Blazor 0.6.0 "wipes" Flurl 兼容性？

Question

将 Blazor 从 0.5.1（使用 Flurl）更新到 0.6.0 后，通过 flurl 调用会抛出异常：

WASM: [Flurl.Http.FlurlHttpException] Call failed. Cannot invoke method 
because it was wiped. See stack trace for details.

该项目创建了一个 HttpClientFactory，它获取 Blazor 的 HttpClient 供 Flurl 使用：

使用 HttpClientFactoryForBlazor 使用 Blazor 的 HttpClient (http) 创建 FlurlClient：

IFlurlClient c = new FlurlClient() { Settings = new Flurl.Http.Configuration.ClientFlurlHttpSettings { HttpClientFactory = new HttpClientFactoryForBlazor(http) }};

例如通过 Flurl 的扩展方法使用 FlurlClient (c) "IFlurlRequest.WithClient(c);"

private class HttpClientFactoryForBlazor : Flurl.Http.Configuration.IHttpClientFactory
{
    private readonly HttpClient httpClient;

    public HttpClientFactoryForBlazor(HttpClient httpClient)
    {
        this.httpClient = httpClient;
    }

    public virtual HttpClient CreateHttpClient(HttpMessageHandler handler)
    {
        return this.httpClient;
    }
}

因此，这种方法似乎不再有效。

有人知道如何使用 Blazor 0.6.0 制作 Flurl 吗？

调用堆栈是：

WASM: [Flurl.Http.FlurlHttpException] Call failed. Cannot invoke method because it was wiped. See stack trace for details. GET http://srv01.servicegrid.eu:4455/API/Status?forceLoadDbs=False blazor.webassembly.js:1:32098
WASM:   at Flurl.Http.FlurlRequest.HandleExceptionAsync (Flurl.Http.HttpCall call, System.Exception ex, System.Threading.CancellationToken token) <0x26945b8 + 0x001c2> in <c38761af4558433f81b1691eb86a1548>:0 blazor.webassembly.js:1:32098
WASM:   at Flurl.Http.FlurlRequest.SendAsync (System.Net.Http.HttpMethod verb, System.Net.Http.HttpContent content, System.Threading.CancellationToken cancellationToken, System.Net.Http.HttpCompletionOption completionOption) <0x2665d30 + 0x005e6> in <c38761af4558433f81b1691eb86a1548>:0 blazor.webassembly.js:1:32098
WASM:   at Flurl.Http.FlurlRequest.SendAsync (System.Net.Http.HttpMethod verb, System.Net.Http.HttpContent content, System.Threading.CancellationToken cancellationToken, System.Net.Http.HttpCompletionOption completionOption) <0x2665d30 + 0x0079a> in <c38761af4558433f81b1691eb86a1548>:0 blazor.webassembly.js:1:32098
WASM:   at Flurl.Http.HttpResponseMessageExtensions.ReceiveJson[T] (System.Threading.Tasks.Task`1[TResult] response) <0x26a2180 + 0x000d6> in <c38761af4558433f81b1691eb86a1548>:0 blazor.webassembly.js:1:32098
WASM:   at DotNetFabrik.FlurlExtensions.FlurlRequestExtensions.HandleWebApiExceptions[T] (System.Threading.Tasks.Task`1[TResult] task) <0x26a43f8 + 0x000e2> in <8c1e6df9d3f545cd831ff49915df2d85>:0 blazor.webassembly.js:1:32098
WASM:   at DotNetFabrik.FlurlExtensions.FlurlRequestExtensions.HandleWebApiExceptions[T] (System.Threading.Tasks.Task`1[TResult] task) <0x26a43f8 + 0x00264> in <8c1e6df9d3f545cd831ff49915df2d85>:0 blazor.webassembly.js:1:32098
WASM:   at BlazorCoreDMSTools.CommunicationService.CommunicationService.SetTokenAsync (System.String token, System.String database, System.String serverUri) <0x260dc60 + 0x00d9e> in <cb925648b50340888772566fbaeac465>:0

Answer 1

仅出于某些背景，Blazor 团队正在显着减少应用程序的占用空间，并采取一些措施 unusual measures 来实现这一目标。简而言之，他们减少了大约 20% "wiping" HttpClientHandler。

wipe means "replace specified method bodies with a single throw instruction". Doing this (instead of actually removing the method entirely) means that the assembly retains a completely standard API surface, and if you try to use one of the wiped methods, you get an easy-to-understand exception stack trace that tells you which wiped method you're trying to call.

这就是您遇到的问题：Blazor 仍然知道 HttpClientHandler 用于编译目的，但如果您（或在本例中为兼容库）尝试使用它，则会抛出运行时异常.

但是 HttpClient 必须包装一些实现 HttpMessageHandler Blazor 有它自己的：BrowserHttpMessageHandler. And Flurl provides an easy way to swap this in via its HttpClientFactory。但是您不需要传入 HttpClient 实例或实现 CreateHttpClient。相反，从 DefaultHttpClientFactory 继承并覆盖 CreateMessageHandler:

private class HttpClientFactoryForBlazor : DefaultHttpClientFactory
{
    public override HttpMessageHandler CreateMessageHandler()
    {
        return new BrowserHttpMessageHandler();
    }
}

我还建议在应用程序启动时全局注册一次，而不是每次创建 FlurlClient:

FlurlHttp.Configure(settings =>
{
    settings.HttpClientFactory = new HttpClientFactoryForBlazor();
});

还应注意，Blazor 仍处于实验阶段，BrowserHttpMessageHandler may be deprecated in a future release，因此预计这可能只是一个临时的解决方法。

Answer 2

目前在我的 3.0 预览版 5 中，BrowserHttpMessageHandler 已经不存在了。这是我目前的修复，只是不使用任何 HttpMessageHandler。据我所知，我还没有遇到任何问题，但我不确定在所有用例中：

class BlazorHttpClientFactory : DefaultHttpClientFactory
{

    public override HttpClient CreateHttpClient(HttpMessageHandler handler)
    {
        return new HttpClient();
    }

    public override HttpMessageHandler CreateMessageHandler()
    {
        return null;
    }

}

Blazor 0.6.0 "wipes" Flurl 兼容性？

Blazor 0.6.0 "wipes" Flurl-compatibility?

flurl

blazor

httpclientfactory