ResponseValidator's Ajv can be useful too.

So we return an object that contains both request ajv and response ajv :
```javascript
ajvs = {
  req : 'Ajv object'
  res : 'Ajv object'
}
```
#683

README.md

@@ -1156,17 +1156,35 @@ Instead of initialize OpenApiValidator with middleware, you can get a configured
 
 
 ```javascript
-const ajv = await OpenApiValidator.ajv({
+const ajvs = await OpenApiValidator.ajv({
   apiSpec: './openapi.yaml',
   validateRequests: true, // (default)
   validateResponses: true, // false by default
 });
 
-const req : ReqClass = {
+const customObj = {
   id : '507f191e810c19729de860ea',
 }
 
-ajv.validate(
+const isReqValid = ajvs.req.validate(
+  {
+    type: 'object',
+    properties: {
+      id: {
+        $ref: '#/components/schemas/ObjectId',
+      },
+    },
+    required: ['token'],
+    additionalProperties: false,
+  }, 
+  customObj
+);
+
+// isReqValid = true
+// No error in ajvs.req.errors
+
+
+const isResValid = ajvs.res.validate(
   {
     type: 'object',
     properties: {
@@ -1177,8 +1195,11 @@ ajv.validate(
     required: ['token'],
     additionalProperties: false,
   },
-  req
+  customObj
 );
+
+// isResValid = true
+// No error in ajvs.res.errors
 ```
 
 ## FAQ

src/framework/types.ts

@@ -1,6 +1,7 @@
 import * as ajv from 'ajv';
 import * as multer from 'multer';
 import { Request, Response, NextFunction } from 'express';
+import { Ajv } from 'ajv';
 export { OpenAPIFrameworkArgs };
 
 export type BodySchema =
@@ -155,6 +156,11 @@ export namespace OpenAPIV3 {
     version: string;
   }
 
+  export interface Ajvs {
+    req?: Ajv,
+    res?: Ajv
+  }
+
   export interface ContactObject {
     name?: string;
     url?: string;

src/middlewares/openapi.response.validator.ts

@@ -17,6 +17,7 @@ import {
 } from '../framework/types';
 import * as mediaTypeParser from 'media-typer';
 import * as contentTypeParser from 'content-type';
+import { Ajv } from 'ajv';
 
 interface ValidateResult {
   validators: { [key: string]: ajv.ValidateFunction };
@@ -318,4 +319,8 @@ export class ResponseValidator {
       mediaTypeParsed.subtype === 'json' || mediaTypeParsed.suffix === 'json'
     );
   }
+
+  public getAJV() : Ajv {
+    return this.ajvBody;
+  }
 }

src/openapi.validator.ts

@@ -21,6 +21,7 @@ import { defaultSerDes } from './framework/base.serdes';
 import { SchemaPreprocessor } from './middlewares/parsers/schema.preprocessor';
 import { AjvOptions } from './framework/ajv/options';
 import { Ajv } from 'ajv';
+import Ajvs = OpenAPIV3.Ajvs;
 
 export {
   OpenApiValidatorOpts,
@@ -91,7 +92,7 @@ export class OpenApiValidator {
     this.ajvOpts = new AjvOptions(options);
   }
 
-  installAjv(spec: Promise<Spec>): Promise<Ajv> {
+  installAjv(spec: Promise<Spec>): Promise<Ajvs> {
     return spec
       .then((spec) => {
         const apiDoc = spec.apiDoc;
@@ -107,7 +108,15 @@ export class OpenApiValidator {
           responseApiDoc: sp.apiDocRes,
           error: null,
         };*/
-        return new middlewares.RequestValidator(apiDoc, this.ajvOpts.request).getAJV();
+        return {
+          req : new middlewares.RequestValidator(apiDoc, this.ajvOpts.request).getAJV(),
+          res : new middlewares.ResponseValidator(
+            apiDoc,
+            this.ajvOpts.response,
+            // This has already been converted from boolean if required
+            this.options.validateResponses as ValidateResponseOpts,)
+            .getAJV(),
+        };
       });
   }
 

test/ajv.return.spec.ts

@@ -3,7 +3,8 @@ import { expect } from 'chai';
 
 import { date, dateTime } from '../src/framework/base.serdes';
 import * as OpenApiValidator  from '../src';
-import { Ajv } from 'ajv';
+import { OpenAPIV3 } from '../src/framework/types';
+import Ajvs = OpenAPIV3.Ajvs;
 
 const apiSpecPath = path.join('test', 'resources', 'serdes.yaml');
 
@@ -20,10 +21,25 @@ class ObjectID {
 }
 
 describe('ajv.return', () => {
-  let ajv : Ajv = null;
+  let ajvs : Ajvs = null;
+
+  class ReqRes {
+    id?: string|ObjectID
+  }
+
+  const customSchema = {
+    type: 'object',
+    properties: {
+      id: {
+        $ref: '#/components/schemas/ObjectId',
+      },
+    },
+    required: ['id'],
+    additionalProperties: false,
+  };
 
   before(async () => {
-    ajv = await OpenApiValidator.ajv({
+    ajvs = await OpenApiValidator.ajv({
       apiSpec: apiSpecPath,
       validateRequests: {
         coerceTypes: true
@@ -44,30 +60,80 @@ describe('ajv.return', () => {
     });
   });
 
-  it('should control BAD id format and throw an error', async () => {
-    class ReqClass {
-      id: string|ObjectID
-    }
-
-    const req : ReqClass = {
+  it('should control request and deserialize string to object', async () => {
+    const req : ReqRes = {
       id : '507f191e810c19729de860ea',
     }
 
-    ajv.validate(
-      {
-        type: 'object',
-        properties: {
-          id: {
-            $ref: '#/components/schemas/ObjectId',
-          },
-        },
-        required: ['token'],
-        additionalProperties: false,
-      },
+    const isValid = ajvs.req.validate(
+      customSchema,
       req
     );
+    expect(isValid).to.be.equal(true);
+    expect(ajvs.req.errors).to.be.equal(null);
     expect(req.id instanceof ObjectID).to.be.true;
   });
+
+  it('should control request and return error if id is not set', async () => {
+    const req : ReqRes = {
+      // No id but it is required
+      // id : '507f191e810c19729de860ea',
+    }
+
+    const isValid = ajvs.req.validate(
+      customSchema,
+      req
+    );
+    expect(isValid).to.be.equal(false);
+    expect(ajvs.req.errors.length).to.be.equal(1);
+    expect(ajvs.req.errors[0].message).to.be.equal('should have required property \'id\'');
+  });
+
+  it('should control request and return error if id is in bad format', async () => {
+    const req : ReqRes = {
+       id : 'notAnObjectId',
+    }
+
+    const isValid = ajvs.req.validate(
+      customSchema,
+      req
+    );
+    expect(isValid).to.be.equal(false);
+    expect(ajvs.req.errors.length).to.be.equal(1);
+    expect(ajvs.req.errors[0].message).to.be.equal('should match pattern "^[0-9a-fA-F]{24}$"');
+  });
+
+
+  it('should control response and serialize object to string', async () => {
+    const res : ReqRes = {
+      id : new ObjectID('507f191e810c19729de860ea'),
+    }
+
+    const isValid = ajvs.res.validate(
+      customSchema,
+      res
+    );
+    expect(res.id).to.be.equal('507f191e810c19729de860ea');
+    expect(isValid).to.be.equal(true);
+    expect(ajvs.res.errors).to.be.equal(null);
+  });
+
+  it('should control response and return an error if id is not set', async () => {
+
+    const res : ReqRes = {
+      // No id but it is required
+      // id : '507f191e810c19729de860ea',
+      //id : new ObjectID('507f191e810c19729de860ea'),
+    }
+
+    const isValid = ajvs.res.validate(
+      customSchema,
+      res
+    );
+    expect(isValid).to.be.equal(false);
+    expect(ajvs.res.errors.length).to.be.equal(1);
+    expect(ajvs.res.errors[0].message).to.be.equal('should have required property \'id\'');
+  });
 });