dotnet core webapi json-api 兼容查询字符串路由

Question

我试图从请求的 URL 中获取“状态”和“全部”键、值，但不知道如何构建我的类对象。

我所指的 JSON API 规范可以在这里找到： http://jsonapi.org/recommendations/#filtering

// requested url
/api/endpoint?filter[status]=all


// my attempt at model binding
public class FilterParams
{
    public Dictionary<string, string> Filter { get; set; }
}

[HttpGet]
public string Get([FromUri] FilterParams filter)
{
    // never gets populated...
    var filterStatus = filter.Filter["status"];
}

Answer 1

如果您在 .Net Core 上构建 json:api 应用程序，我强烈建议您查看这个库：https://github.com/json-api-dotnet/JsonApiDotNetCore

它为您处理所有繁重的工作，对于这个特定示例，（您需要获取过滤器值）解决方案如下所示：

public FooController : JsonApiController<Foo> {
    private readonly IQueryAccessor _queryAccessor;
    public FooController(IQueryAccessor queryAccessor, /* ... */) 
    : base(/* ... */) {
       _queryAccessor = queryAccessor;
    }

    [HttpGet]
    public override async Task<IActionResult> GetAsync() {
        var status = _queryAccessor.GetRequired<string>("status");
        // ...
    }
}

Answer 2

1. 您可以为此使用IModelBinder：

   • 定义模型绑定器：

     public class FilterParamsModelBinder : IModelBinder
     {
         public bool BindModel(HttpActionContext actionContext, ModelBindingContext bindingContext)
         {
             if (bindingContext.ModelType != typeof(FilterParams)) return false;
     
             Dictionary<string, string> result = new Dictionary<string, string>();
     
             var parameters = actionContext.Request.RequestUri.Query.Substring(1);
     
             if(parameters.Length == 0) return false;
     
             var regex = new Regex(@"filter\[(?<key>[\w]+)\]=(?<value>[\w^,]+)");
     
             parameters
                 .Split('&')
                 .ToList()
                 .ForEach(_ =>
                 {
                     var groups = regex.Match(_).Groups;
     
                     if(groups.Count == 0)
                         bindingContext.ModelState.AddModelError(bindingContext.ModelName, "Cannot convert value.");
     
                     result.Add(groups["key"].Value, groups["value"].Value);
                 });
     
             bindingContext.Model = new FilterParams { Filter = result};
     
             return bindingContext.ModelState.IsValid;
         }
     }
     

   • 使用它：

     [HttpGet]
     public string Get([ModelBinderAttribute(typeof(FilterParamsModelBinder))] FilterParams filter)
     {
       //your code
     }
     

2. 如果您可以定义类似“/api/endpoint?filter=status,all”的路由，则可以使用TypeConverter：

   • 定义一个转换器：

     public class FilterConverter : TypeConverter
     {
         public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
         {
             if (!(value is string)) return base.ConvertFrom(context, culture, value);
     
             var keyValue = ((string)value).Split(',');
     
             return new FilterParams 
             {
                 Filter = new Dictionary<string, string> { [keyValue[0]] = keyValue[1] } 
             };
         }
     
         public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType) 
         {
            return sourceType == typeof(string) || base.CanConvertFrom(context, sourceType);
         }            
     }
     

   • 使用它：

     [TypeConverter(typeof(FilterConverter))]
     public class FilterParams
     {
         public Dictionary<string, string> Filter { get; set; }
     }
     
     [HttpGet]
     public string Get(FilterParams filter)
     {
         var filterStatus = filter.Filter["status"]; 
     }