feat: add json-schema validation option for POST endpoints

examples/mock-api/v1/user.post.json

@@ -1,4 +1,5 @@
 {
+    "requestOptions": {},
     "responseOptions": {
         "delay_ms": 2000,
         "statusCode": 201

examples/mock-api/v2/user.post.json

@@ -0,0 +1,34 @@
+{
+    "requestOptions": {
+        "validation": {
+            "jsonSchema": {
+                "type": "object",
+                "properties": {
+                    "id": {
+                        "type": "integer"
+                    },
+                    "firstName": {
+                        "type": "string"
+                    },
+                    "lastName": {
+                        "type": "string"
+                    }                    
+                },
+                "required": [
+                    "id",
+                    "firstName"
+                ],
+                "additionalProperties": false
+            }
+        }
+    },
+    "responseOptions": {
+        "delay_ms": 2000,
+        "statusCode": 201
+    },
+    "response": {
+        "id": 20320,
+        "firstName": "Lord",
+        "lastName": "Bar"
+    }
+}

package.json

@@ -71,6 +71,7 @@
     "url": "https://github.com/diva-e/servemocks/issues"
   },
   "dependencies": {
+    "ajv": "^6.12.6",
     "chalk": "^4.1.0",
     "commander": "^7.2.0",
     "cors": "^2.8.5",

src/serve-mocks.js

@@ -4,6 +4,8 @@ const fs = require('fs')
 const glob = require('glob')
 const chalk = require('chalk')
 const path = require('path')
+const Ajv = require('ajv')
+const ajv = new Ajv()
 
 const mockFileTypes = require('./mock-file-types')
 
@@ -104,11 +106,28 @@ function serveMocks (mockDirectory, port, hostname) {
         app.post(apiPath, function (req, res) {
           const endpointParams =  JSON.parse(fs.readFileSync(fileName, 'utf8'))
           const responseOptions = endpointParams.responseOptions ? endpointParams.responseOptions : {}
+          const requestOptions = endpointParams.requestOptions ? endpointParams.requestOptions : {}
+          const requestValidation = requestOptions.validation ? requestOptions.validation : {}
           const responseDelay = responseOptions.delay_ms ? responseOptions.delay_ms : 2000
           const statusCode = responseOptions.statusCode ? responseOptions.statusCode : 200
           const response = endpointParams.response ? endpointParams.response : { success: true }
           console.log(`receiving POST request on ${apiPath} with body:`, req.body)
+
           setTimeout(() => {
+            // validate request body agains json schema if provided in requestOptions
+            if (requestValidation.jsonSchema) {
+              const isValid = ajv.compile(requestValidation.jsonSchema)
+              if (!isValid(req.body)) {
+                const errors = isValid.errors
+                console.info('validation of request body failed; errors:', errors)
+                res.status(422).send({ 
+                  message: 'request body is not compliant to the expected schema',
+                  errors
+                })
+                return
+              }
+            }
+
             res.status(statusCode).send(response)
           }, responseDelay)
         })

src/serve-mocks.spec.js

@@ -14,31 +14,63 @@ describe('serve-mocks', () => {
 
     const response = await request.get('/v1/user/1')
     const expectedUser = {
-      'id': 1,
-      'firstName': 'Max',
-      'lastName': 'Mustermann'
+      id: 1,
+      firstName: 'Max',
+      lastName: 'Mustermann'
     }
 
     expect(response.status).toBe(200)
     expect(response.headers['content-type']).toBe('application/json')
     expect(response.body).toEqual(expectedUser)
   })
 
-  it('should respond with specified data when posting user', async () => {
+  it('should respond with specified data when posting valid user', async () => {
     expect.assertions(3) // number of expect calls in this test
 
-    const response = await request.post('/v1/user')
+    const response = await request.post('/v1/user').send({ foo: 'bar' })
+
+    const expectedResponse = {
+      id: 20320,
+      firstName: 'Lord',
+      lastName: 'Bar'
+    }
+
+    expect(response.status).toBe(201)
+    expect(response.headers['content-type']).toBe('application/json; charset=utf-8')
+    expect(response.body).toEqual(expectedResponse)
+  })
+
+  it('should respond with 201 when posting valid user', async () => {
+    expect.assertions(3) // number of expect calls in this test
+
+    const response = await request.post('/v2/user').send({
+      id: 42,
+      firstName: 'Valid first name',
+      lastName: 'Valid last name'
+    })
+
     const expectedResponse = {
-      'id': 20320,
-      'firstName': 'Lord',
-      'lastName': 'Bar'
+      id: 20320,
+      firstName: 'Lord',
+      lastName: 'Bar'
     }
 
     expect(response.status).toBe(201)
     expect(response.headers['content-type']).toBe('application/json; charset=utf-8')
     expect(response.body).toEqual(expectedResponse)
   })
 
+  it('should respond with 422 unprocessable entity when posting invalid user', async () => {
+    expect.assertions(1) // number of expect calls in this test
+
+    const response = await request.post('/v2/user').send({
+      id: 2332,
+      firstName: 3232 // numeric value is incorrect
+    })
+
+    expect(response.status).toBe(422)
+  })
+
   it('should delay response to post requests for 2 seconds', async () => {
     expect.assertions(3) // number of expect calls in this test