I created an API spec from some JSON files and I am trying to test if the files validate against the API spec.
There are some good tools to validate against JSON Schema, but I did not have chance to find a tool to validate against specs created in the Swagger (tool for creating API schema). The only solution I found is generating a client/server in the Swagger-Editor, it is quite cumbersome.
Is there already an existing tool to validate JSON against Swagger Schema?
The OpenAPI 2.0 / Swagger schema is available in a few places, it's just a bit hard to find because of the heavy use of the word 'schema' in swagger itself.
So you can point a generic validator at this schema and your document. For example, this works nicely for me using vscode and Red Hat's YAML extension.
Atlassian's swagger-request-validator is a Java library that can do such validation:
The core library is not tied to any specific HTTP library, but they also provide additional modules that integrate with Spring MVC, MockMVC, REST Assured etc.
There is also swagger-schema-validator that can validate a JSON document against a Swagger V2 definition (disclaimer: I'm the author). This Java library is less complete than Atlassian's though.
Arnaud in the comments is correct that there are two separate questions here.
You can
In other words, here's some JSON from a request or response body, is it correct?
Swagger relies on another standard called JSON Schema for its schema objects, which are what actually describes the JSON (rather than endpoints or metadata). Swagger uses a subset of JSON Schema (missing:
oneOf
,patternProperties
, among others). To that end, you can use a JSON Schema validator. There are 37 listed here; I'll give a shoutout to this online validator that also supports YAML schemas.But, when I said Swagger relies on a subset of JSON API, I lied. There are a handful of fixed fields that have special meaning in Swagger that's not part of JSON Schema. One of them is
discriminator
which is used for polymorphism. I am not aware of a Swagger validator that can processdiscriminator
. There are a fair number of tools for swagger and some claim to do validations, but many are abandonware, meant for old versions, not feature-complete, tied to other technologies, and so on. If there's a mature and well-maintained library that I'm missing, I'd love to know.If your Swagger JSON is hosted, you could use the following url: http://online.swagger.io/validator/debug?url=your_url