Collection of Ruby on Rails related snippets and howto's that I find interesting enough to share with you guys.
Liquid error: undefined method `to_liquid' for #<Class:
I was just playing around with liquid markup for Ruby on Rails. Liquid markup is a great template engine created by the folks behind Shopfiy. Liquid allows users to create their own templates, but prevents them from running insecure code on your server. It also allows you to store templates in a database, which is a big plus.
Generally speaking Liquid Markup denies all access to normal variables and functions. Using Drops and Filters you give your users access to functions and pieces of information.
The only big downside is that there is little information available about using Liquid Markup. Don't get me wrong, there is enough information if you google it, but for the size of the project and capabilities it is too little.
Therefor when I ran into the error above and solved it, I thought it might be useful to share it with you guys.
What I was trying to do is generate a menu tree in liquid. I used the acts_as_nested_set plugin to manage the tree. It has a handy function (self_and_siblings) for collecting the active menu item and it's siblings.
I created a Drop containing the function:
class PageDrop < BaseDrop
def initialize(page)
@page = page
end
def self_and_siblings
@page.self_and_siblings
end
end
and the liquid code to build the tree:
<div id="menu">
<ul>
{% for page in page.self_and_ancestors %}
<li><img src="/images/li_icon.png">{{ page.title }}</li>
{% endfor %}
</ul>
</div>
it then generated the following error:
Liquid error: undefined method `to_liquid' for #<Class:0x102aa78e8>
After some googling and debugging the code I noticed the error was produced because acts_as_nested_set returnes class instances and liquid extensions (for security reasons) don't support class instances.
Modifying
@page.self_and_siblings
to
@page.self_and_siblings.to_a
quickly solved the problem, while maintaining the security.
If you ever walk into this error, I hope the above will help you out.
Filed under //
liquid markup
ruby on rails
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Time Zones in Rails 2.1 in under two minutes
In the past, time zones have been very difficult to work with, but no longer! Rails 2.1 brings with it great time zone support.
I got timezones working in under two minutes using Ryan Bates screencast and this blog post.
Filed under //
ruby on rails
timezones
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12 Ruby on Rails Screencasts
A fun way to learn more about Ruby on Rails techniques or plugins is by watching screencast tutorials. Screencasts are short movies covering a specific problem or technique. They are very useful if you are planning on building something with a technique you haven’t used before.
Let’s say you are planning on integrating PayPal into your rails app. Railscasts has a clear screencast on that topic, giving you a runthrough and a example of the entire process needed for ingegrating PayPal.
Filed under //
ruby on rails
screencasts
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Rmagick on Snow Leopard
Thanks to Sheldon's tip on refreshrate.com I got Rmagick and paperclip up and running on my Snow Leopard installation.
First install ImageMagick using port
sudo port install ImageMagickNext go to this directory
cd /usr/local/lib
Backup these two dylib files
sudo mv libexpat.1.dylib libexpat.1.dylib.original
sudo mv libexpat.dylib libexpat.1.dylib.original
Copy dylib files from Developers package
sudo cp /Developer/SDKs/MacOSX10.6.sdk/usr/lib/libexpat.1.dylib .
sudo cp /Developer/SDKs/MacOSX10.6.sdk/usr/lib/libexpat.dylib .
Now gem install rmagick will run smoothly.
You might need to add a file to the initializers directory
/config/initializers/paperclip.rb
containing this line:
Paperclip.options[:command_path] = "/opt/local/bin"
It will tell Paperclip where to find the installed ImageMagick bin files
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Rails Skeletons
A great way to jumpstart your Ruby on Rails project is to use a skeleton or rails template. On github you can find several projects pre-populated with essential plugins and layouts.
Below you will find some of the best Ruby on Rails skeletons on Github:
Bort
Bort is a base Rails 2.2 application that makes creating new projects easier and faster. Bort is developed and maintained by Fudge Studios, Jim Neath and Matt Hall
- RESTful Authentication
- User Roles
- Will Paginate
- Exception Notifier
- Asset Packager
Big Old Rails Template
This template assists in spinning up new Rails applications quickly using Rails 2.3.
* Authlogic for user authentication, including password resets, anonymous_only, authenticated_only, and admin_only application helpers. Optionally installs user activation support.
* World’s simplest authorization system: manage multiple string roles on users with User#add_role, User#remove_role, User#clear_roles, and User#has_role?
* Date formats: :us, :us_with_time, :short_day, :long_day
* Paperclip for attachment management
* /pages/css_test will show most CSS styles in action
* Searchlogic for magic named scopes and search forms. Includes attribute_equals, attribute_does_not_equal, attribute_begins_with, attribute_like, attribute_ends_with, attribute_greater_than, attribute_null, attribute_blank, etc., etc.
* Stringex for extra string functionality – acts_as_url, String#to_ascii, String#to_html, String#to_url, String#remove_formatting, String.random
* US State application helpers
* will-paginate for pagination
* annotate to annotate models, exemplars, and routes
* carmen to handle state and country selects
* rake doc:diagram tasks for use with railroad
Blank
Blank is GiraffeSoft’s starter Rails application.
It makes heavy use of our standard toolset. Controllers are mostly written using ResourceController, and it is tested entirely with Thoughtbot’s Shoulda. Integration testing is taken care of by Cucumber.
- active_presenter
- andand
- hoptoad
- mocha
- rake
- restful_authentication
- ruby-openid
- will_paginate
BaseJumper
There are others, I know, but this is how I like my apps to start out. You probably won’t like it, so move along.
* Authentication (including password reset)
* Welcome page placeholder
* Contact Us form
* Basic styling using Blueprint CSS
* Spec driven development using rspec, without fixtures
* ActiveScaffold admin interface
* Application configuration file
* Less CSS for mixing in style
* JQuery and JQuery-UI installed
* FamFamFam icons where needed
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Installing Ruby on Rails, Passenger, PostgreSQL, MySQL on Snow Leopard
I recently upgraded to Leopard Snow andfinally broke all my ties with locomotive. I have always developed using locomotive bundles, but since I recently started to deploy more and more rails applications on apache and passenger, it made more sense to also switch my development environment to that setup.
This article is the best I found on giving you an accurate description on setting up a user-friendly Ruby on Rails, Passenger, PostgreSQL, MySQL on Snow Leopard system.
Filed under //
passenger
ruby on rails
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Ruby on Rails Book Club
Jumpstart your RoR knowledge! At rubybookclub.com you will find reviews on all the latest Ruby on Rails books. Books that are fun to read and books that will surely give you a head start on development.
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CSV Export
A common requirement from customers is the ability to export tabular data to a CSV file that can be imported into Excel. This snippet shows you how to easily export CSV using the standard Ruby CSV library. No extra plugins required.
Filed under //
csv
ruby on rails
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Not-so-basic authentication
authenticate_or_request_with_http_basic makes it really easy for you to implement fast and simple authentication.
The most common use is only 5 lines:
def authenticate
authenticate_or_request_with_http_basic do |user, password|
user == 'admin' && password == 'pass'
end
end
That's all well and good ... until you want to add a log out button. The browser stores the successful login credentials in a sort of cookie, and applies them to every page which requests basic authentication. Once you’ve logged in, it’s actually quite hard to make the browser forget you until you quit and restart the browser. It’s hard, but not impossible. If you can force basic authentication to fail, the browser will throw away the credentials.
Under the hood: Not-so-basic authentication shows you how to solve that issue and more.
Filed under //
authentication
ruby on rails
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