Support for application/x-ndjson

Content & configuration

Swagger/OpenAPI definition:

---
schemes:
- http
swagger: '2.0'
host: localhost:9866
paths:
 "/foo":
   get:
     description: foo
     produces:
     - application/x-ndjson
     summary: foo
     operationId: foo
     responses:
       '200':
         description: foo
         schema:
           type: string

I’ve made no changes to the default Swagger-UI configuration. I’m just using the dist of v3.22.1 out-of-the-box.

Is your feature request related to a problem?

I’ve been trying to document an application that returns content-type: application/x-ndjson. The format is spec’ed here. An example response:

{"hello": "world"}

{"goodbye": "world"}

When I render my spec in Swagger UI out-of-the-box and click Try It Out > Execute, Swagger UI seems to try and fail to treat the response data as JSON, giving an error message:

I can see by peeking in swagger-ui-bundle.js where it seem to be treating any content-type that contains json as JSON:

                    else if (/json/i.test(n)) {
                        try {
                            m = (0, r.default)(JSON.parse(t), null, "  ")
                        } catch (e) {
                            m = "can't parse JSON.  Raw result:\n\n" + t
                        }

I’m no JavaScript pro, but I found that if I hack this to exclude my data type, now it silently renders it as text.

                    else if (/json/i.test(n) && !/x-ndjson/i.test(n)) {
                        try {
                            m = (0, r.default)(JSON.parse(t), null, "  ")
                        } catch (e) {
                            m = "can't parse JSON.  Raw result:\n\n" + t
                        }

Describe the solution you’d like

It would be lovely if Swagger UI actually parsed x-ndjson according to its spec. But at minimum, it would be an improvement if it just didn’t report an error message due to trying to parse it as JSON, similar to what I’ve done with my hack.

[hhromic]

Another bump from mid-2021 😃 As of today, JSON still seems to be too broadly matched: https://github.com/swagger-api/swagger-ui/blob/92f1507408f442b9d450c986eba1d007352ec045/src/core/components/response-body.jsx#L96-L107

As per RFC 4627, the only content-type for JSON should be application/json. Perhaps Swagger-UI should be more strict in this regard.

Our API platform also is adopting NDJSON more and more and we are also affected by this issue 😦

[reseto]

Hi, I’m also using the steaming json format content-type: application/x-ndjson In general it doesn’t seem a great idea to modify response content. But at least in this special case would it be possible to not include the “can’t parse JSON. Raw result:\n\n” in response?