1 Usage
To apply a template, you need to provide the Rails generator with the location of the template you wish to apply using the -m
option. This can either be a path to a file or a URL.
$ rails new blog -m ~/template.rb $ rails new blog -m http://example.com/template.rb
You can use the app:template
Rake task to apply templates to an existing Rails application. The location of the template needs to be passed in via the LOCATION environment variable. Again, this can either be path to a file or a URL.
$ bin/rails app:template LOCATION=~/template.rb $ bin/rails app:template LOCATION=http://example.com/template.rb
2 Template API
The Rails templates API is easy to understand. Here's an example of a typical Rails template:
# template.rb generate(:scaffold, "person name:string") route "root to: 'people#index'" rails_command("db:migrate") after_bundle do git :init git add: "." git commit: %Q{ -m 'Initial commit' } end
The following sections outline the primary methods provided by the API:
2.1 gem(*args)
Adds a gem
entry for the supplied gem to the generated application's Gemfile
.
For example, if your application depends on the gems bj
and nokogiri
:
gem "bj" gem "nokogiri"
Please note that this will NOT install the gems for you and you will have to run bundle install
to do that.
bundle install
2.2 gem_group(*names, &block)
Wraps gem entries inside a group.
For example, if you want to load rspec-rails
only in the development
and test
groups:
gem_group :development, :test do gem "rspec-rails" end
2.3 add_source(source, options={}, &block)
Adds the given source to the generated application's Gemfile
.
For example, if you need to source a gem from "http://code.whytheluckystiff.net"
:
add_source "http://code.whytheluckystiff.net"
If block is given, gem entries in block are wrapped into the source group.
add_source "http://gems.github.com/" do gem "rspec-rails" end
2.4 environment/application(data=nil, options={}, &block)
Adds a line inside the Application
class for config/application.rb
.
If options[:env]
is specified, the line is appended to the corresponding file in config/environments
.
environment 'config.action_mailer.default_url_options = {host: "http://yourwebsite.example.com"}', env: 'production'
A block can be used in place of the data
argument.
2.5 vendor/lib/file/initializer(filename, data = nil, &block)
Adds an initializer to the generated application's config/initializers
directory.
Let's say you like using Object#not_nil?
and Object#not_blank?
:
initializer 'bloatlol.rb', <<-CODE class Object def not_nil? !nil? end def not_blank? !blank? end end CODE
Similarly, lib()
creates a file in the lib/
directory and vendor()
creates a file in the vendor/
directory.
There is even file()
, which accepts a relative path from Rails.root
and creates all the directories/files needed:
file 'app/components/foo.rb', <<-CODE class Foo end CODE
That'll create the app/components
directory and put foo.rb
in there.
2.6 rakefile(filename, data = nil, &block)
Creates a new rake file under lib/tasks
with the supplied tasks:
rakefile("bootstrap.rake") do <<-TASK namespace :boot do task :strap do puts "i like boots!" end end TASK end
The above creates lib/tasks/bootstrap.rake
with a boot:strap
rake task.
2.7 generate(what, *args)
Runs the supplied rails generator with given arguments.
generate(:scaffold, "person", "name:string", "address:text", "age:number")
2.8 run(command)
Executes an arbitrary command. Just like the backticks. Let's say you want to remove the README.rdoc
file:
run "rm README.rdoc"
2.9 rails_command(command, options = {})
Runs the supplied task in the Rails application. Let's say you want to migrate the database:
rails_command "db:migrate"
You can also run tasks with a different Rails environment:
rails_command "db:migrate", env: 'production'
You can also run tasks as a super-user:
rails_command "log:clear", sudo: true
2.10 route(routing_code)
Adds a routing entry to the config/routes.rb
file. In the steps above, we generated a person scaffold and also removed README.rdoc
. Now, to make PeopleController#index
the default page for the application:
route "root to: 'person#index'"
2.11 inside(dir)
Enables you to run a command from the given directory. For example, if you have a copy of edge rails that you wish to symlink from your new apps, you can do this:
inside('vendor') do run "ln -s ~/commit-rails/rails rails" end
2.12 ask(question)
ask()
gives you a chance to get some feedback from the user and use it in your templates. Let's say you want your user to name the new shiny library you're adding:
lib_name = ask("What do you want to call the shiny library ?") lib_name << ".rb" unless lib_name.index(".rb") lib lib_name, <<-CODE class Shiny end CODE
2.13 yes?(question) or no?(question)
These methods let you ask questions from templates and decide the flow based on the user's answer. Let's say you want to Freeze Rails only if the user wants to:
rails_command("rails:freeze:gems") if yes?("Freeze rails gems?") # no?(question) acts just the opposite.
2.14 git(:command)
Rails templates let you run any git command:
git :init git add: "." git commit: "-a -m 'Initial commit'"
2.15 after_bundle(&block)
Registers a callback to be executed after the gems are bundled and binstubs are generated. Useful for all generated files to version control:
after_bundle do git :init git add: '.' git commit: "-a -m 'Initial commit'" end
The callbacks gets executed even if --skip-bundle
and/or --skip-spring
has
been passed.
3 Advanced Usage
The application template is evaluated in the context of a
Rails::Generators::AppGenerator
instance. It uses the apply
action
provided by
Thor.
This means you can extend and change the instance to match your needs.
For example by overwriting the source_paths
method to contain the
location of your template. Now methods like copy_file
will accept
relative paths to your template's location.
def source_paths [__dir__] end
Feedback
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