added Download file api endpoint to api docs generation

lib/api/storage.js

@@ -377,11 +377,35 @@ module.exports = (db, server, storageHandler) => {
     );
 
     server.get(
-        { name: 'storagefile', path: '/users/:user/storage/:file' },
+        {
+            name: 'storagefile',
+            path: '/users/:user/storage/:file',
+            tags: ['Storage'],
+            summary: 'Download File',
+            description: 'This method returns stored file contents in binary form',
+            responseType: 'application/octet-stream',
+            validationObjs: {
+                requestBody: {},
+                queryParams: {},
+                pathParams: {
+                    user: userId,
+                    file: Joi.string().hex().lowercase().length(24).required().description('ID of the File')
+                },
+                response: {
+                    200: {
+                        description: 'Success',
+                        model: Joi.binary()
+                    }
+                }
+            }
+        },
         tools.responseWrapper(async (req, res) => {
-            const schema = Joi.object().keys({
-                user: Joi.string().hex().lowercase().length(24).required(),
-                file: Joi.string().hex().lowercase().length(24).required()
+            const { requestBody, queryParams, pathParams } = req.route.spec.validationObjs;
+
+            const schema = Joi.object({
+                ...requestBody,
+                ...queryParams,
+                ...pathParams
             });
 
             const result = schema.validate(req.params, {