dbus-osx-examples

Examples and tutorials for setting up and using D-Bus, for OSX users.

The DBus tools are powerful, mature, and robust, but the project doesn't have an OSX maintainer at present. As a result, documentation and support for using DBus on OSX is scarce. This repository is my attempt to remedy that.

Resources

• The installation directory contains a guide on various ways to configure and test DBus on Mac OSX.
• The homebrew-patches directory contains patches to DBus Homebrew formulae, already merged. It only exists for archival reasons.
• The examples directory will eventually contains client/server implementations in various different languages. For now, it only has a (skeleton) Perl example.

FAQ

• "A program I'm using which interacts with dbus can't connect! What should I do?"
  • A local dbus daemon likely is not running; check ps -ef | grep [d]bus to be sure.
  • The easiest way to get a local dbus daemon running is to use the Homebrew package manager. If you haven't already, run brew install dbus.
  • If dbus is already installed, ensure it is running (brew info dbus should tell you whether or not it is). If it's not running, it can be started and set to launch at login via brew services start dbus.
• "A program I'm installing says it just needs dbus-devel or the DBus headers; how can I just get those?"
  • First: the -devel headers are installed along with the DBus homebrew package. They're in $(brew --prefix dbus)/include.
  • Second: most programs that require the dbus-devel also assume that DBus itself is a) installed, b) configured, c) running, and d) has certain common (usually Linux-specific) services online. On OSX, none of these things can be relied upon. For example, many programs that require dbus-devel use that package to compile interfaces for DBus services that respond to, for example, volume button press events, or CD drive load/unload events. Such programs will usually malfunction on OSX unless the DBus services they depend on are also present. Installing those services can require some research and work. To avoid these (often sneaky) issues, always check what dbus-devel is required for, and if there's a way to either prevent the compile-time requirement for DBus, or a way to disable the compiled application's dependence onf DBus. The assumption of DBus service availability based on header availability is, unfortunately, a common one.
• "[some dbus- shell command] keeps saying my syntax is invalid? I swear I'm doing it right! What gives?"
  • A common gotcha with the DBus commandline tools involves switches with values. It's common for many programs usage messages to indicate that a given switch takes a value by saying usage: myprogram --myswitch=VALUE or similar. What that usually means is that both myprogram --myswitch=VALUE and myprogram --myswitch VALUE (without the equals sign) are valid. In DBus this is not the case: when a DBus commandline tool says to use --switch=VALUE, you must supply a verbatim equals sign on the commandline, with no spaces on either side. This may also be affected by which version of getopt DBus was built with.
  • If that doesn't help, try reading the manpage for the command you're having trouble with. In a Homebrew install, manpages should already be installed, so e.g. man dbus-test-tool should Just Work. If not, or if you prefer HTML, the manuals are also available at https://dbus.freedesktop.org/doc; in the index, search for the name of the program you're interested in.
• "I know how to write a DBus service, but there are so many moving parts and I don't have a good sense of what the standards are. How should I write a DBus service?"
  • Check out the services running on your machine (dbus-daemon --introspect) for examples.
  • Check out the design guidelines document. It's great.