(Rails) IMGKIT - Issues in exporting images with html and css

问题

I'm using IMGKIT in one of my projects and had to use their css with html option to satisfy a requirment. I noticed that if stylesheets are set as follows:

kit = IMGKit.new(html, :quality => 50)
kit.stylesheets << '/path/to/css/file'

and the stylesheet has a background property with a relative url('image.png'), image is not generated when exporting it using kit.to_file:

(Rails.root + "public/pngs/" + "image.png")

The request hangs, and if we replace the background url to full url with protocol, host and port, it is well exported.

Do I need to have absolute urls to all my images in my stylesheet?

I have tried defining asset_host in my development.rb file:

config.action_controller.asset_host = Proc.new { |source|
     "#{request.protocol}#{request.host_with_port}"
    }

It does replace the url in the css if I check on browser but still the images are not generated when exported through IMGKIT.

回答1:

IMGKIT reqiured css with absolute url for any background image or other assets. So you can generate it dynamically following this link https://coderwall.com/p/exj0ig and some steps as

A) Put your all images in assets/images folder of rails app

B) Install gem 'sass-rails' if not install https://github.com/rails/sass-rails

C) create another css file name as css_file_name.css.sccs.erb

D) put your all other css file content in it.

E) In css file just put your image file name as below: background-image: image-url('image.png');

F) Use assets pipline (http://guides.rubyonrails.org/asset_pipeline.html#how-to-use-the-asset-pipeline) Run below command as your app mode: (1) Development Mode: RAILS_ENV=development bundle exec rake assets:precompile (2) Production Mode: RAILS_ENV=production bundle exec rake assets:precompile

G) In your config/environments/

(1) In development.rb config.action_controller.asset_host = "YOUR LOCAL HOST URL i.e YOUR_LOCALHOST_ADDRESS"

(2) In production.rb config.action_controller.asset_host = "http://assets.example.com" /YOUR ADDRESS/

H) And last relate your stylesheet with IMGKIT as below

html_content = "YOUR HTML CONTENT"
kit = IMGKit.new(html_content, height: 900, transparent:true, quality:10) /*YOUR SETTING*/
kit.stylesheets << "#{Rails.root}/public/assets/application.css"
file = kit.to_file(Rails.root + "public/pngs/" + "screenshot.png") /*YOUR IMAGE NAME*/
send_file("#{Rails.root}/public/pngs/screenshot.png", :filename => "screenshot.png", :type => "image/png",:disposition => 'attachment',:streaming=> 'true') /*YOUR ADDRESS WHERE U WANT TO STORE PNG FILE*/

I) Restart server and enjoy!!!!!

[NOTE: After every changes please run assets pipline command to get latest application.css which is made from .sccs.erb extension file.]

来源：https://stackoverflow.com/questions/14208403/rails-imgkit-issues-in-exporting-images-with-html-and-css

标签

ruby-on-rails-3

imgkit