file-column学习-优快云博客

本文介绍了如何使用Rails框架中的file_column gem实现图片上传功能，并详细解释了如何在模型、视图中配置及显示上传的图片，同时提供了调整图片尺寸及自动生成不同版本的方法。

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1、
Just make the "image" column ready for handling uploaded files...

class Entry < ActiveRecord::Base
file_column :image
end
#在model中指定一个要上传的字段

2、
... generate file fields that keep uploaded images during form redisplays to your view...

<%= file_column_field "entry", "image" %>
#在view中显示上传表单,
... and display uploaded images in your view:

<%= image_tag url_for_file_column("entry", "image") %>

#在view中显示上传文件

3、To resize every uploaded image to a maximum size of 640x480, you just have to declare an additional option.

class Entry < ActiveRecord::Base
file_column :image, :magick => { :geometry => "640x480>" }
end
#设置上传文件大小为640X480
4、
You can even automatically create versions in different sizes that have nice filenames...
class Entry < ActiveRecord::Base
file_column :image, :magick => {
:versions => { "thumb" => "50x50", "medium" => "640x480>" }
}
end

#建产一个versions，使每个不同大小的文件有不同的大小，如thumb=>"50X50","medium"=>"640X480"
<%= image_tag url_for_file_column 'entry', 'image' %>
#显示为原来大小
<%= image_tag url_for_file_column 'entry', 'image' ,'thumb'%>
#大小为thumb("50X50")
<%= image_tag url_for_file_column 'entry', 'image' ,'medium'%>
#大小为medium("640X480")