From 9253c4ba8a37b97b10d8c21847fff7eb77bf111f Mon Sep 17 00:00:00 2001
From: FX Algrain <fxalgrain@users.noreply.github.com>
Date: Mon, 13 Dec 2021 17:27:31 +0100
Subject: [PATCH] feat(openapi): support patternProperties

---
 lib/spec/openapi/utils.js   |  6 ++++
 test/spec/openapi/schema.js | 57 +++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/lib/spec/openapi/utils.js b/lib/spec/openapi/utils.js
index be4ccac6..8ba7d30a 100644
--- a/lib/spec/openapi/utils.js
+++ b/lib/spec/openapi/utils.js
@@ -80,6 +80,12 @@ function normalizeUrl (url, servers, stripBasePath) {
 
 function transformDefsToComponents (jsonSchema) {
   if (typeof jsonSchema === 'object' && jsonSchema !== null) {
+    // Handle patternProperties, that is not part of OpenAPI definitions
+    if (jsonSchema.patternProperties) {
+      jsonSchema.additionalProperties = { type: 'string' }
+      delete jsonSchema.patternProperties
+    }
+
     Object.keys(jsonSchema).forEach(function (key) {
       if (key === '$ref') {
         jsonSchema[key] = jsonSchema[key].replace('definitions', 'components/schemas')
diff --git a/test/spec/openapi/schema.js b/test/spec/openapi/schema.js
index 52e87cec..b1ecde63 100644
--- a/test/spec/openapi/schema.js
+++ b/test/spec/openapi/schema.js
@@ -416,3 +416,60 @@ test('fluent-json-schema', async t => {
   const definedPath = api.paths['/'].get
   t.same(definedPath.responses['200'].description, 'Default Response')
 })
+
+test('support "patternProperties" parameter', async t => {
+  const opt = {
+    schema: {
+      response: {
+        200: {
+          description: 'Expected Response',
+          type: 'object',
+          properties: {
+            foo: {
+              type: 'object',
+              patternProperties: {
+                '^[a-z]{2,3}-[a-zA-Z]{2}$': {
+                  type: 'string'
+                }
+              },
+              additionalProperties: false
+            }
+          }
+        }
+      }
+    }
+  }
+
+  const fastify = Fastify()
+  fastify.register(fastifySwagger, {
+    openapi: true,
+    routePrefix: '/docs',
+    exposeRoute: true
+  })
+  fastify.get('/', opt, () => {})
+
+  await fastify.ready()
+
+  const swaggerObject = fastify.swagger()
+  const api = await Swagger.validate(swaggerObject)
+
+  const definedPath = api.paths['/'].get
+
+  t.same(definedPath.responses[200], {
+    description: 'Expected Response',
+    content: {
+      'application/json': {
+        schema: {
+          description: 'Expected Response',
+          type: 'object',
+          properties: {
+            foo: {
+              type: 'object',
+              additionalProperties: { type: 'string' }
+            }
+          }
+        }
+      }
+    }
+  })
+})