write stream to paperclip - ruby-on-rails

Question

I want to store received email attachment with usage of paperclip. From email I get part.body and I have no idea how to put it to paperclip'ed model. For now I create temporary file and write port.body to it, store this file to paperclip, and delete file. Here is how I do it with temporary file:
l_file = File.open(l_path, "w+b", 0644)
l_file.write(part.body)
oAsset = Asset.new(
:email_id => email.id,
:asset => l_file,
:header => h,
:original_file_name => o,
:hash => h)
oAsset.save
l_file.close
File.delete(l_path)
:asset is my 'has_attached_file' field. Is there a way to omit file creation and to do something like: :asset => part.body in Asset.new ?

Answer 1

This is how I would do it, assuming your using the mail gem to read the email. you'll need the whole email 'part', not just part.body
file = StringIO.new(part.body) #mimic a real upload file
file.class.class_eval { attr_accessor :original_filename, :content_type } #add attr's that paperclip needs
file.original_filename = part.filename #assign filename in way that paperclip likes
file.content_type = part.mime_type # you could set this manually aswell if needed e.g 'application/pdf'
now just use the file object to save to the Paperclip association.
a = Asset.new
a.asset = file
a.save!
Hope this helps.

Answer 2

Barlow's answer is good, but it is effectively monkey-patching the StringIO class. In my case I was working with Mechanize::Download#body_io and I didn't want to possibly pollute the class leading to unexpected bugs popping up far away in the app. So I define the methods on the instances metaclass like so:
original_filename = "whatever.pdf" # Set local variables for the closure below
content_type = "application/pdf"
file = StringIO.new(part.body)
metaclass = class << file; self; end
metaclass.class_eval do
define_method(:original_filename) { original_filename }
define_method(:content_type) { content_type }
end

Answer 3

I like gtd's answer a lot, but it can be simpler.
file = StringIO.new(part.body)
class << file
define_method(:original_filename) { "whatever.pdf" }
define_method(:content_type) { "application/pdf" }
end
There's not really a need to extract the "metaclass" into a local variable, just append some class to the object.

Answer 4

From ruby 1.9, you can use StringIO and define_singleton_method :
def attachment_from_string(string, original_filename, content_type)
StringIO.new(string).tap do |file|
file.define_singleton_method(:original_filename) { original_filename }
file.define_singleton_method(:content_type) { content_type }
end
end

Answer 5

This would have been better as a comment on David-Barlow's answer but I don't have enough reputation points yet...
But, as others mentioned I didn't love the monkey-patching. Instead, I just created a new class that inherited from StringIO, like so:
class TempFile < StringIO
attr_accessor :original_filename, :content_type
end

Answer 6

For posterity, here is the best answer. Put the top part in vendor/paperclip/data_uri_adapter.rb and the bottom part in config/initializers/paperclip.rb.
https://github.com/thoughtbot/paperclip/blob/43eb9a36deb09ce5655028a1061578dbf0268a5d/lib/paperclip/io_adapters/data_uri_adapter.rb
This requires a data URI scheme stream, but these days that seems pretty common. Simply set your paperclip'd variable to a string with the stream data, and the code takes care of the rest.

Answer 7

I used a similar technique to pull down images into paperclip
this should work, but is obvs untested:
io = part.body
def io.original_filename; part.original_file_name || 'unknown-file-name'; end
asset = Asset.new(:email=>email)
asset.asset = io
When we are assigning the IO directly to the paperclip instance, it needs to have a .original_file_name to it, so that's what we're doing in the second line.