From 57746f7fb481d2674308c431b78f278798a88df3 Mon Sep 17 00:00:00 2001
From: David Teller <d.o.teller+github@gmail.com>
Date: Tue, 21 Dec 2021 15:10:25 +0100
Subject: [PATCH] Wrap MatrixClient into something that displays nicer error
 messages

---
 src/Mjolnir.ts                   |  6 ++--
 src/utils.ts                     | 54 ++++++++++++++++++++++++++++++++
 test/integration/clientHelper.ts |  3 +-
 3 files changed, 60 insertions(+), 3 deletions(-)

diff --git a/src/Mjolnir.ts b/src/Mjolnir.ts
index 97afbc0..602f0dc 100644
--- a/src/Mjolnir.ts
+++ b/src/Mjolnir.ts
@@ -42,6 +42,7 @@ import { EventRedactionQueue, RedactUserInRoom } from "./queues/EventRedactionQu
 import * as htmlEscape from "escape-html";
 import { ReportManager } from "./report/ReportManager";
 import { WebAPIs } from "./webapis/WebAPIs";
+import { makeClientWithSanerExceptions } from "./utils";
 
 export const STATE_NOT_STARTED = "not_started";
 export const STATE_CHECKING_PERMISSIONS = "checking_permissions";
@@ -54,7 +55,7 @@ const PROTECTED_ROOMS_EVENT_TYPE = "org.matrix.mjolnir.protected_rooms";
 const WARN_UNPROTECTED_ROOM_EVENT_PREFIX = "org.matrix.mjolnir.unprotected_room_warning.for.";
 
 export class Mjolnir {
-
+    public readonly client: MatrixClient;
     private displayName: string;
     private localpart: string;
     private currentState: string = STATE_NOT_STARTED;
@@ -153,11 +154,12 @@ export class Mjolnir {
     }
 
     constructor(
-        public readonly client: MatrixClient,
+        client: MatrixClient,
         public readonly protectedRooms: { [roomId: string]: string },
         private banLists: BanList[],
     ) {
         this.explicitlyProtectedRoomIds = Object.keys(this.protectedRooms);
+        this.client = makeClientWithSanerExceptions(client);
 
         for (const reason of config.automaticallyRedactForReasons) {
             this.automaticRedactionReasons.push(new MatrixGlob(reason.toLowerCase()));
diff --git a/src/utils.ts b/src/utils.ts
index 83c05bd..ca227d2 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -28,6 +28,7 @@ import {
 import { logMessage } from "./LogProxy";
 import config from "./config";
 import * as htmlEscape from "escape-html";
+import { ClientRequest, IncomingMessage } from "http";
 
 export function setToArray<T>(set: Set<T>): T[] {
     const arr: T[] = [];
@@ -201,3 +202,56 @@ export async function replaceRoomIdsWithPills(client: MatrixClient, text: string
 
     return content;
 }
+
+export function makeClientWithSanerExceptions(client: MatrixClient): MatrixClient {
+    let result = new Proxy(client, {
+        get: function (obj, key) {
+            let value = obj[key];
+            if (!(typeof value == "function")) {
+                return value;
+            }
+            return function (...args) {
+                let result = value.apply(client, args);
+                if (!(result instanceof Promise)) {
+                    // We're only interested in watching async code.
+                    return result;
+                }
+                return result.catch(reason => {
+                    if (!(reason instanceof IncomingMessage)) {
+                        // In most cases, we're happy with the result.
+                        throw reason;
+                    }
+                    // However, MatrixClient has a tendency of throwing
+                    // instances of `IncomingMessage` instead of instances
+                    // of `Error`. The former take ~800 lines of log and
+                    // provide no stack trace, which makes them typically
+                    // useless.
+                    let method: string | null = null;
+                    let path: string = '';
+                    let body: string | null = null;
+                    if (reason.method) {
+                        method = reason.method;
+                    }
+                    if (reason.url) {
+                        path = reason.url;
+                    }
+                    if ("req" in reason && (reason as any).req instanceof ClientRequest) {
+                        if (!method) {
+                            method = (reason as any).req.method;
+                        }
+                        if (!path) {
+                            path = (reason as any).req.path;
+                        }
+                    }
+                    if ("body" in reason) {
+                        body = JSON.stringify((reason as any).body);
+                    }
+                    let error = new Error(`Error during MatrixClient request ${method} ${path}: ${reason.statusCode} ${reason.statusMessage} -- ${body}`);
+                    //(error as any).message = reason;
+                    throw error;
+                });
+            }
+        }
+    });
+    return result;
+}
\ No newline at end of file
diff --git a/test/integration/clientHelper.ts b/test/integration/clientHelper.ts
index b83d413..169a1ee 100644
--- a/test/integration/clientHelper.ts
+++ b/test/integration/clientHelper.ts
@@ -2,6 +2,7 @@ import axios from "axios";
 import { HmacSHA1 } from "crypto-js";
 import { LogService, MatrixClient, MemoryStorageProvider, PantalaimonClient } from "matrix-bot-sdk";
 import config from "../../src/config";
+import { makeClientWithSanerExceptions } from "../../src/utils";
 
 /**
  * Register a user using the synapse admin api that requires the use of a registration secret rather than an admin user.
@@ -67,7 +68,7 @@ export async function registerNewTestUser(isAdmin: boolean, label: string = "")
 export async function newTestUser(isAdmin: boolean = false, label: string = ""): Promise<MatrixClient> {
     const username = await registerNewTestUser(isAdmin, label);
     const pantalaimon = new PantalaimonClient(config.homeserverUrl, new MemoryStorageProvider());
-    return await pantalaimon.createClientWithCredentials(username, username);
+    return makeClientWithSanerExceptions(await pantalaimon.createClientWithCredentials(username, username));
 }
 
 /**