Remove HTTP response headers for the remoting-based CLI

[daniel-beck]

Related to #2795, #3838, #4350, and aebb3b2.

Untested; PR build and @jglick will be able to tell us whether this is correct. I think these headers are unused now; I couldn't find a reference here or in Remoting at least.

CLI_HOST_NAME is still advertised as X-Jenkins-JNLP-Host, the port as X-Jenkins-JNLP-Port.

Unsure whether to leave

jenkins/test/src/test/java/hudson/cli/CLITest.java

Line 179 in 95e8549

assertNull(rsp.getContentAsString(), rsp.getResponseHeaderValue("X-Jenkins-CLI-Port"));

in. (Edited to add: Now removed in 4bd10a4)

Proposed changelog entries

• Stop sending HTTP response headers related to the remoting-based CLI (removed in 2.165).

Proposed upgrade guidelines

N/A

Submitter checklist

• (If applicable) Jira issue is well described
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• Appropriate autotests or explanation to why this change has no tests
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Desired reviewers

@mention

Maintainer checklist

Before the changes are marked as ready-for-merge:

• There are at least 2 approvals for the pull request and no outstanding requests for change
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[basil]

Looks good to me, but might also want to get rid of the now-dangling reference to X-Jenkins-CLI-Port in test/src/test/java/hudson/cli/CLITest.java.

[jglick]

Yes I think this is safe. (Came up sometime recently but I forget where.)

[oleg-nenashev]

I referenced the advertiseHeaders() method in the FLoC thread, likely this is where @jglick saw it I'd guess. Thanks for the cleanup @daniel-beck !

I see reliance on these headers in https://github.com/jenkinsci/master-to-master-api-plugin/blob/bb48f24779f4873877bbf6500621377e077ffda3/src/main/java/org/jenkinsci/plugins/mastertomasterapi/simple/SIMClient.java . I'd guess we do not care too much about this plugin in the current state (not published in the UC)

We may merge it in 24 hours if there is no negative feedback. Please see the merge process documentation for more information about the merge process

[jglick]

I referenced the advertiseHeaders() method in the FLoC thread, likely this is where @jglick saw it I'd guess.

Somewhere else I think. Does not matter now.

[jtnord]

@daniel-beck what is the correct web header now in order to locate the (sic) JNLP port for remoting connections?

(basically breaks quite a pretty important CloudBees specific feature :) )

This was not the change I thought it was. it did not remove X-Jenkins-JNLP-Port which should still also be found as per https://github.com/jenkinsci/jenkins/blob/master/core/src/main/resources/hudson/TcpSlaveAgentListener/index.jelly#L33