[Mongrel] Win32 service - Errno::EINVAL (Invalid argument)whenuploading image file

Luis Lavena luislavena at gmail.com
Sat Apr 28 00:06:14 EDT 2007

On 4/28/07, Herryanto Siatono <herryanto at gmail.com> wrote:
> Thanks Luis, btw, I found some hints, it failed when the 'puts' statement
> was called.
> That's why the uploading of image failed, while other types are fine, when I
> upload an image, I need to crop the image which instead call
> Base64.b64encode, in which "puts" was called to display the output on
> console.
> So I did a simple test, I added puts before the execution of anything, and
> it failed exactly at that line:
>   def with_image(file_data = nil, &block)
>     puts "testing"
>     img = Magick::Image::read_inline(Base64.b64encode(file_data ||
> self.data)).first
>     block.call(img)
>     img = nil
>     GC.start
>   end

Let me guess, the line :115 is actually... PUTS!

Err, a big problem with this. Let me explain.

A service, also known on *nix fields as "daemon", by default, lacks a
"console" attached to it. That means STDIN, STDOUT and STDERR.

These default "pipes" are used by sentences like puts, which "write"
data to the console.

Since you're inside a service... you don't have one! :-P

Also, lot of folks will correct me on this: adding puts in your code
for debugging purposes is a bad practice. Instead you should use
logger.debug/info/warn/error to log the event inside the
development/production log files.

So, replace puts "testing" with logger.debug "testing" and that should
work fine since is the only place you're using it ;-)

Anyway, next version of service add a workaround for this "bug by
design" of services.

> Now we are getting close, why puts failed when running as windows service?
> Note that it works fine when I'm running with "mongrel_rails start"
> And here are my answers to your questions. Thanks!
> [...]

Everything looks good, actually :-D

Your feedback allowed you to pinpoint where the problem lies, so you
almost solved the issue by yourself, so thank you instead! ;-)

Regards and good weekend.

Luis Lavena
Multimedia systems
Leaders are made, they are not born. They are made by hard effort,
which is the price which all of us must pay to achieve any goal that
is worthwhile.
Vince Lombardi

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