OBus is a pure OCaml implementation of the D-Bus protocol. It aims to provide a clean and easy way for ocaml programmers to access and provide D-Bus services.

OBus uses the cooperative threading library Lwt, which makes it very simple to fully exploit the asynchronous nature of D-Bus.

The recommended way to install obus and its dependencies is via opam: opam install obus.

Make sure you have jbuilder installed, and install all the missing dependencies listed in the output of this command:

$ jbuilder external-lib-deps @install --missing

Then you can build and install obus:

$ jbuilder build -p obus
$ jbuilder install -p obus

To build and execute tests:

$ jbuilder runtest

OBus installs the following packages:

• obus: the core library, implementing the D-Bus protocol.
• obus.ppx: syntax extensions to aid registering OBus exceptions.
• Interfaces to various freedesktop dbus services: obus.notification, obus.network_manager, obus.hal, obus.upower, obus.udisks, obus.policykit.

There are several tools provided in the obus distribution:

• obus-dump, to execute a command and dump all messages that go through the session and/or system message bus.
• obus-introspect which can recursively introspect a D-Bus service.
• obus-gen-interface, to convert D-Bus introspection files into ocaml definition modules.
• obus-gen-client and obus-gen-server, which can generate templates for using or implementing D-Bus services.
• obus-xml2idl and obus-idl2xml, to convert xml introspection documents to the obus idl format, and vice versa.

There are manual pages for all this tools.

Introspection files do not contain enough information to create usable bindings by themselves, so the files generated by obus-gen-client and obus-gen-server are only stubs meant to be edited and adapted.

Here is a simple example of use of the tools:

$ obus-introspect org.freedesktop.Notifications /org/freedesktop/Notifications > notif.xml
$ obus-gen-interface notif.xml
$ obus-gen-client notif.xml