[feature] validate project attachement by mime type

app/models/project_cao.rb

@@ -2,4 +2,13 @@ class ProjectCao < Asset
   mount_uploader :attachment, ProjectCaoUploader
 
   validates :attachment, file_size: { maximum: 20.megabytes.to_i }
+  validates :attachment, :file_mime_type => {
+      :content_type => %w(application/pdf application/postscript application/illustrator application/postscript
+                          image/x-eps image/svg+xml application/sla application/dxf application/acad application/dwg
+                          application/octet-stream application/step application/iges model/iges x-world/x-3dmf
+                          application/ application/vnd.openxmlformats-officedocument.wordprocessingml.document
+                          image/png text/x-arduino text/plain application/scad application/vnd.sketchup.skp
+                          application/x-koan application/vnd-koan koan/x-skm application/vnd.koan application/x-tex
+                          application/x-latex)
+  }
 end

app/uploaders/project_cao_uploader.rb

@@ -39,7 +39,7 @@ class ProjectCaoUploader < CarrierWave::Uploader::Base
   # Add a white list of extensions which are allowed to be uploaded.
   # For images you might use something like this:
   def extension_white_list
-    %w(pdf ai eps cad math svg stl dxf dwg obj step iges 3dm doc docx png ino scad fcad skp sldprt sldasm slddrw slddrt tex latex ps)
+    %w(pdf ai eps cad math svg stl dxf dwg obj step iges igs 3dm 3dmf doc docx png ino scad fcad skp sldprt sldasm slddrw slddrt tex latex ps)
   end
 
   # Override the filename of the uploaded files:

app/validators/file_mime_type_validator.rb

@@ -0,0 +1,81 @@
+# Based on: https://gist.github.com/1298417
+
+class FileMimeTypeValidator < ActiveModel::EachValidator
+  MESSAGES  = { :content_type => :wrong_content_type }.freeze
+  CHECKS    = [ :content_type ].freeze
+
+  DEFAULT_TOKENIZER = lambda { |value| value.split(//) }
+  RESERVED_OPTIONS  = [:content_type, :tokenizer]
+
+  def initialize(options)
+    super
+
+  end
+
+  def check_validity!
+    keys = CHECKS & options.keys
+
+    if keys.empty?
+      raise ArgumentError, 'Patterns unspecified. Specify the :content_type option.'
+    end
+
+    keys.each do |key|
+      value = options[key]
+
+      unless valid_content_type_option?(value)
+        raise ArgumentError, ":#{key} must be a String or a Regexp or an Array"
+      end
+
+      if key.is_a?(Array) && key == :content_type
+        options[key].each do |val|
+          raise ArgumentError, "#{val} must be a String or a Regexp" unless val.is_a?(String) || val.is_a?(Regexp)
+        end
+      end
+    end
+  end
+
+  def validate_each(record, attribute, value)
+    raise(ArgumentError, 'A CarrierWave::Uploader::Base object was expected') unless value.kind_of? CarrierWave::Uploader::Base
+    value = (options[:tokenizer] || DEFAULT_TOKENIZER).call(value) if value.kind_of?(String)
+    return if value.length == 0
+
+    CHECKS.each do |key|
+      next unless check_value = options[key]
+      do_validation(value, check_value, key, record, attribute) if key == :content_type
+    end
+  end
+
+  def help
+    Helper.instance
+  end
+
+  class Helper
+    include Singleton
+    include ActionView::Helpers::NumberHelper
+  end
+
+  private
+
+  def valid_content_type_option?(content_type)
+    return true if %w{Array String Regexp}.include?(content_type.class.to_s)
+    false
+  end
+
+  def do_validation(value, pattern, key, record, attribute)
+    if pattern.is_a?(String) || pattern.is_a?(Regexp)
+      return if value.file.content_type.send((pattern.is_a?(String) ? '==' : '=~' ), pattern)
+    else
+      valid_list = pattern.map do |p|
+        value.file.content_type.send((p.is_a?(String) ? '==' : '=~' ), p)
+      end
+      return if valid_list.include?(true)
+    end
+
+    errors_options = options.except(*RESERVED_OPTIONS)
+
+    default_message = options[MESSAGES[key]]
+    errors_options[:message] ||= default_message if default_message
+
+    record.errors.add(attribute, MESSAGES[key], errors_options)
+  end
+end

config/locales/rails.en.yml

@@ -130,6 +130,7 @@ en:
         one: is the wrong length (should be 1 character)
         other: is the wrong length (should be %{count} characters)
       other_than: must be other than %{count}
+      wrong_content_type: "is the wrong content type"
     template:
       body: 'There were problems with the following fields:'
       header:

config/locales/rails.fr.yml

@@ -132,6 +132,7 @@ fr:
         one: ne fait pas la bonne longueur (doit comporter un seul caractère)
         other: ne fait pas la bonne longueur (doit comporter %{count} caractères)
       other_than: doit être différent de %{count}
+      wrong_content_type: "n'est pas le bon type de contenu"
     template:
       body: 'Veuillez vérifier les champs suivants : '
       header: