Is there a guide to getting free MARC records in the common programming
languages, covering what libaries and modules to use and where to look,
and giving code examples?

If you're like me then sometimes you have an ISBN and you say to yourself,
"Bill"--though why you'd say that if your name isn't Bill, I don't
know--"Bill, I would like a full MARC record for this book.  But I'm not
at a library that's a member of OCLC, so I can't get into WorldCat, and I
don't want to use Amazon's API because I don't want to have to link to
them.  What do I do?"

I looked around and didn't see anything obvious about this, so I hacked up
a Ruby script that solves most of the problem for me.  Given an ISBN, it
searches a series of open Z39.50 servers until it gets an answer.  It uses
ruby-zoom for the Z39.50 business, and gets MARCXML which it hands over to
ruby-marc.  (Thanks for Ed Summers and Jason Ronallo in #code4lib this aft
for help with this.)

I put a copy here, in case anyone wants to see it:

        http://www.miskatonic.org/files/zmarc.rb

Run 'zmarc.rb 0195024028' to see it in action.

There must be something better than this, though.  I have some ISBNs (of
recent English-language books) that aren't found at the Library of
Congress, Library and Archives Canada, U of Toronto, Oxford, Yale, New
York Public Library, the national libraries of Scotland, Australia, and
New Zealand, and others.  One would think they would give pretty good
coverage.

I want tools (in Perl, Ruby, Python, etc.) that will give me back
something in MARC for any book, in any language, that has an ISBN.  Am I
doomed to sometimes not getting any good results?  Has anyone written up
details on how close one can come right now with what's available?

What do you folks do when you need free MARC records or other information
about books?

Bill
--
William Denton, Toronto : www.miskatonic.org www.frbr.org www.openfrbr.org