问题
I have a rails app with a has_many :through model like so:
class Blog < ActiveRecord::Base
has_many :blog_categorizations, dependent: :destroy
has_many :categories, :through => :blog_categorizations
accepts_nested_attributes_for :categories, allow_destroy: true
end
class Category < ActiveRecord::Base
has_many :blog_categorizations, dependent: :destroy
has_many :blog, :through => :blog_categorizations
accepts_nested_attributes_for :blog, allow_destroy: true
end
class BlogCategorization < ActiveRecord::Base
belongs_to :blog
belongs_to :category
end
In my Rails admin configuration I have:
config.model Blog do
edit do
field :title
field :content
field :source
field :author
field :date
field :photos
field :categories
end
end
Now when I attempt to add a new Blog through rails_admin, or attempt to edit a pre-existing one, I get infinite rendering of rails_admin templates like this:
Started GET "/admin/recipe/new?_pjax=%5Bdata-pjax-container%5D" for 127.0.0.1 at 2014-10-29 07:41:35 -0700
ActiveRecord::SchemaMigration Load (0.8ms) SELECT "schema_migrations".* FROM "schema_migrations"
Processing by RailsAdmin::MainController#new as HTML
Parameters: {"_pjax"=>"[data-pjax-container]", "model_name"=>"recipe"}
User Load (1.0ms) SELECT "users".* FROM "users" WHERE "users"."id" = 1 ORDER BY "users"."id" ASC LIMIT 1
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_field.html.haml (2.3ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_text.html.haml (1.0ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_field.html.haml (0.2ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_field.html.haml (0.2ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_datetime.html.haml (1.7ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_nested_many.html.haml (25.6ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_nested_many.html.haml (16.2ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_submit_buttons.html.haml (2.9ms)
(0.6ms) SELECT COUNT(*) FROM "blogs"
Recipe Load (0.7ms) SELECT "blogs".* FROM "blogs" ORDER BY blogs.id desc
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_filtering_select.html.haml (14.3ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_file_upload.html.haml (4.0ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_field.html.haml (0.3ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_field.html.haml (1.6ms)
(0.4ms) SELECT COUNT(*) FROM "blog_categorizations"
BlogCategorization Load (0.3ms) SELECT "blog_categorizations".* FROM "blog_categorizations" ORDER BY blog_categorizations.id desc
Category Load (0.5ms) SELECT "categories".* FROM "categories" WHERE "categories"."id" IN (1, 5)
Recipe Load (0.3ms) SELECT "blogs".* FROM "blogs" WHERE "blogs"."id" IN (65)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_filtering_multiselect.html.haml (22.1ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_nested_many.html.haml (1.6ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_field.html.haml (0.2ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_text.html.haml (0.3ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_field.html.haml (0.2ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_field.html.haml (0.2ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_datetime.html.haml (0.9ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_nested_many.html.haml (1.3ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_nested_many.html.haml (1.2ms)
CACHE (0.0ms) SELECT "blogs".* FROM "blogs" ORDER BY blogs.id desc
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_filtering_select.html.haml (4.0ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_file_upload.html.haml (0.5ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_field.html.haml (0.2ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_field.html.haml (0.2ms)
CACHE (0.0ms) SELECT "blog_categorizations".* FROM "blog_categorizations" ORDER BY blog_categorizations.id desc
CACHE (0.0ms) SELECT "categories".* FROM "categories" WHERE "categories"."id" IN (1, 5)
CACHE (0.0ms) SELECT "blogs".* FROM "blogs" WHERE "blogs"."id" IN (65)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_filtering_multiselect.html.haml (3.9ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_nested_many.html.haml (1.1ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_field.html.haml (0.2ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_text.html.haml (0.3ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_field.html.haml (0.2ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_field.html.haml (0.2ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_datetime.html.haml (1.0ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_nested_many.html.haml (1.2ms)
Rendered /Users/adam419/.rbenv/versions/2.0.0-p481/lib/ruby/gems/2.0.0/gems/rails_admin-0.6.3/app/views/rails_admin/main/_form_nested_many.html.haml (1.2ms)
This same output just occurs infinitely and doesn't seem to stop, almost as if it's entered an infinite loop of loading the blogs categories, then the categories blogs, etc.
How can I stop this from occuring?
回答1:
Removing accepts_nested_attributes_for :blog in Category.rb fixed the problem
accepts_nested_attributes_for :blog
This was previously in Category.rb but removed in the code posted in question.
Also, leaving
accepts_nested_attributes_for :blog
but adding inverse_of: category for blog model like
has_many :blog, :through => :blog_categorizations, inverse_of: category
and
has_many :blog, :through => :blog_categorizations, inverse_of: blog
caused the problem to go away. I'm currently using the inverse_of option even though it isn't supposed to work for :through models, but for some reason works for Rails Admin in many-to-many.
来源：https://stackoverflow.com/questions/26633705/rails-admin-has-many-through-relationship-causing-infinite-rendering-of-templat