Image upload problem

I’ve seen posts of a few people who have this problem, but not a single
response about solving it.

I can’t upload .png files, but .jpg and .gif work fine. When I upload
just a
.png, my action gets a StringIO object which breaks when I try to copy
the
upload to an absolute location. However, using multiple-field upload, as
long as one of the to-upload files is not a .png, all of the png files
will properly upload (TempFile objects now). So:

Upload: test_image.png --> Failure (FileUtils evaluating nil.to_str in
#cp)

Upload: test_image1.png, test_image2.png --> Also fails

Upload: test_image1.png, test_image2.png, test_image3.jpg --> Works
perfectly, I see all three images.

So, what’s going on with Rails and png? Is there a mime type I’m missing
somewhere? It just doesn’t make any sense.

Thanks

Jason

Jason R. wrote:

I’ve seen posts of a few people who have this problem, but not a single
response about solving it.

I can’t upload .png files, but .jpg and .gif work fine. When I upload
just a
.png, my action gets a StringIO object which breaks when I try to copy
the
upload to an absolute location.

Sorry, I can’t picture what you’re doing. What is your “view” and your
“controller” code ?

Stephan

Found out where the problem is, and it’s just coincidence that PNG
images
were showing this problem.

I’ve found the problem in but one place:
http://blog.vixiom.com/2006/07/26/rails-stringio-file-upload/

In short: file uploads that are less than a certain threshold (15K?)
become
StringIO objects, and anything larger is a Tempfile. I thought all would
be
Tempfiles.

Then I checked out file_column (
http://opensvn.csie.org/rails_file_column/plugins/file_column/) and
found
this bit of code:

  # stored uploaded file into local_file_path
  # If it was a Tempfile object, the temporary file will be
  # cleaned up automatically, so we do not have to care for this
  if file.respond_to?(:local_path) and file.local_path and

File.exists?(file.local_path)
FileUtils.copy_file(file.local_path, local_file_path)
elsif file.respond_to?(:read)
File.open(local_file_path, “wb”) { |f| f.write(file.read) }
else
raise ArgumentError.new(“Do not know how to handle
#{file.inspect}”)
end

So somewhere in Rails (this problem is with both WEBrick and Mongrel, so
I’m
assuming it’s not them) there’s logic to turn upload file data into a
tempfile after a certain size, but I cannot find out where. Would it be
possible / feasible to make all file uploads Tempfiles or is this not
possible to know on the server?

Jason

So somewhere in Rails (this problem is with both WEBrick and Mongrel, so
I’m
assuming it’s not them) there’s logic to turn upload file data into a
tempfile after a certain size, but I cannot find out where. Would it be

Look in the ruby file cgi.rb, method “read_multipart”. This is part of
Ruby, not Rails.

On my Linux machine it is found in

/usr/lib/ruby/1.8/cgi.rb

Stephan

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