c# - 在 Web Api Controller 操作中使用正文流参数

Question

我目前从正文中读取输入流是这样的:

public async Task<IActionResult> Post()
{
    byte[] array = new byte[Request.ContentLength.Value];

    using (MemoryStream memoryStream = new MemoryStream(array))
    {
        await Request.Body.CopyToAsync(memoryStream);
    }

    return Ok();
}

由于测试和 swagger 生成，我想在方法签名中指定输入参数。

是否可以通过某种方式将输入参数指定为流？

public async Task<IActionResult> Post([FromBody]Stream body) ...

Answer 1

您必须为流创建模型绑定(bind)器:

public class StreamBinder : IModelBinder
{
    public Task BindModelAsync(ModelBindingContext bindingContext)
    {
        bindingContext.Result = ModelBindingResult.Success(bindingContext.HttpContext.Request.Body);
        return Task.CompletedTask;
    }
}

然后你应该为它创建模型 Binder 提供者:

public class StreamBinderProvider : IModelBinderProvider
{
    public IModelBinder GetBinder(ModelBinderProviderContext context)
    {
        if (context == null)
        {
            throw new ArgumentNullException(nameof(context));
        }

        if (context.Metadata.ModelType == typeof(Stream))
        {
            return new BinderTypeModelBinder(typeof(StreamBinder));
        }

        return null;
    }
}

并注册它:

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllers(options =>
    {
        options.ModelBinderProviders.Insert(0, new StreamBinderProvider());
    });
}

用法:

public async Task<IActionResult> Post([FromBody]Stream body) ...