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Class: ActionView::Base

Overview

Action View templates can be written in several ways. If the template file has a .erb extension, then it uses the erubis template system which can embed Ruby into an HTML document. If the template file has a .builder extension, then Jim Weirich's Builder::XmlMarkup library is used.

ERB

You trigger ::ERB by using embeddings such as <% %>, <% -%>, and <%= %>. The <%= %> tag set is used when you want output. Consider the following loop for names:

<b>Names of all the people</b>
<% @people.each do |person| %>
  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:

<%# WRONG %>
Hi, Mr. <% puts "Frodo" %>

If you absolutely must write from within a function use concat.

When on a line that only contains whitespaces except for the tag, <% %> suppress leading and trailing whitespace, including the trailing newline. <% %> and <%- -%> are the same. Note however that <%= %> and <%= -%> are different: only the latter removes trailing whitespaces.

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 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

By default, ::Rails will compile each template to a method in order to render it. When you alter a template, ::Rails will check the file's modification time and recompile it in development mode.

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 .builder extension.

Here are some basic examples:

xml.em("emphasized")                                 # => <em>emphasized</em>
xml.em { xml.b("emph & bold") }                      # => <em><b>emph &amp; bold</b></em>
xml.a("A Link", "href" => "http://onestepback.org")  # => <a href="http://onestepback.org">A Link</a>
xml.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 do
  xml.h1(@person.name)
  xml.p(@person.bio)
end

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"

    @recent_items.each do |item|
      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..url + @recent_items.url(item))
        xml.link(@person.firm..url + @recent_items.url(item))

        xml.tag!("dc:creator", item.author_name) if item_has_creator?(item)
      end
    end
  end
end

For more information on Builder please consult the [source code](github.com/jimweirich/builder).

Constant Summary

::ERB::Util - Included

HTML_ESCAPE, HTML_ESCAPE_ONCE_REGEXP, HTML_ESCAPE_REGEXP, JSON_ESCAPE, JSON_ESCAPE_REGEXP

Helpers::AssetUrlHelper - Included

ASSET_EXTENSIONS, ASSET_PUBLIC_DIRECTORIES, URI_REGEXP

Helpers::TagHelper - Included

BOOLEAN_ATTRIBUTES, PRE_CONTENT_STRINGS, TAG_PREFIXES

Helpers::DateHelper - Included

MINUTES_IN_QUARTER_YEAR, MINUTES_IN_THREE_QUARTERS_YEAR, MINUTES_IN_YEAR

Helpers::UrlHelper - Included

BUTTON_TAG_METHOD_VERBS

Helpers::JavaScriptHelper - Included

JS_ESCAPE_MAP

RecordIdentifier - Included

JOIN, NEW

Class Attribute Summary

Instance Attribute Summary

Instance Method Summary

Helpers::TranslationHelper - Included

#l
#localize

Delegates to I18n.localize with no additional functionality.

#t
#translate

Delegates to I18n#translate but also performs three additional functions.

Helpers::RenderingHelper - Included

#_layout_for

Overwrites _layout_for in the context object so it supports the case a block is passed to a partial.

#render

Returns the result of a render that's dictated by the options hash.

Helpers::RecordTagHelper - Included

#content_tag_for

content_tag_for creates an HTML element with id and class parameters that relate to the specified Active Record object.

#div_for

Produces a wrapper DIV element with id and class parameters that relate to the specified Active Record object.

RecordIdentifier - Included

#dom_class

The DOM class convention is to use the singular form of an object or class.

#dom_id

The DOM id convention is to use the singular form of an object or class with the id following an underscore.

Helpers::NumberHelper - Included

#number_to_currency

Formats a number into a currency string (e.g., $13.65).

#number_to_human

Pretty prints (formats and approximates) a number in a way it is more readable by humans (eg.: 1200000000 becomes “1.2 Billion”).

#number_to_human_size

Formats the bytes in number into a more understandable representation (e.g., giving it 1500 yields 1.5 KB).

#number_to_percentage

Formats a number as a percentage string (e.g., 65%).

#number_to_phone

Formats a number into a US phone number (e.g., (555) 123-9876).

#number_with_delimiter

Formats a number with grouped thousands using delimiter (e.g., 12,324).

#number_with_precision

Formats a number with the specified level of :precision (e.g., 112.32 has a precision of 2 if :significant is false, and 5 if :significant is true).

Helpers::JavaScriptHelper - Included

#escape_javascript

Escapes carriage returns and single and double quotes for JavaScript segments.

#j
#javascript_tag

Returns a JavaScript tag with the content inside.

Helpers::FormOptionsHelper - Included

#collection_check_boxes

Returns check box tags for the collection of existing return values of method for object's class.

#collection_radio_buttons

Returns radio button tags for the collection of existing return values of method for object's class.

#collection_select

Returns <select> and <option> tags for the collection of existing return values of method for object's class.

#grouped_collection_select

Returns <select>, <optgroup> and <option> tags for the collection of existing return values of method for object's class.

#grouped_options_for_select

Returns a string of <option> tags, like options_for_select, but wraps them with <optgroup> tags:

#option_groups_from_collection_for_select

Returns a string of <option> tags, like options_from_collection_for_select, but groups them by <optgroup> tags based on the object relationships of the arguments.

#options_for_select

Accepts a container (hash, array, enumerable, your type) and returns a string of option tags.

#options_from_collection_for_select

Returns a string of option tags that have been compiled by iterating over the collection and assigning the result of a call to the value_method as the option value and the text_method as the option text.

#select

Create a select tag and a series of contained option tags for the provided object and method.

#time_zone_options_for_select

Returns a string of option tags for pretty much any time zone in the world.

#time_zone_select

Returns select and option tags for the given object and method, using #time_zone_options_for_select to generate the list of option tags.

Helpers::FormHelper - Included

#check_box

Returns a checkbox tag tailored for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object).

#color_field

Returns a text_field of type “color”.

#date_field

Returns a text_field of type “date”.

#datetime_field

Returns a text_field of type “datetime”.

#datetime_local_field

Returns a text_field of type “datetime-local”.

#email_field

Returns a text_field of type “email”.

#fields_for

Creates a scope around a specific model object like form_for, but doesn't create the form tags themselves.

#file_field

Returns a file upload input tag tailored for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object).

#form_for

Creates a form that allows the user to create or update the attributes of a specific model object.

#hidden_field

Returns a hidden input tag tailored for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object).

#label

Returns a label tag tailored for labelling an input field for a specified attribute (identified by method) on an object assigned to the template (identified by object).

#month_field

Returns a text_field of type “month”.

#number_field

Returns an input tag of type “number”.

#password_field

Returns an input tag of the “password” type tailored for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object).

#phone_field
#radio_button

Returns a radio button tag for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object).

#range_field

Returns an input tag of type “range”.

#search_field

Returns an input of type “search” for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object_name).

#telephone_field

Returns a text_field of type “tel”.

#text_area

Returns a textarea opening and closing tag set tailored for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object).

#text_field

Returns an input tag of the “text” type tailored for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object).

#time_field

Returns a text_field of type “time”.

#url_field

Returns a text_field of type “url”.

#week_field

Returns a text_field of type “week”.

ModelNaming - Included

#convert_to_model

Converts the given object to an ::ActiveModel compliant one.

#model_name_from_record_or_class

Helpers::FormTagHelper - Included

#button_tag

Creates a button element that defines a submit button, resetbutton or a generic button which can be used in JavaScript, for example.

#check_box_tag

Creates a check box form input tag.

#color_field_tag

Creates a text field of type “color”.

#date_field_tag

Creates a text field of type “date”.

#datetime_field_tag

Creates a text field of type “datetime”.

#datetime_local_field_tag

Creates a text field of type “datetime-local”.

#email_field_tag

Creates a text field of type “email”.

#field_set_tag

Creates a field set for grouping HTML form elements.

#file_field_tag

Creates a file upload field.

#form_tag

Starts a form tag that points the action to an url configured with url_for_options just like ActionController::Base#url_for.

#hidden_field_tag

Creates a hidden form input field used to transmit data that would be lost due to HTTP's statelessness or data that should be hidden from the user.

#image_submit_tag

Displays an image which when clicked will submit the form.

#label_tag

Creates a label element.

#month_field_tag

Creates a text field of type “month”.

#number_field_tag

Creates a number field.

#password_field_tag

Creates a password field, a masked text field that will hide the users input behind a mask character.

#phone_field_tag
#radio_button_tag

Creates a radio button; use groups of radio buttons named the same to allow users to select from a group of options.

#range_field_tag

Creates a range form element.

#search_field_tag

Creates a text field of type “search”.

#select_tag

Creates a dropdown selection box, or if the :multiple option is set to true, a multiple choice selection box.

#submit_tag

Creates a submit button with the text value as the caption.

#telephone_field_tag

Creates a text field of type “tel”.

#text_area_tag

Creates a text input area; use a textarea for longer text inputs such as blog posts or descriptions.

#text_field_tag

Creates a standard text field; use these text fields to input smaller chunks of text like a username or a search query.

#time_field_tag

Creates a text field of type “time”.

#url_field_tag

Creates a text field of type “url”.

#utf8_enforcer_tag

Creates the hidden UTF8 enforcer tag.

#week_field_tag

Creates a text field of type “week”.

Helpers::TextHelper - Included

#concat

The preferred method of outputting text in your views is to use the <%= “text” %> eRuby syntax.

#current_cycle

Returns the current cycle string after a cycle has been started.

#cycle

Creates a Cycle object whose to_s method cycles through elements of an array every time it is called.

#excerpt

Extracts an excerpt from text that matches the first instance of phrase.

#highlight

Highlights one or more phrases everywhere in text by inserting it into a :highlighter string.

#pluralize

Attempts to pluralize the singular word unless count is 1.

#reset_cycle

Resets a cycle so that it starts from the first element the next time it is called.

#safe_concat,
#simple_format

Returns text transformed into HTML using simple formatting rules.

#truncate

Truncates a given text after a given :length if text is longer than :length (defaults to 30).

#word_wrap

Wraps the text into lines no longer than line_width width.

Helpers::SanitizeHelper - Included

#sanitize

Sanitizes HTML input, stripping all tags and attributes that aren't whitelisted.

#sanitize_css

Sanitizes a block of CSS code.

#strip_links

Strips all link tags from html leaving just the link text.

#strip_tags

Strips all HTML tags from html, including comments.

Helpers::UrlHelper - Included

#button_to

Generates a form containing a single button that submits to the URL created by the set of options.

#current_page?

True if the current request ::URI was generated by the given options.

#link_to

Creates a link tag of the given name using a URL created by the set of options.

#link_to_if

Creates a link tag of the given name using a URL created by the set of options if condition is true, otherwise only the name is returned.

#link_to_unless

Creates a link tag of the given name using a URL created by the set of options unless condition is true, in which case only the name is returned.

#link_to_unless_current

Creates a link tag of the given name using a URL created by the set of options unless the current request ::URI is the same as the links, in which case only the name is returned (or the given block is yielded, if one exists).

#mail_to

Creates a mailto link tag to the specified email_address, which is also used as the name of the link unless name is specified.

Helpers::DebugHelper - Included

#debug

Returns a YAML representation of object wrapped with <pre> and </pre>.

Helpers::DateHelper - Included

#date_select

Returns a set of select tags (one for year, month, and day) pre-selected for accessing a specified date-based attribute (identified by method) on an object assigned to the template (identified by object).

#datetime_select

Returns a set of select tags (one for year, month, day, hour, and minute) pre-selected for accessing a specified datetime-based attribute (identified by method) on an object assigned to the template (identified by object).

#distance_of_time_in_words

Reports the approximate distance in time between two ::Time, ::Date or ::DateTime objects or integers as seconds.

#distance_of_time_in_words_to_now
#select_date

Returns a set of HTML select-tags (one for year, month, and day) pre-selected with the date.

#select_datetime

Returns a set of HTML select-tags (one for year, month, day, hour, minute, and second) pre-selected with the datetime.

#select_day

Returns a select tag with options for each of the days 1 through 31 with the current day selected.

#select_hour

Returns a select tag with options for each of the hours 0 through 23 with the current hour selected.

#select_minute

Returns a select tag with options for each of the minutes 0 through 59 with the current minute selected.

#select_month

Returns a select tag with options for each of the months January through December with the current month selected.

#select_second

Returns a select tag with options for each of the seconds 0 through 59 with the current second selected.

#select_time

Returns a set of HTML select-tags (one for hour and minute).

#select_year

Returns a select tag with options for each of the five years on each side of the current, which is selected.

#time_ago_in_words

Like distance_of_time_in_words, but where to_time is fixed to Time.now.

#time_select

Returns a set of select tags (one for hour, minute and optionally second) pre-selected for accessing a specified time-based attribute (identified by method) on an object assigned to the template (identified by object).

#time_tag

Returns an HTML time tag for the given date or time.

Helpers::CsrfHelper - Included

#csrf_meta_tag
#csrf_meta_tags

Returns meta tags “csrf-param” and “csrf-token” with the name of the cross-site request forgery protection parameter and token, respectively.

Helpers::CacheHelper - Included

#cache

This helper exposes a method for caching fragments of a view rather than an entire action or page.

#cache_fragment_name

This helper returns the name of a cache key for a given fragment cache call.

#cache_if

Cache fragments of a view if condition is true.

#cache_unless

Cache fragments of a view unless condition is true.

Helpers::AtomFeedHelper - Included

#atom_feed

Adds easy defaults to writing Atom feeds with the Builder template engine (this does not work on ::ERB or any other template languages).

Helpers::AssetTagHelper - Included

#audio_tag

Returns an HTML audio tag for the source.

#auto_discovery_link_tag

Returns a link tag that browsers and feed readers can use to auto-detect an RSS or Atom feed.

#favicon_link_tag

Returns a link tag for a favicon managed by the asset pipeline.

#image_alt

Returns a string suitable for an HTML image tag alt attribute.

#image_tag

Returns an HTML image tag for the source.

#javascript_include_tag

Returns an HTML script tag for each of the sources provided.

#stylesheet_link_tag

Returns a stylesheet link tag for the sources specified as arguments.

#video_tag

Returns an HTML video tag for the sources.

Helpers::TagHelper - Included

#cdata_section

Returns a CDATA section with the given content.

#content_tag

Returns an HTML block tag of type name surrounding the content.

#escape_once

Returns an escaped version of html without affecting existing escaped entities.

#tag

Returns an empty HTML tag of type name which by default is XHTML compliant.

Helpers::CaptureHelper - Included

#capture

The capture method allows you to extract part of a template into a variable.

#content_for

Calling content_for stores a block of markup in an identifier for later use.

#content_for?

content_for? checks whether any content has been captured yet using content_for.

#provide

The same as content_for but when used with streaming flushes straight back to the layout.

Helpers::AssetUrlHelper - Included

#asset_path

Computes the path to asset in public directory.

#asset_url

Computes the full URL to an asset in the public directory.

#audio_path

Computes the path to an audio asset in the public audios directory.

#audio_url

Computes the full URL to an audio asset in the public audios directory.

#compute_asset_extname

Compute extname to append to asset path.

#compute_asset_host

Pick an asset host for this source.

#compute_asset_path

Computes asset path to public directory.

#font_path

Computes the path to a font asset.

#font_url

Computes the full URL to a font asset.

#image_path

Computes the path to an image asset.

#image_url

Computes the full URL to an image asset.

#javascript_path

Computes the path to a JavaScript asset in the public javascripts directory.

#javascript_url

Computes the full URL to a JavaScript asset in the public javascripts directory.

#path_to_asset
#path_to_audio
#path_to_font
#path_to_image
#path_to_javascript
#path_to_stylesheet
#path_to_video
#stylesheet_path

Computes the path to a stylesheet asset in the public stylesheets directory.

#stylesheet_url

Computes the full URL to a stylesheet asset in the public stylesheets directory.

#url_to_asset
#url_to_audio
#url_to_font
#url_to_image
#url_to_javascript
#url_to_stylesheet
#url_to_video
#video_path

Computes the path to a video asset in the public videos directory.

#video_url

Computes the full URL to a video asset in the public videos directory.

::ActiveSupport::Benchmarkable - Included

#benchmark

Allows you to measure the execution time of a block in a template and records the result to the log.

Context - Included

#_layout_for

Encapsulates the interaction with the view flow so it returns the correct buffer on yield.

#_prepare_context

Prepares the context by setting the appropriate instance variables.

Class Attribute Details

._routes (rw)

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 156

class_attribute :_routes

._routes?Boolean (rw)

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# File 'actionview/lib/action_view/base.rb', line 156

class_attribute :_routes

.cache_template_loading (rw)

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# File 'actionview/lib/action_view/base.rb', line 162

def cache_template_loading
  ActionView::Resolver.caching?
end

.cache_template_loading=(value) (rw)

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 166

def cache_template_loading=(value)
  ActionView::Resolver.caching = value
end

.default_formats (rw) Also known as: #default_formats

Specify default_formats that can be rendered.

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 150

cattr_accessor :default_formats

.field_error_proc (rw) Also known as: #field_error_proc

Specify the proc used to decorate input tags that refer to attributes with errors.

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 135

cattr_accessor :field_error_proc

.logger (rw)

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 157

class_attribute :logger

.logger?Boolean (rw)

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# File 'actionview/lib/action_view/base.rb', line 157

class_attribute :logger

.prefix_partial_path_with_controller_namespace (rw) Also known as: #prefix_partial_path_with_controller_namespace

Specify whether rendering within namespaced controllers should prefix the partial paths for ::ActiveModel objects with the namespace. (e.g., an Admin::PostsController would render @post using /admin/posts/_post.erb)

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 146

cattr_accessor :prefix_partial_path_with_controller_namespace

.raise_on_missing_translations (rw) Also known as: #raise_on_missing_translations

Specify whether an error should be raised for missing translations

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 153

cattr_accessor :raise_on_missing_translations

.streaming_completion_on_exception (rw) Also known as: #streaming_completion_on_exception

How to complete the streaming when an exception occurs. This is our best guess: first try to close the attribute, then the tag.

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 140

cattr_accessor :streaming_completion_on_exception

Instance Attribute Details

#_routes (rw)

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 156

class_attribute :_routes

#_routes?Boolean (rw)

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# File 'actionview/lib/action_view/base.rb', line 156

class_attribute :_routes

#assigns (rw)

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# File 'actionview/lib/action_view/base.rb', line 176

attr_internal :config, :assigns

#config (rw)

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# File 'actionview/lib/action_view/base.rb', line 176

attr_internal :config, :assigns

#default_formats (rw)

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 150

cattr_accessor :default_formats

#field_error_proc (rw)

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 135

cattr_accessor :field_error_proc

#formats (rw)

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 179

delegate :formats, :formats=, :locale, :locale=, :view_paths, :view_paths=, :to => :lookup_context

#locale (rw)

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 179

delegate :formats, :formats=, :locale, :locale=, :view_paths, :view_paths=, :to => :lookup_context

#logger (rw)

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 157

class_attribute :logger

#logger?Boolean (rw)

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# File 'actionview/lib/action_view/base.rb', line 157

class_attribute :logger

#lookup_context (readonly)

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 178

delegate :lookup_context, :to => :view_renderer

#prefix_partial_path_with_controller_namespace (rw)

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 146

cattr_accessor :prefix_partial_path_with_controller_namespace

#raise_on_missing_translations (rw)

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 153

cattr_accessor :raise_on_missing_translations

#streaming_completion_on_exception (rw)

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 140

cattr_accessor :streaming_completion_on_exception

#view_paths (rw)

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 179

delegate :formats, :formats=, :locale, :locale=, :view_paths, :view_paths=, :to => :lookup_context

#view_renderer (rw)

[ GitHub ]

  
# File 'actionview/lib/action_view/base.rb', line 175

attr_accessor :view_renderer