base64 type properties fail validation for lack of example

[shoffmeister]

Whenever an object has a property of base64 (i.e. type: string, format: byte) validation will fail the error message

*ERROR* in Model '...', property 'content', field 'example' -> This field should be present and not empty

although the field example is present. This is really tied to the property being of type base64; remove the "format: byte" and the specification document will pass validation.

To reproduce, download the attached Zip file y.zip which contains two files minimally reproducing:

• pom.xml
• broken-validation-base64-response.yaml

Run mvn verify

//exp: passes validation
//act: ERROR in Model

[JFCote]

@shoffmeister Thanks for the bug report! I'm not sure when I'll be able to look at this, I'm very busy for the next 2 weeks but if you send me a PR, I will try to review it quickly and make sure we do a release. Otherwise, it might take a couple of weeks.

Thanks!

[gervaisb]

I made a quick test, it seems that the parser does not set the example property for the "byte" format.

• A test that use the parser fail: https://github.com/gervaisb/openapi-style-validator/blob/e5fe49551c8103856dacd632948dd4c91019b9ae/cli/src/test/java/org/openapitools/openapistylevalidator/cli/MainTest.java#L320
• Another that use a "hand made" OpenApi pass: https://github.com/gervaisb/openapi-style-validator/blob/e5fe49551c8103856dacd632948dd4c91019b9ae/lib/src/test/java/org/openapitools/openapistylevalidator/OpenApiSpecStyleValidatorTest.java#L262

[JFCote]

@gervaisb So either it's a bug with swagger-parser that we use under the hood or swagger-parser follow specification and a byte field should not have example. I can't find any specific information about the byte field examples here: https://swagger.io/docs/specification/adding-examples/

If it's a bug: We need to create a bug in their project. https://github.com/swagger-api/swagger-parser

If it's meant to be like that and follow spec, we need to create a special validation that when the field is "byte", we don't count it as an error when there are no examples.

I don't have time right now to dig deeper but if you have some time, you could go and create an issue in their project since you already have examples.

[gervaisb]

It seems to be a bug on the parser that tries to cast the example to the wrong type: swagger-api/swagger-parser#1630 (comment)

[tymonx]

I have the same issue here. As temporary workaround I use format: base64 with additional pattern: '^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$'.

[JFCote]

@gervaisb and @tymonx. As soon as swagger-parser release a new version with this fix, I will update our dependency and create a new release.

Thanks for the workaround in the meantime! :)

[acabarbaye]

same seems to be true with format: binary