ASP.NET Core通过特性实现参数验证
作者：互联网
微软在ASP.NET Core框架中内置了一些验证参数的特性，让我们可以通过这些特性对API请求中的参数进行验证，常用的特性一般有：
[ValidateNever]： ValidateNeverAttribute 指示应从验证中排除属性或参数。[CreditCard]：验证属性是否具有信用卡格式。[Compare]：验证模型中的两个属性是否匹配。[EmailAddress]：验证属性是否具有电子邮件格式。[Phone]：验证属性是否具有电话号码格式。[Range]：验证属性值是否位于指定范围内。[RegularExpression]：验证 属性值是否与指定的正则表达式匹配。[Required]：验证字段是否不为 null。[StringLength]：验证字符串属性值是否不超过指定的长度限制。[Url]：验证属性是否具有 URL 格式。
但除了上面这些，还缺少一些我们平时在项目中会经常碰到的验证，例如：需要是纯汉字的姓名、必须包含大小写字母和数字的强密码、QQ号、IPV4或者IPV6地址，以及中国的手机号码和身份证号码等等。
当我们碰到这些参数需要验证的时候，我们需要如何实现自定义的验证特性呢？此时微软已经指出，让我们去继承ValidationAttribute类，并重写IsValid()即可。
1 /// <summary>
2 /// 是否是英文字母、数字组合
3 /// </summary>
4 public class EnglishNumberCombinationAttribute : ValidationAttribute
5 {
6 /// <summary>
7 /// 默认的错误提示信息
8 /// </summary>
9 private const string error = "无效的英文字母加数字组合";
10
11 public EnglishNumberCombinationAttribute()
12 {
13 }
14
15 /// <param name="errorMessage">自定义的错误信息</param>
16 public EnglishNumberCombinationAttribute(string errorMessage) : base(errorMessage)
17 {
18 }
19
20 protected override ValidationResult IsValid(object value, ValidationContext validationContext)
21 {
22 //这里是验证的参数的逻辑 value是需要验证的值 而validationContext中包含了验证相关的上下文信息 这里我是有一个自己封装的验证格式的FormatValidation类
23 if (FormatValidation.IsCombinationOfEnglishNumber(value as string))
24 //验证成功返回 success
25 return ValidationResult.Success;
26 //不成功 提示验证错误的信息 这里注意不要用ErrorMessage，要用ErrorMessageString
27 else return new ValidationResult(ErrorMessageString ?? error);
28 }
29 }
这里是实现一个英文字母数字组合的验证特性，这样我们就可以把它附在在我们请求的参数上，可以是DTO里的属性，也可以是Action上的形参。
1 public class CreateDTO
2 {
3 [Required]
4 public string StoreName { get; init; }
5 [Required]
6 [EnglishNumberCombination(errorMessage: "UserId必须是英文字母加数字的组合")]
7 public string UserId { get; init; }
8 }
9
10 ...
11
12 [HttpGet]
13 public async ValueTask<ActionResult> Delete([EnglishNumberCombination]string UserId, string StoreName)
Postman测试结果：
至于验证的过程，我看了下源码，具体的过程是当我们在startup中services.AddControllers()或者services.AddMvc()的时候，有一个默认的MvcOptions（这个我们是可以配置的），其中有一个ModelValidatorProviders属性，看名字就知道模型验证提供器。ASP.NET Core实现了默认的提供器：
options.ModelValidatorProviders.Add(new DataAnnotationsModelValidatorProvider(
_validationAttributeAdapterProvider,
_dataAnnotationLocalizationOptions,
_stringLocalizerFactory));
其中_validationAttributeAdapterProvider，是已经依赖注入的IValidationAttributeAdapterProvider，下面是微软实现的代码，感兴趣的小伙伴可以去看一下，可以学到很多设计模式的运用：
1 namespace Microsoft.AspNetCore.Mvc.DataAnnotations
2 {
3 /// <summary>
4 /// Creates an <see cref="IAttributeAdapter"/> for the given attribute.
5 /// </summary>
6 public class ValidationAttributeAdapterProvider : IValidationAttributeAdapterProvider
7 {
8 /// <summary>
9 /// Creates an <see cref="IAttributeAdapter"/> for the given attribute.
10 /// </summary>
11 /// <param name="attribute">The attribute to create an adapter for.</param>
12 /// <param name="stringLocalizer">The localizer to provide to the adapter.</param>
13 /// <returns>An <see cref="IAttributeAdapter"/> for the given attribute.</returns>
14 public IAttributeAdapter? GetAttributeAdapter(ValidationAttribute attribute, IStringLocalizer? stringLocalizer)
15 {
16 if (attribute == null)
17 {
18 throw new ArgumentNullException(nameof(attribute));
19 }
20
21 var type = attribute.GetType();
22
23 if (typeof(RegularExpressionAttribute).IsAssignableFrom(type))
24 {
25 return new RegularExpressionAttributeAdapter((RegularExpressionAttribute)attribute, stringLocalizer);
26 }
27 else if (typeof(MaxLengthAttribute).IsAssignableFrom(type))
28 {
29 return new MaxLengthAttributeAdapter((MaxLengthAttribute)attribute, stringLocalizer);
30 }
31 else if (typeof(RequiredAttribute).IsAssignableFrom(type))
32 {
33 return new RequiredAttributeAdapter((RequiredAttribute)attribute, stringLocalizer);
34 }
35 else if (typeof(CompareAttribute).IsAssignableFrom(type))
36 {
37 return new CompareAttributeAdapter((CompareAttribute)attribute, stringLocalizer);
38 }
39 else if (typeof(MinLengthAttribute).IsAssignableFrom(type))
40 {
41 return new MinLengthAttributeAdapter((MinLengthAttribute)attribute, stringLocalizer);
42 }
43 else if (typeof(CreditCardAttribute).IsAssignableFrom(type))
44 {
45 return new DataTypeAttributeAdapter((DataTypeAttribute)attribute, "data-val-creditcard", stringLocalizer);
46 }
47 else if (typeof(StringLengthAttribute).IsAssignableFrom(type))
48 {
49 return new StringLengthAttributeAdapter((StringLengthAttribute)attribute, stringLocalizer);
50 }
51 else if (typeof(RangeAttribute).IsAssignableFrom(type))
52 {
53 return new RangeAttributeAdapter((RangeAttribute)attribute, stringLocalizer);
54 }
55 else if (typeof(EmailAddressAttribute).IsAssignableFrom(type))
56 {
57 return new DataTypeAttributeAdapter((DataTypeAttribute)attribute, "data-val-email", stringLocalizer);
58 }
59 else if (typeof(PhoneAttribute).IsAssignableFrom(type))
60 {
61 return new DataTypeAttributeAdapter((DataTypeAttribute)attribute, "data-val-phone", stringLocalizer);
62 }
63 else if (typeof(UrlAttribute).IsAssignableFrom(type))
64 {
65 return new DataTypeAttributeAdapter((DataTypeAttribute)attribute, "data-val-url", stringLocalizer);
66 }
67 else if (typeof(FileExtensionsAttribute).IsAssignableFrom(type))
68 {
69 return new FileExtensionsAttributeAdapter((FileExtensionsAttribute)attribute, stringLocalizer);
70 }
71 else
72 {
73 return null;
74 }
75 }
76 };
77 }
源码
最后附上自己写的验证类，都是一些常用的验证：
1 /// <summary>
2 /// 格式验证
3 /// </summary>
4 public static class FormatValidation
5 {
6 private readonly static Regex IPV4Regex = new(@"^((2(5[0-5]|[0-4]\d))|[0-1]?\d{1,2})(\.((2(5[0-5]|[0-4]\d))|[0-1]?\d{1,2})){3}$", RegexOptions.Compiled);
7 private readonly static Regex IPV6Regex = new(@"^\s*((([0-9A-Fa-f]{1,4}:){7}([0-9A-Fa-f]{1,4}|:))|(([0-9A-Fa-f]{1,4}:){6}(:[0-9A-Fa-f]{1,4}|((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){5}(((:[0-9A-Fa-f]{1,4}){1,2})|:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){4}(((:[0-9A-Fa-f]{1,4}){1,3})|((:[0-9A-Fa-f]{1,4})?:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){3}(((:[0-9A-Fa-f]{1,4}){1,4})|((:[0-9A-Fa-f]{1,4}){0,2}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){2}(((:[0-9A-Fa-f]{1,4}){1,5})|((:[0-9A-Fa-f]{1,4}){0,3}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){1}(((:[0-9A-Fa-f]{1,4}){1,6})|((:[0-9A-Fa-f]{1,4}){0,4}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(:(((:[0-9A-Fa-f]{1,4}){1,7})|((:[0-9A-Fa-f]{1,4}){0,5}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:)))(%.+)?\s*$", RegexOptions.Compiled);
8 private readonly static Regex DomainRegex = new(@"^[a-zA-Z0-9][-a-zA-Z0-9]{0,62}(\.[a-zA-Z0-9][-a-zA-Z0-9]{0,62})+\.?$", RegexOptions.Compiled);
9 private readonly static Regex UrlRegex = new(@"^[a-zA-z]+://[^\s]*$", RegexOptions.Compiled);
10 private readonly static Regex PhoneNumberRegex = new(@"^(13[0-9]|14[5|7]|15[0|1|2|3|4|5|6|7|8|9]|18[0|1|2|3|5|6|7|8|9])\d{8}$", RegexOptions.Compiled);
11 private readonly static Regex EnglishRegex = new(@"^[A-Za-z]+$", RegexOptions.Compiled);
12 private readonly static Regex IdentityNumberRegex = new(@"(^\d{15}$)|(^\d{18}$)|(^\d{17}(\d|X|x)$)", RegexOptions.Compiled);
13 private readonly static Regex EmailRegex = new(@"^\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$", RegexOptions.Compiled);
14 private readonly static Regex ChineseRegex = new(@"^[\u4e00-\u9fa5]{0,}$", RegexOptions.Compiled);
15 private readonly static Regex LandlineRegex = new(@"^\d{3}-\d{8}|\d{4}-\d{7}|\d{7}$", RegexOptions.Compiled);
16
17 /// <summary>
18 /// 是否是IPV4格式的IP
19 /// </summary>
20 /// <returns></returns>
21 public static bool IsIPV4(string input)
22 {
23 return IPV4Regex.IsMatch(input);
24 }
25
26 /// <summary>
27 /// 是否是IPV6格式的IP
28 /// </summary>
29 /// <returns></returns>
30 public static bool IsIPV6(string input)
31 {
32 return IPV6Regex.IsMatch(input);
33 }
34
35 /// <summary>
36 /// 是否是一个域名
37 /// </summary>
38 /// <returns></returns>
39 public static bool IsDomain(string input)
40 {
41 return DomainRegex.IsMatch(input);
42 }
43
44 /// <summary>
45 /// 是否是一个网址
46 /// </summary>
47 /// <returns></returns>
48 public static bool IsUrl(string input)
49 {
50 return UrlRegex.IsMatch(input);
51 }
52
53 /// <summary>
54 /// 是否是一个手机号码（中国大陆）
55 /// </summary>
56 /// <returns></returns>
57 public static bool IsPhoneNumber(string input)
58 {
59 return PhoneNumberRegex.IsMatch(input);
60 }
61
62 /// <summary>
63 /// 是否是纯英文字母
64 /// </summary>
65 /// <returns></returns>
66 public static bool IsEnglish(string input)
67 {
68 return EnglishRegex.IsMatch(input);
69 }
70
71 /// <summary>
72 /// 只包含英文字母和数字的组合
73 /// </summary>
74 /// <returns></returns>
75 public static bool IsCombinationOfEnglishNumber(string input, int? minLength = null, int? maxLength = null)
76 {
77 var pattern = @"(?=.*\d)(?=.*[a-zA-Z])[a-zA-Z0-9]";
78 if (minLength is null && maxLength is null)
79 pattern = $@"^{pattern}+$";
80 else if (minLength is not null && maxLength is null)
81 pattern = $@"^{pattern}{{{minLength},}}$";
82 else if (minLength is null && maxLength is not null)
83 pattern = $@"^{pattern}{{1,{maxLength}}}$";
84 else
85 pattern = $@"^{pattern}{{{minLength},{maxLength}}}$";
86 return Regex.IsMatch(input, pattern);
87 }
88
89 /// <summary>
90 /// 只包含英文字母、数字和特殊字符的组合
91 /// </summary>
92 /// <returns></returns>
93 public static bool IsCombinationOfEnglishNumberSymbol(string input, int? minLength = null, int? maxLength = null)
94 {
95 var pattern = @"(?=.*\d)(?=.*[a-zA-Z])(?=.*[^a-zA-Z\d]).";
96 if (minLength is null && maxLength is null)
97 pattern = $@"^{pattern}+$";
98 else if (minLength is not null && maxLength is null)
99 pattern = $@"^{pattern}{{{minLength},}}$";
100 else if (minLength is null && maxLength is not null)
101 pattern = $@"^{pattern}{{1,{maxLength}}}$";
102 else
103 pattern = $@"^{pattern}{{{minLength},{maxLength}}}$";
104 return Regex.IsMatch(input, pattern);
105 }
106
107 /// <summary>
108 /// 是否是身份证号码（中国大陆）
109 /// </summary>
110 /// <returns></returns>
111 public static bool IsIdentityNumber(string input)
112 {
113 return IdentityNumberRegex.IsMatch(input);
114 }
115
116 /// <summary>
117 /// 是否是电子邮箱
118 /// </summary>
119 /// <returns></returns>
120 public static bool IsEmail(string input)
121 {
122 return EmailRegex.IsMatch(input);
123 }
124
125 /// <summary>
126 /// 是否是汉字
127 /// </summary>
128 /// <returns></returns>
129 public static bool IsChinese(string input)
130 {
131 return ChineseRegex.IsMatch(input);
132 }
133
134 /// <summary>
135 /// 是否是座机号码（中国大陆）
136 /// </summary>
137 /// <returns></returns>
138 public static bool IsLandline(string input)
139 {
140 return LandlineRegex.IsMatch(input);
141 }
142 }
每天了解多一点，日积月累，基础就会慢慢牢固。
author:https://www.cnblogs.com/abnerwong/
标签：Core,ASP,return,9A,static,new,input,NET,public 来源： https://www.cnblogs.com/abnerwong/p/15204270.html