Blazor does not support System.Net.Http.HttpClientHandler

[linvi]

Describe the bug

Trying to use an HttpClientHandler in blazor results in:

WASM: System.PlatformNotSupportedException: System.Net.Http.HttpClientHandler is not supported on the current platform.
WASM:   at System.Net.Http.HttpClientHandler.set_UseCookies (System.Boolean value) <0x34686c8 + 0x0000c>

or

 System.NotImplementedException: Cannot invoke method because it was wiped. See stack trace for details.

To Reproduce

• Create a Blazor WebAssembly 3.0 project.
• Modify a page and put the following code:

@page "/counter"

<h1>Example</h1>
<p>Status: @status</p>

<button class="btn btn-primary" @onclick="Try">Click...</button>

@code {
    public class ClientHandler : HttpClientHandler
    {
    }

    string status = "Not yet loaded...";

    async Task Try()
    {
        status = "loading...";

        var client = new HttpClient(new ClientHandler());
        var response = await client.GetAsync("https://www.google.com");

        status = response.IsSuccessStatusCode ? "success" : "failure";
    }
}

• Click on the button

You can also try with the Tweetinvi library that intensively use custom HttpClientHandlers

dotnet add package TweetinviApi -v 5.0.0-alpha-8

@page "/counter"
@using Tweetinvi.Models
@using Tweetinvi

<h1>Counter</h1>

<p>Username: @username</p>

<button class="btn btn-primary" @onclick="LoadUser">Load user</button>

@code {
    string username = "Not yet loaded...";

    async Task LoadUser()
    {
        username = "loading..."
    
        var creds = new TwitterCredentials("CONSUMER_KEY",
            "CONSUMER_SECRET",
            "ACCESS_TOKEN", "ACCESS_TOKEN_SECRET");

        ITwitterClient client = new TwitterClient(creds);
        var user = await client.Users.GetAuthenticatedUserAsync();
        username = user.Name;
    }
}

Exceptions (if any)

WASM: System.PlatformNotSupportedException: System.Net.Http.HttpClientHandler is not supported on the current platform.
WASM:   at System.Net.Http.HttpClientHandler.set_UseCookies (System.Boolean value) <0x34686c8 + 0x0000c>

Further technical details

• ASP.NET Core version

Microsoft.AspNetCore.Blazor : Version=3.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60

• Include the output of dotnet --info

.NET Core SDK (reflecting any global.json):
 Version:   3.1.201
 Commit:    b1768b4ae7

Runtime Environment:
 OS Name:     Mac OS X
 OS Version:  10.15
 OS Platform: Darwin
 RID:         osx.10.15-x64
 Base Path:   /usr/local/share/dotnet/sdk/3.1.201/

Host (useful for support):
  Version: 3.1.3
  Commit:  4a9f85e9f8

.NET Core SDKs installed:
  2.1.4 [/usr/local/share/dotnet/sdk]
  2.1.503 [/usr/local/share/dotnet/sdk]
  2.1.504 [/usr/local/share/dotnet/sdk]
  2.1.505 [/usr/local/share/dotnet/sdk]
  2.2.104 [/usr/local/share/dotnet/sdk]
  2.2.401 [/usr/local/share/dotnet/sdk]
  3.0.103 [/usr/local/share/dotnet/sdk]
  3.1.101 [/usr/local/share/dotnet/sdk]
  3.1.200 [/usr/local/share/dotnet/sdk]
  3.1.201 [/usr/local/share/dotnet/sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.1 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.2 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.7 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.8 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.9 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.2 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.6 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.1 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.2 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.7 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.8 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.9 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.2 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.6 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.3 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.1 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.2 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.3 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 1.0.4 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 1.1.1 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.0.5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.1 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.2 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.7 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.8 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.9 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.16 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.2 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.6 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.3 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.1 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.2 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.3 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

To install additional .NET Core runtimes or SDKs:
  https://aka.ms/dotnet-download

• The IDE (VS / VS Code/ VS4Mac) you're running on, and it's version

• Rider MacOS

[campersau]

Yes, not all features of HttpClientHandler are supported inside the browser sandbox. See

runtime/src/libraries/System.Net.Http/src/System/Net/Http/BrowserHttpHandler/BrowserHttpHandler.cs

Lines 51 to 131 in 7f9b8ce

	public bool UseCookies
	{
	get => throw new PlatformNotSupportedException();
	set => throw new PlatformNotSupportedException();
	}
	public CookieContainer CookieContainer
	{
	get => throw new PlatformNotSupportedException();
	set => throw new PlatformNotSupportedException();
	}
	public DecompressionMethods AutomaticDecompression
	{
	get => throw new PlatformNotSupportedException();
	set => throw new PlatformNotSupportedException();
	}
	public bool UseProxy
	{
	get => throw new PlatformNotSupportedException();
	set => throw new PlatformNotSupportedException();
	}
	public IWebProxy? Proxy
	{
	get => throw new PlatformNotSupportedException();
	set => throw new PlatformNotSupportedException();
	}
	public ICredentials? DefaultProxyCredentials
	{
	get => throw new PlatformNotSupportedException();
	set => throw new PlatformNotSupportedException();
	}
	public bool PreAuthenticate
	{
	get => throw new PlatformNotSupportedException();
	set => throw new PlatformNotSupportedException();
	}
	public ICredentials? Credentials
	{
	get => throw new PlatformNotSupportedException();
	set => throw new PlatformNotSupportedException();
	}
	public bool AllowAutoRedirect
	{
	get => _allowAutoRedirect;
	set
	{
	_allowAutoRedirect = value;
	_isAllowAutoRedirectTouched = true;
	}
	}
	public int MaxAutomaticRedirections
	{
	get => throw new PlatformNotSupportedException();
	set => throw new PlatformNotSupportedException();
	}
	public int MaxConnectionsPerServer
	{
	get => throw new PlatformNotSupportedException();
	set => throw new PlatformNotSupportedException();
	}
	public int MaxResponseHeadersLength
	{
	get => throw new PlatformNotSupportedException();
	set => throw new PlatformNotSupportedException();
	}
	public SslClientAuthenticationOptions SslOptions
	{
	get => throw new PlatformNotSupportedException();
	set => throw new PlatformNotSupportedException();
	}

I guess tweetinvi would need to be updated to account for that here https://github.com/linvi/tweetinvi/blob/0381167535872ba94b89237213b6929536449476/src/Tweetinvi.WebLogic/TwitterClientHandler.cs#L22-L23

[ghost]

Tagging subscribers to this area: @dotnet/ncl
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[pranavkm]

Thanks @campersau for responding to this. For rc2, we've added an analyzer that should tell you at build time if these APIs are going to be unavailable.

/cc @kjpou1 in case you'd like to add more content.

[kjpou1]

Not sure what else can be added. The HttpClient uses the browsers underlying fetch implementation. Fetch does not support Cookies thus the Properties referencing cookies are marked as not supported.

Will close for now. If someone sees this in error please reopen.

[wfurt]

is it not possible to set cookie header @kjpou1 ? From the link it seems like headers can be passed in...?

[campersau]

You can set some custom headers but not for cookies, they are handled entirely by the browser. You can only tell the browser to include them by setting the credentials option.
See JakeChampion/fetch#349

Also sending custom headers only works partially when doing cross domain requests.
See https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch and https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS

Browser specific settings like including credentials (aka cookies) in cross domain requests can be set via these methods:
https://github.com/dotnet/aspnetcore/blob/f52077f599f0d3b4545d8f87a0c3d15217b33069/src/Components/WebAssembly/WebAssembly/src/Http/WebAssemblyHttpRequestMessageExtensions.cs

[kjpou1]

Thanks for the follow up @campersau