move RequestWrapper to own file

and add tests, improve comments, and and don't use timeout connection
error as that's not what happens if aborted request from service worker
is reported as TypeError either.

src/matrix/net/HomeServerApi.js

@@ -15,100 +15,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import {HomeServerError, ConnectionError} from "../error.js";
+import {encodeQueryParams, encodeBody} from "./common.js";
-import {encodeQueryParams} from "./common.js";
+import {HomeServerRequest} from "./HomeServerRequest.js";
-
-class RequestWrapper {
-    constructor(method, url, requestResult, log) {
-        this._log = log;
-        this._requestResult = requestResult;
-        this._promise = requestResult.response().then(response => {
-            log?.set("status", response.status);
-            // ok?
-            if (response.status >= 200 && response.status < 300) {
-                log?.finish();
-                return response.body;
-            } else {
-                if (response.status >= 500) {
-                    const err = new ConnectionError(`Internal Server Error`);
-                    log?.catch(err);
-                    throw err;
-                } else if (response.status >= 400 && !response.body?.errcode) {
-                    const err = new ConnectionError(`HTTP error status ${response.status} without errcode in body, assume this is a load balancer complaining the server is offline.`);
-                    log?.catch(err);
-                    throw err;
-                } else {
-                    const err = new HomeServerError(method, url, response.body, response.status);
-                    log?.set("errcode", err.errcode);
-                    log?.catch(err);
-                    throw err;
-                }
-            }
-        }, err => {
-            // if this._requestResult is still set, the abort error came not from calling abort here
-            if (err.name === "AbortError" && this._requestResult) {
-                // The service worker sometimes (only on Firefox, on long, large request,
-                // perhaps it has its own timeout?) aborts the request, see #187.
-                // When it happens, the best thing to do seems to be to retry.
-                // 
-                // In the service worker, we will also actively abort requests when trying to
-                // get a new service worker to activate, as the service worker will only be replaced
-                // when there are no more (fetch) events for the current one to handle.
-                // 
-                // In that case, the request function (in fetch.js) will check 
-                // the haltRequests flag on the service worker handler, and it will
-                // actually not do any requests, as that would break the update process.
-                // 
-                // So it is OK to return a timeout ConnectionError here.
-                // If we're updating the service worker, the /versions polling will
-                // actually be blocked at the fetch level because haltRequests is set.
-                // And for #187, retrying is the right thing to do.
-                const err = new ConnectionError(`Service worker aborted, either updating or hit #187.`, true);
-                log?.catch(err);
-                throw err;
-            } else {
-                if (err.name === "ConnectionError") {
-                    log?.set("timeout", err.isTimeout);
-                }
-                log?.catch(err);
-                throw err;
-            }
-        });
-    }
-
-    abort() {
-        if (this._requestResult) {
-            this._log?.set("aborted", true);
-            this._requestResult.abort();
-            // to mark that it was on purpose in above rejection handler
-            this._requestResult = null;
-        }
-    }
-
-    response() {
-        return this._promise;
-    }
-}
-
-function encodeBody(body) {
-    if (body.nativeBlob && body.mimeType) {
-        const blob = body;
-        return {
-            mimeType: blob.mimeType,
-            body: blob, // will be unwrapped in request fn
-            length: blob.size
-        };
-    } else if (typeof body === "object") {
-        const json = JSON.stringify(body);
-        return {
-            mimeType: "application/json",
-            body: json,
-            length: body.length
-        };
-    } else {
-        throw new Error("Unknown body type: " + body);
-    }
-}
 
 export class HomeServerApi {
     constructor({homeServer, accessToken, request, createTimeout, reconnector}) {
@@ -159,10 +67,10 @@ export class HomeServerApi {
             format: "json"  // response format
         });
 
-        const wrapper = new RequestWrapper(method, url, requestResult, log);
+        const hsRequest = new HomeServerRequest(method, url, requestResult, log);
         
         if (this._reconnector) {
-            wrapper.response().catch(err => {
+            hsRequest.response().catch(err => {
                 // Some endpoints such as /sync legitimately time-out
                 // (which is also reported as a ConnectionError) and will re-attempt,
                 // but spinning up the reconnector in this case is ok,
@@ -173,7 +81,7 @@ export class HomeServerApi {
             });
         }
 
-        return wrapper;
+        return hsRequest;
     }
 
     _unauthedRequest(method, url, queryParams, body, options) {
@@ -280,22 +188,13 @@ export class HomeServerApi {
     }
 }
 
-export function tests() {
+import {Request as MockRequest} from "../../mocks/Request.js";
-    function createRequestMock(result) {
-        return function() {
-            return {
-                abort() {},
-                response() {
-                    return Promise.resolve(result);
-                }
-            }
-        }
-    }
 
+export function tests() {
     return {
         "superficial happy path for GET": async assert => {
             const hsApi = new HomeServerApi({
-                request: createRequestMock({body: 42, status: 200}),
+                request: () => new MockRequest().respond(200, 42),
                 homeServer: "https://hs.tld"
             });
             const result = await hsApi._get("foo", null, null, null).response();

src/matrix/net/HomeServerRequest.js

@@ -0,0 +1,139 @@
+/*
+Copyright 2020 Bruno Windels <bruno@windels.cloud>
+Copyright 2020 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {HomeServerError, ConnectionError} from "../error.js";
+
+export class HomeServerRequest {
+    constructor(method, url, sourceRequest, log) {
+        this._log = log;
+        this._sourceRequest = sourceRequest;
+        this._promise = sourceRequest.response().then(response => {
+            log?.set("status", response.status);
+            // ok?
+            if (response.status >= 200 && response.status < 300) {
+                log?.finish();
+                return response.body;
+            } else {
+                if (response.status >= 500) {
+                    const err = new ConnectionError(`Internal Server Error`);
+                    log?.catch(err);
+                    throw err;
+                } else if (response.status >= 400 && !response.body?.errcode) {
+                    const err = new ConnectionError(`HTTP error status ${response.status} without errcode in body, assume this is a load balancer complaining the server is offline.`);
+                    log?.catch(err);
+                    throw err;
+                } else {
+                    const err = new HomeServerError(method, url, response.body, response.status);
+                    log?.set("errcode", err.errcode);
+                    log?.catch(err);
+                    throw err;
+                }
+            }
+        }, err => {
+            // if this._sourceRequest is still set, the abort error came not from calling abort here
+            if (err.name === "AbortError" && this._sourceRequest) {
+                // The service worker sometimes (only on Firefox, on long, large request,
+                // perhaps it has its own timeout?) aborts the request, see #187.
+                // When it happens, the best thing to do seems to be to retry.
+                // 
+                // In the service worker, we will also actively abort requests
+                // (this may surface in the app as a TypeError, which already gets mapped
+                // to a ConnectionError in the request function, or an AbortError,
+                // depending on the browser)
+                // when trying to get a new service worker to activate,
+                // as the service worker will only be replaced when there are
+                // no more (fetch) events for the current one to handle.
+                // 
+                // In that case, the request function (in fetch.js) will check 
+                // the haltRequests flag on the service worker handler, and it will
+                // actually not do any requests, as that would break the update process.
+                // 
+                // So it is OK to return a ConnectionError here.
+                // If we're updating the service worker, the /versions polling will
+                // actually be blocked at the fetch level because haltRequests is set.
+                // And for #187, retrying is the right thing to do.
+                const err = new ConnectionError(`Service worker aborted, either updating or hit #187.`);
+                log?.catch(err);
+                throw err;
+            } else {
+                if (err.name === "ConnectionError") {
+                    log?.set("timeout", err.isTimeout);
+                }
+                log?.catch(err);
+                throw err;
+            }
+        });
+    }
+
+    abort() {
+        if (this._sourceRequest) {
+            this._log?.set("aborted", true);
+            this._sourceRequest.abort();
+            // to mark that it was on purpose in above rejection handler
+            this._sourceRequest = null;
+        }
+    }
+
+    response() {
+        return this._promise;
+    }
+}
+
+import {Request as MockRequest} from "../../mocks/Request.js";
+import {AbortError} from "../error.js";
+
+export function tests() {
+    return {
+        "Response is passed through": async assert => {
+            const request = new MockRequest();
+            const hsRequest = new HomeServerRequest("GET", "https://hs.tld/foo", request);
+            request.respond(200, "foo");
+            assert.equal(await hsRequest.response(), "foo");
+        },
+        "Unexpected AbortError is mapped to ConnectionError": async assert => {
+            const request = new MockRequest();
+            const hsRequest = new HomeServerRequest("GET", "https://hs.tld/foo", request);
+            request.reject(new AbortError());
+            await assert.rejects(hsRequest.response(), ConnectionError);
+        },
+        "500 response is mapped to ConnectionError": async assert => {
+            const request = new MockRequest();
+            const hsRequest = new HomeServerRequest("GET", "https://hs.tld/foo", request);
+            request.respond(500);
+            await assert.rejects(hsRequest.response(), ConnectionError);
+        },
+        "4xx response is mapped to HomeServerError": async assert => {
+            const request = new MockRequest();
+            const hsRequest = new HomeServerRequest("GET", "https://hs.tld/foo", request);
+            request.respond(400, {errcode: "FOO"});
+            await assert.rejects(hsRequest.response(), HomeServerError);
+        },
+        "4xx response without errcode is mapped to ConnectionError": async assert => {
+            const request = new MockRequest();
+            const hsRequest = new HomeServerRequest("GET", "https://hs.tld/foo", request);
+            request.respond(400);
+            await assert.rejects(hsRequest.response(), ConnectionError);
+        },
+        "Other errors are passed through": async assert => {
+            class MyError extends Error {}
+            const request = new MockRequest();
+            const hsRequest = new HomeServerRequest("GET", "https://hs.tld/foo", request);
+            request.reject(new MyError());
+            await assert.rejects(hsRequest.response(), MyError);
+        },
+    };
+}

src/matrix/net/common.js

@@ -26,3 +26,23 @@ export function encodeQueryParams(queryParams) {
         })
         .join("&");
 }
+
+export function encodeBody(body) {
+    if (body.nativeBlob && body.mimeType) {
+        const blob = body;
+        return {
+            mimeType: blob.mimeType,
+            body: blob, // will be unwrapped in request fn
+            length: blob.size
+        };
+    } else if (typeof body === "object") {
+        const json = JSON.stringify(body);
+        return {
+            mimeType: "application/json",
+            body: json,
+            length: body.length
+        };
+    } else {
+        throw new Error("Unknown body type: " + body);
+    }
+}

src/mocks/Request.js

@@ -0,0 +1,41 @@
+/*
+Copyright 2020 Bruno Windels <bruno@windels.cloud>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {AbortError} from "../utils/error.js";
+
+export class Request {
+    constructor() {
+        this._responsePromise = new Promise((resolve, reject) => {
+            this.resolve = resolve;
+            this.reject = reject;
+        });
+        this.aborted = false;
+    }
+
+    respond(status, body) {
+        this.resolve({status, body});
+        return this;
+    }
+
+    abort() {
+        this.aborted = true;
+        this.reject(new AbortError());
+    }
+
+    response() {
+        return this._responsePromise;
+    }
+}