fix: Ignore the Upgrade Websocket request

[houkunlin]

spring:
  cloud:
    gateway:
      globalcors:
        cors-configurations:
          '[/**]':
            allowedOriginPatterns: "*"
            allowedHeaders: "*"
            allowedMethods: "*"
            allowCredentials: true
      routes:
        - id: test-stomp-info
          uri: lb://test
          predicates:
            - Path=/test/ws/stomp/info/**
        - id: rbac-stomp
          uri: lb:ws://test
          predicates:
            - Path=/test/ws/stomp/**
        - id: rbac
          uri: lb://test
          predicates:
            - Path=/**
      default-filters:
        - AddResponseHeader=Access-Control-Allow-Origin, *
        - AddResponseHeader=Access-Control-Allow-Methods, *
        - AddResponseHeader=Access-Control-Allow-Headers, *
        - AddResponseHeader=Access-Control-Allow-Credentials, true
        - DedupeResponseHeader=Vary Access-Control-Allow-Origin Access-Control-Allow-Credentials, RETAIN_FIRST

When forwarding the Websocket request in the above configuration, the forwarding may fail due to the modification of the Header. In this case, the DedupeResponseHeader needs to ignore the processing of the Upgrade request

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[spencergibb]

I don't understand, you're saying don't dedupe in certain cases? I think then, the dedupe filter shouldn't be a default one.

[houkunlin]

Header information of cross-domain scenarios is processed at the gateway, and cross-domain headers are deduplicated. If they are not placed in the default filter, each of them needs to be set.

[spencergibb]

Can you explain how to duplicate this? or add a test?