pg_dump of only the structure from a client such as ruby

How hard would it be to do the following two statements (the equivalent of the following two statements) using a client?

pg_dump -i -U uuuuu -s -x -O -f file dbname

psql -U uuuuu -f file dbname

I'm trying to help out the rails people.  Currently they have "rake" scripts which call pg_dump, dropdb, createdb, and psql.  It would be nicer if this could be done via a database connection.

The psql piece I believe is fairly easy.  But I don't know where to begin with the pg_dump piece of it.  I took a glance at the pg_dump code and it is hugh... so I got scared and ran away.