Validator accepting plugins

packages/validator/README.md

@@ -41,6 +41,7 @@ response to the user.
 
 It can also be used in combination with [`httpcontentnegotiation`](#httpContentNegotiation) to load localised translations for the error messages (based on the currently requested language). This feature uses internally [`ajv-i18n`](http://npm.im/ajv-i18n) module, so reference to this module for options and more advanced use cases. By default the language used will be English (`en`), but you can redefine the default language by passing it in the `ajvOptions` options with the key `defaultLanguage` and specifying as value one of the [supported locales](https://www.npmjs.com/package/ajv-i18n#supported-locales).
 
+Also, this middleware accepts an object with plugins to be applied to customize the internal `ajv` instance. Out-of-the-box, `ajv-i18n`, `ajv-errors` and `ajv-keywords` are being used.
 
 ## Install
 
@@ -57,8 +58,9 @@ npm install --save @middy/validator
    to validate the input (`handler.event`) of the Lambda handler.
  - `outputSchema` (object) (optional): The JSON schema object that will be used
    to validate the output (`handler.response`) of the Lambda handler.
- - `ajvOptions` (object) (optional): Options to pass to [ajv](https://epoberezkin.github.io/ajv/)
-    class constructor. Defaults are `{v5: true, coerceTypes: 'array', $data: true, allErrors: true, useDefaults: true, defaultLanguage: 'en'}`
+ - `ajvOptions` (object) (optional): Options to pass to [ajv](https://ajv.js.org)
+    class constructor. Defaults are `{v5: true, coerceTypes: 'array', $data: true, allErrors: true, useDefaults: true, defaultLanguage: 'en', jsonPointers: true}`. Note that `jsonPointers` is needed by `ajv-errors`.
+ - `ajvPlugins` (object) (optional): Plugin names (without `ajv-` preffix) as key and its options for the value, to apply to [ajv](https://ajv.js.org) once intantiated. Defaults are `{keywords: null, errors: null, i18n: null}`. Note that for no options `null` is used as value.
 
 
 ## Sample usage
@@ -131,6 +133,38 @@ handler({}, {}, (err, response) => {
 })
 ```
 
+Example for plugins applied with `ajv-bsontype`:
+
+```javascript
+const middy = require('@middy/core')
+const validator = require('@middy/validator')
+
+const handler = middy((event, context, cb) => {
+  cb(null, {})
+})
+
+const schema = {
+  required: ["name", "gpa"],
+  properties: {
+    name: {
+      bsonType: "string"
+    },
+    gpa: {
+      bsonType: [ "double" ]
+    }
+  }
+}
+
+handler.use(validator({ inputSchema: schema, ajvPlugins: { bsontype: null } }))
+
+// invokes the handler, note that property foo is string and should be integer
+const event = {
+  body: JSON.stringify({ name: "Leo", gpa: "4" })
+}
+handler(event, {}, (err, response) => {
+  expect(err.details[0].message).toEqual('should be double got 4')
+})
+```
 
 ## Middy documentation and examples
 

packages/validator/__tests__/index.js

@@ -241,4 +241,74 @@ describe('📦  Middleware Validator', () => {
       }
     })
   })
+
+  describe('🔌 Ajv plugins setup', () => {
+    beforeEach(() => {
+      jest.resetModules()
+    })
+
+    test('It should use out-of-the-box ajv-errors plugin', async () => {
+      expect.assertions(2)
+
+      const schema = {
+        type: 'object',
+        required: ['foo'],
+        properties: {
+          foo: { type: 'integer' }
+        },
+        errorMessage: 'should be an object with an integer property foo only'
+      }
+
+      const validator = require('../')
+
+      const handler = middy((event, context, cb) => {
+        cb(null, {})
+      })
+
+      handler.use(validator({ inputSchema: schema }))
+
+      try {
+        await invoke(handler, { foo: 'a' })
+      } catch (err) {
+        expect(err.message).toEqual('Event object failed validation')
+        expect(err.details).toEqual(
+          expect.arrayContaining([
+            expect.objectContaining({ message: 'should be an object with an integer property foo only' })
+          ])
+        )
+      }
+    })
+
+    test('It should apply added plugin bsontype', async () => {
+      expect.assertions(2)
+      const schema = {
+        required: ['name', 'gpa'],
+        properties: {
+          name: {
+            bsonType: 'string'
+          },
+          gpa: {
+            bsonType: ['double']
+          }
+        }
+      }
+
+      const handler = middy((event, context, cb) => {
+        cb(null, {})
+      })
+
+      handler.use(validator({ inputSchema: schema, ajvPlugins: { bsontype: null } }))
+
+      try {
+        await invoke(handler, { name: 'Leo', gpa: '4' })
+      } catch (err) {
+        expect(err.message).toEqual('Event object failed validation')
+        expect(err.details).toEqual(
+          expect.arrayContaining([
+            expect.objectContaining({ message: 'should be double got 4' })
+          ])
+        )
+      }
+    })
+  })
 })

packages/validator/index.d.ts

@@ -6,6 +6,7 @@ interface IValidatorOptions {
   inputSchema?: any;
   outputSchema?: any;
   ajvOptions?: Partial<AjvOptions>;
+  ajvPlugins?: object;
 }
 
 declare const validator : middy.Middleware<IValidatorOptions, any, any>

packages/validator/index.js

@@ -1,21 +1,26 @@
 const createError = require('http-errors')
 const Ajv = require('ajv')
-const ajvKeywords = require('ajv-keywords')
-const ajvLocalize = require('ajv-i18n')
 const { deepStrictEqual } = require('assert')
 
 let ajv
 let previousConstructorOptions
-const defaults = {
+const optionsDefault = {
   v5: true,
   coerceTypes: 'array', // important for query string params
   allErrors: true,
   useDefaults: true,
   $data: true, // required for ajv-keywords
-  defaultLanguage: 'en'
+  defaultLanguage: 'en',
+  jsonPointers: true
+}
+const pluginsInstances = {}
+const pluginsDefault = {
+  keywords: null,
+  errors: null,
+  i18n: null
 }
 
-const availableLanguages = Object.keys(ajvLocalize)
+let availableLanguages
 
 /* in ajv-i18n Portuguese is represented as pt-BR */
 const languageNormalizationMap = {
@@ -38,9 +43,10 @@ const chooseLanguage = ({ preferredLanguage }, defaultLanguage) => {
   return defaultLanguage
 }
 
-module.exports = ({ inputSchema, outputSchema, ajvOptions }) => {
-  const options = Object.assign({}, defaults, ajvOptions)
-  lazyLoadAjv(options)
+module.exports = ({ inputSchema, outputSchema, ajvOptions, ajvPlugins }) => {
+  const options = Object.assign({}, optionsDefault, ajvOptions)
+  const pluginsOptions = Object.assign({}, pluginsDefault, ajvPlugins)
+  lazyLoadAjv(options, pluginsOptions)
 
   const validateInput = inputSchema ? ajv.compile(inputSchema) : null
   const validateOutput = outputSchema ? ajv.compile(outputSchema) : null
@@ -57,7 +63,7 @@ module.exports = ({ inputSchema, outputSchema, ajvOptions }) => {
         const error = new createError.BadRequest('Event object failed validation')
         handler.event.headers = Object.assign({}, handler.event.headers)
         const language = chooseLanguage(handler.event, options.defaultLanguage)
-        ajvLocalize[language](validateInput.errors)
+        pluginsInstances.i18n[language](validateInput.errors)
 
         error.details = validateInput.errors
         throw error
@@ -84,9 +90,9 @@ module.exports = ({ inputSchema, outputSchema, ajvOptions }) => {
   }
 }
 
-function lazyLoadAjv (options) {
+function lazyLoadAjv (options, plugins) {
   if (shouldInitAjv(options)) {
-    initAjv(options)
+    initAjv(options, plugins)
   }
 
   return ajv
@@ -106,9 +112,17 @@ function areConstructorOptionsNew (options) {
   return false
 }
 
-function initAjv (options) {
+function initAjv (options, pluginsOptions) {
   ajv = new Ajv(options)
-  ajvKeywords(ajv)
+
+  Object.keys(pluginsOptions).forEach(p => {
+    pluginsInstances[p] = require(`ajv-${p}`)
+    if (typeof pluginsInstances[p] === 'function') {
+      pluginsInstances[p](ajv, pluginsOptions[p])
+    }
+  })
+
+  availableLanguages = Object.keys(pluginsInstances.i18n)
 
   previousConstructorOptions = options
 }

packages/validator/package.json

@@ -44,12 +44,14 @@
   "dependencies": {
     "@types/http-errors": "^1.6.1",
     "ajv": "^6.5.0",
+    "ajv-errors": "^1.0.1",
     "ajv-i18n": "^3.3.0",
     "ajv-keywords": "^3.2.0",
     "http-errors": "^1.6.3"
   },
   "devDependencies": {
     "@middy/core": "^1.2.0",
+    "ajv-bsontype": "^1.0.7",
     "es6-promisify": "^6.0.2"
   },
   "gitHead": "7a6c0fbb8ab71d6a2171e678697de9f237568431"