Module: Merb::RenderMixin

Includes:
ControllerExceptions
Included in:
AbstractController
Defined in:
lib/merb-core/controller/mixins/render.rb

Defined Under Namespace

Modules: ClassMethods

Constant Summary

Constants included from ControllerExceptions

ControllerExceptions::STATUS_CODES

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object

Parameters

base<Module>

Module that is including RenderMixin (probably a controller)


9
10
11
12
13
14
# File 'lib/merb-core/controller/mixins/render.rb', line 9

def self.included(base)
  base.extend(ClassMethods)
  base.class_eval do
    class_inheritable_accessor :_default_render_options
  end
end

Instance Method Details

#_get_layout(layout = nil) ⇒ Object

Get the layout that should be used. The content-type will be appended to the layout unless the layout already contains a “.” in it.

If no layout was passed in, this method will look for one with the same name as the controller, and finally one in “application.#content_type”.

Parameters

layout<~to_s>

A layout, relative to the layout root. Defaults to nil.

Returns

String

The method name that corresponds to the found layout.

Raises

TemplateNotFound

If a layout was specified (either via layout in the class or by passing one in to this method), and not found. No error will be raised if no layout was specified, and the default layouts were not found.

:api: private


373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
# File 'lib/merb-core/controller/mixins/render.rb', line 373

def _get_layout(layout = nil)
  return false if layout == false
  
  layout = layout.instance_of?(Symbol) && self.respond_to?(layout, true) ? send(layout) : layout
  layout = layout.to_s if layout

  # If a layout was provided, throw an error if it's not found
  if layout      
    template_method, template_location = 
      _template_for(layout, layout.index(".") ? nil : content_type, "layout")
      
    raise TemplateNotFound, "No layout found at #{template_location}" unless template_method
    template_method

  # If a layout was not provided, try the default locations
  else
    template, location = _template_for(controller_name, content_type, "layout")
    template, location = _template_for("application", content_type, "layout") unless template
    template
  end
end

#_handle_options!(opts) ⇒ Object

Take the options hash and handle it as appropriate.

Parameters

opts<Hash>

The options hash that was passed into render.

Options

:status<~to_i>

The status of the response will be set to opts.to_i

Returns

Hash

The options hash that was passed in.

:api: private


348
349
350
351
352
# File 'lib/merb-core/controller/mixins/render.rb', line 348

def _handle_options!(opts)
  self.status = opts.delete(:status).to_i if opts[:status]
  headers["Location"] = opts.delete(:location) if opts[:location]
  opts
end

#_template_for(context, content_type, controller = nil, template = nil, locals = []) ⇒ Object

Iterate over the template roots in reverse order, and return the template and template location of the first match.

Parameters

context<Object>

The controller action or template (basename or absolute path).

content_type<~to_s>

The content type (like html or json).

controller<~to_s>

The name of the controller. Defaults to nil.

locals>

A list of locals to assign from the args passed into the compiled template.

Options (opts)

:template<String>

The location of the template to use. Defaults to whatever matches this context, content_type and controller.

Returns

Array[Symbol, String]

A pair consisting of the template method and location.

:api: private


414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
# File 'lib/merb-core/controller/mixins/render.rb', line 414

def _template_for(context, content_type, controller=nil, template=nil, locals=[])
  tmp = self.class._templates_for[[context, content_type, controller, template, locals]]
  return tmp if tmp

  template_method, template_location = nil, nil

  # absolute path to a template (:template => "/foo/bar")
  if template.is_a?(String) && template =~ %r{^/}
    template_location = self._absolute_template_location(template, content_type)
    return [_template_method_for(template_location, locals), template_location]
  end

  self.class._template_roots.reverse_each do |root, template_meth|
    # :template => "foo/bar.html" where root / "foo/bar.html.*" exists
    if template
      template_location = root / self.send(template_meth, template, content_type, nil)
    # :layout => "foo" where root / "layouts" / "#{controller}.html.*" exists        
    else
      template_location = root / self.send(template_meth, context, content_type, controller)
    end
  
    break if template_method = _template_method_for(template_location.to_s, locals)
  end

  # template_location is a Pathname
  ret = [template_method, template_location.to_s]
  unless Merb::Config[:reload_templates]
    self.class._templates_for[[context, content_type, controller, template, locals]] = ret
  end
  ret
end

#_template_method_for(template_location, locals) ⇒ Object

Return the template method for a location, and check to make sure the current controller actually responds to the method.

Parameters

template_location<String>

The phyical path of the template

locals>

A list of locals to assign from the args passed into the compiled template.

Returns

String

The method, if it exists. Otherwise return nil.

:api: private


457
458
459
460
# File 'lib/merb-core/controller/mixins/render.rb', line 457

def _template_method_for(template_location, locals)
  meth = Merb::Template.template_for(template_location, [], locals)
  meth && self.respond_to?(meth) ? meth : nil
end

#append_content(obj, string = nil) { ... } ⇒ Object

Called in templates to append content for later use. Works like throw_content.

:api: public

Parameters:

  • obj (Object)

    Key used in the thrown_content hash.

  • string (String) (defaults to: nil)

    Textual content. Default to nil.

Yields:

  • Evaluated with result concatenated to string.

Raises:

  • (ArgumentError)

    Neither string nor block given


523
524
525
526
527
528
529
# File 'lib/merb-core/controller/mixins/render.rb', line 523

def append_content(obj, string = nil, &block)
  unless string || block_given?
    raise ArgumentError, "You must pass a block or a string into append_content"
  end
  @_caught_content[obj] = "" if @_caught_content[obj].nil?
  @_caught_content[obj] << string.to_s << (block_given? ? capture(&block) : "")
end

#catch_content(obj = :for_layout) ⇒ Object

Called in templates to get at content thrown in another template. The results of rendering a template are automatically thrown into :for_layout, so catch_content or catch_content(:for_layout) can be used inside layouts to get the content rendered by the action template.

Parameters

obj<Object>

The key in the thrown_content hash. Defaults to :for_layout.

:api: public


471
472
473
# File 'lib/merb-core/controller/mixins/render.rb', line 471

def catch_content(obj = :for_layout)
  @_caught_content[obj] || ''
end

#clear_content(obj = :for_layout) ⇒ Object

Called when renderers need to be sure that existing thrown content is cleared before throwing new content. This prevents double rendering of content when multiple templates are rendered after each other.

Parameters

obj<Object>

The key in the thrown_content hash. Defaults to :for_layout.

:api: public


539
540
541
# File 'lib/merb-core/controller/mixins/render.rb', line 539

def clear_content(obj = :for_layout)
  @_caught_content.delete(obj) unless @_caught_content[obj].nil?
end

#display(object, thing = nil, opts = {}) ⇒ Object

Renders an object using to registered transform method based on the negotiated content-type, if a template does not exist. For instance, if the content-type is :json, Merb will first look for current_action.json.*. Failing that, it will run object.to_json.

Parameter

object<Object>

An object that responds_to? the transform method registered for the negotiated mime-type.

thing<String, Symbol>

The thing to attempt to render via #render before calling the transform method on the object. Defaults to nil.

opts<Hash>

An options hash that will be used for rendering (passed on to #render or serialization methods like #to_json or #to_xml)

Returns

String

The rendered template or if no template is found, the transformed object.

Raises

NotAcceptable

If there is no transform method for the specified mime-type or the object does not respond to the transform method.

Alternatives

A string in the second parameter will be interpreted as a template:

display @object, "path/to/foo"
#=> display @object, nil, :template => "path/to/foo"

A hash in the second parameters will be interpreted as opts:

display @object, :layout => "zoo"
#=> display @object, nil, :layout => "zoo"

If you need to pass extra parameters to serialization method, for instance, to exclude some of attributes or serialize associations, just pass options for it. For instance,

display @locations, :except => [:locatable_type, :locatable_id], :include => [:locatable]

serializes object with polymorphic association, not raw locatable_* attributes.

Options

:template a template to use for rendering :layout a layout to use for rendering :status the status code to return (defaults to 200) :location the value of the Location header

all other options options that will be pass to serialization method

like #to_json or #to_xml

Notes

The transformed object will not be used in a layout unless a :layout is explicitly passed in the opts.

:api: public


209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
# File 'lib/merb-core/controller/mixins/render.rb', line 209

def display(object, thing = nil, opts = {})
  template_opt = thing.is_a?(Hash) ? thing.delete(:template) : opts.delete(:template)

  case thing
  # display @object, "path/to/foo" means display @object, nil, :template => "path/to/foo"
  when String
    template_opt, thing = thing, nil
  # display @object, :template => "path/to/foo" means display @object, nil, :template => "path/to/foo"
  when Hash
    opts, thing = thing, nil
  end

  # Try to render without the object
  render(thing || action_name.to_sym, opts.merge(:template => template_opt))

# If the render fails (i.e. a template was not found)
rescue TemplateNotFound => e
  # Merge with class level default render options
  # @todo can we find a way to refactor this out so we don't have to do it everywhere?
  opts = self.class.default_render_options.merge(opts)

  # Figure out what to transform and raise NotAcceptable unless there's a transform method assigned
  transform = Merb.mime_transform_method(content_type)
  if !transform
    raise NotAcceptable, "#{e.message} and there was no transform method registered for #{content_type.inspect}"
  elsif !object.respond_to?(transform)
    raise NotAcceptable, "#{e.message} and your object does not respond to ##{transform}"
  end

  layout_opt = opts.delete(:layout)
  _handle_options!(opts)
  throw_content(:for_layout, opts.empty? ? object.send(transform) : object.send(transform, opts))
  
  meth, _ = _template_for(layout_opt, layout_opt.to_s.index(".") ? nil : content_type, "layout") if layout_opt
  meth ? send(meth) : catch_content(:for_layout)
end

#partial(template, opts = {}) ⇒ Object

Render a partial template.

Parameters

template<~to_s>

The path to the template, relative to the current controller or the template root; absolute path will work too. If the template contains a “/”, Merb will search for it relative to the template root; otherwise, Merb will search for it relative to the current controller.

opts<Hash>

A hash of options (see below)

Options (opts)

:with<Object, Array>

An object or an array of objects that will be passed into the partial.

:as<~to_sym>

The local name of the :with Object inside of the partial.

:format<Symbol>

The mime format that you want the partial to be in (:js, :html, etc.)

others

A Hash object names and values that will be the local names and values inside the partial.

Examples

partial :foo, :hello => @object

The “_foo” partial will be called, relative to the current controller, with a local variable of hello inside of it, assigned to @object.

partial :bar, :with => ['one', 'two', 'three']

The “_bar” partial will be called once for each element of the array specified by :with for a total of three iterations. Each element of the array will be available in the partial via a local variable named bar. Additionally, there will be two extra local variables: collection_index and collection_size. collection_index is the index of the object currently referenced by bar in the collection passed to the partial. collection_size is the total size of the collection.

By default, the object specified by :with will be available through a local variable with the same name as the partial template. However, this can be changed using the :as option.

partial :bar, :with => "one", :as => :number

In this case, “one” will be available in the partial through the local variable named number.

:api: public


291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
# File 'lib/merb-core/controller/mixins/render.rb', line 291

def partial(template, opts={})

  # partial :foo becomes "#{controller_name}/_foo"
  # partial "foo/bar" becomes "foo/_bar"
  template = template.to_s
  if template =~ %r{^/}
    template_path = File.dirname(template) / "_#{File.basename(template)}"
  else
    kontroller = (m = template.match(/.*(?=\/)/)) ? m[0] : controller_name
  end
  template = "_#{File.basename(template)}"

  # This handles no :with as well
  with = [opts.delete(:with)].flatten
  as = (opts.delete(:as) || template.match(%r[(?:.*/)?_([^\./]*)])[1]).to_sym

  # Ensure that as is in the locals hash even if it isn't passed in here
  # so that it's included in the preamble. 
  locals = opts.merge(:collection_index => -1, :collection_size => with.size, as => opts[as])
  template_method, template_location = _template_for(
    template, 
    opts.delete(:format) || content_type, 
    kontroller, 
    template_path, 
    locals.keys)
  
  # this handles an edge-case where the name of the partial is _foo.* and your opts
  # have :foo as a key.
  named_local = opts.key?(as)
  
  sent_template = with.map do |temp|
    locals[as] = temp unless named_local

    if template_method && self.respond_to?(template_method)
      locals[:collection_index] += 1
      send(template_method, locals)
    else
      raise TemplateNotFound, "Could not find template at #{template_location}.*"
    end
  end.join
  
  sent_template
end

#render(thing = nil, opts = {}) ⇒ Object

Render the specified item, with the specified options.

Parameters

thing<String, Symbol, nil>

The thing to render. This will default to the current action

opts<Hash>

An options hash (see below)

Options (opts)

:format<Symbol>

A registered mime-type format

:template<String>

The path to the template relative to the template root

:status<~to_i>

The status to send to the client. Typically, this would be an integer (200), or a Merb status code (Accepted)

:layout<~to_s, FalseClass>

A layout to use instead of the default. This should be relative to the layout root. By default, the layout will be either the controller_name or application. If you want to use an alternative content-type than the one that the base template was rendered as, you will need to do :layout => “foo.#content_type” (i.e. “foo.json”). If you want to render without layout, use :layout => false. This overrides layout set by layout method.

Returns

String

The rendered template, including layout, if appropriate.

Raises

TemplateNotFound

There is no template for the specified location.

Alternatives

If you pass a Hash as the first parameter, it will be moved to opts and “thing” will be the current action

:api: public


104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
# File 'lib/merb-core/controller/mixins/render.rb', line 104

def render(thing = nil, opts = {})
  # render :format => :xml means render nil, :format => :xml
  opts, thing = thing, nil if thing.is_a?(Hash)

  # Merge with class level default render options
  opts = self.class.default_render_options.merge(opts)

  # If you don't specify a thing to render, assume they want to render the current action
  thing ||= action_name.to_sym

  # Content negotiation
  self.content_type = opts[:format] if opts[:format]

  # Handle options (:status)
  _handle_options!(opts)

  # Do we have a template to try to render?
  if thing.is_a?(Symbol) || opts[:template]

    template_method, template_location = 
      _template_for(thing, content_type, controller_name, opts[:template])

    # Raise an error if there's no template
    unless template_method && self.respond_to?(template_method)
      template_files = Merb::Template.template_extensions.map { |ext| "#{template_location}.#{ext}" }
      raise TemplateNotFound, "Oops! No template found. Merb was looking for #{template_files.join(', ')} " + 
        "for content type '#{content_type}'. You might have mispelled the template or file name. " + 
        "Registered template extensions: #{Merb::Template.template_extensions.join(', ')}. " +
        "If you use Haml or some other template plugin, make sure you required Merb plugin dependency " + 
        "in your init file."
    end

    # Call the method in question and throw the content for later consumption by the layout
    throw_content(:for_layout, self.send(template_method))

  # Do we have a string to render?
  elsif thing.is_a?(String)

    # Throw it for later consumption by the layout
    throw_content(:for_layout, thing)
  end

  # If we find a layout, use it. Otherwise, just render the content thrown for layout.
  (layout = _get_layout(opts[:layout])) ? send(layout) : catch_content(:for_layout)
end

#throw_content(obj, string = nil, &block) ⇒ Object

Called in templates to store up content for later use. Takes a string and/or a block. First, the string is evaluated, and then the block is captured using the capture() helper provided by the template languages. The two are concatenated together.

Parameters

obj<Object>

The key in the thrown_content hash.

string<String>

Textual content. Defaults to nil.

&block

A block to be evaluated and concatenated to string.

Raises

ArgumentError

Neither string nor block given.

Example

throw_content(:foo, "Foo")
catch_content(:foo) #=> "Foo"

:api: public


503
504
505
506
507
508
# File 'lib/merb-core/controller/mixins/render.rb', line 503

def throw_content(obj, string = nil, &block)
  unless string || block_given?
    raise ArgumentError, "You must pass a block or a string into throw_content"
  end
  @_caught_content[obj] = string.to_s << (block_given? ? capture(&block) : "")
end

#thrown_content?(obj = :for_layout) ⇒ Boolean

Called in templates to test for the existence of previously thrown content.

Parameters

obj<Object>

The key in the thrown_content hash. Defaults to :for_layout.

:api: public

Returns:

  • (Boolean)

481
482
483
# File 'lib/merb-core/controller/mixins/render.rb', line 481

def thrown_content?(obj = :for_layout)
  @_caught_content.key?(obj)
end