json - 将 JSON 数据发布到 Dotnet Core webapi

Question

我正在使用 aspnet core 开发 WebApi。我已经能够设置一个基本项目并且获取请求运行良好。

现在我正在尝试使用 postman 将复杂的 JSON 对象发布到 API。 API 代码如下:

//controller class
public class DemoController : ControllerBase {

    [HttpPost]
    public IActionResult Action1([FromBody]TokenRequest request) {
        /* This works. I get request object with properties populated */
    }

    [HttpPost]
    public IActionResult Action2(TokenRequest request) {
        /* The request is received. But properties are null */
    }
}

//TokenRequest Class
public class TokenRequest {
    public string Username { get; set; }
    public string Password { get; set; }
}

尝试用 postman 进行相同的测试。

请求 1:(Action1 和 Action2 均失败)

POST /Demo/Action2 HTTP/1.1
Host: localhost:5001
Content-Type: application/json
Cache-Control: no-cache
Postman-Token: 42642430-bbd3-49ca-a56c-cb3f5f2177cc

{
    "request": {
        "Username": "saurabh",
        "Password": "******"
    }
}

请求 2:(Action1 成功，Action2 失败)

POST /User/Register HTTP/1.1
Host: localhost:5001
Content-Type: application/json
Cache-Control: no-cache
Postman-Token: 94141e01-7fef-4847-953e-a9acb4e6c445

{
    "Username": "saurabh",
    "Password": "******"
}

由于 [FromBody[ 标签，这些东西与 Action1 一起工作。但是万一我需要接受多个参数呢？喜欢

public IActionResult Action1(int param1, TokenRequest request)

选项 1:使用包装器类(如 Francisco Goldenstein 所建议的那样)

[FromBody] 不能与两个不同的参数一起使用。有什么优雅的解决方案可以让我在 Action 方法中接受它们作为单独的参数吗？

Answer 1

另一种发布多个对象的解决方案是使用 Form 并将每个 json 对象发布在表单的单独字段中。将 JsonBinder 应用到它，我们可以像使用 [FromBody] 一样在参数中使用模型。

public class FormDataJsonBinder : IModelBinder
{
    public Task BindModelAsync(ModelBindingContext bindingContext)
    {
        if (bindingContext == null) throw new ArgumentNullException(nameof(bindingContext));

        // Fetch the value of the argument by name and set it to the model state
        string fieldName = bindingContext.FieldName;
        var valueProviderResult = bindingContext.ValueProvider.GetValue(fieldName);
        if (valueProviderResult == ValueProviderResult.None) return Task.CompletedTask;
        else bindingContext.ModelState.SetModelValue(fieldName, valueProviderResult);

        // Do nothing if the value is null or empty
        string value = valueProviderResult.FirstValue;
        if (string.IsNullOrEmpty(value)) return Task.CompletedTask;

        try
        {
            // Deserialize the provided value and set the binding result
            object result = JsonConvert.DeserializeObject(value, bindingContext.ModelType);
            bindingContext.Result = ModelBindingResult.Success(result);
        }
        catch (JsonException)
        {
            bindingContext.Result = ModelBindingResult.Failed();
        }

        return Task.CompletedTask;
    }
}

Action 将是:

public IActionResult Action1(
    [FromForm][ModelBinder(BinderType = typeof(FormDataJsonBinder))] TokenRequest request,
    [FromForm][ModelBinder(BinderType = typeof(FormDataJsonBinder))] TokenRequest request1)
{
    return Ok();
}

虽然我会选择包装类选项。