In my rails 3.1 App, I have 3 different javascript files for my html table. Let say, table1.js.coffee, table2 and table3.
In my application.js file, I have :
// = require table
And in my table.js.coffee.erb, I wish to do something like that :
// = require <%= 'table2' %>
// or (more useful)
// = require <%= Settings.js_table %>
Like this, I will be able to change my table's behavior from an extern config file. For the moment, it's not working. And I was wondering if it's possible ?
Thank you!
It won't work.
Files in the pipeline are compiled on the first request, based on their contents (and any resolved erb) at that time.
If you reference something inside a pipeline file it will not update if that is changed elsewhere.
Edit in response to comment:
Sorry, I should have been clearer. The general case of this won't work.
In the case of using it with require, the require statement is a Sprockets specific directive. It is processed by Sprockets before the erb handler gets it.
The directive requires one argument - a string. In this case you have passed 3 arguments to the require directive: an opening erb tag, a quoted string, and a closing erb tag.
Thats why you get a 3 for 1 argument error.
The best (and possibly) only way to include files dynamically at run time is from your view layer.
Related
I've converted this multi skinned app of mine to make use of the assets pipeline introduced in Rails 3.1. For the most part it's been surprisingly easy and I'm in love with the preprocessing ability which allows you to use inline Ruby in your CSS/JS files.
I have run into a major problem though, which despite the power of Sprockets seems tricky to solve. My app can be run with any number of skins (or "identities" rather) which is chosen at runtime. This "identity" parameter sets up stuff like cache directory, database connection, view paths - and indeed asset paths. While all "identities" can have their own stylesheet there is also a shared one which is used across all instances. So the assets folder structure looks something like this:
In /app/assets/stylesheets/aplication.css.erb:
<% require_asset("shared.css") %>
<% require_asset("overrides.css") %>
This loads two stylesheets, and crucially it uses the configured asset paths to resolve them (that's why i use require_assets instead of the standard require and include directives, as they don't hit the resolver). It returns the first matches found and allows me to very easily override part or whole of the default styling. So
/app/assets/stylesheets/shared.css
can be overridden by putting a file with the same name in the instance assets folder
/app/assets/[identity]/stylesheets/shared.css
and if no such file exists it silently falls back to the default shared.css.
It all works brilliantly - I use the same technique for JavaScripts, images and fonts and everything gets neatly processed and packaged during precompilation. BUT. There is a type of (sideways) inheritance that I'm unable to achieve; sometimes the skin for an identity is so similar to another one that only a few dozen lines differ (e.g. identical layout but with a different color scheme) and I really want to be able to do something like this:
assets/stylesheets/application.css.erb:
<% require_asset("shared.css") %>
<% require_asset("overrides.css") %>
assets/current_identity/stylesheets/overrides.css:
<% require_asset("../../some_other_identity/stylesheets/overrides.css") %>
/* followed by the dozen or so lines that differ for this skin */
...
This FAILS because in the current context "some_other_identity" is not in the asset paths - Rails does not find the file in dev mode, and of course it's not included during precompilation either. And if I do include it in the assets path it loads the wrong overrides.css (there can be only one). So I've been experimenting with putting something like this at the top of overrides.css:
<%= File.read(Rails.root.join("app/assets/some_other_identity/stylesheets/overrides.css")) %>
/* rest of CSS */
...
And indeed that works just as expected. BUT. Because I'm now using the assets pipeline to serve all assets I can no longer reference images in the CSS with a fixed path - I have to use <%= asset_path("some_image.png") %> so that the path resolver can work its magic. This means my overrides.css is really overrides.css.erb, and of course the ERB preprocessing doesn't happen when you do File.read(). So, I'm stuck! Help! Anyone?
Edit: If I use
<%= ERB.new(File.read(Rails.root.join("app/assets/some_other_identity/stylesheets/overrides.css.erb"))).result %>
it does try to parse the ERB, but I get
undefined method `asset_path' for main:Object
which of course is due to me using asset_path("some_image.png") etc in the file I'm trying to include.
Ok, after hours of searching I came upon the list of available helper methods in Sprockets - it would have saved me a lot of time had this been linked to from the Sprockets man page on GitHub (there is a link, but it points to #FIXME). From the Sprockets API docs:
(Object) evaluate(path, options = {})
Reads path and runs processors on the file.
This allows you to capture the result of an asset and include it directly in another.
<%= evaluate "bar.js" %>
Bingo! I changed my include directive to:
<%= evaluate(Rails.root.join("app/assets/some_other_identity/stylesheets/overrides.css.erb")) %>
and the CSS gets processed and the results inserted, just the way I wanted it to work.
So I want to avoid processing JavaScript files with ERB just so I can get a proper asset path to, say, an image.
Currently, this seems like the popular approach:
var myImage = "<%= asset_path('my_image') %>";
Which, of course, requires the filename be changed to "*.erb" so that it'll be processed.
I'd much rather isolate the ERB ugliness to one point in my project making a single manifest file (say, "assets.js.erb") that computes and makes available all the asset paths my JavaScript needs.
I can certainly do it WETly by tackling it case-by-case:
ASSETS =
"my_image": "<%= asset_path('my_image') %>"
window.assetPath = (path) -> ASSETS[path]
But, I'd really rather just write some ERB to recurse through all of my asset_paths.asset_environment.paths and build a big object literal manifest for me, so that my real application JavaScript can confidently call:
var myImage = assetPath('my_image');
Any ideas on (1) if there's an easier way to do this that I missed, or (2) how I'd accomplish a search of all the potential valid arguments to asset_path?.
An easier way :
Get the assets prefix in your .js.erb : <%= Rails.configuration.assets.prefix %>. If an absolute path is needed, you can also get the application URL (it's more complicated to get it from rails, so you can just hardcode it in your .js.erb ?)
If you are working with precompiled assets, get the fingerprint of your file which is stored in manifest.yml (at <%= Rails.configuration.assets.manifest %>). The manifest contains a list with all your assets and their respective fingerprints (documentation)
Make assetPath just prepending the application URL + prefix to your image name or fingerprint
An inconvenient is that you have to specify the full image name (included the extension).
Old question, but there is nice way to accomplish this. Just to explain the context of my solution: I need to display markers in a map, which have different possible icons based on the JS dynamic variables. Strangely, using the <%= asset_path('" + somefunction(raw_value) + "') %> was not working. Then, I've looked for the solution bellow.
Concretely, the solution I am using has only one js.erb file which stores the values of the images, and their fingerprinted names, which can be get by a function, image_path. After that, all my other JS files can be free of the asset_path and, consequently, of the .erb
Create a file images.js.erb in your_application/app/assets/javascripts with the following content:
<%
imgs = {}
Dir.chdir("#{Rails.root}/app/assets/images/") do
imgs = Dir["**"].inject({}) {|h,f| h.merge! f => image_path(f)}
end
%>
window.image_path = function(name) {
return <%= imgs.to_json %>[name];
};
Require this file in your application.js, which is normally in the same directory as above:
//= require ...
//= require ...
//= require images
//= require_tree .
Then, inside the JS that you've been using <%= asset_path('image.png') %>, you will use instead image_path('image.png');
Credits to this blog post for posting a Coffee script version from which I've based mine.
It depends on the context of where this image is used.
Use Case 1: The image is decorative and needs to be dynamically swapped.
Example: Spinner, while data is loading.
In this case, I refer to is in my sass and java script.
.spinner
background-image: url(image_path("spinner.png"))
Then I would operate with classes in java script and not images.
$.addClass('spinner')
Use Case 2: Image is part of an object.
There are many situations, when an image actually belongs to a object. In this case, I create a json file, which stores the data and the image reference like this. Then I use erb to unwrap the image reference - my_object.json.erb:
{
"icon" : "<%=image_path("icons/my_icon.png")%>",
"label":"My label",
"description":"My description"
}
Use case 2 requires more work on javascript side to load the json files, but it opens very powerful extensibility options.
Asset pipeline handles both cases famously.
I have a Rails 3.1 app that uses the codebrew/backbone-rails. In a .jst.ejs template, I would like to include an image, like so:
<img src="<%= image_path("foo.png") %>"/>
But of course the asset helpers are not available in JavaScript.
Chaining ERB (.jst.ejs.erb) does not work, because the EJS syntax conflicts with ERB.
Here is what I know:
The asset helpers are not available in the browser, so I need to run them on the server side.
I can work around the problem by making the server dump various asset paths into the HTML (through data attributes or <script> and JSON) and reading them back in JS, but this seems rather kludgy.
Is there a way to somehow use the asset helpers in EJS files?
There is a way, actually, to chain a .jst.ejs.erb file, although it's fairly undocumented, and I only found it through looking at the EJS test cases. You can tell EJS to use {{ }} (or [% %] or whatever else you want) instead of <% %>, and then ERB won't try to evaluate your EJS calls.
Make sure to require EJS somewhere in your code (I just included gem 'ejs' in my Gemfile), and then create an initializer (I called it ejs.rb) that includes the following:
EJS.evaluation_pattern = /\{\{([\s\S]+?)\}\}/
EJS.interpolation_pattern = /\{\{=([\s\S]+?)\}\}/
Then just make sure to rename your templates to .jst.ejs.erb, and replace your existing <% %> EJS-interpreted code with {{ }}. If you want to use something other than {{ }}, change the regular expressions in the initializer.
I wish there were an option in Sprockets to handle this through the config rather than having to explicitly include EJS, but as of the moment, there's no way to do that that I know of.
I can see two ways. Neither are great.
When you say <%%= variable %> then this is rendered by ERB as <%= variable %>, so you could double percent escape everything but the asset_tags and that would survive the trip through one ERB pass on the way to EJS.
If you find that too gross...
How about making a different javascript file, with an ERB extension, that defines your asset paths? And then use the asset pipeline to require that.
So say assets.js.erb defines something like:
MyAssets = {
'foo': <%= image_path("foo.png") %>,
...
}
And then require this somewhere near the top of your manifest. And then reference the globals however that works in EJS.
For those willing to try HAML instead of EJS: Using haml-coffee through haml_coffee_assets has worked well for me as well.
You can have the following in a .hamlc.erb file:
%img(src="<%= image_path('foo.png') %>")
(It still doesn't give you routing helpers though, only asset helpers.)
Ryan Fitzgerald was kind enough to post a gist of his JavaScript asset helpers (which get precompiled with ERB): https://gist.github.com/1406349
You can use corresponding Javascript helper via the following gem:
https://github.com/kavkaz/js_assets
Finally (after installing and configuring) you will be able to use it like this:
<img src="<%= asset_path("foo.png") %>"/>
I'm trying to allow the user to customize my application using YML files.
When the user updates certain things the CSS needs to be updated as well.
I'd like to solve this problem using dynamic CSS instead. The way I was planning on doing this is to have a settings SCSS file which the other css files import and use.
Here is what I have so far:
settings.scss.erb:
$width: <%= Rails.application.config.width %>px;
main.css.scss:
//= require settings
#import "settings";
#main {
width: $width;
}
But I get this error:
Invalid CSS after "$width: ": expected expression (e.g. 1px, bold), was "<%= Rails.appli..."`
So It seems that the settings are not being passed through the erb parser before being handed off to the SCSS parser, is there any way to solve this.
I'd rather not put everything in .erb files since my text editor doesn't support (syntax highlighting and commands) when having scss in erb files
Side stepping the problem where ERB is not being parsed, you are not going to be able to customize the CSS dynamically (I think the main file may require an erb extension). The asset pipeline is designed to serve assets in a way that tells browsers that the are static and are not going to change.
Assuming the erb parsing was working, the width would be rendered during the precompile phase, or on the first request. If you are using Sprockets far-future headers are set to tell the remote clients to cache the content for 1 year. And Sprockets only picks up changes if the timestamp of the file changes, so would never get any new values.
You could force Sprockets to dynamically serve every request, and to not send any headers, but it is not really designed for this and there are significant performance risks in doing so.
I noticed that some jquery effects requires that scripts are loaded in proper order.. in my case it is working if they are loaded like this:
jquery 1.4.4
jquery-ui-1.8.16.custom.min.js
autocomplete-rails.js
jquery.cycle.all.js
....
if they load in different way then some of my animation or jquery feature is not working. So how do I specify in rails wich script to load first?
Right now I did it in a primitive way by adding 1 2 3 numbers in front of names of every script I have in order that I need resulting in:
1jquery 1.4.4
2jquery-ui-1.8.16.custom.min.js
3autocomplete-rails.js
4jquery.cycle.all.js
It's primitive but it's working. Is there another way of doing it?
Rails 3
For Rails 3.0:
javascript_include_tag takes an array of sources, and includes them in the order that you define. You can omit :defaults, or define it in your application.rb file with config.action_view.javascript_expansions[:defaults] = %w(foo.js bar.js). :all includes all the javascripts in your /javascripts/ folder.
Therefore, it's best to have jQuery at the beginning, since most or all of your javascript files will use jQuery.
More documentation: http://apidock.com/rails/ActionView/Helpers/AssetTagHelper/JavascriptTagHelpers/javascript_include_tag