CODEWITHSUNDEEP
ruby-on-railsimagemagickpaperclip
evedovelli
evedovelli

Reputation: 2135

How to Validates an uploaded png image using PaperClip by its contents rather than its extension

My model looks like:

class Art < ActiveRecord::Base
  attr_accessible :image
  has_attached_file :image, :styles => { :medium => "620x620>", :thumb => "200x200>" }
  validates_attachment :image, :content_type =>  { :content_type => "image/png" }
end

It validates and allows me to upload a PNG file png_file.png and does not allow me to upload a JPG file jpg_file.jpg.

But if I rename the PNG file to png_file.jpg it does not allow me to upload the image. And if I rename the JPG file to jpg_file.png it wrongly succeeds to upload the file.

I would like to know how can I validates the uploaded file by its real contents rather than the file extension. Does anyone knows how to solve this problem?

Upvotes: 0

Views: 444

Answers (1)

Juanito Fatas
Juanito Fatas

Reputation: 9969

You could read the file in raw binary and check if it's of type PNG:

File.open('path-to-your-file', 'rb').read(9).include?('PNG')

The 9 is the magic number of file.

Upvotes: 2

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