An annoying part of using font icons is that the icons usually need to live in the DOM. This is a step back from the time when we defined raster icons with background-image, in the CSS.

It doesn't have to be that way.

Copy the attached file font-awesome-sass.css.sass to your assets (we recommend /vendor/asset-libs/font-awesome-sass).

You can now use Font Awesome icons from your Sass files:

@import font-awesome-sass

...

CarrierWave attachments have two distinct methods #url and #path which appear to behave the same:

document.file.url   # => /storage/documents/4/letter.doc
document.file.path  # => /storage/documents/4/letter.doc

However, starting with CarrierWave 0.9, #url will properly escape high-ASCII characters:

document.file.url   # => /storage/documents/4/h%C3%BCte.doc
document.file.path  # => /storage/documents/4/hüte.doc

So always use #url if you mean an actual URL (e.g. to display an <img>). But use #path if y...

Assert rmagick provision ...

Gemfile

gem 'rmagick', '2.13.2' # at this moment the latest stable version

config/initializer/carrierwave.rb

require 'carrierwave/processing/rmagick'

... and define a custom processor

MyUploader.rb

class MyUploader < CarrierWave::Uploader::Base
  include CarrierWave::RMagick

  def cover
    manipulate! do |frame, index|
      frame if index.zero? # take only the first page of the file
    end
  end

  version :preview do
    process :cover
    process :resize_to_fit => [310,...

Say you have a User with a Carrierwave attribute #avatar:

class User < ActiveRecord::Base
  mount_uploader :avatar, AvatarUploader
end

When whitelisting the avatar field in the controller, you might do this:

params[:user].permit(:avatar)

But you probably want this:

params[:user].permit(:avatar, :avatar_cache, :remove_avatar)

In this example:

• :avatar_cache allows a newly upload image to persist through form roundtrips in the case of validation errors (something that isn't possibl...

When I upgraded from 0.5.4 PDFKit deadlocked or crashed when an ApplicationController::RouteError occured. If this error happens only because of a broken image link you probably still wan't the page to render and get a PDF with a "missing image placeholder" instead.

I don't know yet in which version (0.5.2, 0.5.3 or 0.5.4) the bug was built in. At the moment I'm doing fine with 0.5.1 and I didn't evaluate any other versions yet.

I will update this card as soon as I know further information (State 4th Nov. 2013).

Ubuntu 12.04 LTS x64, Ruby 1.8.7, Rails 2.13, PDFKit 0.5.4, Phusion Passenger Apache 2

I ran into this, when I started using passenger to deal with the Single Thread Issue which caused my webrick to deadlock when an ActionController::RoutingError (No route matches "...") occurred.

These steps brought me a little further

(1) assert dependencies are installed

 sudo aptitude install openssl build-essential xorg libssl-dev

(2) only for 64bits OS Run one by one the follo...

A snippet of the carrierwave documentation

You might come to a situation where you want to retroactively change a version or add a new one. You can use the recreate_versions! method to recreate the versions from the base file. This uses a naive approach which will re-upload and process the specified version or all versions, if none is passed as an argument.

Call recreate_versions! on a mounted uploader.

A common usecase

User.all.each { |user| user.avatar.r...

For all late night coders:

The program "redshift" changes your monitors' white balance according to your position on the planet and your local time. This is supposed to put less strain on your eyeballs than staring at a "daylight white" screen all day and night.
The program is in the Ubuntu repositories, so a simple "sudo apt-get install gtk-redshift" transfers it onto your hard drive.

I find the effect rather pleasing and so I have set the following alias on my computer:

alias rdshft='gtk-redshift -l 48.3714407:10.8982552 -t 6500:4200 &'...

Using CSS sprites for background images is a technique for optimizing page load time by combining smaller images into a larger image sprite.

There are ongoing arguments on how useful this still is, as modern browsers become more comfortable to load images in parallel. However, many major websites still use them, for example amazon, [facebook](...

1. Saving files to a directory that is not shared between deploys or servers

If you save your uploads to a made up directory like "RAILS_ROOT/uploads", this directory goes away after every deploy (since every release gets a new). Also this directory is not shared between multiple application servers, so your uploads are randomly saved to one local filesystem or another. Fixing this afterwards is a lot of fun.

Only two folders are, by default, shared between our application servers and deployments: "RAILS_ROOT/storage" and `"RAILS...

If you need to capture signatures on an IPad or similar device, you can use Thomas J Bradley's excellent Signature Pad plugin for jQuery.

To implement, just follow the steps on the Github page.

The form

If you have a model Signature with name: string, signature: text, you can use it with regular rails form like this:

- form_for @signature, :html => { :class => 'signature_form' } do |form|
  %dl
    %dt
      = form...

Ruby has two different ways to match the start and the end of a text:

• ^ (Start of line) and $ (End of line)
• \A (Start of string) and \z (End of string)

Most often you want to use \A and \z.

Here is a short example in which we want to validate the content type of a file attachment. Normally we would not expect content_type_1 to be a valid content type with the used regular expression image\/(jpeg|png). But as ^ and $ will match lines, it matches both content_type_1 and content_type_2. Using \A and \z will wo...

If - for whatever reason - you have to render stylesheets dynamically, the following snippet might be of help. It emulates what "sprockets" would to when precompiling your assets, and give your stylesheets access to all the regular bells and whistles (like asset_path, proper @imports etc):

class DynamicStylesheetsController < ApplicationController

    def show
      logical_path = RELATIVE_PATH_TO_YOUR_TEMPLATE
      path = File.join(Rails.root, logical_path)
      template = Sass::Rails::SassTemplate.new(path)
      environment = ...

If you have a PNG and want to know a pixel's alpha channel value, you can use Gimp:

• Use the color picker tool
• Hold the Shift key while clicking the pixel

A window will appear, containing color information, including the alpha channel.