How do I get an absolute URL for an asset in Rails 3.1?

Question

image_path returns a path only (no host).

The url_for helper won't accept a single path, so something like url_for(image_path('image.png')) wouldn't work. While the internal url_for in ActionDispatch::Http::Url.url_for would appear to do the trick (source), there doesn't seem to be a public interface for it.

How should I go about doing it? Ultimately, it'd be nice to have a function like image_url that works like url_for does for routes so that I could call image_url('image.png') and get the absolute URL given all of the default_url_options.

this blog has a snippet that you can use: http://stick.gk2.sk/blog/2009/12/image_url-function-in-ruby-on-rails/ — Spike Gronim, Jun 27 '11 at 23:17
@Spike: the shortcoming with that approach is that it ignores the default url options. There would, for instance, be no way to override the inferred request params either manually or through a default_url_options hash in the app configuration. — Steven, Jun 28 '11 at 01:50
@SpikeGronim This will not work with delayed jobs as request will be empty — lulalala, Dec 22 '11 at 10:03
For those on Rails ~> 4.2.1, use `:host` option of `asset_url` and friends, e.g. `asset_url('my_image.png', host: root_url)`. See [asset_url docs](http://apidock.com/rails/v4.2.1/ActionView/Helpers/AssetUrlHelper/asset_url). — Nic Nilov, Mar 09 '17 at 21:27

score 53 · Answer 1 · answered Sep 01 '12 at 23:26

53

def image_url(source)
  URI.join(root_url, image_path(source))
end

This way you get url either using assets_host or joining with root_url.

answered Sep 01 '12 at 23:26

tig

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for info you must add `add_template_helper(MailerHelper)` to the mailer to make the helper works in 3.2 – Syl Jul 05 '13 at 08:46
@Syl Why MailerHelper? It is about assets not about mailing – tig Jul 05 '13 at 09:54

score 14 · Answer 2 · edited Aug 19 '11 at 14:19

14

Try this in your application_helper.rb (from one of the comments on the page Spike listed):

def image_url(source)
  "#{root_url}#{image_path(source)}"
end

edited Aug 19 '11 at 14:19

Phil Calvin

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answered Aug 08 '11 at 11:47

JofoCodin

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To remove the extra slash: `def image_url(source) "#{root_url[0...-1]}#{image_path(source)}" end` – iGEL Nov 15 '11 at 09:47
I had trouble using this in Rails 3.1 until I changed the name to `url_for_image`. I am not sure, but I think the method `image_url` was being looked for as a route. – Luke Francl Dec 08 '11 at 17:33
I also had to change image_url method name to get_image_url to get this to work. – tdewell Jan 22 '13 at 17:55

score 6 · Answer 3 · answered Sep 18 '12 at 18:55

6

Our production and staging assets are on s3/cloudfront... but not locally/dev. So I wrote this (may be overkill, and probably can be simplified):

  def get_digest_file(source)
     return asset_path(source.to_s.downcase) unless Rails.application.config.assets.digests.present?
     return ActionController::Base.asset_host + "/assets/" + Rails.application.config.assets.digests[source.to_s.downcase]
  end

answered Sep 18 '12 at 18:55

courtsimas

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this answer is slightly different if using turbo-sprockets, btw. – courtsimas Feb 22 '13 at 22:45

score 5 · Accepted Answer · answered Aug 08 '11 at 11:58

5

It would appear that as of recently, sass-rails now interprets the image_url command within a scss file in the expected manner, resolving to the final location of the image in question.

answered Aug 08 '11 at 11:58

Steven

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Any way to do this outside of Sass? `image_url` doesn't work in views. – Luke Francl Dec 08 '11 at 00:14
1

yep. here's where i've used it before (an inline style): `"background:url(#{asset_path('desktop-header@2x.jpg')}) top center no-repeat;"` – courtsimas Feb 22 '13 at 22:46

score 4 · Answer 5 · edited May 23 '17 at 12:09

4

From Full url for an image-path in Rails 3

request.protocol + request.host_with_port + image_path('image.png')

You can even create a helper to DRY it, something like

def full_image_path(img_path)
    request.protocol + request.host_with_port + image_path(img_path)
end

edited May 23 '17 at 12:09

Community

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answered Apr 29 '12 at 02:00

Hezad

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score 0 · Answer 6 · answered Jan 14 '14 at 10:44

You can define css with absolute url for any background image or other assets. So you can generate it dynamically following this How to get absolute image paths in your css files using sass/scss.

CSS

body {
  background-image: image-url(background.png);
}

In your environment file change it with yours

config.action_controller.asset_host = "http://your.domain.com/"

Then your css will look something like that:

body {
  background-image: url(http://your.domain.com/assets/background.png);
}

score 0 · Answer 7 · answered Apr 09 '20 at 18:06

0

If you are having an issue with not being able to reach root_url from a view, you can either pass it to the view, or you could also add an .env variable and then call it in the root.

asset_url('image.png', host: "https://#{ENV['HOSTNAME']}/")

answered Apr 09 '20 at 18:06

Michael Wiltbank

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How do I get an absolute URL for an asset in Rails 3.1?

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