For a plugin I want to hack the following feature into Rails:
When a (partial) template does not exist (regardless of the format) I want to render a default template.
So say I call an action 'users/index' if users/index.html.erb does not (or other format) exist, 'default/index.html.erb' should be rendered.
Similarly, If I call an action 'locations/edit' and 'locations/edit.html.erb' does not exist, 'default/edit.html.erb' should be rendered
For partials, If I call an action 'locations/index' and the template 'locations/index.html.erb' calls the partial 'locations/_location' which does not exist, it should render 'default/_object'
The solution is seek gives me access to the templates variables (e.g. #users, #locations) and information on the requested path (e.g. users/index, locations/edit). And it should also work with partials.
I have thought of some options which I'll post below. None of them are completely satisfactory.
Solution 2:
Use 'rescue_from' in ApplicationController
class ApplicationController > ActionController::Base
rescue_from ActionView::MissingTemplate do |exception|
# use exception.path to extract the path information
# This does not work for partials
end
end
Drawback: does not work for partials.
Rails 3.1 automatically looks for files in application/template.html.erb after looking in controller/template.html.erb you can see this in the Exception like so:
Missing template [controller name]/index, application/index with {:locale=>[:en, :en], :formats=>[:html], :handlers=>[:erb, :coffee, :builder]}. Searched in: * "/path/to/rails_project/app/views"
so, just put your default templates in app/views/application
I found a patch that is relatively clean, it only patches the lookup of the template which is exactly what was required in the question.
module ActionView
class PathSet
def find_template_with_exception_handling(original_template_path, format = nil, html_fallback = true)
begin
find_template_without_exception_handling(original_template_path, format, html_fallback)
rescue ActionView::MissingTemplate => e
# Do something with original_template_path, format, html_fallback
raise e
end
end
alias_method_chain :find_template, :exception_handling
end
end
Solution 1:
Monkey patch ActionView::Base#render
module ActionView
class Base
def render_with_template_missing(*args, &block)
# do something if template does not exist
render_without_template_missing(*args, &block)
end
alias_method_chain :render, :template_missing
end
end
This monkey patch requires to look into the (changing) internals of rails and results in ugly code, but probably works.
Related
I am creating a mountable rails engine for a wrapper around a 3rd party API.
controllers:
app/controllers/myengine/v1/application_controller.rb
app/controllers/myengine/v1/customers_controller.rb
module Myengine
class V1::CustomersController < V1::ApplicationController
respond_to :json
def create
...
end
end
end
models:
app/models/myengine/customer.rb
views:
app/views/myengine/v1/customers/_customer.json.jbuilder
app/views/myengine/v1/customers/create.json.jbuilder
I am using JBuilder for my views. Whenever I hit my create action via a REST client, rails will figure out the appropriate view for it (ie. app/views/myengine/v1/customers/create.json.jbuilder).
However, when I reference the partial inside create.json.jbuilder, it complains that the template is missing.
ActionView::MissingTemplate at /v1/customers
Missing partial myengine/customers/_customer with {:locale=>[:en],
:formats=>[:json], :variants=>[], :handlers=>[:jbuilder]}. Searched in:
engines/myengine/app/views/myengine/v1/customers/create.json.jbuilder, line 1
---------------------------------------------------------------------
ruby
> 1 json.partial! #customer
As you can see its looking for the partial in myengine/customers/_customer when it should be looking in myengine/v1/customers/_customer.
I could add json.partial! 'myengine/v1/customers/customer', customer: #customer to specify where the partial is located and this works. However, typically rails magically knows where to find the partial, just not here for some odd reason.
Your help is much appreciated!!
I'm using Rails 3.2.21 with JBuilder.
I have an example where I'm using an a JBuilder partial inside of a js.erb file to pre populate some fields:
var orderData = <%= raw render :partial => 'orders/orders', formats: [:json], handlers: [:jbuilder], locals: {orders: #orders} %>;
I have a weird problem where if an error is thrown in the jbuilder template, it renders a missing template error. so
If _orders.json.jbuilder looks like this
json.array! orders do |order|
json.someProperty order.a_missing_property
end
I get this:
ActionView::Template::Error (Missing partial orders/orders with {:locale=>[:en], :formats=>[:js, :html], :handlers=>[:erb, :builder, :coffee, :haml, :jbuilder, :riif]}
But if there is no error, this renders properly.
Any idea how my error is getting swallowed?
Update
I've created a demo app here: https://github.com/earnold/error-demo
If you load home/index you get a missing template error. If you comment out the bad line in the template, you render the template normally. What I am trying to do is make sure that errors aren't swallowed, but instead are shown on the page.
I was able to get an answer on Github here: https://github.com/rails/jbuilder/issues/40
Short version: this can be remedied by monkey patching Rails. Put this in an initializer and you're good to go.
if Rails.env.development? || Rails.env.staging?
module ActionView
class Template
protected
def handle_render_error(view, e) #:nodoc:
if e.is_a?(Template::Error)
e.sub_template_of(self)
raise e
else
assigns = view.respond_to?(:assigns) ? view.assigns : {}
template = self
unless template.source
# If an error occurs while the Jbuilder template is being rendered in
# in a nested context, you have a mismatch between the template format
# and the view context. Therefore, this block of code would raise
# a false exception (ActionView::MissingTemplate) and swallow the original
# error. This monkey patch tricks rails into thinking it was a json request
# so that refreshing the source hits the right partial
if template.formats == [:json]
view.lookup_context.formats = [:json]
end
template = refresh(view)
template.encode!
end
raise Template::Error.new(template, assigns, e)
end
end
end
end
end
I'm not asking how to use them, I'm asking how do they work. My controller (just used one of the scaffold generators for my controller) has a method:
def index
#users = User.all
end
From that method, I can either get the html response (index.html.erb), even without specifying "html" in the request, or I can get a json response (index.json.jbuilder).
In other methods there's format.html and format.json. In the above example method index, there's no reference to either "type" of response. Why/how does it work?!?
Request for /users -- expected default html
Request for /users.html -- expected html response
Request for /users.js -- I get back the html content of <body> (maybe that's the partial?)
I do not have a template specified for .js anywhere.
Request for /users.txt -- I get the expected error message:
Missing template users/index, application/index with {:locale=>[:en], :formats=>[:text], :handlers=>[:erb, :builder, :raw, :ruby, :jbuilder]}.
Request for /users.xml -- I get the expected error message, even though xml seems more practical than a .js handler of a main resource:
Missing template users/index, application/index with {:locale=>[:en], :formats=>[:xml], :handlers=>[:erb, :builder, :raw, :ruby, :jbuilder]}
Why is a request for .abc even being processed at all? Even though it's not indicating that it's html, that's how it's processing it.
Started GET "/users.abc" ...
Processing by UsersController#index as
I see that there are :handlers specified, but none specify how/what should be handling the .js request. Why isn't the .js request spitting out an error? Hell, how is this all working without a respond_to block? I guess I expect the html handler by default, but I do not expect the .json response by default. There are often cases where I'd like all kinds of formats to be able to be returned, sometimes I'd prefer only to have a .json response over an html one. How/where do I find the documentation for dealing with this? It's not really related to the respond_to block, since even in the absence of respond_to, I'm getting multi format output.
In a controller, when no mime types are defined, rails will simply render the default one:
def index
#users = User.all
end
is equivalent to
respond_to :html
def index
#users = User.all
respond_with #users
end
This being said, let's take a look at other mime types:
Request for /users.js
This one is interesting, looking at the rails code base here we can see that it will render a template using default_render:
# to_js simply tries to render a template. If no template is found, raises the error.
def to_js
default_render
end
This is the default case for the html mime type also:
# HTML format does not render the resource, it always attempt to render a
# template.
#
def to_html
default_render
rescue ActionView::MissingTemplate => e
# ...
end
One does it means ? -- If a js template is defined, rails will render it. Otherwise, it will fallback to render the default html template. This is why you get the html content of <body>. Look your app/views/layouts/application.html.erb file:
<body>
<%= yield %>
</body>
Request for /users.txt and Request for /users.xml
Basically all "undefined by default" mime types will require you define some logic to not throw an exception. From rails source:
def respond
method = "to_#{format}"
respond_to?(method) ? send(method) : to_format
end
Rails define by default to_html and to_js. For other mime types, you will need to satisfy the conditions of the following method. For json and xml, it simply means calling to_json, to_xml or using respond_to.
For more information, take a look at the responder.rb file in rails source here. It's always good to look at rails source to really understand how things work. Of course sometimes it requires to spare some time and jumping around methods and files.
I'm not sure what would be the reaction of rails if a controller's method get request of, let's say, JS format while there's no "reposnd_to" block, but I think that it'd answer with error "unacceptible format". So I think that by default it assumes that request is of html format and to answer for other than html you have to point out with respond_to format block.
What about how the mechanism work, "rails determines the desired response format from the HTTP Accept header submitted by the client" (https://github.com/rails/rails/blob/master/actionpack/lib/action_controller/metal/mime_responds.rb#L85) rails sources says. So accepted formats is stated explicitly while generating request in mime-type
I have an index.js in place which is fired ok from desktop but gives the following error when I try to open from Mobile Safari.
ActionView::MissingTemplate: Missing template ads/thumbs/index, application/index with {:locale=>[:es, :en], :formats=>[:mobile], :handlers=>[:erb, :builder, :haml]}. Searched in: * "/app/app/views" * "/app/vendor/bundle/ruby/1.9.1/gems/devise-1.5.2/app/views" * "/app/app/views"
I'm not sure why it is looking for a :formats=>[:mobile] when there's no such a file in the folder.
Same thing happens after trying to sign in with devise from mobile phone. I tries to render a nonexistent create.mobile.haml file.
P.S. Is there a way to make :mobile views to fallback default :html views when not found? That would make the trick.
You should in general respond with content-type specific views. In this case, a simple way to get past this short-term issue is to rename index.js to index.mobile.js.
Rails attempts to render views that are specific to the content-type requested -- for example, index.html.haml when html is requested or show.json.haml if you request json. In this case the content-type requested is :mobile.
In the long run you should develop views that will be sent back when different content types are requested.
Here's a simple solution.
class ApplicationController
...
def formats=(values)
values << :html if values == [:mobile]
super(values)
end
...
end
It turns out Rails (3.2.11) already adds an :html fallback for requests with the :js format. Here's ActionView::LookupContext#formats=
# Override formats= to expand ["*/*"] values and automatically
# add :html as fallback to :js.
def formats=(values)
if values
values.concat(default_formats) if values.delete "*/*"
values << :html if values == [:js]
end
super(values)
end
So you can override #formats= yourself and it will be conceivably no more gross and hacky than the existing Rails implementation.
I just started using Rails and am not sure what I'm not doing correctly.
In routes.rb I have
resources :pages
In app/controllers/pages_controller.rb I have
class PagesController < ApplicationController
def index
end
end
I have a layout in app/views/layouts/application.html.erb and a template in app/views/home/pages/index.html.erb which I want rendered when I request "/pages". However, I get the error
Template is missing
Missing template pages/index, application/index with {:locale=>[:en],
:formats=>[:html], :handlers=>[:erb, :builder, :coffee]}. Searched in:
* "/###/app/views"
I've been using stackoverflow for ages without posting, but so many different things seem to trigger this error that it's hard to find answers for my particular case. Also I'm a noob :3 Please help!
You say you have app/views/home/pages/index.html.erb to represent the index view for your pages resource. I think the home/ directory is not required.
In other words, your view file should be app/views/pages/index.html.erb.
It's looking to find it in app/views/pages/index but you have it in app/views/home/pages/index. That slight difference makes it so that the Rails convention is lost.
If you must keep your new directory hierarchy, do this on your controller:
class PagesController < ApplicationController
def index
render :partial => "home/pages/index"
end
end
But, by default, if you have a resource, like :pages, it will automatically look in app/views/pages.
I had this problem and I resolved it by just changing the folder name from car to cars. I had to change the folder name from singular to plural.