Allow websocketSubscriptionHandler Bean to be overridden.

[hwhh]

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Pull Request type

• Bugfix
• Feature
• Refactoring (no functional changes, no api changes)
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Changes in this PR

Describe the new behavior from this PR, and why it's needed
Issue #

Currently the implementation of the WebsocketGraphQLTransportWSProtocolHandler does have any functionality to authenticate token in the connection_init message. This is a problem because the graphql-ws library from NPM only supports authentication method within the connection_init message i.e.

  const wsLink = new GraphQLWsLink(
        createClient({
          url: WS_LINK,
          connectionParams: async () => {
            const credentials = await getCredentials();
            if (credentials) {
              return {
                Authorization: `Bearer ${credentials.accessToken}`,
              };
            }
          },
        }),

Therefore I needed to write my own WebsocketReactiveProtocolHandler which populates the security context if a CONNECTION_INIT message is sent.

Alternatives considered

Describe alternative implementation you have considered

[srinivasankavitha]

Looks good to me.