Always send back an httpStatus property if one is known

Previously, non-JSON responses would be missing the `httpStatus`
property, which was different to how `request()` used to work.

Ensure we always send this property, even for non-JSON responses.

src/http-api/errors.ts

@@ -22,6 +22,19 @@ interface IErrorJson extends Partial<IUsageLimit> {
     error?: string;
 }
 
+/**
+ * Construct a generic HTTP error. This is a JavaScript Error with additional information
+ * specific to HTTP responses.
+ * @constructor
+ * @param {string} msg The error message to include.
+ * @param {number} httpStatus The HTTP response status code.
+ */
+export class HTTPError extends Error {
+    constructor(msg: string, public readonly httpStatus?: number) {
+        super(msg);
+    }
+}
+
 /**
  * Construct a Matrix error. This is a JavaScript Error with additional
  * information specific to the standard Matrix error response.
@@ -33,11 +46,11 @@ interface IErrorJson extends Partial<IUsageLimit> {
  * @prop {Object} data The raw Matrix error JSON used to construct this object.
  * @prop {number} httpStatus The numeric HTTP status code given
  */
-export class MatrixError extends Error {
+export class MatrixError extends HTTPError {
     public readonly errcode?: string;
     public readonly data: IErrorJson;
 
-    constructor(errorJson: IErrorJson = {}, public httpStatus?: number, public url?: string) {
+    constructor(errorJson: IErrorJson = {}, public readonly httpStatus?: number, public url?: string) {
         let message = errorJson.error || "Unknown message";
         if (httpStatus) {
             message = `[${httpStatus}] ${message}`;
@@ -45,7 +58,7 @@ export class MatrixError extends Error {
         if (url) {
             message = `${message} (${url})`;
         }
-        super(`MatrixError: ${message}`);
+        super(`MatrixError: ${message}`, httpStatus);
         this.errcode = errorJson.errcode;
         this.name = errorJson.errcode || "Unknown error code";
         this.data = errorJson;

src/http-api/utils.ts

@@ -18,7 +18,7 @@ import { parse as parseContentType, ParsedMediaType } from "content-type";
 
 import { logger } from "../logger";
 import { sleep } from "../utils";
-import { ConnectionError, MatrixError } from "./errors";
+import { ConnectionError, HTTPError, MatrixError } from "./errors";
 
 // Ponyfill for https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal/timeout
 export function timeoutSignal(ms: number): AbortSignal {
@@ -87,9 +87,9 @@ export function parseErrorResponse(response: XMLHttpRequest | Response, body?: s
         );
     }
     if (contentType?.type === "text/plain") {
-        return new Error(`Server returned ${response.status} error: ${body}`);
+        return new HTTPError(`Server returned ${response.status} error: ${body}`, response.status);
     }
-    return new Error(`Server returned ${response.status} error`);
+    return new HTTPError(`Server returned ${response.status} error`, response.status);
 }
 
 function isXhr(response: XMLHttpRequest | Response): response is XMLHttpRequest {