Can you reference images from css without using re

问题:

I'd like to create a div with a background image css:

#mydiv {
  background-image:url('/public/images/foo.png');
  background-repeat: repeat-x;
}

Now, I can't use routes in css, so as a result I have to use a relative path, or my app will break if installed at a non-root path.

Is there a way around this? Something like

background-image:url('@{publicFolder}/images/foo.png');

I did find this thread from a year ago that claims it's impossible. Is this still the case?

Edit: I know I can inline the css in the page, that's not really an acceptable solution, but rather a work around.

回答1:

The way around /is/ possible.

The problem is that CSS files are static, so Play! does not do anything on them - except serving them to the clients.

Just make your css files into views, write a generic controller that takes the filename as a parameter and they will be served as Play! Templates.

something in the lines of (beware: PSEUDOCODE!):

ROUTE:

get /css/{filename}  Application.getCSS

CONTROLLER

class public void getCSS(filename)
{
     renderTemplate(filename);
}

Then in your css you can use any groovy template feature you want. The installation path is available as http.path in the conf

This will be very inefficient though, so you will have to add nginx or similar frontend to do some caching and set high expiration values for those files.

I'm not sure if it's worth doing it just to avoid relative paths!

I definitely think that the relative path is better suited generic deployment, and you are more likely to break things with this dynamic absolute approach.

A better overall deployment strategy

Anothe important point is that if you do like absolute URLs, there's no problem. I actually do too.

But when I deploy my web applications (be them play!, django, pure wsgi, or whatever else) I always put a web frontend.

Usually nginx.

This means that your play framework will be an upstream server, and you can do everything you want with the URLs on your :80 port - and manage several services with subdomains or subfolders...

but when you access your play application on its own port(s) everything will be absolute.

Finally, if you were deploying Play! as a war I would have the feeling you have chosen the wrong framework or the wrong deployment pattern! But then your jboss or whatever other application webserver will do some magic on the subfolders...

回答2:

Since the play framework compiles all the files in /public, I used the following statement in the css to acces background images.

background: url("/assets/images/my-image-background.jpg");

It worked for me so far, not sure if it's a good practice though! Hope it can be of help. Cheers.

回答3:

The path always goes from your stylesheet. So why don't you use relative paths?

Example, your css is in /public/css/, so your path in your css file has to be ../images. That's it.

But maybe less.css has something similiar you're looking for.

回答4:

take a look at conf/routes file.

in it you will find the following something like

# Map static resources from the /public folder to the /assets URL path GET /assets/*file controllers.Assets.at(path="/public", file)

which means in order to access resources in the public folder, you would use /assets in your url.

so in your css you do url(/assets/images/myimage.png) and it will work.