This is a Pd external which lets you publish and discover network services via mDNS/DNS-SD a.k.a. Zeroconf. It works with the prevalent Zeroconf implementations on Linux and MacOS, Avahi and Bonjour. One obvious application are services which transmit OSC (Open Sound Control) between mobile applications such as TouchOSC and Pd. But this external may conceivably be used to advertise any kind of networked-based service between Pd and other host-based or mobile applications.
NOTE: This is based on an earlier external which is still available from Bitbucket. The present module is now Lua-based and thus much easier to install than the previous module written in the Pure language.
mdnsbrowser is Copyright (c) 2022 by Albert Gräf. It is distributed under the 3-clause BSD license, please check the COPYING file for details.
The external is written in Lua, so pd-lua is required. Lua 5.4 has been tested, Lua 5.3 likely works as well, but earlier Lua versions probably require some fiddling with the sources. Lua can be found in many Linux distributions and on Homebrew. A version of pd-lua compatible with Lua 5.3 and 5.4 is available from https://github.com/agraef/pd-lua.
You'll also need Avahi on Linux (readily available in most Linux distributions) and Bonjour on MacOS (comes preinstalled on Mac computers). On Linux you'll also have to make sure that the avahi-daemon service is running (systemctl start avahi-daemon; see, e.g., https://wiki.archlinux.org/title/avahi for details).
Run make to compile the Lua mdns module. The Makefile should figure out on its own whether it runs on Linux or Mac and compile the right source module (avahi.c on Linux, bonjour.c on Mac) to mdns.so.
After running make you can immediately test that the external works by opening the mdnsbrowser-help.pd patch in Pd. If you're getting a bunch of error messages from pd-lua complaining that it couldn't find the mdns module, then most likely you've forgotten to run make; this module needs to be present so that mdnsbrowser.pd_lua will work. On the other hand, if Pd just complains that it couldn't create the mdnsbrowser object then pd-lua is missing; make sure that pd-lua is installed and in Pd's startup libraries.
Also note that the included help patch assumes that you have the mrpeach externals installed and on Pd's search path. If you're getting a bunch of creation errors for externals like udpsend and udpreceive when loading the help patch, it's a sure sign that mrpeach is missing. Try to install it from Deken or compile it from source; it's not that hard to do.
Installation isn't necessary, the external can simply be run in-place, editing the provided help patch to adjust it for your needs. But if you want to make sure that the mdnsbrowser object and the help patch can be invoked from anywhere, you can just copy the entire mdnsbrowser directory to some convenient location and make sure that you add that directory to Pd's search path. The Pd FAQ has an article about some common locations on the various platforms that you might want to use.
Please check the included help patch for usage information and the comments at the beginning of the mdnsbrowser.pd_lua script for further information. In brief, the external is invoked as:
mdnsbrowser [name [type] [port]]
The arguments are all optional, but if any are specified, you need to give at least the service name, possibly followed by a service type and a port number. Reasonable defaults (service name OSC, type _osc._udp, and port number 8000) will be provided which match TouchOSC's defaults. mdnsbrowser will also tack on your system's hostname to the service name to make it easier to identify different instances of mdnsbrowser running on different computers on your local network.
Note that mdsnbrowser only helps you advertise OSC endpoints and discover them in your local network, it does not implement the actual transport of OSC messages from/to your mobile devices. You'll still have to use either Pd's built-in facilities or the mrpeach externals to do that. The included help patch shows how this can be implemented using the mrpeach externals.
The package also includes two useful abstractions named oscbrowser.pd and osclisten.pd which help with establishing OSC connections. oscbrowser.pd implements a list store for discovered services which makes it easy to choose other OSC services on the local network. osclisten.pd listens to OSC data on port 8000, detects where the data came from and connects back to the data source. These provide two different ways to establish bidirectional communication. You can see how these are used by studying the provided help patch.
To get TouchOSC hooked up to Pd, it's generally sufficient to activate the publish checkbox in the help patch, and then select the corresponding service in TouchOSC's OSC configuration. Once the connection from TouchOSC has been established, press the bang control above the osclisten object and operate any of the controls in your TouchOSC layout to make Pd connect back to the TouchOSC instance. I suggest to use TouchOSC's Mix2 layout for this purpose. The two sliders in the help patch are both mapped to the /1/fader1 control which is the left fader on the first page in the Mix2 layout. One of the sliders in the help patch will show movements of the fader in TouchOSC, while the other can be used to control the TouchOSC fader from Pd.
This should hopefully be enough to get you started. Note that the help patch doesn't do any real processing of received OSC messages. It only provides a simple example from where you can start adding messages and the actual control and audio processing that you want to perform.
As usual, bug reports, patches, feature requests, other comments and source contributions are more than welcome. Just drop me an email, file an issue or send me a pull request on mdnsbrowser's GitHub page.
Enjoy! :)
Albert Gräf aggraef@gmail.com