diff options
Diffstat (limited to 'actionpack/lib/action_controller/metal/implicit_render.rb')
-rw-r--r-- | actionpack/lib/action_controller/metal/implicit_render.rb | 91 |
1 files changed, 74 insertions, 17 deletions
diff --git a/actionpack/lib/action_controller/metal/implicit_render.rb b/actionpack/lib/action_controller/metal/implicit_render.rb index 17fcc2fa02..3a6f784507 100644 --- a/actionpack/lib/action_controller/metal/implicit_render.rb +++ b/actionpack/lib/action_controller/metal/implicit_render.rb @@ -1,29 +1,80 @@ +require 'active_support/core_ext/string/strip' + module ActionController + # Handles implicit rendering for a controller action when it did not + # explicitly indicate an appropiate response via methods such as +render+, + # +respond_to+, +redirect+ or +head+. + # + # For API controllers, the implicit render always renders "204 No Content" + # and does not account for any templates. + # + # For other controllers, the following conditions are checked: + # + # First, if a template exists for the controller action, it is rendered. + # This template lookup takes into account the action name, locales, format, + # variant, template handlers, etc. (see +render+ for details). + # + # Second, if other templates exist for the controller action but is not in + # the right format (or variant, etc.), an <tt>ActionController::UnknownFormat</tt> + # is raised. The list of available templates is assumed to be a complete + # enumeration of all the possible formats (or variants, etc.); that is, + # having only HTML and JSON templates indicate that the controller action is + # not meant to handle XML requests. + # + # Third, if the current request is an "interactive" browser request (the user + # navigated here by entering the URL in the address bar, submiting a form, + # clicking on a link, etc. as opposed to an XHR or non-browser API request), + # <tt>ActionView::UnknownFormat</tt> is raised to display a helpful error + # message. + # + # Finally, it falls back to the same "204 No Content" behavior as API controllers. module ImplicitRender + # :stopdoc: include BasicImplicitRender - # Renders the template corresponding to the controller action, if it exists. - # The action name, format, and variant are all taken into account. - # For example, the "new" action with an HTML format and variant "phone" - # would try to render the <tt>new.html+phone.erb</tt> template. - # - # If no template is found <tt>ActionController::BasicImplicitRender</tt>'s implementation is called, unless - # a block is passed. In that case, it will override the super implementation. - # - # default_render do - # head 404 # No template was found - # end def default_render(*args) if template_exists?(action_name.to_s, _prefixes, variants: request.variant) render(*args) - else - if block_given? - yield(*args) - else - logger.info "No template found for #{self.class.name}\##{action_name}, rendering head :no_content" if logger - super + elsif any_templates?(action_name.to_s, _prefixes) + message = "#{self.class.name}\##{action_name} does not know how to respond " \ + "to this request. There are other templates available for this controller " \ + "action but none of them were suitable for this request.\n\n" \ + "This usually happens when the client requested an unsupported format " \ + "(e.g. requesting HTML content from a JSON endpoint or vice versa), but " \ + "it might also be failing due to other constraints, such as locales or " \ + "variants.\n" + + if request.formats.any? + message << "\nRequested format(s): #{request.formats.join(", ")}" end + + if request.variant.any? + message << "\nRequested variant(s): #{request.variant.join(", ")}" + end + + raise ActionController::UnknownFormat, message + elsif interactive_browser_request? + message = "You did not define any templates for #{self.class.name}\##{action_name}. " \ + "This is not necessarily a problem (e.g. you might be building an API endpoint " \ + "that does not require any templates), and the controller would usually respond " \ + "with `head :no_content` for your convenience.\n\n" \ + "However, you appear to have navigated here from an interactive browser request – " \ + "such as by navigating to this URL directly, clicking on a link or submitting a form. " \ + "Rendering a `head :no_content` in this case could have resulted in unexpected UI " \ + "behavior in the browser.\n\n" \ + "If you expected the `head :no_content` response, you do not need to take any " \ + "actions – requests coming from an XHR (AJAX) request or other non-browser clients " \ + "will receive the \"204 No Content\" response as expected.\n\n" \ + "If you did not expect this behavior, you can resolve this error by adding a " \ + "template for this controller action (usually `#{action_name}.html.erb`) or " \ + "otherwise indicate the appropriate response in the action using `render`, " \ + "`redirect_to`, `head`, etc.\n" + + raise ActionController::UnknownFormat, message + else + logger.info "No template found for #{self.class.name}\##{action_name}, rendering head :no_content" if logger + super end end @@ -32,5 +83,11 @@ module ActionController "default_render" end end + + private + + def interactive_browser_request? + request.format == Mime[:html] && !request.xhr? + end end end |