Rails图像URLvalidation
假设我在表中有记录,并且每个都有一个图标属性,它采用表单的URL:
- 球/ x.png
- 球/ y.png
- 球/ z.png
- …
如何编写validation,确保url以“balls /”开头,以.png,.gif结尾。 还是.jpg?
我当前的validation只是检查文件扩展名:
validates_format_of :icon, :with => %r{\.(gif|jpg|png)$}i, :message => 'must be a URL for GIF, JPG ' + 'or PNG image.'
如何编写validation,确保url以“balls /”开头,以.png,.gif结尾。 还是.jpg?
这将有效:
validates_format_of :icon, :with => %r{^balls/.+\.(gif|jpe?g|png)$}i, :message => "must start with 'balls/' and have an image extension"
但是您可以在同一个字段上进行多次validation。 所以,这也会起作用,并且更具可读性:
validates_format_of :icon, :with => %r{^balls/.+}i, :message => "must start with 'balls/' and have a filename" validates_format_of :icon, :with => %r{\.(gif|jpe?g|png)$}i, :message => "must have an image extension"
一个直接的正则表达怎么样:
validates_format_of :icon, :with => %r{^(balls\/)[A-Za-z]+\.(gif|jpg|png)$}i, :message => 'icon must start with balls'