Can't link JIRA issue to Confluence page by using tiny URL when Confluence uses a Context Path

Summary

If Confluence uses a context path in its URL, JIRA is unable to find a page using its tiny link when linking a JIRA issue to a Confluence page.

Steps to reproduce

1. Configure JIRA to run on http://localhost:8730/jira
2. Configure Confluence to run on http://localhost:6001/cfl
3. Link them together using applinks
4. Open a Confluence page and get its tiny link
5. Open a JIRA issue -> More -> Link -> Confluence Page -> paste the tiny link -> Link

Expected behavior

The link is added successfully.

Actual behavior

JIRA cannot find the link and throws a 404 error in the log:

2017-02-14 23:13:40,939 http-nio-8730-exec-2 ERROR admin 1393x1101x1 ki7q6c 0:0:0:0:0:0:0:1 /secure/LinkConfluencePage.jspa [c.a.j.p.link.confluence.LinkConfluencePage] Invalid response from getting the pageId: 404: Not Found

Notes / Workarounds

• By default, Confluence will resolve the tiny link to a relative URL when used with HTTP/1.1, which fails when a context path is used for Confluence.
• The standard (non-tiny) link of the same Confluence page can be linked successfully
• If Confluence has no context path e.g. http://localhost:6001, tiny links can be linked successfully
• If using a context path, two possible workarounds would be to either:
  • append the system property org.apache.catalina.STRICT_SERVLET_COMPLIANCE=true to Confluence's catalina.properties file and restart Confluence, or
  • modify the context element in Confluence's context.xml file to disallow relative redirects, e.g.:
    <Context useRelativeRedirects="false">
    and restart Confluence.

Be sure to thoroughly test either of the above two workarounds in a test environment before implementing in production to ensure no functionality is impacted.