如何在桌面應用程式.NET6.0發布的C#中讀取最小API中的POST引數？

我正在嘗試構建一個從 .NET 6.0 最小 API 服務器獲取資料的小型桌面應用程式 (.NET 6.0)。

API 服務器代碼為：

//app.MapPost("/show/", async Task<string> (string myName) =>
app.MapPost("/show/", async Task<string> (HttpRequest request) =>
{
    //return await Task.FromResult(myName);
    return await Task.FromResult(request.Query["myName"]);
});

郵遞員可以郵寄到

http://127.0.0.1:5400/show?myName=Srikanth S

并在未注釋和已注釋版本中得到答復。

桌面應用程式的回應物件有

狀態碼：500，原因短語：“內部服務器錯誤”

致電后

app.MapPost("/show/", async Task<string> (string myName)

版本，而它回應

StatusCode: 400, ReasonPhrase: 'Bad Request'

在回應物件和

查詢字串未提供必需的引數“string myName”

在結果物件上。

我的桌面應用程式只有這個簡單的代碼

    private async void button1_Click(object sender, EventArgs e)
    {
        Dictionary<string, string> content = new Dictionary<string, string>();
        content.Add("myName", "Srikanth S");

        using (HttpClient client = new HttpClient())
        {
            HttpResponseMessage response = await client.PostAsync("http://127.0.0.1:5400/show", new FormUrlEncodedContent(content));
            string result = await response.Content.ReadAsStringAsync();
            Debug.WriteLine(result);
        }
    }

StringContent我嘗試了, FormUrlEncodedContent, Dictionary, KeyvaluePair...的排列組合；

看起來它沒有在HttpRequest版本中捕獲“myName”。

請問有什么指導或解決方案嗎？

更新：創建新的 .net core web api 專案（天氣預報示例），添加

app.MapPost("/show/", (string myName) =>
{
    return myName;
});

以及嘗試過

app.MapPost("/show/", async (string myName) =>
{
    return await Task.FromResult(myName);
});

桌面應用程式沒有變化，我在除錯輸出中得到這個，如下所示

Microsoft.AspNetCore.Http.BadHttpRequestException: Required parameter "string myName" was not provided from query string.
   at Microsoft.AspNetCore.Http.RequestDelegateFactory.Log.RequiredParameterNotProvided(HttpContext httpContext, String parameterTypeName, String parameterName, String source, Boolean shouldThrow)
   at lambda_method2(Closure , Object , HttpContext )
   at Microsoft.AspNetCore.Http.RequestDelegateFactory.<>c__DisplayClass36_0.<Create>b__0(HttpContext httpContext)
   at Microsoft.AspNetCore.Routing.EndpointMiddleware.Invoke(HttpContext httpContext)
--- End of stack trace from previous location ---
   at Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext)
   at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

HEADERS
=======
Host: 127.0.0.1:5145
Content-Type: application/x-www-form-urlencoded
Content-Length: 17

非常感謝任何幫助。對于背景，我使用的是 Visual Studio 2022 社區版版本 17.3.6，dotnet 6.0.402

求救

uj5u.com熱心網友回復：

使用 Postman 檢查 API 方法時，可以看到請求 URL 中添加了引數。

Dictionary<string, string> content = new Dictionary<string, string>();
content.Add("myName", "Srikanth S");

using (HttpClient client = new HttpClient())
{
    HttpResponseMessage response = await client.PostAsync("http://127.0.0.1:5400/show", new  FormUrlEncodedContent(content));
    string result = await response.Content.ReadAsStringAsync();
    Debug.WriteLine(result);
}

但是在桌面應用中，引數被添加到請求體中，所以在這種場景下，API方法無法從請求URL中找到值，所以該值為null，會拋出例外。

為了解決這個問題，您可以嘗試通過 Query String 發送引數：在請求 URL 的末尾添加引數，如下所示：

    var name = "Srikanth S";
    using (HttpClient client = new HttpClient())
    {
        HttpResponseMessage response = await client.PostAsync($"http://127.0.0.1:5400?myName={name}", null);
        string result = await response.Content.ReadAsStringAsync();
        Debug.WriteLine(result);
    }

API方法：

app.MapPost("/show/", async Task<string> (HttpRequest request) =>
{
    //return await Task.FromResult(myName);
    return await Task.FromResult(request.Query["myName"]);
});

或者您可以從請求正文中發送引數：在 API 方法中，您可以從表單中獲取引數。修改API方法如下：

app.MapPost("/show/", async Task<string> (HttpRequest request) =>
{
    //return await Task.FromResult(myName);
    return await Task.FromResult(request.Form["myName"]); //get value from form.
});

這時候，HttpClient 方法是這樣的：

   Dictionary<string, string> content = new Dictionary<string, string>();
    content.Add("myName", "Srikanth S");

    using (HttpClient client = new HttpClient())
    {
        HttpResponseMessage response = await client.PostAsync("http://127.0.0.1:5400/show", new FormUrlEncodedContent(content));
        string result = await response.Content.ReadAsStringAsync();
        Debug.WriteLine(result);
    }

請參閱以下螢屏截圖：

uj5u.com熱心網友回復：

PostAsync的第二個引數用于正文，而不是查詢字串資料。只需將myName查詢引數添加到 URL。

HttpResponseMessage response = await Client.PostAsync(
    "http://127.0.0.1:5400/show?myName=Jose", // <----- Like this
    new FormUrlEncodedContent(content)
);

uj5u.com熱心網友回復：

謝謝大家的指導和幫助。最后我破解了它:)希望這對每個人都有用。關鍵是要從 api 服務器上的請求正文中讀取發布資料。這是我的做法

app.MapPost("/show/", async (HttpRequest request) =>
{
    var body = new StreamReader(request.Body);
    string postData = await body.ReadToEndAsync();
    Dictionary<string, dynamic> keyValuePairs = JsonSerializer.Deserialize<Dictionary<string, dynamic>>(postData) ?? new Dictionary<string, dynamic>();
    // here after you can play as you like :)
    return await Task.FromResult<string>(postData);
});

我的桌面應用程式代碼

        private async void button1_Click(object sender, EventArgs e)
        {
            var client = new HttpClient();

            using StringContent jsonContent = new(
            JsonSerializer.Serialize(new {myName = "Srikanth S"}), Encoding.UTF8, "application/json");

            using HttpResponseMessage response = await client.PostAsync("http://127.0.0.1:5145/show", jsonContent);

            response.EnsureSuccessStatusCode();
            var jsonResponse = await response.Content.ReadAsStringAsync();
            // here after you can play as you like :)
            Debug.WriteLine(jsonResponse);
        }

標籤：。网asp.net 核心.net-6.0桌面应用程序最小的 API

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