[RUBY] Create a static file that expands variables using the ERB class

I would like to use the ERB class to expand variables like the Rails html.erb file and save it as a static file.

The situation is, for example, each user has his or her favorite stylesheet settings in the preferences settings, but once set, the stylesheet itself is a static file dedicated to that user until there is a change. It is more efficient to read it as.

For example, write a stylesheet that contains these variables.


body {
  background-color: <%= bg_color %>;
.header {
  color: <%= title_color %>;
.text {
  color: <%= text_color %>

The preference settings read by ActiveRecord are If you have an object variable called @preference with @ preference.bg_color, @ preference.title_color, @ preference.text_color

style_erb = ERB.new(File.read("_style.css.erb"))
style_res = style_erb.result_with_hash(@preference.attributes)
File.write("style_#{@preference.user_id}.css", style_res)

You can get a static file with the variables expanded as follows.

At first, I thought it would simply expand the instance variable @preference, but I couldn't do that, probably because I was reading the template from a file, so I used the method I passed as hash.

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