.NET Core 使用ModelBinder去掉所有参数的空格

一.前言

　　通过各种姿势搜索都没搜到这方面的,唯一找到一个比较符合的,但是只适合简单类型,而且代码还没贴全,心累。。

然后查看官网和源码之后,发现继承并实现 IModelBinder和IModelBinderProvider 即可。

我这里是WebApi,所以要区分绑定属性[FromBody]、[FromForm]等。不同的绑定方法要实现不同的IModelBinder。

二:正文

　　api主要设计到的就是[FromBody]和[FromQuery],我这里也只实现了这两种,其余的方式没测试过。

public class StringTrimModelBinderProvider : IModelBinderProvider

    {

        private readonly IList<IInputFormatter> _formatters;

        public StringTrimModelBinderProvider(IList<IInputFormatter> formatters)

        {

            _formatters = formatters;

        }

        public IModelBinder GetBinder(ModelBinderProviderContext context)

        {

            if (context == null)

                throw new ArgumentNullException(nameof(context));

            if (!context.Metadata.IsComplexType && context.Metadata.ModelType == typeof(string))

            {

                //简单类型

                var loggerFactory = (ILoggerFactory)context.Services.GetService(typeof(ILoggerFactory));

                return new SimpleStringTrimModelBinder(context.Metadata.ModelType);

            }

            else if (context.BindingInfo.BindingSource != null &&

                context.BindingInfo.BindingSource.CanAcceptDataFrom(BindingSource.Body))

            {

                //通过[FromBody]绑定的

                return new BodyStringTrimModelBinder(_formatters, context.Services.GetRequiredService<IHttpRequestStreamReaderFactory>());

            }

            //else

            //if (context.Metadata.IsComplexType && !context.Metadata.IsCollectionType)

            //{

            //    //复杂类型

            //    var propertyBinders = context.Metadata.Properties

            //        .ToDictionary(modelProperty => modelProperty, modelProperty => context.CreateBinder(modelProperty));

            //    var loggerFactory = (ILoggerFactory)context.Services.GetService(typeof(ILoggerFactory));

            //    return new AComplexTypeModelBinder(propertyBinders);

            //}

            return null;

        }

    }

下面的是实现IModelBinder

public class SimpleStringTrimModelBinder : IModelBinder

    {

        private readonly Type _type;

        public SimpleStringTrimModelBinder(Type type)

        {

            _type = type;

        }

        public Task BindModelAsync(ModelBindingContext bindingContext)

        {

            if (bindingContext == null)

            {

                throw new ArgumentNullException(nameof(bindingContext));

            }

            var valueProvider = bindingContext.ValueProvider;

            var modelName = bindingContext.ModelName;

            var valueProviderResult = valueProvider.GetValue(modelName);

            if (valueProviderResult == ValueProviderResult.None)

            {

                return Task.CompletedTask;

            }

            string value = valueProviderResult.FirstValue.Trim();

            //bindingContext.ModelState.SetModelValue(modelName, new ValueProviderResult(value));

            //替换原有ValueProvider

            bindingContext.ValueProvider = new CompositeValueProvider

                {

                    new ElementalValueProvider(modelName, value, valueProviderResult.Culture),

                    bindingContext.ValueProvider

                };

            //调用默认系统绑定

            SimpleTypeModelBinder simpleTypeModelBinder = new SimpleTypeModelBinder(_type, (ILoggerFactory)bindingContext.HttpContext.RequestServices.GetService(typeof(ILoggerFactory)));

            simpleTypeModelBinder.BindModelAsync(bindingContext);

            //bindingContext.Result = ModelBindingResult.Success(value);

            return Task.CompletedTask;

        }

    }

public class BodyStringTrimModelBinder : IModelBinder

    {

        private readonly BodyModelBinder bodyModelBinder;

        public BodyStringTrimModelBinder(IList<IInputFormatter> formatters, IHttpRequestStreamReaderFactory readerFactory)

        {

            bodyModelBinder = new BodyModelBinder(formatters,readerFactory);

        }

        public Task BindModelAsync(ModelBindingContext bindingContext)

        {

            if (bindingContext == null)

            {

                throw new ArgumentNullException(nameof(bindingContext));

            }

            //调用原始body绑定数据

            bodyModelBinder.BindModelAsync(bindingContext);

            //判断是否设置了值

            if (!bindingContext.Result.IsModelSet)

            {

                return Task.CompletedTask;

            }

            //获取绑定对象

            var model = bindingContext.Result.Model;

            /*通过反射修改值,

            也可以实现 IInputFormatter接口里面的ReadAsync方法,自己从Request.Body里面获取数据进行处理,但是那样考虑的比较多也比较复杂,原谅我能力有限。。*/

            var stringPropertyInfo = model.GetType().GetProperties().Where(c=>c.PropertyType == typeof(string));

            foreach (PropertyInfo property in stringPropertyInfo)

            {

                string value = property.GetValue(model)?.ToString()?.Trim();

                property.SetValue(model, value);

            }

            //bindingContext.Result = ModelBindingResult.Success(value);

            return Task.CompletedTask;

        }

    }

最后,需要将我们自定义的在Startup注册进去,

services.AddMvc(options =>

            {

                //需要插入到第一条,内置默认是匹配到合适的Provider就不会在向下继续绑定;如果添加到末尾,即不会调用到我们实现的

                options.ModelBinderProviders.Insert(,new StringTrimModelBinderProvider(options.InputFormatters));

            })

记录成长中的点点滴滴。。

巴特西

.NET Core 使用ModelBinder去掉所有参数的空格

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