pull fetch code out of homeserverapi

src/main.js

@@ -1,4 +1,5 @@
 import HomeServerApi from "./matrix/hs-api.js";
+import fetchRequest from "./matrix/net/fetch.js";
 import StorageFactory from "./matrix/storage/idb/create.js";
 import SessionsStore from "./matrix/sessions-store/localstorage/SessionsStore.js";
 import BrawlViewModel from "./domain/BrawlViewModel.js";
@@ -6,9 +7,10 @@ import BrawlView from "./ui/web/BrawlView.js";
 
 export default async function main(container) {
     try {
+        const request = fetchRequest;
         const vm = new BrawlViewModel({
             storageFactory: new StorageFactory(),
-            createHsApi: (homeServer, accessToken = null) => new HomeServerApi(homeServer, accessToken),
+            createHsApi: (homeServer, accessToken = null) => new HomeServerApi({homeServer, accessToken, request}),
             sessionStore: new SessionsStore("brawl_sessions_v1"),
             clock: Date //just for `now` fn
         });

src/matrix/hs-api.js

@@ -1,30 +1,25 @@
 import {
     HomeServerError,
-    RequestAbortError,
-    NetworkError
 } from "./error.js";
 
 class RequestWrapper {
-    constructor(promise, controller) {
-        if (!controller) {
-            const abortPromise = new Promise((_, reject) => {
-                this._controller = {
-                    abort() {
-                        const err = new Error("fetch request aborted");
-                        err.name = "AbortError";
-                        reject(err);
-                    }
-                };
-            });
-            this._promise = Promise.race([promise, abortPromise]);
+    constructor(method, url, requestResult) {
+        this._requestResult = requestResult;
+        this._promise = this._requestResult.response().then(response => {
+            // ok?
+            if (response.status >= 200 && response.status < 300) {
+                return response.body;
             } else {
-            this._promise = promise;
-            this._controller = controller;
+                switch (response.status) {
+                    default:
+                        throw new HomeServerError(method, url, response.body);
                 }
             }
+        });
+    }
 
     abort() {
-        this._controller.abort();
+        return this._requestResult.abort();
     }
 
     response() {
@@ -32,13 +27,13 @@ class RequestWrapper {
     }
 }
 
-// todo: everywhere here, encode params in the url that could have slashes ... mainly event ids?
 export default class HomeServerApi {
-    constructor(homeserver, accessToken) {
+    constructor({homeServer, accessToken, request}) {
         // store these both in a closure somehow so it's harder to get at in case of XSS?
         // one could change the homeserver as well so the token gets sent there, so both must be protected from read/write
-        this._homeserver = homeserver;
+        this._homeserver = homeServer;
         this._accessToken = accessToken;
+        this._requestFn = request;
     }
 
     _url(csPath) {
@@ -66,42 +61,12 @@ export default class HomeServerApi {
             headers.append("Content-Type", "application/json");
             bodyString = JSON.stringify(body);
         }
-        const controller = typeof AbortController === "function" ? new AbortController() : null;
-        // TODO: set authenticated headers with second arguments, cache them
-        let promise = fetch(url, {
+        const requestResult = this._requestFn(url, {
             method,
             headers,
             body: bodyString,
-            signal: controller && controller.signal,
-            mode: "cors",
-            credentials: "omit",
-            referrer: "no-referrer",
-            cache: "no-cache",
         });
-        promise = promise.then(async (response) => {
-            if (response.ok) {
-                return await response.json();
-            } else {
-                switch (response.status) {
-                    default:
-                        throw new HomeServerError(method, url, await response.json())
-                }
-            }
-        }, err => {
-            if (err.name === "AbortError") {
-                throw new RequestAbortError();
-            } else if (err instanceof TypeError) {
-                // Network errors are reported as TypeErrors, see
-                // https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch#Checking_that_the_fetch_was_successful
-                // this can either mean user is offline, server is offline, or a CORS error (server misconfiguration).
-                // 
-                // One could check navigator.onLine to rule out the first
-                // but the 2 later ones are indistinguishable from javascript.
-                throw new NetworkError(`${method} ${url}: ${err.message}`);
-            }
-            throw err;
-        });
-        return new RequestWrapper(promise, controller);
+        return new RequestWrapper(method, url, requestResult);
     }
 
     _post(csPath, queryParams, body) {

src/matrix/net/fetch.js

@@ -0,0 +1,66 @@
+import {
+    RequestAbortError,
+    NetworkError
+} from "../error.js";
+
+class RequestResult {
+    constructor(promise, controller) {
+        if (!controller) {
+            const abortPromise = new Promise((_, reject) => {
+                this._controller = {
+                    abort() {
+                        const err = new Error("fetch request aborted");
+                        err.name = "AbortError";
+                        reject(err);
+                    }
+                };
+            });
+            this._promise = Promise.race([promise, abortPromise]);
+        } else {
+            this._promise = promise;
+            this._controller = controller;
+        }
+    }
+
+    abort() {
+        this._controller.abort();
+    }
+
+    response() {
+        return this._promise;
+    }
+}
+
+export default function fetchRequest(url, options) {
+    const controller = typeof AbortController === "function" ? new AbortController() : null;
+    if (controller) {
+        options = Object.assign(options, {
+            signal: controller.signal
+        });
+    }
+    options = Object.assign(options, {
+        mode: "cors",
+        credentials: "omit",
+        referrer: "no-referrer",
+        cache: "no-cache",
+    });
+    const promise = fetch(url, options).then(async response => {
+        const {status} = response;
+        const body = await response.json();
+        return {status, body};
+    }, err => {
+        if (err.name === "AbortError") {
+            throw new RequestAbortError();
+        } else if (err instanceof TypeError) {
+            // Network errors are reported as TypeErrors, see
+            // https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch#Checking_that_the_fetch_was_successful
+            // this can either mean user is offline, server is offline, or a CORS error (server misconfiguration).
+            // 
+            // One could check navigator.onLine to rule out the first
+            // but the 2 later ones are indistinguishable from javascript.
+            throw new NetworkError(`${options.method} ${url}: ${err.message}`);
+        }
+        throw err;
+    });
+    return new RequestResult(promise, controller);
+}