Class: Manipulator

Inherits:
Object
  • Object
show all
Defined in:
lib/manipulator/manipulator.rb

Overview

Using Manipulator is as simple as creating an instance and calling manipulate.

The connection to S3 is opened using credentials read from AWSCredentials.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Manipulator

Returns a new instance of Manipulator.



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# File 'lib/manipulator/manipulator.rb', line 8

def initialize(options = {})
  MiniMagick.processor = options[:processor]
end

Instance Attribute Details

#temp_file_path ⇒ Object

Returns the value of attribute temp_file_path.



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# File 'lib/manipulator/manipulator.rb', line 7

def temp_file_path
  @temp_file_path
end

Instance Method Details

#cleanup ⇒ Object

Removes the temp file



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# File 'lib/manipulator/manipulator.rb', line 73

def cleanup
  File.delete(temp_file_path)
end

#connect_to_s3 ⇒ Object

Establishes a connection to S3 if not already connected



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# File 'lib/manipulator/manipulator.rb', line 13

def connect_to_s3
  unless AWS::S3::Base.connected?
    AWS::S3::Base.establish_connection!(:access_key_id => AWSCredentials.access_key, :secret_access_key => AWSCredentials.secret_access_key)
  end
end

#download(bucket, key) ⇒ Object

Downloads the specified key from the S3 bucket to a local temp file



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# File 'lib/manipulator/manipulator.rb', line 20

def download(bucket, key)
  connect_to_s3
  @temp_file_path = File.join(Dir.tmpdir, key.gsub('/', '-'))
  File.open(temp_file_path, 'w+') do |f|
    f.puts AWS::S3::S3Object.value(key,bucket)
  end
end

#manipulate(options, &block) ⇒ Object

Specify a S3 key to manipulate (and its bucket).

Block yields a MiniMagick::Image image instance with access to MiniMagick’s methods Note that you don’t have to chain methods to return the image with all manipulations using MiniMagick: For example, use

m.manipulate('my-bucket', 'my-key') do |img|
  img.rotate(90)
  img.resize(100x100)
end

Want to do something that MiniMagick doesn’t directly support, like removing all profiles from an image with GraphicsMagick (aka ImageMagick’s strip method) m.manipulate(‘my-bucket’, ‘my-key’ do |img|

`gm mogrify +profile '*' #{manipulator.temp_file_path}`

end



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# File 'lib/manipulator/manipulator.rb', line 50

def manipulate(options, &block)

  download(options[:bucket], options[:key])
  begin
    image = MiniMagick::Image.open(temp_file_path)
    image.combine_options do |i|
      yield(i)
    end
    image.write(temp_file_path)

    unless options[:keep_local]
      target_key = options[:target_key] || options[:key]
      upload(options[:bucket], target_key)
    end
  rescue Exception => e
    puts e.message
    puts e.backtrace
  ensure
    cleanup
  end
end

#upload(bucket, key) ⇒ Object

Pushes contents of temp file back to specified bucket, key on S3 Returns the url for the file



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# File 'lib/manipulator/manipulator.rb', line 30

def upload(bucket, key)
  connect_to_s3
  AWS::S3::S3Object.store(key, File.open(temp_file_path, 'r'), bucket, :access => :public_read)
  AWS::S3::S3Object.url_for(key, bucket, :authenticated => false)
end