SteveSandersonMS/Home.cshtml

## Home.cshtml
@using StandaloneApp.Util
@(Layout<StandaloneApp.Shared.MainLayout>())
<h1>Hello, world!</h1>

Welcome to your new app.

<button @onclick(DoRequest)>Do request</button>
<div><strong>Response: </strong>@responseText</div>

@functions {
    string responseText;

    private async void DoRequest()
    {
        responseText = await new MyHttpClient().GetStringAsync("/index.html");
        StateHasChanged();
    }
}

## index.html
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8" />
    <title>Blazor standalone</title>
    <link href="/css/bootstrap/bootstrap.min.css" rel="stylesheet" />
    <link href="/css/site.css" rel="stylesheet" />
</head>
<body>
    <app>Loading...</app>

    <script src="/css/bootstrap/bootstrap-native.min.js"></script>
    <script type="blazor-boot"></script>
    <script src="myhttpclient.js"></script>
</body>
</html>

## MyHttpClient.cs
using Microsoft.AspNetCore.Blazor.Browser.Interop;
using System.Collections.Generic;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;

namespace StandaloneApp.Util
{
    public class MyHttpClient
    {
        static object _idLock = new object();
        static int _nextRequestId = 0;
        static IDictionary<int, TaskCompletionSource<HttpResponseMessage>> _pendingRequests
            = new Dictionary<int, TaskCompletionSource<HttpResponseMessage>>();

        public async Task<string> GetStringAsync(string requestUri)
        {
            var response = await GetAsync(requestUri);
            if (!response.IsSuccessStatusCode)
            {
                throw new HttpRequestException($"The response status code was {response.StatusCode}");
            }
            return await response.Content.ReadAsStringAsync();
        }

        public Task<HttpResponseMessage> GetAsync(string requestUri)
        {
            var tcs = new TaskCompletionSource<HttpResponseMessage>();
            int id;
            lock (_idLock)
            {
                id = _nextRequestId++;
                _pendingRequests.Add(id, tcs);
            }

            RegisteredFunction.Invoke<object>("HttpClientSend", id, requestUri);

            return tcs.Task;
        }

        private static void ReceiveResponse(string id, string statusCode, string responseText, string errorText)
        {
            TaskCompletionSource<HttpResponseMessage> tcs;
            var idVal = int.Parse(id);
            lock (_idLock)
            {
                tcs = _pendingRequests[idVal];
                _pendingRequests.Remove(idVal);
            }

            if (errorText == null)
            {
                tcs.SetResult(new HttpResponseMessage
                {
                    StatusCode = (HttpStatusCode)int.Parse(statusCode),
                    Content = new StringContent(responseText)
                });
            }
            else
            {
                tcs.SetException(new HttpRequestException(errorText));
            }
        }
    }
}

## myhttpclient.js
(function () {
    function dispatchResponse(id, statusCode, responseText, errorInfo) {
        var method = Blazor.platform.findMethod('StandaloneApp', 'StandaloneApp.Util', 'MyHttpClient', 'ReceiveResponse');
        Blazor.platform.callMethod(method, null, [
            Blazor.platform.toDotNetString(id.toString()),
            Blazor.platform.toDotNetString(statusCode.toString()),
            responseText === null ? null : Blazor.platform.toDotNetString(responseText),
            errorInfo === null ? null : Blazor.platform.toDotNetString(errorInfo.toString())
        ]);
    }
    Blazor.registerFunction('HttpClientSend', function (id, requestUri) {
        fetch(requestUri).then(function (response) {
            return response.text().then(function (responseText) {
                dispatchResponse(id, response.status, responseText, null);
            });
        }).catch(function (errorInfo) { dispatchResponse(id, 0, null, errorInfo); });
    });
})();
	@using StandaloneApp.Util
	@(Layout<StandaloneApp.Shared.MainLayout>())
	<h1>Hello, world!</h1>

	Welcome to your new app.

	<button @onclick(DoRequest)>Do request</button>
	<div><strong>Response: </strong>@responseText</div>

	@functions {
	string responseText;

	private async void DoRequest()
	{
	responseText = await new MyHttpClient().GetStringAsync("/index.html");
	StateHasChanged();
	}
	}
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8" />
	<title>Blazor standalone</title>
	<link href="/css/bootstrap/bootstrap.min.css" rel="stylesheet" />
	<link href="/css/site.css" rel="stylesheet" />
	</head>
	<body>
	<app>Loading...</app>

	<script src="/css/bootstrap/bootstrap-native.min.js"></script>
	<script type="blazor-boot"></script>
	<script src="myhttpclient.js"></script>
	</body>
	</html>
	using Microsoft.AspNetCore.Blazor.Browser.Interop;
	using System.Collections.Generic;
	using System.Net;
	using System.Net.Http;
	using System.Threading.Tasks;

	namespace StandaloneApp.Util
	{
	public class MyHttpClient
	{
	static object _idLock = new object();
	static int _nextRequestId = 0;
	static IDictionary<int, TaskCompletionSource<HttpResponseMessage>> _pendingRequests
	= new Dictionary<int, TaskCompletionSource<HttpResponseMessage>>();

	public async Task<string> GetStringAsync(string requestUri)
	{
	var response = await GetAsync(requestUri);
	if (!response.IsSuccessStatusCode)
	{
	throw new HttpRequestException($"The response status code was {response.StatusCode}");
	}
	return await response.Content.ReadAsStringAsync();
	}

	public Task<HttpResponseMessage> GetAsync(string requestUri)
	{
	var tcs = new TaskCompletionSource<HttpResponseMessage>();
	int id;
	lock (_idLock)
	{
	id = _nextRequestId++;
	_pendingRequests.Add(id, tcs);
	}

	RegisteredFunction.Invoke<object>("HttpClientSend", id, requestUri);

	return tcs.Task;
	}

	private static void ReceiveResponse(string id, string statusCode, string responseText, string errorText)
	{
	TaskCompletionSource<HttpResponseMessage> tcs;
	var idVal = int.Parse(id);
	lock (_idLock)
	{
	tcs = _pendingRequests[idVal];
	_pendingRequests.Remove(idVal);
	}

	if (errorText == null)
	{
	tcs.SetResult(new HttpResponseMessage
	{
	StatusCode = (HttpStatusCode)int.Parse(statusCode),
	Content = new StringContent(responseText)
	});
	}
	else
	{
	tcs.SetException(new HttpRequestException(errorText));
	}
	}
	}
	}
	(function () {
	function dispatchResponse(id, statusCode, responseText, errorInfo) {
	var method = Blazor.platform.findMethod('StandaloneApp', 'StandaloneApp.Util', 'MyHttpClient', 'ReceiveResponse');
	Blazor.platform.callMethod(method, null, [
	Blazor.platform.toDotNetString(id.toString()),
	Blazor.platform.toDotNetString(statusCode.toString()),
	responseText === null ? null : Blazor.platform.toDotNetString(responseText),
	errorInfo === null ? null : Blazor.platform.toDotNetString(errorInfo.toString())
	]);
	}
	Blazor.registerFunction('HttpClientSend', function (id, requestUri) {
	fetch(requestUri).then(function (response) {
	return response.text().then(function (responseText) {
	dispatchResponse(id, response.status, responseText, null);
	});
	}).catch(function (errorInfo) { dispatchResponse(id, 0, null, errorInfo); });
	});
	})();