Author: Blancer

Quick Tip: Learning and Understanding CSS3 Gradients

Creating an image only for the purpose of displaying a gradient is inflexible, and is quickly becoming a bad practice. Unfortunately, at the time of this writing, they very well might still be required, but hopefully not for much longer. Thanks to Firefox and Safari/Chrome, we can now create powerful gradients with minimal effort. In this video quick tip, we’ll examine some of the differences in syntax when working with the -moz and -webkit vendor prefixes.

Webkit CSS3

While Mozilla and Webkit generally adopt the same syntax for CSS3 properties, they unfortunately don’t quite agree when it comes to gradients. Webkit was first to embrace gradients, and uses the following structure:

/* Syntax, taken from: http://webkit.org/blog/175/introducing-css-gradients/ */
-webkit-gradient(<type>, <point> [, <radius>]?, <point> [, <radius>]? [, <stop>]*)

/* In practice... */
background: -webkit-gradient(linear, 0 0, 0 100%, from(red), to(blue));

Don’t worry if your eyes gloss over at that syntax; mine did too! Just note that we require a comma-separated list of parameters.

• What type of gradient? (linear)
• X and Y axis coordinates of where to begin. (0 0 – or left-top corner)
• X and Y axis coordinates of where to conclude (0 100% – or left-bottom corner)
• What color to begin with? (from(red))
• What color to conclude with? (to(blue))

Mozilla

Firefox, which implemented gradient support with version 3.6, prefers a slightly different syntax.

/* Syntax, taken from: http://hacks.mozilla.org/2009/11/css-gradients-firefox-36/ */
 -moz-linear-gradient( [<point> || <angle>,]? <stop>, <stop> [, <stop>]* )

/* In Practice */
background: -moz-linear-gradient(top, red, blue);

• Note how we’ve placed the type of gradient, linear, within the vendor extension.
• Where should the gradient begin? (top – we could also pass in degrees, as in -45deg)
• What color to start with? (red)
• What color to conclude with? (blue)

Color-Stops

What if you don’t need a 100% gradient from one color to another? This is where color stops come into play. A common design technique is to apply a short and subtle gradient, like this:

Note the subtle off-white to white gradient at the top.

In the past, the standard implementation was to create an image, set it as the background of an element, and set it to repeat horizontally. However, with CSS3, this is a cinch.

background: white; /* fallback for older/unsupporting browsers */
background: -moz-linear-gradient(top, #dedede, white 8%);
background: -webkit-gradient(linear, 0 0, 0 8%, from(#dedede), to(white));
border-top: 1px solid white;

This time, we set the gradient to conclude at 8%, rather than 100%, which is the default. Note that we’re also applying a border top to add contrast; this is very common.

If we wish to add a third (or Nth) color, we can do:

background: white; /* fallback for older/unsupporting browsers */
background: -moz-linear-gradient(top, #dedede, white 8%, red 20%);
background: -webkit-gradient(linear, 0 0, 0 100%, from(#dedede), color-stop(8%, white), color-stop(20%, red);

• With the -moz version, we designate that, at 20% of the element height, we should now be at the color red.
• For -webkit, we use color-stop, and pass in two parameters: where the stop should occur, and what the color should be.

Important Notes About CSS Gradients

• Use them as much as you can. If it’s okay to let IE users see a solid color, I encourage you to use this method.
• IE6/7/8, Opera, Safari 3, and Firefox 3 cannot render CSS3 gradients. Firefox and Safari users generally upgrade often, so that’s not as big of a deal.
• Always apply a default, solid color, background for browsers that won’t understand the vendor prefixes.
• Never use a red to blue gradient, as I did for the examples.
• Webpages don’t need to look the same in every browser!

Setting up a Rails Server and Deploying with Capistrano on Fedora from Scratch

This article and video tutorial will teach you how to setup a basic Fedora server for Rails and PostgreSQL deployments. First, we’ll setup Apache and PostgreSQL. Then, we’ll use phpPgAdmin to create our application’s user and databases. After that, we’ll setup the Ruby platform using Passenger to run our application. Once all the components are installed, we’ll prep our application for deployment using Capistrano.

I’ll show you how to use Capistrano to automate remote tasks and take advantage of other features.

On With The Show

Understanding the Deployment Process

There is always a lot of confusion around deploying Rails applications. This tutorial hopes to sort some of that out. Most people know LAMP: Linux, Apache, MySQL, and PHP. We will setup LAPR: Linux, Apache, PostgreSQL, and Ruby. Setting up a LAPR server is very similar to setting up a LAMP server. The only wrinkle is getting Rails to talk to Apache. Thankfully, there is Passenger aka mod\_rails. Passenger is like mod\_php. It makes running Rails applications easy as pie. In order to run a Rails application through Apache, create a virtual host pointing the document root to the applications public directory and you’ll be riding on rails.

Capistrano is another part that people may not be familiar with. Capistrano is a Ruby gem designed to execute tasks on one or more remote machines. You’ll need SSH access to use Capistrano. Capistrano, affectionately known as Cap, automates the deploy process. We can use cap to take our code from some a repo and push it to the server, stop/start/restart the server, write custom tasks required by our application (think install required gems), or disable/enable a maintenance page. Using cap is not required but it sure beats using FTP to copy all the files around! Cap’s real power comes from the ability to write custom tasks in Ruby to manipulate the server. I’ve written a lot of applications that allow user file uploads. Then on the server side, some directory needs to be created with proper permissions for the uploads to succeed. It’s easy enough to write a cap task to create the directory and set the permissions. Then, if you ever change servers, you can simply run the cap task to setup the server again. There are many things you can do with Capistrano. You could even automate this entire tutorial to set up any number of machines at once!

Tutorial Sandbox

In order to complete this tutorial, you’ll need SSH + sudo access. If you don’t have a spare server sitting around, you can create one in VirtualBox. You can easily create a new VM and network it with your host system. I did this for the tutorial. When you start your virtual machine, make sure you use a bridged adapter so your VM gets an IP on the same subnet. I started with a fresh install without any customization. If you have access to a VPS like SliceHost, you can use these instructions as well.

Be sure to view the screencast before analyzing the code below.

Creating The Deployer

    $ sudo adduser -m deployer
    $ sudo passwd deployer
    $ sudo visudo deployer ALL=(ALL) NOPASSWD: ALL
    $ su deployer
    $ mkdir ~/.ssh
    $ touch ~/.ssh/authorized_keys2
    $ chmod -R 0700 ~/.ssh
    # copy your public key and paste it into the authorized_keys2 file
    $ service sshd start

Setting Up Postgres

    $ sudo yum groupinstall "PostgreSQL Database"
    $ sudo service postgresql initdb
    $ sudo service postgresql start
    $ su - postgres
    $ psql -d template1
    $ alter user postgres with password 'yourpostgresuserpassword';
    $ \q
    # Replace ident in /var/usr/lib/pgsql/data/pg_hba.conf with md5
    $ passwd postgres
    # set extra security in /etc/phpPgAdmin/config.inc.php to false
    # add 'Allow from YOUR_IP_HERE' to vhost in /etc/httpd/conf.d/phpPgAdmin.conf
    # enable http in the firewall
    $ sudo yum install httpd
    $ sudo service httpd start
    $ sudo service postgresql restart

Configuring Ruby, RubyGems, and Passenger

    $ sudo yum groupinstall Ruby
    $ sudo yum install rubygems
    $ sudo gem install gemcutter
    $ sudo yum install postgresql-devel
    $ sudo gem install pg
    $ sudo gem install passenger
    $ yum install gcc-c++ httpd-devel apr-devel
    $ sudo passenger-install-apache2-module
    # create this file /etc/http/conf.d/passenger.conf with these contents:
      LoadModule passenger_module     /usr/lib/ruby/gems/1.8/gems/passenger-2.2.9/ext/apache2/mod_passenger.so
      PassengerRoot /usr/lib/ruby/gems/1.8/gems/passenger-2.2.9
      PassengerRuby /usr/bin/ruby

    $ sudo setenforce 0
    $ sudo service httpd restart

Creating the Deployer Folder

    $ sudo mkdir /var/www/html/apps
    $ sudo chown deployer:apache /var/www/html/apps
    $ sudo yum install git
    # at this point, create your databases in phpPgAdmin
 

Configuring Apache

    # echo "Include vhost.d/*.vhost" >> /etc/httpd/conf/httpd.conf
    $ sudo mkdir /etc/httpd/vhost.d
    $ sudo touch /etc/httpd/vhost.d/nettuts-demo.vhost
    # update that files conttents to:
      
          ServerName www.nettuts-demo.com
          DocumentRoot /var/www/html/apps/nettuts-demo/current/public
          
            Options FollowSymLinks
              Allow from all
              Options -MultiViews
          

          RewriteEngine On
          RewriteCond %{DOCUMENT_ROOT}/system/maintenance.html -f
          RewriteCond %{SCRIPT_FILENAME} !maintenance.html
          RewriteRule $ /system/maintenance.html [R=302,L]
      

Complete Cap File

    set :application, "nettuts-demo"
    set :repository,  "git://github.com/Adman65/Nettuts-Capistrano-Deployments.git"

    set :user, :deployer

    set :deploy_to, "/var/www/html/apps/#{application}"

    set :use_sudo, false

    set :scm, :git

    role :web, "192.168.1.112"                          # Your HTTP server, Apache/etc
    role :app, "192.168.1.112"                          # This may be the same as your `Web` server
    role :db,  "192.168.1.112", :primary => true # This is where Rails migrations will run
    role :db,  "192.168.1.112"

    default_run_options[:pty] = true

    namespace :deploy do
       task :start do ; end
       task :stop do ; end
       task :restart, :roles => :app, :except => { :no_release => true } do
         run "#{try_sudo} touch #{File.join(current_path,'tmp','restart.txt')}"
       end

       desc "Installs required gems"
       task :gems, :roles => :app do
         run "cd #{current_path} && sudo rake gems:install RAILS_ENV=production"
       end
       after "deploy:setup", "deploy:gems"   

       before "deploy", "deploy:web:disable"
       after "deploy", "deploy:web:enable"
    end