From 5ae1be9a9c0a1c58dd4515b22d638448ac3fd27d Mon Sep 17 00:00:00 2001
From: Bruno Windels <brunow@matrix.org>
Date: Mon, 5 Oct 2020 17:18:05 +0200
Subject: [PATCH] ignore invalid json on error pages

---
 src/matrix/net/request/fetch.js | 10 +++++++++-
 src/matrix/net/request/xhr.js   |  2 +-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/matrix/net/request/fetch.js b/src/matrix/net/request/fetch.js
index d1561692..eaa891ed 100644
--- a/src/matrix/net/request/fetch.js
+++ b/src/matrix/net/request/fetch.js
@@ -85,7 +85,15 @@ export function createFetchRequest(createTimeout) {
         }
         const promise = fetch(url, options).then(async response => {
             const {status} = response;
-            const body = await response.json();
+            let body;
+            try {
+                body = await response.json();
+            } catch (err) {
+                // some error pages return html instead of json, ignore error
+                if (!(err.name === "SyntaxError" && status >= 400)) {
+                    throw err;
+                }
+            }
             return {status, body};
         }, err => {
             if (err.name === "AbortError") {
diff --git a/src/matrix/net/request/xhr.js b/src/matrix/net/request/xhr.js
index 3cde1b14..6685131e 100644
--- a/src/matrix/net/request/xhr.js
+++ b/src/matrix/net/request/xhr.js
@@ -66,7 +66,7 @@ export function xhrRequest(url, options) {
     const xhr = send(url, options);
     const promise = xhrAsPromise(xhr, options.method, url).then(xhr => {
         const {status} = xhr;
-        let body = xhr.responseText;
+        let body = null;
         if (xhr.getResponseHeader("Content-Type") === "application/json") {
             body = JSON.parse(body);
         }