EugenDueck / openslp-java

OpenSLP Java API

openslp-java

This is basically just a copy of OpenSLP Java API, as taken from http://sourceforge.net/projects/openslp/files/OpenSLP-Java/1.0.0/java_slp_api-1.0.tar.gz/download

Differences to original:

• made it compile with Java >= 1.5, which just meant renaming all occurences of the variable name enum to something else
• mavenized (quick and dirty) so we can e.g. mvn install it. A simple mvn install:install-file of the jar file created by ant would not have done the trick, as we need to specify the dependency on log4j

Please check the original license in license.txt if you want to use the library.

Why SLP?

There is not a lot of information out there on configuration-less service discovery. Besides SLP, there is SSPD, which, for this basic and simple task, uses one of the most complex and generic protocols out there - HTTP. I decided to stop onvestigating that one right there.

Another contender is DNS-SD, and it is used by Apple, so everyone who pretends to be hip (calm down, I didn't say that every Apple user is necessarily a poser) is using it these days - wittingly or not. I haven't investigated it too deeply either, but it does look interesting and might in fact even be technically superior to SLP. Don't know.

Why openslp-java?

Why a Java (or rather, JVM) library? Because it can be easily used from great languages such as clojure.

Why openslp-java? Because in contrast to jSLP, I could get it to work with multiple processes registering services on the same box. This is what jSLP gives me instead:

[ERROR] SLPCore - Exception: <java.net.SocketTimeoutException: Receive timed out>java.net.SocketTimeoutException: Receive timed out
        at java.net.PlainDatagramSocketImpl.receive0(Native Method)
        at java.net.AbstractPlainDatagramSocketImpl.receive(AbstractPlainDatagramSocketImpl.java:145)
        at java.net.DatagramSocket.receive(DatagramSocket.java:786)
        at ch.ethz.iks.slp.impl.SLPCore.sendMessage(SLPCore.java:729)
        at ch.ethz.iks.slp.impl.AdvertiserImpl.register(AdvertiserImpl.java:135)
        at clojure_jslp.core$register_service.invoke(core.clj:31)

Also, it is easy to use openslp-java on the standard port 427 - assuming you are running slpd. jSLP needs to run as root to be able to listen on 427.