I have a Rails 3.1 app with an image:
app/assets/images/icons/button.png
It seems like the image should be served at this URL:
assets/icons/button.png
but if I go to this URL I get a 404. To fix this I created an initializer and added my images/icons subdirectory to the asset path:
Rails.application.assets.append_path "app/assets/images/icons"
However, this does not seem like it can possibly be the recommended way to accomplish this. I'm aware of the require and require_tree directives for JavaScript and CSS assets, is there an equivalent for image assets? How are other people doing this?
EDIT: As of Rails 3.2.rc1 this is now fixed! asset_path now generates proper paths when deploying to sub-uri!
For images it just works. Rails packages everything in images/ tree. I personally use them like this (actual code):
CSS:
a#icon-followers{
background: url(<%= asset_data_uri "icons/followers.png" %>) center center no-repeat;
}
(asset_data_uri actually makes the images inline in the CSS file using base64, but that's irrelevant in this case)
No custom configuration required. After precompiling, images from app/assets/icons/ end up in public/assets/icons/.
You can open public/assets/manifest.yml to see how Rails translates the paths to actual files.
Related
This should be a simple thing but for some reason it won't work.
I'm having trouble getting a background image displayed on my page. I'm using Rails 3.2 with the asset pipeline. I am trying to display it on pages related to my home controller.
The image location is: app/assets/images/dna.jpg
home.css.scss
background: url('/assets/images/dna.jpg');
I've also tried the following:
background: url('dna.jpg');
background: url('/assets/dna.jpg');
background-image: image-url("dna.jpg");
background-image:url(image_path('dna.jpg'));
Regardless of which approach I try, I get the same error:
Sass::SyntaxError at /
Invalid CSS after "background:": expected pseudoclass or pseudoelement, was " url('/assets/i..."
(in /Users/sean/Dropbox/bin/rails/assay/app/assets/stylesheets/home.css.scss)
See also this SO post: Adding a background image in Ruby on Rails 2 in CSS
EDIT
Referring to this post: sass-rails asset pipeline: generating image paths incorrectly; `url(/images/blah.png)` instead of `url(/assets/blah.png)`
I cleared the asset cache
rake tmp:cache:clear
And bundle updated my sass-rails gem. It's at 3.2.6 now.
None of that made any difference.
I suspect a very simple reason for your troubles: indentation. Most of the times in scss it happens that there is no space after the statement, in your case background:. Try also this in your scss prefixed file:
background: url(dna.jpg);
It always works for me.
I found a work-around: turned the scss file into a normal css file.
home.css
body {background-image:url('dna.jpg');
background-size:cover;}
Now it works fine. It doesn't seem like the right solution though.
I had the exact same issue and it was a result of me using Sass Indented Syntax in an SCSS file.
More info on the differences between Sass and SCSS: http://sass-lang.com/documentation/file.INDENTED_SYNTAX.html
There's a strange issue with Rails 4 on Heroku. When images are compiled they have hashes added to them, yet the reference to those files from within CSS don't have the proper name adjusted. Here's what I mean. I have a file called logo.png. Yet when it shows up on heroku it is viewed as:
/assets/logo-200a00a193ed5e297bb09ddd96afb953.png
However the CSS still states:
background-image:url("./logo.png");
The result: the image doesn't display. Anybody run into this? How can this be resolved?
Sprockets together with Sass has some nifty helpers you can use to get the job done. Sprockets will only process these helpers if your stylesheet file extensions are either .css.scss or .css.sass.
Image specific helper:
background-image: image-url("logo.png")
Agnostic helper:
background-image: asset-url("logo.png", image)
background-image: asset-url($asset, $asset-type)
Or if you want to embed the image data in the css file:
background-image: asset-data-url("logo.png")
Don't know why, but only thing that worked for me was using asset_path instead of image_path, even though my images are under the assets/images/ directory:
Example:
app/assets/images/mypic.png
In Ruby:
asset_path('mypic.png')
In .scss:
url(asset-path('mypic.png'))
UPDATE:
Figured it out- turns out these asset helpers come from the sass-rails gem (which I had installed in my project).
In Rails 4, you can reference an image located in assets/images/ in your .SCSS files easily like this:
.some-div {
background-image: url(image-path('pretty-background-image.jpg'));
}
When you launch the application in development mode (localhost:3000), you should see something like:
background-image: url("/assets/pretty-background-image.jpg");
In production mode, your assets will have the cache helper numbers:
background-image: url("/assets/pretty-background-image-8b313354987c309e3cd76eabdb376c1e.jpg");
The hash is because the asset pipeline and server Optimize caching
http://guides.rubyonrails.org/asset_pipeline.html
Try something like this:
background-image: url(image_path('check.png'));
Goodluck
In css
background: url("/assets/banner.jpg");
although the original path is /assets/images/banner.jpg, by convention you have to add just /assets/ in the url method
None of the answers says about the way, when I'll have .css.erb extension, how to reference images. For me worked both in production and development as well :
2.3.1 CSS and ERB
The asset pipeline automatically evaluates ERB. This means if you add an erb extension to a CSS asset (for example, application.css.erb), then helpers like asset_path are available in your CSS rules:
.class { background-image: url(<%= asset_path 'image.png' %>) }
This writes the path to the particular asset being referenced. In this example, it would make sense to have an image in one of the asset load paths, such as app/assets/images/image.png, which would be referenced here. If this image is already available in public/assets as a fingerprinted file, then that path is referenced.
If you want to use a data URI - a method of embedding the image data directly into the CSS file - you can use the asset_data_uri helper.
.logo { background: url(<%= asset_data_uri 'logo.png' %>) }
This inserts a correctly-formatted data URI into the CSS source.
Note that the closing tag cannot be of the style -%>.
Only this snippet does not work for me:
background-image: url(image_path('transparent_2x2.png'));
But rename stylename.scss to stylename.css.scss helps me.
WHAT I HAVE FOUND AFTER HOURS OF MUCKING WITH THIS:
WORKS :
background-image: url(image_path('transparent_2x2.png'));
// how to add attributes like repeat, center, fixed?
The above outputs something like: "/assets/transparent_2x2-ec47061dbe4fb88d51ae1e7f41a146db.png"
Notice the leading "/", and it's within quotes.
Also note the scss extension and image_path helper in yourstylesheet.css.scss. The image is in the app/assets/images directory.
Doesn't work:
background: url(image_path('transparent_2x2.png') repeat center center fixed;
doesn't work, invalid property:
background:url(/assets/pretty_photo/default/sprite.png) 2px 1px repeat center fixed;
My last resort was going to be to put these in my public s3 bucket and load from there, but finally got something going.
Referencing the Rails documents we see that there are a few ways to link to images from css. Just go to section 2.3.2.
First, make sure your css file has the .scss extension if it's a sass file.
Next, you can use the ruby method, which is really ugly:
#logo { background: url(<%= asset_data_uri 'logo.png' %>) }
Or you can use the specific form that is nicer:
image-url("rails.png") returns url(/assets/rails.png)
image-path("rails.png") returns "/assets/rails.png"
Lastly, you can use the general form:
asset-url("rails.png") returns url(/assets/rails.png)
asset-path("rails.png") returns "/assets/rails.png"
Interestingly, if I use 'background-image', it does not work:
background-image: url('picture.png');
But just 'background', it does:
background: url('picture.png');
In some cases the following can also be applier
logo { background: url(<%= asset_data_uri 'logo.png' %>) }
Source: http://guides.rubyonrails.org/asset_pipeline.html
You can add to your css .erb extension. Ej: style.css.erb
Then you can put:
background: url(<%= asset_path 'logo.png' %>) no-repeat;
When using gem 'sass-rails', in Rails 5, bootstrap 4, the following worked for me,
in .scss file:
background-image: url(asset_path("black_left_arrow.svg"));
in view file(e.g. .html.slim):
style=("background-image: url(#{ show_image_path("event_background.png") })");
This should get you there every single time.
background-image: url(<%= asset_data_uri 'transparent_2x2.png'%>);
By default Rails 4 will not serve your assets. To enable this functionality you need to go into config/application.rb and add this line:
config.serve_static_assets = true
https://devcenter.heroku.com/articles/rails-4-asset-pipeline#serve-assets
In Rails 4, simply use .hero {
background-image: url("picture.jpg");
} in your style.css file as long as the background image is tucked in app/assets/images.
This worked for me:
background: #4C2516 url('imagename.png') repeat-y 0 0;
Asset Pipeline is made up of 3 processes - precompile, concatenation, and minification.
I understand that JavaScript and CSS can benefit from it. However, I can't think of any benefits for images.
Can you explain it, please?
Thanks.
Sam
Assuming you use Rails helpers for images (e.g. image_tag), versioning/fingerprining is the primary benefit.
The fingerprinting helps to bust cache (both from a CDN and browser perspective).
See this rails guide section.
One benefit to passing images through the Rails asset pipeline is to take advantage of asset fingerprinting, which lets you set far-future caching headers and busts the cache when the asset changes.
When a filename is unique and based on its content, HTTP headers can be set to encourage caches everywhere (whether at CDNs, at ISPs, in networking equipment, or in web browsers) to keep their own copy of the content. When the content is updated, the fingerprint will change. This will cause the remote clients to request a new copy of the content. This is generally known as cache busting. ( from the Ruby on Rails Guides: Asset Pipeline)
When rendering SVG files in your Ruby CSS files
Example
.benefits__icon::after {
content: "";
background: url("learn-investment-investxd.svg") no-repeat;
background-size: 52px;
}
with an assets.rb file as such
Rails.application.config.assets.precompile += %w( application.css dashboard.css dashboard.js)` with no other configuration.
The example above, the background url would restore to http://localhost:3001/learn-investment-investxd.png even if I place the image file learn-investment-investxd.png in my assets/images folder.
My workaround
I added assets to the url.
.benefits__icon::after {
content: "";
background: url("assets/learn-investment-investxd.svg") no-repeat;
background-size: 52px;
}
This works.
It can be improved
I have a Rails app with the following in /app/assets/stylesheets/styles.css.erb:
...
#nestedbg {
background-position: left top;
background-image: url(<%= asset_path 'siteheader2.png' %>);
background-repeat: repeat-x;
background-attachment: fixed;
}
...
When I run rake assets:precompile and then run rails s -e production, everything works as expected. However, when I remove the precompiled assets and run rails s in development, the CSS file comes up as shown above instead of being properly substituted.
I tried putting config.assets.compile = true in /config/environments/development.rb and that did not help.
Any ideas?
Thanks.
I honestly cannot say why this is not interpreted correctly in your case, but I have a much better workaround to offer: skip erb interpreting altogether.
You can do this like so:
/* styles.css.scss */
background-image:url(image_path("siteheader2.png"));
If you did not have a chance to I would also suggest to have a look at SASS: it is integrated in the Rails asset pipeline and lets you do cool things like variable declarations, nesting, mixins, ...
I found that my css files wouldn't be processed by ERB unless SCSS processing was also added.
I changed my screen.css.erb to screen.css.scss.erb and now <%= asset_path 'file.png' %> is rendered correctly as /assets/file.png.
I'm on Rails 3.1.3.
I was using Rails 3.1.1 and when I switched the app to use Rails 3.1.3, the problem went away. I switched back to 3.1.1 to see if the issue came back and it did not.
I'm guessing that it was a problem with one of the gems and the update to 3.1.3 brought other gem updates with it.
Bizarrely, I found that changing asset_path to asset_data_uri and then back to asset_path worked for me. Was using Rails 3.1.3 all along.
Strange.
Sam Oliver's advice did the trick for me, simply renaming the extensions didn't update the timestamp on the files.
CSS and ERB
The asset pipeline automatically evaluates ERB. This means that if you add an erb extension to a CSS asset (for example, application.css.erb), then helpers like asset_path are available in your CSS rules:
.class { background-image: url(<%= asset_path 'image.png' %>) }
This writes the path to the particular asset being referenced. In this example, it would make sense to have an image in one of the asset load paths, such as app/assets/images/image.png, which would be referenced here. If this image is already available in public/assets as a fingerprinted file, then that path is referenced.
If you want to use a data URI — a method of embedding the image data directly into the CSS file — you can use the asset_data_uri helper.
CSS and Sass:
When using the asset pipeline, paths to assets must be re-written and sass-rails provides -url and -path helpers (hyphenated in Sass, underscored in Ruby) for the following asset classes: image, font, video, audio, JavaScript and stylesheet.
image-url("rails.png") becomes url(/assets/rails.png)
image-path("rails.png") becomes "/assets/rails.png".
The more generic form can also be used but the asset path and class must both be specified:
asset-url("rails.png", image) becomes url(/assets/rails.png)
asset-path("rails.png", image) becomes "/assets/rails.png"
Referenced By: Rails Guide Asset Pipe Line
Heading: 2.2.1 and 2.2.2 respectively.
Is there an elegant way to access images with fingerprints in production from css?
I know I can use erb for css, but adding urls with erb looks ugly, and I think it should be someway automated. Besides I don't want to change vendor stylesheets.
Thanks!
I think image-url should solve this problem
.btn_back:hover {background-image: image-url('btn_back_push.png');}
it works for me in dev. mode as well as in the production with precompiled assets as result
dev. mode:
.btn_nav:hover {
background-image: url("btn_nav_push.png");
}
production:
.btn_nav:hover{background-image:url(/assets/btn_nav_push-094b577d7e9e1cc6d5aced334f3fe8b3.png)}.
sass-rails has added a helper for this called image-path. You can use it like this:
#image {
background: image-path("rails.png")
}
This won't work for normal css files, but because scss is a superset of css, so you should be able to change the extension to .scss and all will be good.