Module: Fleximage::Model::ClassMethods

Defined in:
lib/fleximage/model.rb

Overview

Provides class methods for Fleximage for use in model classes. The only class method is acts_as_fleximage which integrates Fleximage functionality into a model class.

The following class level accessors also get inserted.

  • image_directory: (String, no default) Where the master images are stored, directory path relative to your app root.

  • use_creation_date_based_directories: (Boolean, default true) If true, master images will be stored in directories based on creation date. For example: "#{image_directory}/2007/11/24/123.png" for an image with an id of 123 and a creation date of November 24, 2007. Turing this off would cause the path to be “#image_directory/123.png” instead. This helps keep the OS from having directories that are too full.

  • image_storage_format: (:png or :jpg, default :png) The format of your master images. Using :png will give you the best quality, since the master images as stored as lossless version of the original upload. :jpg will apply lossy compression, but the master image file sizes will be much smaller. If storage space is a concern, us :jpg.

  • require_image: (Boolean, default true) The model will raise a validation error if no image is uploaded with the record. Setting to false allows record to be saved with no images.

  • missing_image_message: (String, default “is required”) Validation message to display when no image was uploaded for a record.

  • invalid_image_message: (String default “was not a readable image”) Validation message when an image is uploaded, but is not an image format that can be read by RMagick.

  • output_image_jpg_quality: (Integer, default 85) When rendering JPGs, this represents the amount of compression. Valid values are 0-100, where 0 is very small and very ugly, and 100 is near lossless but very large in filesize.

  • default_image_path: (String, nil default) If no image is present for this record, the image at this path will be used instead. Useful for a placeholder graphic for new content that may not have an image just yet.

  • default_image: A hash which defines an empty starting image. This hash look like: :size => '123x456', :color => :transparent, where :size defines the dimensions of the default image, and :color defines the fill. :color can be a named color as a string (‘red’), :transparent, or a Magick::Pixel object.

  • preprocess_image: (Block, no default) Call this class method just like you would call operate in a view. The image transoformation in the provided block will be run on every uploaded image before its saved as the master image.

Example:

class Photo < ActiveRecord::Base
  acts_as_fleximage do 
    image_directory 'public/images/uploaded'
    use_creation_date_based_directories true
    image_storage_format      :png
    require_image             true
    missing_image_message     'is required'
    invalid_image_message     'was not a readable image'
    default_image_path        'public/images/no_photo_yet.png'
    default_image             nil
    output_image_jpg_quality  85

    preprocess_image do |image|
      image.resize '1024x768'
    end
  end

  # normal model methods...
end

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.db_store? ⇒ Boolean

Internal method to ask this class if it stores image in the DB.

Returns:

  • (Boolean) 


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# File 'lib/fleximage/model.rb', line 88

def self.db_store?
  if respond_to?(:columns)
    columns.find do |col|
      col.name == 'image_file_data'
    end
  else
    false
  end
end

.file_store? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fleximage/model.rb', line 98

def self.file_store?
  !db_store?
end

.has_store? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fleximage/model.rb', line 102

def self.has_store?
  respond_to?(:columns) && (db_store? || image_directory)
end

.image_too_small_message(str = nil) ⇒ Object

Image too small message Should include {minimum}



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# File 'lib/fleximage/model.rb', line 168

def self.image_too_small_message(str = nil)
  fb = "is too small (Minimum: %{minimum})"
  if str.nil?
    minimum_size = Fleximage::Operator::Base.size_to_xy(validates_image_size).join('x')
    if @image_too_small_message
      @image_too_small_message.gsub("%{minimum}", minimum_size)
    else
      translate_error_message("image_too_small", fb.gsub("%{minimum}", minimum_size), :minimum => minimum_size)
    end
  else
    @image_too_small_message = str
  end
end

.invalid_image_message(str = nil) ⇒ Object

Invalid image message dsl_accessor :invalid_image_message, :default => ‘was not a readable image’



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# File 'lib/fleximage/model.rb', line 154

def self.invalid_image_message(str = nil)
  if str.nil?
    if @invalid_image_message
      @invalid_image_message
    else
      translate_error_message("invalid_image", "was not a readable image")
    end
  else
    @invalid_image_message = str
  end
end

.missing_image_message(str = nil) ⇒ Object

Missing image message dsl_accessor :missing_image_message, :default => ‘is required’



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# File 'lib/fleximage/model.rb', line 138

def self.missing_image_message(str = nil)
  if str.nil?
    if @missing_image_message
      @missing_image_message
    else
      translate_error_message("missing_image", "is required")
    end
    
  else
    @missing_image_message = str
  end
end

.preprocess_image(&block) ⇒ Object

Call this class method just like you would call operate in a view. The image transoformation in the provided block will be run on every uploaded image before its saved as the master image.



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# File 'lib/fleximage/model.rb', line 83

def self.preprocess_image(&block)
  preprocess_image_operation(block)
end

.translate_error_message(name, fallback, options = {}) ⇒ Object 



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# File 'lib/fleximage/model.rb', line 129

def self.translate_error_message(name, fallback, options = {})
  translation = I18n.translate "activerecord.errors.models.#{self.model_name.underscore}.#{name}", options
  if translation.match /translation missing:/
    I18n.translate "activerecord.errors.messages.#{name}", options.merge({ :default => fallback })
  end
end

Instance Method Details

#acts_as_fleximage(options = {}) ⇒ Object

Use this method to include Fleximage functionality in your model. It takes an options hash with a single required key, :image_directory. This key should point to the directory you want your images stored on your server. Or configure with a nice looking block.



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# File 'lib/fleximage/model.rb', line 75

def acts_as_fleximage(options = {})
  
  # Include the necesary instance methods
  include Fleximage::Model::InstanceMethods
  
  # Call this class method just like you would call +operate+ in a view.
  # The image transoformation in the provided block will be run on every uploaded image before its saved as the 
  # master image.
  def self.preprocess_image(&block)
    preprocess_image_operation(block)
  end
  
  # Internal method to ask this class if it stores image in the DB.
  def self.db_store?
    if respond_to?(:columns)
      columns.find do |col|
        col.name == 'image_file_data'
      end
    else
      false
    end
  end
  
  def self.file_store?
    !db_store?
  end
  
  def self.has_store?
    respond_to?(:columns) && (db_store? || image_directory)
  end
  
  # validation callback
  validate :validate_image if respond_to?(:validate)
  
  # The filename of the temp image.  Used for storing of good images when validation fails
  # and the form needs to be redisplayed.
  attr_reader :image_file_temp
  
  # Setter for jpg compression quality at the instance level
  attr_accessor :jpg_compression_quality
  
  # Where images get stored
  dsl_accessor :image_directory
  
  # Put uploads from different days into different subdirectories
  dsl_accessor :use_creation_date_based_directories, :default => true
  
  # The format that master images are stored in
  dsl_accessor :image_storage_format, :default => Proc.new { :png }
  
  # Require a valid image.  Defaults to true.  Set to false if its ok to have no image for
  dsl_accessor :require_image, :default => true
  
  
  def self.translate_error_message(name, fallback, options = {})
    translation = I18n.translate "activerecord.errors.models.#{self.model_name.underscore}.#{name}", options
    if translation.match /translation missing:/
      I18n.translate "activerecord.errors.messages.#{name}", options.merge({ :default => fallback })
    end
  end
  
  # Missing image message
  #dsl_accessor :missing_image_message, :default => 'is required'
  def self.missing_image_message(str = nil)
    if str.nil?
      if @missing_image_message
        @missing_image_message
      else
        translate_error_message("missing_image", "is required")
      end
      
    else
      @missing_image_message = str
    end
  end
  
  
  # Invalid image message
  #dsl_accessor :invalid_image_message, :default => 'was not a readable image'
  def self.invalid_image_message(str = nil)
    if str.nil?
      if @invalid_image_message
        @invalid_image_message
      else
        translate_error_message("invalid_image", "was not a readable image")
      end
    else
      @invalid_image_message = str
    end
  end
  
  # Image too small message
  # Should include {{minimum}}
  def self.image_too_small_message(str = nil)
    fb = "is too small (Minimum: %{minimum})"
    if str.nil?
      minimum_size = Fleximage::Operator::Base.size_to_xy(validates_image_size).join('x')
      if @image_too_small_message
        @image_too_small_message.gsub("%{minimum}", minimum_size)
      else
        translate_error_message("image_too_small", fb.gsub("%{minimum}", minimum_size), :minimum => minimum_size)
      end
    else
      @image_too_small_message = str
    end
  end
  
  # Sets the quality of rendered JPGs
  dsl_accessor :output_image_jpg_quality, :default => 85
  
  # Set a default image to use when no image has been assigned to this record
  dsl_accessor :default_image_path
  
  # Set a default image based on a a size and fill
  dsl_accessor :default_image
  
  # A block that processes an image before it gets saved as the master image of a record.
  # Can be helpful to resize potentially huge images to something more manageable. Set via
  # the "preprocess_image { |image| ... }" class method.
  dsl_accessor :preprocess_image_operation
  
  # Set a minimum size ([x, y] e.g. 200, '800x600', [800, 600])
  # Set '0x600' to just enforce y size or
  # '800x0' to just validate x size.
  dsl_accessor :validates_image_size
  
  # Image related save and destroy callbacks
  if respond_to?(:before_save)
    after_destroy :delete_image_file
    before_save   :pre_save
    after_save    :post_save
  end
  
  # execute configuration block
  yield if block_given?
  
  # set the image directory from passed options
  image_directory options[:image_directory] if options[:image_directory]
  
  # Require the declaration of a master image storage directory
  if respond_to?(:validate) && !image_directory && !db_store? && !default_image && !default_image_path
    raise "No place to put images!  Declare this via the :image_directory => 'path/to/directory' option\n"+
          "Or add a database column named image_file_data for DB storage\n"+
          "Or set :virtual to true if this class has no image store at all\n"+
          "Or set a default image to show with :default_image or :default_image_path"
  end
end

#image_file_exists(file) ⇒ Object 



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# File 'lib/fleximage/model.rb', line 223

def image_file_exists(file)
  # File must be a valid object
  return false if file.nil?
  
  # Get the size of the file.  file.size works for form-uploaded images, file.stat.size works
  # for file object created by File.open('foo.jpg', 'rb').  It must have a size > 0.
  return false if (file.respond_to?(:size) ? file.size : file.stat.size) <= 0
  
  # object must respond to the read method to fetch its contents.
  return false if !file.respond_to?(:read)
  
  # file validation passed, return true
  true
end