The problem

After importing a customer's Confluence data and fixing its base URL to be 'http://<customer>.jira.com/wiki', I went to JIRA's Application Links page and tried to register an applink in JIRA to the new Confluence, URL 'http://<customer>.jira.com/wiki'.

This failed with the error message 'The specified URL returned a 404 error.':

Not a single line in the JIRA logs. Nothing in the Confluence logs but:

  -- referer: http://<customer>.jira.com/wiki/admin/console.action | url: /wiki/admin/editinstances.action | userName: sysadmin
 2010-03-31 07:43:37,391 WARN [ajp-j2ee.instance.jirastudio.com-confluence%2F127.0.0.101-8009-1] [studio.core.navbar.NavbarRenderer] getNavbarTopHtml Confluence base URL is unavailable.
  -- referer: http://<customer>.jira.com/wiki/admin/console.action | url: /wiki/admin/editinstances.action | userName: sysadmin
 2010-03-31 07:43:37,392 WARN [ajp-j2ee.instance.jirastudio.com-confluence%2F127.0.0.101-8009-1] [studio.core.navbar.NavbarRenderer] getUserMenuHtml Confluence base URL is unavailable.
  -- referer: http://<customer>.jira.com/wiki/admin/console.action | url: /wiki/admin/editinstances.action | userName: sysadmin

To replicate:

• Go to Admin -> Wiki -> Configuration -> Application Links and Remove the JIRA applink from Confluence.
• Go to Admin -> Issues -> System -> Application Links
  • Remove any existing Confluence applinks (keep the project links)
  • Click 'Add Instance' and add a Confluence applink, URL http://<customer>.jira.com/wiki

The cause

The reason for the 404 is that http://<customer>.jira.com/wiki goes through a series of redirects, the last being from

http://<customer>.jira.com/wiki/login.action?os_destination=%2Fhomepage.action

to

http://<customer>.jira.com/wiki/login.jsp?os_destination=%2Fwiki%2Fhomepage.action

The path /wiki/login.jsp doesn't exist, hence the 404. It should be /login.jsp without the /wiki.

Studio apps use the JiraLoginRedirect servlet filter to intercept requests to the application's default login URL (/login.action for Confluence) and redirect the user to JIRA's login. JiraLoginRedirect uses a StudioInfo instance to look up the Studio base URL. DefaultStudioInfo.java has this code:

    public String getStudioBaseUrl()
    {
        final ApplicationInstances jiras = appLinksManager.getApplicationInstances(Application.JIRA);

        if (jiras.getPrimary() != null)
            return jiras.getPrimary().getUrl();
        else
            return getCurrentAppBaseUrl();
    }

The else clause is the problem: when running in Confluence, the application base URL is Confluence's, complete with /wiki ending. This is not the same as the Studio base URL. This code is therefore broken for any Confluence that doesn't have a appLinks-JIRA-urls bandana entry, eg:

    524289 | _GLOBAL        | appLinks-JIRA-urls             | <properties>
                                                             :   <property name="jira" value="http://test.jira.com"/>
                                                             : </properties>

The workaround

First add an applink in Confluence, to JIRA. Then you can go to JIRA and add an applink to Confluence, and synchronize.