# HoboFields -- Rich Types

This doctest describes the rich types bundled with HoboFields, and the process by which you can create and register your own types.

Our test requires to prepare the testapp:
{.hidden}

    doctest_require: 'prepare_testapp'

    >>
     ActiveRecord::Migration.create_table :articles do |t|
       t.text :body
       t.string :status
     end
    >>

{.hidden}

## `to_html` method

The rich types provide a `to_html` method. If you are using the full Hobo stack you don't need to be aware of this unless you're defining your own rich types -- the `<view>` tag uses `to_html` to render a rich type. If you are not using DRYML and Rapid, you can simply call `to_html` in your views, e.g.

        <div class="post-body"><%= @post.body.to_html %></div>

If you ever decide to change from, say, plain text to markdown formatted, your view won't need to change.

## Defining your own Rich Type

Defining a rich type is very simple. We'll show an example here before we go through the bundled types so that you start with the idea that there's really nothing sophisticated going on here.

This class defines the methods `to_html` to customize the way the type is rendered, and `validate` to provide a custom validation. It also defined the `COLUMN_TYPE` constant to tell the migration generator what underlying type should represent these values in the database.

        # Loud text always renderd in caps.
        # It's rude to shout too much so it's not allowed to be
        # longer than 100 characters
        >>
         class LoudText < String

           COLUMN_TYPE = :string

           HoboFields.register_type(:loud, self)

           def validate
             "is too long (you shouldn't shout that much)" if length > 100
           end

           def format
             # make sure we have enough exclamation marks
             self =~ /!!!$/ ? self + "!!!" : self
           end

           def to_html(xmldoctype = true)
             upcase
           end

         end
        >>

        >> LoudText.new("foO<BAa").to_html
        => "FOO<BAA"
        >> LoudText.new("foO<BAa").to_html.html_safe?
        => false

If you place this class in `app/rich_types/loud_text.rb`, Hobo will load it automatically.

That's all there is to it. Defining `to_html`, `format` and `validate` are optional, defining `COLUMN_TYPE` and calling `HoboFields.register_type` are not.

We inherit from String in this instance.   This does not work for all types -- for example, with Fixnum, you should inherit from `DelegateClass(Fixnum)` instead.

The format function is added as a before\_validation hook.  Ensure that multiple invocations of your format function is safe -- shout.format.format should return the same as shout.format.

You can use `LoudText` in your model with

    fields do
      shout :loud
    end

## Bundled types

Here we'll give a quick overview of the bundled types. Remember that along with the specific features the type provides (e.g. validation), the simple fact that the type exists is also useful in the other layers of Hobo. For example `HoboFields::Types::PasswordString` doesn't add any features to `String`, but the fact that a specific type exists for passwords means that the view layer can automatically render an `<input type="password">`.


### `HoboFields::Types::EmailAddress`

Provides validation of correct email address format.

        >> good = HoboFields::Types::EmailAddress.new("foo@baa.com")
        >> bad  = HoboFields::Types::EmailAddress.new("foo.baa.com")
        >> !!good.valid?
        => true
        >> good.validate
        => nil
        >> !!bad.valid?
        => false
        >> bad.validate
        => "is invalid"

        >> nasty = HoboFields::Types::EmailAddress.new("foo<nasty>&lt;nasty&gt;@baa.com")
        >> nasty.to_html
        => "foo&lt;nasty&gt;&amp;lt;nasty&amp;gt; at baa dot com"
        >> nasty.to_html.html_safe?
        => true

### `HoboFields::Types::HtmlString`

`HtmlString` provides no special behavior. The main reason for using this type is that the `to_html` method does not do any html-escaping. Use this for columns that store raw HTML in the database.

        # no safety treatments are done by `to_html`.
        # even if `nasty.to_html` is actually unsafe, it is marked as html_safe.
        >> nasty = HoboFields::Types::HtmlString.new("p1<p>p2</p>p3<nasty>p4</nasty>p5&lt;script&gt;p6<script>p7</script>p8")
        >> nasty.to_html
        => "p1<p>p2</p>p3<nasty>p4</nasty>p5&lt;script&gt;p6<script>p7</script>p8"
        >> nasty.to_html.html_safe?
        => true

        >>
         class Article < ActiveRecord::Base
           fields do
             body HoboFields::Types::HtmlString
           end
           attr_accessible :body
         end
        >> article = Article.create!(:body => "</div>>>p1<p>p2</p>p3<nasty>p4</nasty>p5&lt;script&gt;p6<script>p7</script>p8")
        # some unsafe html fragements are removed on save,
        # but there's no guarantees that it is well-formed
        >> article.body
        => "</div>>>p1<p>p2</p>p3p4p5&lt;script&gt;p6p8"
        >> article.body == article.body.to_html
        => true
        >> article.body.to_html.html_safe?
        => true


### `HoboFields::Types::MarkdownString`

`HoboFields::Types::MarkdownString` provides a `to_html` that renders markdown syntax into html. It requires the bluecloth gem.

        >> markdown = HoboFields::Types::MarkdownString.new %(
          This is a heading
          =================

          And text can be *emphasised*
          )
        >> markdown.to_html
        => "<h1>This is a heading</h1>\n\n<p>And text can be <em>emphasised</em></p>"
        >> markdown.to_html.html_safe?
        => true

        # some unsafe html fragements are removed by `to_html`,
        # but there's no guarantees that it is well-formed
        >> markdown = HoboFields::Types::MarkdownString.new("</div>>>p1<script>p2")
        >> markdown.to_html
        => "<p></div>>>p1</p>"
        >> markdown.to_html.html_safe?
        => true

### `HoboFields::Types::TextileString`

`HoboFields::Types::TextileString` provides a `to_html` that renders markdown syntax into html. It requires the redcloth gem.

        >> textile = HoboFields::Types::TextileString.new %(
         Text can be _emphasised_
         )
        >> textile.to_html
        => "<p>Text can be <em>emphasised</em></p>"
        >> textile.to_html.html_safe?
        => true

        # some unsafe html fragements are removed by `to_html`,
        # but there's no guarantees that it is well-formed
        >> textile = HoboFields::Types::TextileString.new("</div>>>p1<script>p2")
        >> textile.to_html
        => "<p></div>&gt;&gt;p1</p>"
        >> textile.to_html.html_safe?
        => true

### `HoboFields::Types::Text`

`HoboFields::Types::Text` provides a `to_html` method with HTML escaping and conversion of newlines to `<br />` tags.

        >> text = HoboFields::Types::Text.new %(Tom & Jerry

         Cat & Mouse)
        >> text.to_html
        => "Tom &amp; Jerry<br />\n<br />\n         Cat &amp; Mouse"
        >> text.to_html.html_safe?
        => true

        # `to_html` always returns actually html-safe string
        >> text = HoboFields::Types::Text.new("</div>>>p1<script>p2")
        >> text.to_html
        => "&lt;/div&gt;&gt;&gt;p1&lt;script&gt;p2"
        >> text.to_html.html_safe?
        => true

### `HoboFields::Types::PasswordString`

`HoboFields::Types::PasswordString` provides a simple `to_html` to prevent accidental display of a password. It simply returns "`[password hidden]`". The type is also used to indicate the need for an `<input type='password'>`

        >> HoboFields::Types::PasswordString.new("pass<word>").to_html
        => "[password hidden]"
        >> HoboFields::Types::PasswordString.new("pass<word>").to_html.html_safe?
        => true

### `HoboFields::Serialized`

This type lets you store an arbitrary object as serialized text into
the database column.   You can optionally pass the :class option to
restrict the column type.

    >>
    >>
     def migrate(renames={})
       up, down = Generators::Hobo::Migration::Migrator.run(renames)
       ActiveRecord::Migration.class_eval(up)
       ActiveRecord::Base.send(:descendants).each { |model| model.reset_column_information }
       [up, down]
     end
{.hidden}

    >>
     class Vault1 < ActiveRecord::Base
       fields do
         content :serialized
       end
       attr_accessible :content
     end

    >> migrate
    >> Vault1.create!(:content => {:key => "in Vault"})
    >> Vault1.first.content
    => {:key => "in Vault"}

    >>
     class Vault2 < ActiveRecord::Base
       fields do
         content :serialized, :class => Hash
       end
       attr_accessible :content
     end

    >> migrate
    >> Vault2.create!(:content => {:key => "in Vault"})
    >> Vault2.first.content
    => {:key => "in Vault"}
    >> puts Vault2.count
    >> v = Vault2.create!(:content => 17) rescue 'broken' # ActiveRecord::SerializationTypeMismatch
    => 'broken'

## Enum Strings

`HoboFields::Types::EnumString` is not a rich type that you use directly. It's a "type generator", rather like Ruby's `Struct`. It's used for the common situation in database driven apps that you want an enumerated type, but it's not worth going to the extra bother of a separate table enumerating the values. For example you could create a type to represent the status of an article:

        >> ArticleStatus = HoboFields::Types::EnumString.for('', :draft, :approved, :published)
        => ArticleStatus

Note that, like all dynamically created classes in Ruby, the class is anonymous until assigned to a constant:

        >> klass = HoboFields::Types::EnumString.for(:draft, :approved, :published)
        => #<EnumString draft approved published>
        >> AritcleStatus = klass
        >> ArticleStatus
        => ArticleStatus

The values in the enum are available as class constants:

        >> ArticleStatus::DRAFT
        => "draft"
        >> ArticleStatus::DRAFT.class
        => ArticleStatus

There are also instance methods to check for each of the values:

        >> a = ArticleStatus::APPROVED
        >> a.is_draft?
        => false
        >> a.is_approved?
        => true

They can be constructed from strings:

        >> a = ArticleStatus.new("approved")
        >> a.is_approved?
        => true

Equality is string equality, with symbols first converted to strings:

        >> a == "approved"
        => true
        >> a == :approved
        => true


Note that every enum you create is a subclass of HoboFields::Types::EnumString:

        >> a.is_a?(HoboFields::Types::EnumString)
        => true

EnumString's have a `validate` function defined to fit in with the
ActiveRecord validation framework.

       >> a.validate
       => nil
       >> ArticleStatus.new("junked").validate
       => "must be one of '', draft, approved, published"

### Using EnumString in your models

`HoboFields::Types::EnumString` extends the field declaration DSL with a shorthand for creating enum types:

        >>
         class Article < ActiveRecord::Base
           fields do
             status enum_string(:draft, :approved, :published)
           end
         end
        >> Article.attr_type :status
        => #<EnumString draft approved published>

Sometimes it's nice to have a proper type name. Here's one way you might go about it:

        >>
         class Article < ActiveRecord::Base
           Status = HoboFields::Types::EnumString.for(:draft, :approved, :published)
           fields do
             status Article::Status
           end
         end
        >> Article.attr_type :status
        => Article::Status

        >> Article::Status::PUBLISHED.to_html
        => "published"
        >> Article::Status::PUBLISHED.to_html.html_safe?
        => true

### Translating EnumString's

Named EnumString's may be translated.   Here is an example fr.yml:

    fr:
      article/statuses:
        draft: "esquisse"
        approved: "approuvé"
        published: "publiés"

Alternatively, the translations may be supplied in ruby:

    >> Article::Status.translated_values = { "draft"=>"esquisse", "approved"=>"approuvé", "published"=>"publiés" }

EnumString's can be created with the translated values.  Internally,
they always store the native version.

    >> a=Article::Status.new("esquisse")
    => "draft"
    >> a.is_draft?
    => true

The translated value is available via `to_html`:

    >> Article::Status::PUBLISHED.to_html
    => "publiés"
    >> Article::Status::PUBLISHED.to_html.html_safe?
    => true

Translations only work with named EnumString's.  The recommended way of naming the EnumString is to assign it to a constant, but if you do not wish to do this, you can supply the name in an option:

    >> HoboFields::Types::EnumString.for('one', 'two', 'three', :name => "Count").inspect
    => "Count"

`tableize` will be called on your name to provide the translation key.


###

### `HoboFields::Types::RawHtmlString`

        # no safety treatments are done by `to_html`.
        # even if `nasty.to_html` is actually unsafe, it is marked as html_safe.
        >> nasty = HoboFields::Types::RawHtmlString.new("p1<p>p2</p>p3<nasty>p4</nasty>p5&lt;script&gt;p6<script>p7</script>p8")
        >> nasty.to_html
        => "p1<p>p2</p>p3<nasty>p4</nasty>p5&lt;script&gt;p6<script>p7</script>p8"
        >> nasty.to_html.html_safe?
        => true

### `HoboFields::Types::RawMarkdownString`

        # no safety treatments are done by `to_html`.
        # even if `markdown.to_html` is actually unsafe, it is marked as html_safe.
        >> markdown = HoboFields::Types::RawMarkdownString.new("</div>>>p1<script>p2")
        >> markdown.to_html
        => "<p></div>>>p1<script>p2</p>"
        >> markdown.to_html.html_safe?
        => true