使用ajv校驗json schema

使用ajv-errors生成json-schema錯誤信息

ajv-errors給Json-schema添加了一個errorMessage關鍵字,通過這個關鍵字來輸出錯誤信息

const Ajv = require('ajv')
const ajv = new Ajv({ allErrors: true, jsonPointers: true })
require('ajv-errors')(ajv)
//一個json schema規範的對象
const schema = {}
//待校驗的json對象
const data = {}
const validate = ajv.compile(schema)
validate(data) //返回boolean，是否校驗通過
validate.errors //錯誤詳細信息

用法

1. 單個錯誤信息

   用一條消息替換當前schema和sub schema中的所有錯誤

   var schema = {
     type: 'object',
     required: ['foo'],
     properties: {
       foo: { type: 'integer' }
     },
     additionalProperties: false,
     errorMessage: 'should be an object with an integer property foo only'
   };
   

2. 關鍵字錯誤

   var schema = {
     type: 'object',
     required: ['foo'],
     properties: {
       foo: { type: 'integer' }
     },
     additionalProperties: false,
     errorMessage: {
       type: 'should be an object', // will not replace internal "type" error for the property "foo"
       required: 'should have property foo',
       additionalProperties: 'should not have properties other than foo'
     }
   };
   

   required和dependencies可以使用對象指定特定的屬性的錯誤信息。示例如下：

   var schema = {
     type: 'object',
     required: ['foo', 'bar'],
     properties: {
       foo: { type: 'integer' },
       bar: { type: 'string' }
     },
     errorMessage: {
       type: 'should be an object', // will not replace internal "type" error for the property "foo"
       required: {
         foo: 'should have an integer property "foo"',
         bar: 'should have a string property "bar"'
       }
     }
   };
   

3. 屬性的錯誤信息

   無論屬性是在哪裏創建的

   var schema = {
     type: 'object',
     required: ['foo', 'bar'],
     allOf: [{
       properties: {
         foo: { type: 'integer', minimum: 2 },
         bar: { type: 'string', minLength: 2 }
       },
       additionalProperties: false
     }],
     errorMessage: {
       properties: {
         foo: 'data.foo should be integer >= 2',
         bar: 'data.bar should be string with length >= 2'
       }
     }
   };
   

4. 默認錯誤信息

   當errorMessage是一個對象時，可以指定一個默認錯誤來兜底錯誤。

   var schema = {
     type: 'object',
     required: ['foo', 'bar'],
     allOf: [{
       properties: {
         foo: { type: 'integer', minimum: 2 },
         bar: { type: 'string', minLength: 2 }
       },
       additionalProperties: false
     }],
     errorMessage: {
       type: 'data should be an object',
       properties: {
         foo: 'data.foo should be integer >= 2',
         bar: 'data.bar should be string with length >= 2'
       },
       _: 'data should have properties "foo" and "bar" only'
     }
   };
   

5. 模板語法

   配合json pointer可以展示當前json的實際值

   var schema = {
     "type": "object",
     "properties": {
       "size": {
         "type": "number",
         "minimum": 4
       }
     },
     "errorMessage": {
       "properties": {
         "size": "size should be a number bigger or equal to 4, current value is ${/size}"
       }
     }
   }
   
   
   validate({size:1})
   //validate.error是個對象。其中會有錯誤信息如下。error具體結構參考https://www.npmjs.com/package/ajv-errors
   //"size should be a number bigger or equal to 4, current value is 1"
   

   可以將minimum設置成一個變量，然後errorMessage配合變量和es6模板字符串達到改變變量，自動更改校驗提示。

   注意：json pointer需要使用\轉義

   //同上一個校驗
   const minimum = 4
   var schema = {
     "type": "object",
     "properties": {
       "size": {
         "type": "number",
         minimum
       }
     },
     "errorMessage": {
       "properties": {
         "size": `size should be a number bigger or equal to ${minimum}, current value is \${/size}`
       }
     }
   }
   

參考

1. ajv-errors readme