webflux: contextPath not used while behind a load balancer/reverse proxy

[mxmrlt]

SwaggerUI doesn't work at all while behind a reverse proxy like Traefik even if good HTTP Headers are sent.

contextPath is available but doesn't seem to be used as you can see below

springdoc-openapi/springdoc-openapi-common/src/main/java/org/springdoc/ui/AbstractSwaggerWelcome.java

Line 207 in 1346f01

return this.swaggerConfigUrl;

springdoc-openapi/springdoc-openapi-common/src/main/java/org/springdoc/ui/AbstractSwaggerWelcome.java

Line 197 in 1346f01

return this.apiDocsUrl;

I tried setting this.swaggerConfigUrl and this.apiDocsUrl by appending default urls to the contextPath as we could expect according to the method signatures and it works well behind Traefik.

Is it really an issue that contextPath variable in thoses methods are not used?

[bnasslahsen]

Please read this section:

[mxmrlt]

@bnasslahsen I did read this section actually.

I tried all of it (version 1.5.6 BTW)

server.forward-headers-strategy=native OR framework
server.use-forward-headers=true

I also added cause I'm using reactive.

@Bean
ForwardedHeaderTransformer forwardedHeaderTransformer() {
    return new ForwardedHeaderTransformer();
}

the contextPath is '/transcodification'

First root call is good with a temporary redirect

Then redirect to UI with the right contextPath but not the queryParam configUrl

Then and so we've got a 404

[bnasslahsen]

@ethali,

You should make sure your proxy sends the correct headers, as described. Make sure your restart your application after the configuration changes.

For example, using Apache 2, configuration:

• X-Forwarded-Prefix "/custom-path"

If you are still facing this problem: You can set manually the configurl as workaround and test if it's ok.
springdoc.swagger-ui.configUrl = /transcodification/v3/api-docs/swagger-config

If it's working after setting the configUrl manually, this means it's a bug and we can reopen the issue.

[mxmrlt]

@bnasslahsen

• X-Forwarded-Prefix "/transcodification" is sent

I set server.forward-headers-strategy=framework wiith the ForwardedHeaderTransformer Bean as mentioned above.

Only redirect to /transcodification/webjars/swagger-ui/index.html is OK.

if I set springdoc.swagger-ui.configUrl = /transcodification/v3/api-docs/swagger-config all is OK about networking but I get PetStore example...

[bnasslahsen]

@ethali,

Can you Provide a Minimal, Reproducible Example - with HelloController that reproduces the problem ?

[mxmrlt]

@bnasslahsen

OK here's a minimal project that reproduces the problem.
https://github.com/ethali/hello

Sorry if I did something wrong.

[bnasslahsen]

@ethali,

This should be fixed with the latest SNAPSHOT.
You can test it, and if you are still facing other issues you can let me know.

[mxmrlt]

@bnasslahsen,

Just tested with 1.5.7-SNAPSHOT and it seems to work great behind my Traefik container.

It works with:

just server.forward-headers-strategy=framework set

OR just with bean injected

@Bean
ForwardedHeaderTransformer forwardedHeaderTransformer() {
    return new ForwardedHeaderTransformer();
}

Thank you!

[s-volkov-1]

For now, you can try springdoc version 1.4.8, it works fine for me.

[evan-qianjh]

@bnasslahsen Hi. This bug reappears in version 1.6.9