diff options
Diffstat (limited to 'actionpack/lib/action_controller/metal/implicit_render.rb')
| -rw-r--r-- | actionpack/lib/action_controller/metal/implicit_render.rb | 87 |
1 files changed, 34 insertions, 53 deletions
diff --git a/actionpack/lib/action_controller/metal/implicit_render.rb b/actionpack/lib/action_controller/metal/implicit_render.rb index 3a6f784507..6192fc0f9c 100644 --- a/actionpack/lib/action_controller/metal/implicit_render.rb +++ b/actionpack/lib/action_controller/metal/implicit_render.rb @@ -1,33 +1,31 @@ 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+. + # Handles implicit rendering for a controller action that does not + # explicitly respond with +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 API controllers, the implicit response is always 204 No Content. # - # For other controllers, the following conditions are checked: + # For all other controllers, we use these heuristics to decide whether to + # render a template, raise an error for a missing template, or respond with + # 204 No Content: # - # 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). + # First, if we DO find a template, it's rendered. Template lookup accounts + # for the action name, locales, format, variant, template handlers, and more + # (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. + # Second, if we DON'T find a template but the controller action does have + # templates for other formats, variants, etc., then we trust that you meant + # to provide a template for this response, too, and we raise + # <tt>ActionController::UnknownFormat</tt> with an explanation. # - # 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. + # Third, if we DON'T find a template AND the request is a page load in a web + # browser (technically, a non-XHR GET request for an HTML response) where + # you reasonably expect to have rendered a template, then we raise + # <tt>ActionView::UnknownFormat</tt> with an explanation. # - # Finally, it falls back to the same "204 No Content" behavior as API controllers. + # Finally, if we DON'T find a template AND the request isn't a browser page + # load, then we implicitly respond with 204 No Content. module ImplicitRender # :stopdoc: @@ -37,39 +35,23 @@ module ActionController if template_exists?(action_name.to_s, _prefixes, variants: request.variant) render(*args) 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 + message = "#{self.class.name}\##{action_name} is missing a template " \ + "for this request format and variant.\n" \ + "\nrequest.formats: #{request.formats.map(&:to_s).inspect}" \ + "\nrequest.variant: #{request.variant.inspect}" 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" + message = "#{self.class.name}\##{action_name} is missing a template " \ + "for this request format and variant.\n\n" \ + "request.formats: #{request.formats.map(&:to_s).inspect}\n" \ + "request.variant: #{request.variant.inspect}\n\n" \ + "NOTE! For XHR/Ajax or API requests, this action would normally " \ + "respond with 204 No Content: an empty white screen. Since you're " \ + "loading it in a web browser, we assume that you expected to " \ + "actually render a template, not… nothing, so we're showing an " \ + "error to be extra-clear. If you expect 204 No Content, carry on. " \ + "That's what you'll get from an XHR or API request. Give it a shot." raise ActionController::UnknownFormat, message else @@ -85,9 +67,8 @@ module ActionController end private - def interactive_browser_request? - request.format == Mime[:html] && !request.xhr? + request.get? && request.format == Mime[:html] && !request.xhr? end end end |