Class: ActionView::Base
- Includes:
- ERB::Util
- Defined in:
- lib/action_view/base.rb,
lib/action_view/helpers/active_record_helper.rb
Overview
Action View templates can be written in two ways. If the template file has a .rhtml
extension then it uses a mixture of ERb (included in Ruby) and HTML. If the template file has a .rxml
extension then Jim Weirich’s Builder::XmlMarkup library is used.
ERb
You trigger ERb by using embeddings such as <% %> and <%= %>. The difference is whether you want output or not. Consider the following loop for names:
<b>Names of all the people</b>
<% for person in @people %>
Name: <%= person.name %><br/>
<% end %>
The loop is setup in regular embedding tags (<% %>) and the name is written using the output embedding tag (<%= %>). Note that this is not just a usage suggestion. Regular output functions like print or puts won’t work with ERb templates. So this would be wrong:
Hi, Mr. <% puts "Frodo" %>
(If you absolutely must write from within a function, you can use the TextHelper#concat)
Using sub templates
Using sub templates allows you to sidestep tedious replication and extract common display structures in shared templates. The classic example is the use of a header and footer (even though the Action Pack-way would be to use Layouts):
<%= render "shared/header" %>
Something really specific and terrific
<%= render "shared/footer" %>
As you see, we use the output embeddings for the render methods. The render call itself will just return a string holding the result of the rendering. The output embedding writes it to the current template.
But you don’t have to restrict yourself to static includes. Templates can share variables amongst themselves by using instance variables defined in using the regular embedding tags. Like this:
<% @page_title = "A Wonderful Hello" %>
<%= render "shared/header" %>
Now the header can pick up on the @page_title variable and use it for outputting a title tag:
<title><%= @page_title %></title>
Passing local variables to sub templates
You can pass local variables to sub templates by using a hash with the variable names as keys and the objects as values:
<%= render "shared/header", { "headline" => "Welcome", "person" => person } %>
These can now be accessed in shared/header with:
Headline: <%= headline %>
First name: <%= person.first_name %>
Template caching
The parsing of ERb templates are cached by default, but the reading of them are not. This means that the application by default will reflect changes to the templates immediatly. If you’d like to sacrifice that immediacy for the speed gain given by also caching the loading of templates (reading from the file system), you can turn that on with ActionView::Base.cache_template_loading = true
.
Builder
Builder templates are a more programmatic alternative to ERb. They are especially useful for generating XML content. An XmlMarkup
object named xml
is automatically made available to templates with a .rxml
extension.
Here are some basic examples:
xml.em("emphasized") # => <em>emphasized</em>
xml.em { xml.b("emp & bold") } # => <em><b>emph & bold</b></em>
xml.a("A Link", "href"=>"http://onestepback.org") # => <a href="http://onestepback.org">A Link</a>
xm.target("name"=>"compile", "option"=>"fast") # => <target option="fast" name="compile"\>
# NOTE: order of attributes is not specified.
Any method with a block will be treated as an XML markup tag with nested markup in the block. For example, the following:
xml.div {
xml.h1(@person.name)
xml.p(@person.bio)
}
would produce something like:
<div>
<h1>David Heinemeier Hansson</h1>
<p>A product of Danish Design during the Winter of '79...</p>
</div>
A full-length RSS example actually used on Basecamp:
xml.rss("version" => "2.0", "xmlns:dc" => "http://purl.org/dc/elements/1.1/") do
xml.channel do
xml.title(@feed_title)
xml.link(@url)
xml.description "Basecamp: Recent items"
xml.language "en-us"
xml.ttl "40"
for item in @recent_items
xml.item do
xml.title(item_title(item))
xml.description(item_description(item)) if item_description(item)
xml.pubDate(item_pubDate(item))
xml.guid(@person.firm.account.url + @recent_items.url(item))
xml.link(@person.firm.account.url + @recent_items.url(item))
xml.tag!("dc:creator", item.) if item_has_creator?(item)
end
end
end
end
More builder documentation can be found at builder.rubyforge.org.
Constant Summary collapse
- @@cache_template_loading =
Turn on to cache the reading of templates from the file system. Doing so means that you have to restart the server when changing templates, but that rendering will be faster.
false
- @@compiled_erb_templates =
{}
- @@loaded_templates =
{}
- @@template_handlers =
{}
- @@field_error_proc =
Proc.new{ |html_tag, instance| "<div class=\"fieldWithErrors\">#{html_tag}</div>" }
Instance Attribute Summary collapse
-
#assigns ⇒ Object
Returns the value of attribute assigns.
-
#base_path ⇒ Object
Returns the value of attribute base_path.
-
#controller ⇒ Object
Returns the value of attribute controller.
-
#first_render ⇒ Object
readonly
Returns the value of attribute first_render.
-
#flash ⇒ Object
readonly
Returns the value of attribute flash.
-
#headers ⇒ Object
readonly
Returns the value of attribute headers.
-
#logger ⇒ Object
readonly
Returns the value of attribute logger.
-
#params ⇒ Object
readonly
Returns the value of attribute params.
-
#response ⇒ Object
readonly
Returns the value of attribute response.
-
#session ⇒ Object
readonly
Returns the value of attribute session.
-
#template_extension ⇒ Object
Returns the value of attribute template_extension.
Class Method Summary collapse
Instance Method Summary collapse
-
#builder_template_exists?(template_path) ⇒ Boolean
:nodoc:.
-
#delegate_template_exists?(template_path) ⇒ Boolean
:nodoc:.
-
#erb_template_exists?(template_path) ⇒ Boolean
:nodoc:.
-
#file_exists?(template_path) ⇒ Boolean
:nodoc:.
-
#file_public?(template_path) ⇒ Boolean
Returns true is the file may be rendered implicitly.
-
#initialize(base_path = nil, assigns_for_first_render = {}, controller = nil) ⇒ Base
constructor
:nodoc:.
-
#pick_rendering_method(template_extension) ⇒ Object
:nodoc:.
-
#pick_template_extension(template_path) ⇒ Object
:nodoc:.
-
#render(options = {}, old_local_assigns = {}) ⇒ Object
Renders the template present at
template_path
(relative to the template_root). -
#render_file(template_path, use_full_path = true, local_assigns = {}) ⇒ Object
Renders the template present at
template_path
. -
#render_template(template_extension, template, local_assigns = {}) ⇒ Object
Renders the
template
which is given as a string as either rhtml or rxml depending ontemplate_extension
.
Constructor Details
#initialize(base_path = nil, assigns_for_first_render = {}, controller = nil) ⇒ Base
:nodoc:
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# File 'lib/action_view/base.rb', line 151 def initialize(base_path = nil, assigns_for_first_render = {}, controller = nil)#:nodoc: @base_path, @assigns = base_path, assigns_for_first_render @controller = controller end |
Instance Attribute Details
#assigns ⇒ Object
Returns the value of attribute assigns.
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# File 'lib/action_view/base.rb', line 123 def assigns @assigns end |
#base_path ⇒ Object
Returns the value of attribute base_path.
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# File 'lib/action_view/base.rb', line 123 def base_path @base_path end |
#controller ⇒ Object
Returns the value of attribute controller.
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# File 'lib/action_view/base.rb', line 124 def controller @controller end |
#first_render ⇒ Object (readonly)
Returns the value of attribute first_render.
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# File 'lib/action_view/base.rb', line 122 def first_render @first_render end |
#flash ⇒ Object (readonly)
Returns the value of attribute flash.
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# File 'lib/action_view/base.rb', line 126 def flash @flash end |
#headers ⇒ Object (readonly)
Returns the value of attribute headers.
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# File 'lib/action_view/base.rb', line 126 def headers @headers end |
#logger ⇒ Object (readonly)
Returns the value of attribute logger.
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# File 'lib/action_view/base.rb', line 126 def logger @logger end |
#params ⇒ Object (readonly)
Returns the value of attribute params.
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# File 'lib/action_view/base.rb', line 126 def params @params end |
#response ⇒ Object (readonly)
Returns the value of attribute response.
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# File 'lib/action_view/base.rb', line 126 def response @response end |
#session ⇒ Object (readonly)
Returns the value of attribute session.
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# File 'lib/action_view/base.rb', line 126 def session @session end |
#template_extension ⇒ Object
Returns the value of attribute template_extension.
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# File 'lib/action_view/base.rb', line 123 def template_extension @template_extension end |
Class Method Details
.load_helpers(helper_dir) ⇒ Object
:nodoc:
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# File 'lib/action_view/base.rb', line 137 def self.load_helpers(helper_dir)#:nodoc: Dir.foreach(helper_dir) do |helper_file| next unless helper_file =~ /_helper.rb$/ require helper_dir + helper_file helper_module_name = helper_file.capitalize.gsub(/_([a-z])/) { |m| $1.capitalize }[0..-4] class_eval("include ActionView::Helpers::#{helper_module_name}") if Helpers.const_defined?(helper_module_name) end end |
.register_template_handler(extension, klass) ⇒ Object
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# File 'lib/action_view/base.rb', line 147 def self.register_template_handler(extension, klass) @@template_handlers[extension] = klass end |
Instance Method Details
#builder_template_exists?(template_path) ⇒ Boolean
:nodoc:
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# File 'lib/action_view/base.rb', line 240 def builder_template_exists?(template_path)#:nodoc: template_exists?(template_path, "rxml") end |
#delegate_template_exists?(template_path) ⇒ Boolean
:nodoc:
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# File 'lib/action_view/base.rb', line 232 def delegate_template_exists?(template_path)#:nodoc: @@template_handlers.find { |k,| template_exists?(template_path, k) } end |
#erb_template_exists?(template_path) ⇒ Boolean
:nodoc:
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# File 'lib/action_view/base.rb', line 236 def erb_template_exists?(template_path)#:nodoc: template_exists?(template_path, "rhtml") end |
#file_exists?(template_path) ⇒ Boolean
:nodoc:
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# File 'lib/action_view/base.rb', line 244 def file_exists?(template_path)#:nodoc: erb_template_exists?(template_path) || builder_template_exists?(template_path) || delegate_template_exists?(template_path) end |
#file_public?(template_path) ⇒ Boolean
Returns true is the file may be rendered implicitly.
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# File 'lib/action_view/base.rb', line 249 def file_public?(template_path)#:nodoc: template_path.split("/").last[0,1] != "_" end |
#pick_rendering_method(template_extension) ⇒ Object
:nodoc:
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# File 'lib/action_view/base.rb', line 224 def pick_rendering_method(template_extension)#:nodoc: if @@template_handlers[template_extension] "delegate_render" else (template_extension.to_s == "rxml" ? "rxml" : "rhtml") + "_render" end end |
#pick_template_extension(template_path) ⇒ Object
:nodoc:
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# File 'lib/action_view/base.rb', line 212 def pick_template_extension(template_path)#:nodoc: if match = delegate_template_exists?(template_path) match.first elsif erb_template_exists?(template_path) "rhtml" elsif builder_template_exists?(template_path) "rxml" else raise ActionViewError, "No rhtml, rxml, or delegate template found for #{template_path}" end end |
#render(options = {}, old_local_assigns = {}) ⇒ Object
Renders the template present at template_path
(relative to the template_root). The hash in local_assigns
is made available as local variables.
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# File 'lib/action_view/base.rb', line 186 def render( = {}, old_local_assigns = {}) if .is_a?(String) render_file(, true, old_local_assigns) elsif .is_a?(Hash) [:locals] ||= {} [:use_full_path] = [:use_full_path].nil? ? true : [:use_full_path] if [:file] render_file([:file], [:use_full_path], [:locals]) elsif [:partial] && [:collection] render_partial_collection([:partial], [:collection], [:spacer_template], [:locals]) elsif [:partial] render_partial([:partial], [:object], [:locals]) elsif [:inline] render_template([:type] || :rhtml, [:inline], [:locals] || {}) end end end |
#render_file(template_path, use_full_path = true, local_assigns = {}) ⇒ Object
Renders the template present at template_path
. If use_full_path
is set to true, it’s relative to the template_root, otherwise it’s absolute. The hash in local_assigns
is made available as local variables.
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# File 'lib/action_view/base.rb', line 159 def render_file(template_path, use_full_path = true, local_assigns = {}) @first_render = template_path if @first_render.nil? if use_full_path template_extension = pick_template_extension(template_path) template_file_name = full_template_path(template_path, template_extension) else template_file_name = template_path template_extension = template_path.split(".").last end template_source = read_template_file(template_file_name) begin render_template(template_extension, template_source, local_assigns) rescue Exception => e if TemplateError === e e.sub_template_of(template_file_name) raise e else raise TemplateError.new(@base_path, template_file_name, @assigns, template_source, e) end end end |
#render_template(template_extension, template, local_assigns = {}) ⇒ Object
Renders the template
which is given as a string as either rhtml or rxml depending on template_extension
. The hash in local_assigns
is made available as local variables.
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# File 'lib/action_view/base.rb', line 207 def render_template(template_extension, template, local_assigns = {}) send(pick_rendering_method(template_extension), template_extension, template, local_assigns) end |