: [PATCH] Throw more understandable error when we fail to fetch from
 the homeserver room directory (#84)

Fix https://github.com/matrix-org/matrix-public-archive/issues/80

```
RethrownError: Unable to fetch rooms from room directory (homeserver=http://localhost:8008/)
    searchTerm=, paginationToken=undefined, limit=9
    at matrix-public-archive\server\routes\room-directory-routes.js:55:13
    --- Original Error ---
    Error: HTTP Error Response: 500 Internal Server Error: {"errcode":"M_UNKNOWN","error":"Internal server error"}
        URL=http://localhost:8008/_matrix/client/v3/publicRooms?
        at checkResponseStatus (matrix-public-archive\server\lib\fetch-endpoint.js:21:11)
        at processTicksAndRejections (node:internal/process/task_queues:96:5)
        at async fetchEndpoint (matrix-public-archive\server\lib\fetch-endpoint.js:38:3)
        at async fetchEndpointAsJson (matrix-public-archive\server\lib\fetch-endpoint.js:63:15)
        at async fetchPublicRooms (matrix-public-archive\server\lib\matrix-utils\fetch-public-rooms.js:26:26)
        at async matrix-public-archive\server\tracing\trace-utilities.js:31:24
        at async matrix-public-archive\server\routes\room-directory-routes.js:45:62
```
---
 server/routes/room-directory-routes.js | 39 +++++++++++++++++---------
 1 file changed, 26 insertions(+), 13 deletions(-)

diff --git a/server/routes/room-directory-routes.js b/server/routes/room-directory-routes.js
index d5fae06..c6ded28 100644
--- a/server/routes/room-directory-routes.js
+++ b/server/routes/room-directory-routes.js
@@ -6,6 +6,7 @@ const urlJoin = require('url-join');
 const express = require('express');
 const asyncHandler = require('../lib/express-async-handler');
 
+const RethrownError = require('../lib/rethrown-error');
 const fetchPublicRooms = require('../lib/matrix-utils/fetch-public-rooms');
 const renderHydrogenVmRenderScriptToPageHtml = require('../hydrogen-render/render-hydrogen-vm-render-script-to-page-html');
 
@@ -31,19 +32,31 @@ router.get(
     const paginationToken = req.query.page;
     const searchTerm = req.query.search;
 
-    const { rooms, nextPaginationToken, prevPaginationToken } = await fetchPublicRooms(
-      matrixAccessToken,
-      {
-        //server: TODO,
-        searchTerm,
-        paginationToken,
-        // It would be good to grab more rooms than we display in case we need
-        // to filter any out but then the pagination tokens with the homeserver
-        // will be out of sync. XXX: It would be better if we could just filter
-        // `/publicRooms` directly via the API (needs MSC).
-        limit: 9,
-      }
-    );
+    // It would be good to grab more rooms than we display in case we need
+    // to filter any out but then the pagination tokens with the homeserver
+    // will be out of sync. XXX: It would be better if we could just filter
+    // `/publicRooms` directly via the API (needs MSC).
+    const limit = 9;
+
+    let rooms;
+    let nextPaginationToken;
+    let prevPaginationToken;
+    try {
+      ({ rooms, nextPaginationToken, prevPaginationToken } = await fetchPublicRooms(
+        matrixAccessToken,
+        {
+          //server: TODO,
+          searchTerm,
+          paginationToken,
+          limit,
+        }
+      ));
+    } catch (err) {
+      throw new RethrownError(
+        `Unable to fetch rooms from room directory (homeserver=${matrixServerUrl})\n    searchTerm=${searchTerm}, paginationToken=${paginationToken}, limit=${limit}`,
+        err
+      );
+    }
 
     const hydrogenStylesUrl = urlJoin(basePath, '/hydrogen-styles.css');
     const stylesUrl = urlJoin(basePath, '/css/styles.css');