Unable to load RELATIVE ref

[nickcmaynard]

With swagger-codegen 2.1.4, we receive this error when attempting to generate JAX-RS server from a swagger.json:

reading from http://localhost:9080/swagger.json
Exception in thread "main" java.lang.RuntimeException: Unable to load RELATIVE ref: ./parameters.json
    at io.swagger.parser.util.RefUtils.readExternalRef(RefUtils.java:85)
    at io.swagger.parser.ResolverCache.loadRef(ResolverCache.java:91)
    at io.swagger.parser.processors.ParameterProcessor.processParameters(ParameterProcessor.java:38)
    at io.swagger.parser.processors.OperationProcessor.processOperation(OperationProcessor.java:28)
    at io.swagger.parser.processors.PathsProcessor.processPaths(PathsProcessor.java:58)
    at io.swagger.parser.SwaggerResolver.resolve(SwaggerResolver.java:38)
    at io.swagger.parser.SwaggerParser.read(SwaggerParser.java:62)
    at io.swagger.codegen.config.CodegenConfigurator.toClientOptInput(CodegenConfigurator.java:317)
    at io.swagger.codegen.cmd.Generate.run(Generate.java:186)
    at io.swagger.codegen.SwaggerCodegen.main(SwaggerCodegen.java:35)
Caused by: java.lang.NullPointerException
    at io.swagger.parser.util.RefUtils.readExternalRef(RefUtils.java:75)
    ... 9 more

I've seen other issues (#214) where @fehguy states this should be fixed, but we're not seeing this... does anyone have any ideas, please?

[wing328]

Here is the error:
Exception in thread "main" java.lang.RuntimeException: Unable to load RELATIVE ref: ./parameters.json

Seems like you're using relative path for the definition of parameters.

Can you replace ./parameters.json with full URL instead as the parser is expecting the full URL (https://github.com/swagger-api/swagger-parser/blob/master/modules/swagger-parser/src/main/java/io/swagger/parser/util/RefUtils.java#L71) ?

[wing328]

You can find an example for reference at #1544 (comment)

[nickcmaynard]

That's the issue. Sadly, we need to use relative references - this gets deployed on a number of servers with different URLs.

[nickcmaynard]

To be clear, we expect this relative style to work, in line with @fehguy's assertion.

[wing328]

@nickcmaynard I read #214 twice but didn't see how it's related to this issue (relative URL) that you reported.

Are you referring to another issue instead?

[nickcmaynard]

Definitely a typo. Will try to track down the real issue number. However, this issue should be sufficient. Essentially, @fehguy states "swagger-parser supports relative, so swagger-codegen should too". Clearly, not the case. Hence, raising the issue.

[nickcmaynard]

#742 is the issue I'm referring to.

[wing328]

I've read #742 and the issue #1193 associated with it. My understanding is that the thread/issue refers to relative "file" path (not URI).

Looking at the swagger spec, canonical dereferencing is supported so in your case swagger parser should look for http://localhost:9080/parameter.json

[nickcmaynard]

swagger-codegen is being passed a URI. The URI contains a relative $ref. It throws the error linked in the original report. We expect it to work.

[nicksloan]

Until this is fixed, I have worked around it by using swagger-parser (the JavaScript library). Here is a quick node.js script I wrote to help: https://gist.github.com/nicksloan/b4aeb117734c5c1cec81

I simply run that with $ node consolidate.js > full.json to serialize my schema to a single JSON file, which I can then build using swagger-codegen. The extra step is a bummer, but not really that much of a problem in the grand scheme of things.

This is tested and working for local file schemas, but not for hosted schema URIs. It's probably worth a try though.

[nicksloan]

I'm not sure but I believe that this will be fixed when swagger-codegen depends on the next release of swagger-parser. More information is here: swagger-api/swagger-parser#213.

[wing328]

@nickcmaynard @nicksloan do you mind pull the latest master of Swagger Codegen to see if you're still facing the issue? Thanks.

[nicksloan]

I'll try to take a look this weekend.

[wing328]

@nicksloan may I know if you've a chance to take another look?

[fehguy]

This should be fixed by 92af2cf