I need to extend PDF::Writer to allow it to include an external XML
file into the PDF file. It looks pretty straight forward from the PDF
spec in that it will be seperate component of the file, distinct from
the PDF document itself. I’ve pulled down the PDF::Writer source and
am looking through it to see what I need to do on that front. I
thought I’d ask if anybody 1) has any experience with mods to
PDF::Writer or 2) has experience with extending other GEMS they’d be
willing to share to help me avoid problems.
TIA,
Bill
On 12/18/06, bill walton [email protected] wrote:
…
thought I’d ask if anybody 1) has any experience with mods to
PDF::Writer or 2) has experience with extending other GEMS they’d be
willing to share to help me avoid problems.
I haven’t done anything with PDF::Writer, but I have extended several
gems
on my own system. Because of Ruby’s open classes, its easy to add or
override definitions of existing classes. I’ve used this to “patch” bugs
in
gems, or to add new features to them, without affecting the original
source
files. For example, if you’re code lives in “make_my_pdf.rb”, you can do
somethign like this:
require ‘pdf_writer’ # original gem
class PDF::Writer
… add new methods, override existing ones, etc.
end
PDF::Wrtier.new # do your work
If I find myself needing to fix a bug within a method, I’ve just pasted
the
definition in to my “local” copy and modified it there.
I have also found that most gem maintainers are glad to accept patches
and
apply them. If you include some unit tests, your patch is even more
likely
to get accepted.
HTH.
Justin
On 12/18/06, bill walton [email protected] wrote:
I need to extend PDF::Writer to allow it to include an external XML
file into the PDF file. It looks pretty straight forward from the PDF
spec in that it will be seperate component of the file, distinct from
the PDF document itself. I’ve pulled down the PDF::Writer source and
am looking through it to see what I need to do on that front. I
thought I’d ask if anybody 1) has any experience with mods to
PDF::Writer or 2) has experience with extending other GEMS they’d be
willing to share to help me avoid problems.
(1) Didn’t you ask me this directly a couple of weeks ago, and I asked
you what you for clarification? I don’t recall seeing such
clarification, but I will admit to being many hundreds of messages
behind (I’m about 800 “conversations” behind on ruby-talk).
(2) I strongly recommend against trying to extend (e.g.,
monkeypatch) PDF::Writer. The internals are pretty much guaranteed to
change in 2007. If you need a new PDF “object”, then you will either
need to (a) work with me or (b) monkeypatch. (b) has already been
pointed out as a bad idea.
(3) The best way to extend PDF::Writer is to make a “consumer” of
PDF::Writer.
-austin