json schema validator

lib/conditions/json-schema.js

@@ -0,0 +1,33 @@
+const express = require('express');
+const schemas = require('../schemas');
+const logger = require('../logger').gateway;
+
+module.exports = {
+  name: 'json-schema',
+  schema: {
+    $id: 'http://express-gateway.io/schemas/policies/json-schema.json',
+    type: 'object',
+    properties: {
+      schema: {
+        type: 'object',
+        description: 'Json schema to validate against.',
+        examples: ['{"type":"string"}']
+      },
+      extendedErrors: {
+        type: 'boolean',
+        default: false,
+        description: 'Value istructing the gateway to return the extended Schema Validation errors or a generic Unprocessable Entity'
+      }
+    },
+    required: ['schema', 'extendedErrors']
+  },
+  handler: config => {
+    const validator = schemas.register(String(), String(), config.schema);
+    return req => {
+      const { isValid, error } = validator(req.body);
+      logger.warn(error);
+      return isValid;
+    };
+  },
+  middlewares: [express.json(), express.urlencoded({ extended: false })]
+};

lib/conditions/predefined.js

@@ -1,4 +1,5 @@
 const minimatch = require('minimatch');
+const jsonSchema = require('./json-schema');
 
 const grabArray = config => {
   const { conditions } = require('./index');
@@ -190,6 +191,6 @@ module.exports = [
     schema: {
       $id: 'http://express-gateway.io/schemas/conditions/tlsClientAuthenticated.json'
     }
-  }
-
+  },
+  jsonSchema
 ];

lib/gateway/pipelines.js

@@ -126,7 +126,7 @@ function configurePipeline(pipelinePoliciesConfig, config) {
       policySteps.push({});
     }
 
-    const middlewares = policySteps.map(policyStep => {
+    const middlewares = policySteps.flatMap(policyStep => {
       const conditionConfig = policyStep.condition;
 
       let condition;
@@ -138,7 +138,7 @@ function configurePipeline(pipelinePoliciesConfig, config) {
       const action = Object.assign({}, policyStep.action, ActionParams.prototype);
       const policyMiddleware = policy(action, config);
 
-      return (req, res, next) => {
+      const fn = (req, res, next) => {
         if (!conditionConfig || condition(req)) {
           log.debug('request matched condition for action', policyStep.action, 'in policy', policyName);
           policyMiddleware(req, res, next);
@@ -147,6 +147,9 @@ function configurePipeline(pipelinePoliciesConfig, config) {
           next();
         }
       };
+
+      if (conditionConfig && conditionConfig.middlewares) { return [...middlewares, fn]; }
+      return fn;
     });
 
     router.use(middlewares);