Support arbitrary 'fetch' arguments

src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Services/Http.ts

@@ -7,19 +7,22 @@ const httpClientTypeName = 'BrowserHttpMessageHandler';
 const httpClientFullTypeName = `${httpClientNamespace}.${httpClientTypeName}`;
 let receiveResponseMethod: MethodHandle;
 
-registerFunction(`${httpClientFullTypeName}.Send`, (id: number, method: string, requestUri: string, body: string | null, headersJson: string | null) => {
-  sendAsync(id, method, requestUri, body, headersJson);
+registerFunction(`${httpClientFullTypeName}.Send`, (id: number, method: string, requestUri: string, body: string | null, headersJson: string | null, fetchArgs: RequestInit | null) => {
+  sendAsync(id, method, requestUri, body, headersJson, fetchArgs);
 });
 
-async function sendAsync(id: number, method: string, requestUri: string, body: string | null, headersJson: string | null) {
+async function sendAsync(id: number, method: string, requestUri: string, body: string | null, headersJson: string | null, fetchArgs: RequestInit | null) {
   let response: Response;
   let responseText: string;
+
+  const requestInit = fetchArgs || {};
+  requestInit.method = method;
+  requestInit.body = body || undefined;
+
   try {
-    response = await fetch(requestUri, {
-      method: method,
-      body: body || undefined,
-      headers: headersJson ? (JSON.parse(headersJson) as string[][]) : undefined
-    });
+    requestInit.headers = headersJson ? (JSON.parse(headersJson) as string[][]) : undefined;
+
+    response = await fetch(requestUri, requestInit);
     responseText = await response.text();
   } catch (ex) {
     dispatchErrorResponse(id, ex.toString());

src/Microsoft.AspNetCore.Blazor.Browser/Http/BrowserHttpMessageHandler.cs

@@ -22,6 +22,8 @@ namespace Microsoft.AspNetCore.Blazor.Browser.Http
         static IDictionary<int, TaskCompletionSource<HttpResponseMessage>> _pendingRequests
             = new Dictionary<int, TaskCompletionSource<HttpResponseMessage>>();
 
+        public const string FetchArgs = "BrowserHttpMessageHandler.FetchArgs";
+
         /// <inheritdoc />
         protected override async Task<HttpResponseMessage> SendAsync(
             HttpRequestMessage request, CancellationToken cancellationToken)
@@ -36,13 +38,16 @@ namespace Microsoft.AspNetCore.Blazor.Browser.Http
                 _pendingRequests.Add(id, tcs);
             }
 
+            request.Properties.TryGetValue(FetchArgs, out var fetchArgs);
+
             RegisteredFunction.Invoke<object>(
                 $"{typeof(BrowserHttpMessageHandler).FullName}.Send",
                 id,
                 request.Method.Method,
                 request.RequestUri,
                 request.Content == null ? null : await GetContentAsString(request.Content),
-                SerializeHeadersAsJson(request));
+                SerializeHeadersAsJson(request),
+                fetchArgs);
 
             return await tcs.Task;
         }

test/Microsoft.AspNetCore.Blazor.E2ETest/Tests/HttpClientTest.cs

@@ -97,6 +97,15 @@ namespace Microsoft.AspNetCore.Blazor.E2ETest.Tests
             Assert.Equal("{\"id\":123,\"name\":\"Bert\"}", _responseBody.Text);
         }
 
+        [Fact]
+        public void CanSetRequestReferer()
+        {
+            SetValue("request-referrer", "/test-referrer");
+            IssueRequest("GET", "/api/person/referrer");
+            Assert.Equal("OK", _responseStatus.Text);
+            Assert.EndsWith("/test-referrer", _responseBody.Text);
+        }
+
         private void IssueRequest(string requestMethod, string relativeUri, string requestBody = null)
         {
             var targetUri = new Uri(_apiServerFixture.RootUri, relativeUri);

test/testapps/BasicTestApp/HttpClientTest/HttpRequestsComponent.cshtml

@@ -1,5 +1,6 @@
 @using System.Net
 @using System.Net.Http
+@using Microsoft.AspNetCore.Blazor.Browser.Http
 @inject HttpClient Http
 
 <h1>HTTP request tester</h1>
@@ -37,6 +38,11 @@
     <button id="add-header" @onclick(AddHeader)>Add</button>
 </p>
 
+<p>
+    <div>Request referrer:</div>
+    <input id="request-referrer" type="text" value=@requestReferrer @onchange(value => { requestReferrer = (string)value; }) />
+</p>
+
 <button id="send-request" @onclick(DoRequest)>Request</button>
 
 @if (responseStatusCode.HasValue)
@@ -59,6 +65,7 @@
     string method = "GET";
     string requestBody = "";
     List<RequestHeader> requestHeaders = new List<RequestHeader>();
+    string requestReferrer = "";
 
     HttpStatusCode? responseStatusCode;
     string responseBody;
@@ -87,6 +94,14 @@
                 }
             }
 
+            if (!string.IsNullOrEmpty(requestReferrer))
+            {
+                requestMessage.Properties[BrowserHttpMessageHandler.FetchArgs] = new
+                {
+                    referrer = requestReferrer
+                };
+            }
+
             var response = await Http.SendAsync(requestMessage);
             responseStatusCode = response.StatusCode;
             responseBody = await response.Content.ReadAsStringAsync();

test/testapps/TestServer/Controllers/PersonController.cs

@@ -1,7 +1,6 @@
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
 using System.IO;
-using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Cors;
@@ -32,6 +31,12 @@ namespace TestServer.Controllers
             }
         }
 
+        [HttpGet("referrer")]
+        public string GetReferer()
+        {
+            return $"The referrer is: {Request.Headers["Referer"].ToString()}";
+        }
+
         // PUT api/person
         [HttpPut]
         public Person Put([FromBody, Required] Person person)