Getting Origami-pdf to work with Amazon S3 files - pdf

Question

I've implemented a local script to insert digital signatures into local pdf files recurring to Origami, but don't quite know what would be the best approach to do this within a rails server, and with amazon s3 stored files.
I am guessing i would need to download the file from s3 to my server (or capture it before uploading to amazon, which is what i am doing with paperclip) insert the signature, and sent it back to s3 again.
Here is the PDF.read method in pdf.rb file of origami solution:
class << self
#
# Reads and parses a PDF file from disk.
#
def read(filename, options = {})
filename = File.expand_path(filename) if filename.is_a?(::String)
PDF::LinearParser.new(options).parse(filename)
end
How could i adapt this so that i treat an in-memory binary file?
Do you have any suggestions?
You can find more about origami here
And my code below
require 'openssl'
begin
require 'origami'
rescue LoadError
ORIGAMIDIR = "C:\RailsInstaller\Ruby1.9.3\lib\ruby\gems\1.9.1\gems\origami-1.2.4\lib"
$: << ORIGAMIDIR
require 'origami'
end
include Origami
INPUTFILE = "Sample.pdf"
#inputfile = String.new(INPUTFILE)
OUTPUTFILE = #inputfile.insert(INPUTFILE.rindex("."),"_signed")
CERTFILE = "certificate.pem"
RSAKEYFILE = "private_key.pem"
passphrase = "your passphrase"
key4pem=File.read RSAKEYFILE
key = OpenSSL::PKey::RSA.new key4pem, passphrase
cert = OpenSSL::X509::Certificate.new(File.read CERTFILE)
pdf = PDF.read(INPUTFILE)
page = pdf.get_page(1)
# Add signature annotation (so it becomes visibles in pdf document)
sigannot = Annotation::Widget::Signature.new
sigannot.Rect = Rectangle[:llx => 89.0, :lly => 386.0, :urx => 190.0, :ury => 353.0]
page.add_annot(sigannot)
# Sign the PDF with the specified keys
pdf.sign(cert, key,
:method => 'adbe.pkcs7.sha1',
:annotation => sigannot,
:location => "Portugal",
:contact => "myemail#email.tt",
:reason => "Proof of Concept"
)
# Save the resulting file
pdf.save(OUTPUTFILE)

Answer 1

PDF.read and PDF.save methods both accept either a file path or a Ruby IO object.
One method to create a PDF instance from a string (which, I suppose, is what you mean when you say "in-memory") is to use a StringIO object.
For example, the following session in the Origami shell will create a PDF instance, save it to a StringIO object and reload it using its own output string.
>>> PDF.new.save(strio = StringIO.new)
...
>>> strio.string
"%PDF-1.0\r\n1 0 obj\r\n<<\r\n\t/Pages 2 0 R ..."
>>> strio.reopen(strio.string, 'r')
#<StringIO:0xffbea6cc>
>>> pdf = PDF.read(strio)
...
>>> pdf.class
Origami::PDF

Answer 2

After a deep further analysis into the origami code, i noticed that PDF.Read accepts a binary file, and so instead of sending the local file path, we can send the file instance as a whole.

Answer 3

As #MrWater wrote, Origami::PDF.read accepts a stream (more precisely, the Origami::PDF::LinearParser does, look at the source here).
Here's my simple solution:
require 'open-uri'
# pdf_url = 'http://someurl.com/somepdf.pdf'
pdf = Origami::PDF.read(URI.parse(pdf_url))
References
open-uri URI
Origami::PDF::LinearParser