Calling dbus from Apache and getting the X11 initialization error.

[John Palmieri]

----- "Thiago Macieira" <thiago at kde.org> wrote:

> Em Segunda-feira 28. Dezembro 2009, às 04.04.48, Mike MacHenry
> escreveu:
> > I am looking for a work around to the "Autolaunch error: X11
> > initialization failed." that it seems a lot of forums have
> discussions
> > about. There have been suggests to solve this problem by setting
> the
> > DISPLAY environment variable, but this does not work for me. I
> think
> > because that trick works for cron jobs but not Apache processes.
> > Here's the simple description of my problem:
> > 
> > I have a DBus server process running. It has an interface with one
> > method, skip_ahead, which has no arguments. I run the following
> Python
> > code from a normal user's account:
> 
> If that's the system bus that you're talking about, then the X11 
> initialisation should not happen. The address of the system bus is
> known.
> 
> But I doubt you're talking about the system bus. You're probably
> talking about 
> the session bus.
> 
> To access the session bus, you must have the address of the bus and
> the proper 
> UID. The address is given by the DBUS_SESSION_BUS_ADDRESS environment
> 
> variable, that is set by dbus-launch at the start of the session and
> is shared 
> by all processes in that session. If you don't have that variable set,
> your 
> process probably doesn't belong to the session in the first place
> (Apache 
> processes certainly look like they don't belong).
> 
> If the environment variable isn't set, the library tries to use
> something else 
> that is also keyed to the session and that's the X11 display. Your
> process is 
> apparently not able to connect to X11 either.
> 
> So, please ask yourself: does your process belong to the session or
> not?
> 
> If it doesn't, you probably want to use the system bus.
> -- 
> Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
>   Senior Product Manager - Nokia, Qt Development Frameworks
>       PGP/GPG: 0x6EF45358; fingerprint:
>       E067 918B B660 DBD1 105C  966C 33F5 F005 6EF4 5358
> 
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I would also suggest perhaps setting up a special bus for apache apps to use when talking to your module or, for performance reasons, having the module accept direct connections using the bus APIs.  As Thiago suggested, using a session bus is wrong here.  They are primarily designed for use with X Sessions.  The system bus could be used for simplicity but it is really designed for use with system specific services, not for isolated environments like an apache module.  
  
--
John (J5) Palmieri
Software Engineer
Red Hat, Inc.