From 71a8092cb9ca270672b441b19d263c339c62379f Mon Sep 17 00:00:00 2001
From: Harley Adams <hadams@microsoft.com>
Date: Thu, 25 Jul 2019 11:20:59 -0700
Subject: [PATCH] Add FetchHttpClient

---
 .../ts/signalr/src/DefaultHttpClient.ts       |   5 +-
 .../clients/ts/signalr/src/FetchHttpClient.ts | 130 ++++++++++++++++++
 2 files changed, 134 insertions(+), 1 deletion(-)
 create mode 100644 src/SignalR/clients/ts/signalr/src/FetchHttpClient.ts

diff --git a/src/SignalR/clients/ts/signalr/src/DefaultHttpClient.ts b/src/SignalR/clients/ts/signalr/src/DefaultHttpClient.ts
index fece43020d..8058e5716a 100644
--- a/src/SignalR/clients/ts/signalr/src/DefaultHttpClient.ts
+++ b/src/SignalR/clients/ts/signalr/src/DefaultHttpClient.ts
@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 import { AbortError } from "./Errors";
+import { FetchHttpClient } from "./FetchHttpClient";
 import { HttpClient, HttpRequest, HttpResponse } from "./HttpClient";
 import { ILogger } from "./ILogger";
 import { NodeHttpClient } from "./NodeHttpClient";
@@ -15,7 +16,9 @@ export class DefaultHttpClient extends HttpClient {
     public constructor(logger: ILogger) {
         super();
 
-        if (typeof XMLHttpRequest !== "undefined") {
+        if (typeof fetch !== "undefined") {
+            this.httpClient = new FetchHttpClient(logger);
+        } else if (typeof XMLHttpRequest !== "undefined") {
             this.httpClient = new XhrHttpClient(logger);
         } else {
             this.httpClient = new NodeHttpClient(logger);
diff --git a/src/SignalR/clients/ts/signalr/src/FetchHttpClient.ts b/src/SignalR/clients/ts/signalr/src/FetchHttpClient.ts
new file mode 100644
index 0000000000..0b4c2754a7
--- /dev/null
+++ b/src/SignalR/clients/ts/signalr/src/FetchHttpClient.ts
@@ -0,0 +1,130 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+import { AbortError, HttpError, TimeoutError } from "./Errors";
+import { HttpClient, HttpRequest, HttpResponse } from "./HttpClient";
+import { ILogger, LogLevel } from "./ILogger";
+
+export class FetchHttpClient extends HttpClient {
+    private readonly logger: ILogger;
+
+    public constructor(logger: ILogger) {
+        super();
+        this.logger = logger;
+    }
+
+    /** @inheritDoc */
+    public send(request: HttpRequest): Promise<HttpResponse> {
+        // Check that abort was not signaled before calling send
+        if (request.abortSignal && request.abortSignal.aborted) {
+            return Promise.reject(new AbortError());
+        }
+
+        if (!request.method) {
+            return Promise.reject(new Error("No method defined."));
+        }
+        if (!request.url) {
+            return Promise.reject(new Error("No url defined."));
+        }
+
+        return new Promise<HttpResponse>((resolve, reject) => {
+            const abortController = new AbortController();
+
+            const fetchRequest = new Request(request.url!, {
+                body: request.content!,
+                cache: "no-cache",
+                credentials: "include",
+                headers: {
+                    "Content-Type": "text/plain;charset=UTF-8",
+                    "X-Requested-With": "Fetch",
+                    ...request.headers,
+                },
+                method: request.method!,
+                mode: "cors",
+                signal: abortController.signal,
+            });
+
+            // Hook our abourtSignal into the abort controller
+            if (request.abortSignal) {
+                request.abortSignal.onabort = () => {
+                    abortController.abort();
+                    reject(new AbortError());
+                };
+            }
+
+            // If a timeout has been passed in setup a timeout to call abort
+            // Type needs to be any to fit window.setTimeout and NodeJS.setTimeout
+            let timeoutId: any = null;
+            if (request.timeout) {
+                const msTimeout = request.timeout!;
+                timeoutId = setTimeout(() => {
+                    abortController.abort();
+                    reject(new TimeoutError());
+                }, msTimeout);
+            }
+
+            fetch(fetchRequest)
+                .then((response: Response) => {
+                    if (timeoutId) {
+                        clearTimeout(timeoutId);
+                    }
+                    if (!response.ok) {
+                        throw new Error(`${response.status}: ${response.statusText}.`);
+                    } else {
+                        return response;
+                    }
+                })
+                .then((response: Response) => {
+                    if (request.abortSignal) {
+                        request.abortSignal.onabort = null;
+                    }
+
+                    const content = deserializeContent(response, request.responseType);
+
+                    content.then((payload) => {
+                        resolve(new HttpResponse(
+                            response.status,
+                            response.statusText,
+                            payload,
+                        ));
+                    }).catch(() => {
+                        reject(new HttpError(response.statusText, response.status));
+                    });
+                })
+                .catch((error) => {
+                    this.logger.log(
+                        LogLevel.Warning,
+                        `Error from HTTP request. ${error.message}.`,
+                    );
+                    const [statusText, status] = error.message.split(":");
+                    reject(new HttpError(statusText, status));
+                });
+        });
+    }
+}
+
+function deserializeContent(response: Response, responseType?: XMLHttpRequestResponseType): Promise<any> {
+    let content;
+    switch (responseType) {
+        case "arraybuffer":
+            content = response.arrayBuffer();
+            break;
+        case "blob":
+            content = response.blob();
+            break;
+        case "document":
+            content = response.json();
+            break;
+        case "json":
+            content = response.json();
+            break;
+        case "text":
+            content = response.text();
+            break;
+        default:
+            content = response.text();
+            break;
+    }
+
+    return content;
+}