Installing Ruby XMPP Simple

I'm no Ruby expert but a friend of mine was asking me how to write a simple XMPP bot using Ruby, and I had seen a couple of recent posts announcing a simple ruby library.

So after installing RubyGems (I had a total virgin Mac OS X stock install of Ruby), I did the usual:

sudo gem install xmpp4r-simple

That did not work well. One of the dependencies, rcov, does not install in my system. The error message is something like this:

gcc -fno-common -g -Os -pipe -fno-common -pipe  -fno-common -pipe -fno-common  -I. -I/usr/lib/ruby/1.8/universal-darwin8.0 -I/usr/lib/ruby/1.8/universal-darwin8.0 -I.   -c callsite.c
callsite.c:121: error: parse error before 'event'
callsite.c: In function 'coverage_event_callsite_hook':
callsite.c:131: error: 'klass' undeclared (first use in this function)
callsite.c:131: error: (Each undeclared identifier is reported only once
callsite.c:131: error: for each function it appears in.)
callsite.c:136: error: 'mid' undeclared (first use in this function)
callsite.c:141: error: 'node' undeclared (first use in this function)
callsite.c: In function 'cov_install_callsite_hook':
callsite.c:162: error: 'RUBY_EVENT_CALL' undeclared (first use in this function)
make: *** [callsite.o] Error 1

To solve this, I did the following: first I manually downloaded the latest version of rcov from the rcov site. Doing the classic ruby setup.rb dies with the same error, but there is an alternative:

sudo ruby setup.rb all --without-ext

This works. Basically it skips installation of a C-based extension to the rcov package that makes the package a lot faster. Given that I don't intend to run coverage tests in ruby, I don't mind skipping this.

At this time, gem install xmpp4r-simple still tries to install the dependency of rcov although we already have rcov installed. So we skip the dependencies:

sudo gem install --ignore-dependencies xmpp4r-simple

This works, and now we can play.