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  1. Jenkins
  2. JENKINS-59393

Fix malformed XML in Atom and RSS 2.0 feeds

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    • Icon: Bug Bug
    • Resolution: Fixed
    • Icon: Minor Minor
    • core
    • None
    • jenkins-2.196

      While fixing JENKINS-59231, I noticed that Jenkins RSS 2.0 and Atom XML feeds have malformed XML.

      Inserting an interactive break and fetching the URL, we see that Jenkins is returning malformed XML:

      $ curl http://localhost:43969/jenkins/rssAll
<?xml version="1.0" encoding="UTF-8"?>
<feed xmlns="http://www.w3.org/2005/Atom"><title>All all builds</title><link rel="alternate" type="text/html" href="http://localhost:43969/jenkins/"><updated>2001-01-01T00:00:00Z</updated><author><name>Jenkins Server</name></author><id>urn:uuid:903deee0-7bfa-11db-9fe1-0800200c9a66</id></feed>

      Note that the <link> tag is not terminated, despite the fact that it is terminated in the template:

      $ grep link core/src/main/resources/hudson/atom.jelly
<link rel="alternate" type="text/html" href="${app.rootUrl}${url}"/>
<link rel="alternate" type="text/html" href="${app.rootUrl}${h.encode(adapter.getEntryUrl(e))}"/>

      So Jelly must be screwing this up when filling in the template. Where is that happening? Stepping through the code in the debugger reveals this stack trace:

      createXMLOutput:68, DefaultScriptInvoker (org.kohsuke.stapler.jelly)
invokeScript:51, DefaultScriptInvoker (org.kohsuke.stapler.jelly)
execute:56, ScriptInvoker (org.kohsuke.stapler.jelly)
execute:43, ScriptInvoker (org.kohsuke.stapler.jelly)
forward:95, ScriptRequestDispatcher (org.kohsuke.stapler)
forwardToRss:91, RSS (hudson.model)

      CreateXMLOutput looks like this:

      protected XMLOutput createXMLOutput(StaplerRequest req, StaplerResponse rsp, Script script, Object it) throws IOException {
    // TODO: make XMLOutput auto-close OutputStream to avoid leak
    String ct = rsp.getContentType();
    XMLOutput output;
    if (ct != null && !ct.startsWith("text/html")) {
        output = XMLOutput.createXMLOutput(createOutputStream(req, rsp, script, it));
    } else {
        output = HTMLWriterOutput.create(createOutputStream(req, rsp, script, it));

    }
    return output;
}

      As you can see, there are two paths, one for XML output and one for HTML output. Stepping through this, I see that for RSS feeds rsp.getContentType() is null, so we go through the (incorrect) HTML output path. This results in malformed XML.

      The solution is to set the content type appropriately on the response in RSS#forwardToRss. I stole the existing content types from core/src/main/resources/hudson/atom.jelly and core/src/main/resources/hudson/rss20.jelly. With this set, we now use the XML output path in RSS#forwardToRss and produce well-formed XML:

      $ curl  http://localhost:43831/jenkins/rssAll
<?xml version="1.0" encoding="UTF-8"?>
<feed xmlns="http://www.w3.org/2005/Atom"><title>All all builds</title><link rel="alternate" type="text/html" href="http://localhost:43831/jenkins/"></link><updated>2019-09-13T20:13:05Z</updated><author><name>Jenkins Server</name></author><id>urn:uuid:903deee0-7bfa-11db-9fe1-0800200c9a66</id><entry><title>test0 #1 (stable)</title><link rel="alternate" type="text/html" href="http://localhost:43831/jenkins/job/test0/1/"></link><id>tag:hudson.dev.java.net,2019:test0:1</id><published>2019-09-13T20:13:05Z</published><updated>2019-09-13T20:13:05Z</updated></entry></feed>

            Unassigned Unassigned
            basil Basil Crow
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              Created:
              Updated:
              Resolved: