OpenAPI Mocker
An API mocker based in the OpenAPI 3.0 specification.
Installation and usage
Using npm
npm i -g open-api-mocker
open-api-mocker -s my-schema.json -w
open-api-mocker --help # To prompt every available setting.
Using docker
docker run -v "$PWD/myschema.json:/app/schema.json" -p "5000:5000" jormaechea/open-api-mocker
Or to run an specific version
docker run -v "$PWD/myschema.json:/app/schema.json" -p "5000:5000" jormaechea/open-api-mocker:X.Y.Z`
You can set any parameter when running inside a docker container
docker run -v "$PWD/myschema.json:/app/schema.json" -p "3000:3000" jormaechea/open-api-mocker:X.Y.Z -s /app/schema.json -p 3000`
Capabilities
- [x] Read yaml and json OpenAPI v3 schemas.
- [x] Port binding selection
- [x] Request parameters validation
- [x] Request body validation
- [x] Response body and headers generation based on examples or schemas
- [x] Response selection using request header:
Prefer: statusCode=XXX
orPrefer: example=name
- [x] Request and response logging
- [x] Servers basepath support
- [x] Support x-faker and x-count extension methods to customise generated responses
- [ ] API Authentication
Customizing Generated Responses
The OpenAPI specification allows custom properties to be added to an API definition in the form of x-*. OpenAPI Mocker supports the use of two custom extensions to allow data to be randomised which should allow for more realistic looking data when developing a UI against a mock API for instance.
x-faker
The x-faker extension is valid for use on properties that have a primitive type (e.g. string
/integer
, etc.)
and can be used within an API definition to use one or more methods from the excellent
faker library for generating random data.
Given the following API definition:
openapi: '3.0.2'
info:
title: Cats
version: '1.0'
servers:
- url: https://api.cats.test/v1
paths:
/cat:
get:
responses:
'200':
description: OK
content:
application/json:
schema:
type: object
properties:
firstName:
type: string
x-faker: name.firstName
lastName:
type: string
x-faker: name.lastName
fullName:
type: string
x-faker: '{{name.firstName}} {{name.lastName}}'
age:
type: string
x-faker: 'random.number({ "min": 1, "max": 20 })'
A JSON response similar to the following would be produced:
{
"firstName": "Ted",
"lastName": "Kozey",
"fullName": "Herbert Lowe",
"age": 12
}
The x-faker extension accepts values in 3 forms:
-
fakerNamespace.method. e.g.
random.uuid
-
fakerNamespace.method({ "methodArgs": "in", "json": "format" }). e.g.
random.number({ "max": 100 })
- A mustache template string making use of the 2 forms above. e.g.
My name is {{name.firstName}} {{name.lastName}}
NOTE: To avoid new fake data from being generated on every call, up to 10 responses per endpoint are cached based on the incoming query string, request body and headers.
x-count
The x-count extension has effect only when used on an array
type property.
If encountered, OpenAPI Mocker will return an array with the given number of elements instead of the default of an
array with a single item.
For example, the following API definition:
openapi: '3.0.2'
info:
title: Cats
version: '1.0'
servers:
- url: https://api.cats.test/v1
paths:
/cat:
get:
responses:
'200':
description: OK
content:
application/json:
schema:
type: array
x-count: 5
items:
type: string
Will produce the following response:
[
"string",
"string",
"string",
"string",
"string"
]
Advanced usage
See the advanced usage docs to extend or build your own app upon OpenAPI Mocker.
Tests
Simply run npm t
Contributing
Issues and PRs are welcome.