rails3.2 中的 carrierwave 的快速开发

项目地址： https://github.com/jnicklas/carrierwave

gem 'carrierwave', "0.6.2"  

bundle install 

rails generate uploader Video

生成uploader文件

如果需要处理图片，可增加Minimagick gem

gem 'mini_magick', "3.3"

修改uploader

  include CarrierWave::MiniMagick

  # Create different versions of your uploaded files:
  version :thumb do
    process resize_to_fill: [150, 150]
  end
  
  version :main do 
    process resize_to_fill: [600, 400]
  end
  
  version :cif do 
    process resize_to_fill: [320, 240]
  end

生成model

rails g scaffold video title:string file:string message_id:integer deleted:boolean user_id:intege

rake db:migrate

bootstrap 格式化Html

rails g bootstrap:themed Videos

修改video model

mount_uploader :file, VideoUploader

引用

u.avatar.url # => '/url/to/file.png'
u.avatar.current_path # => 'path/to/file.png'
u.avatar.identifier # => 'file.png'

修改form表单

<%= form_for @user, :html => {:multipart => true} do |f| %>
<% end %>

修改图片大小的方法

 def resize_to_limit(width, height)
        process :resize_to_limit => [width, height]
      end

      def resize_to_fit(width, height)
        process :resize_to_fit => [width, height]
      end

      def resize_to_fill(width, height, gravity='Center')
        process :resize_to_fill => [width, height, gravity]
      end

      def resize_and_pad(width, height, background=:transparent, gravity=::Magick::CenterGravity)
        process :resize_and_pad => [width, height, background, gravity]
      end

resize_to_limit       保存图片完整性
resize_to_fill  图片大小优先

一个需求：
限制width: 320, 高度任意
process :resize_fo_limit: [320, '']