I have on my Message model, an after_create which creates a new instance of a Notification like such.
after_create :send_notification
def send_notification
n = Notification.new :name => "#{self.sender.smart_name} sent you a message:", :user_id => self.receiver_id, :notification_type => 'message', :subject => self.subject
n.save
end
However, the objects that are created all have their created_at and updated_at set to nil.
#<Notification:0x0000000c486208
id: 123123,
user_id: 3423,
name: "I sent you a message:\n" + "10:27",
notification_type: "message",
created_at: nil,
updated_at: nil>
I've checked to see that the model.record_timestamps is set to true based on this answer.
I don't have anything set on active_record as suggested here.
I'm using Mysql on Rails 4.
You should call n.reload after n.save just to get the timestamps read after save
Related
I've added ActionText into my Rails 5.2 app, according to this tutorial. I performed installation, migration and added action_text_rich_texts column. I also updated my model:
class LiveEvent < ApplicationRecord
has_rich_text :description_long
end
However has_rich_text helper seems to not working. When I try to initialize new record this way:
#live_event = LiveEvent.new(live_event_params)
description_long attribute returns nil because of this helper. Which crashes my app due to the validation constrains.
Strong param permission for description_long it's also not a case since that attribute was permitted before. This error occurs even if I want to add new record directly through the Rails console:
le = LiveEvent.new(description_long: 'test')
le[:description_long] // returns nil
Maybe there is no established binding between action_text_rich_texts and my LiveEvent model? I'm not sure what it the possible cause of this error. How can I fix it?
ActionText is providing polymorphic association with Model we mention has_rich_text.
So when we define has_rich_text is actually we are defining an association, like we do has_one, 'has_many', belongs_to.
So when you write
#live_event = LiveEvent.new(description_long: 'test')
It will create a new instance of ActionText::RichText model and assign the "text" in the body column as instance of ActionText::Content. So what ever value we assigned to description_long as rich text will automatically wrapped into into a div tag <div class="trix-content">.
Here is the example.
pry(main)> e = Email.new(content: "Asd")
=> #<Email:0x00007fd612746018
id: nil,
user_id: nil,
subject: nil,
created_at: nil,
updated_at: nil>
pry(main)> e.content
=> #<ActionText::RichText:0x00007fd612745c80
id: nil,
name: "content",
body: #<ActionText::Content "<div class=\"trix-conte...">,
record_type: "Email",
record_id: nil,
created_at: nil,
updated_at: nil>
pry(main)> e[:content]
=> nil
pry(main)> e.content.body.to_s
=> "<div class=\"trix-content\">\n Asd\n</div>\n"
so content in this example is not actually a column but it's a association. same way description_long in your example is an association not a column.
Please fine the note below "Note: you don't need to add a content field to your messages table." here in this guide https://edgeguides.rubyonrails.org/action_text_overview.html
I'm trying to create a callback for a Post model. The callback should update the slug post attribute. This is the relevant code in post.rb:
class Post < ApplicationRecord
after_create :set_slug
SLUG_FILTER = '/\!?##$`\'%^&*+=",.()[]{}‘’'
private
def set_slug
self.slug = title.delete(SLUG_FILTER).strip.gsub(/\s+/,'-').downcase
end
end
When I create a Post in rails console I get this output:
irb> author(1).posts.create!(title: 'some post title', markdown: 'test **123**')
=> #<Post id: 25, title: "some post title", markdown: "test **123**", ..., slug: "some-post-title">
irb> Post.find(25)
=> #<Post id: 25, title: "some post title", markdown: "test **123**", ..., slug: nil>
It seems that the slug attribute is created but then it becomes nil. Why is the slug attribute nil and not some-post-title? I'd appreciate any help.
self.slug = is just assign slug variable so not save to database.
So you should like the below code.
before_create :set_slug
This code assign to slug before writing to database.
the after_create callback is trigger after the object was saved. If you modify an attribute it will not be save again.
Before_create should work :)
Suppose there are users records in the database. And we decided to add validation in model. Model:
class User < ActiveRecord::Base
validates_format_of :name, with: /\A[^\d]*\z/, allow_blank: true
before_validation :delete_digits_from_name
def delete_digits_from_name
self.name = name.gsub!(/\d/, '')
end
end
Scenario 1 in console:
User.create(name: 'Username 15')
User.last
=> #<User id: 14154, name: "Username"
And it's ok. But there are old record (created before adding validation) and.. scenario 2:
user = User.first
=> #<User id: 1, name: "Username 15"
user.save
=> true
user
=> #<User id: 1, name: "Username"
user.reload
=> #<User id: 1, name: "Username 15"
But why?? Why changes not saved?
The gsub! in delete_digits_from_name changes the name in place, so Rails thinks name is the same thing it loaded from the DB. It's the same object, even though you've changed its value. Rails does this to optimize away DB updates when no data has changed, and in-place editing confuses it.
Switching to self.name = self.name.gsub(/\d/, '') (no !) assigns a new String that Rails will recognize as dirty and needing saving.
You can also add name_will_change! after your gsub! to tell Rails the attribute needs saving.
I have a standard model with a few fields that are saved to a DB, and I need 1 field that doesn't have to be saved.
I tried attr_accessor but that doesn't cover it. Using Attr_accessor I can set and get the field, but it is not part of the model. If I add the models to an array and then see what is in the virtual field is not part of it. I also tried to add the field :headerfield to attr_accessible but that didn't change anything.
How can I get a field that is part of the model but not saved to the database?
The model
class Mapping < ActiveRecord::Base
attr_accessible :internalfield, :sourcefield
attr_accessor :headerfield
end
console output:
1.9.3-p194 :001 > m = Mapping.new
=> #<Mapping id: nil, internalfield: nil, sourcefield: nil, created_at: nil, updated_at: nil, data_set_id: nil>
1.9.3-p194 :002 > m.headerfield = "asef"
=> "asef"
1.9.3-p194 :003 > m
=> #<Mapping id: nil, internalfield: nil, sourcefield: nil, created_at: nil, updated_at: nil, data_set_id: nil>
Because ActiveRecord::Base has custom implementations for the standard serializiation methods (including to_s and as_json), you will never see your model attributes that do not have backing database columns unless you intervene in some way.
You can render it to JSON using the following:
render json: my_object, methods: [:virtual_attr1, :virtual_attr2]
Or you can use the as_json serializer directly:
my_object.as_json(methods: [:virtual_attr1, :virtual_attr2])
The return you see in the console is nothing else but the value of to_s. For this case, code should be better than natural language, take a look in the following code and see if you understand
class A
end
=> nil
A.new
=> #<A:0xb73d1528>
A.new.to_s
=> "#<A:0xb73d1528>"
class A
def to_s
"foobar"
end
end
=> nil
A.new
=> ble
A.new.to_s
=> "ble"
You can see this output because ActiveRecord::Base defines a method to_s that take into account only the attributes that are defined in the database, not the attr_accessor methods, maybe using the attributes call.
This is not exactly a question, it's rather a report on how I solved an issue with write_attribute when the attribute is an object, on Rails' Active Record. I hope this can be useful to others facing the same problem.
Let me explain with an example. Suppose you have two classes, Book and Author:
class Book < ActiveRecord::Base
belongs_to :author
end
class Author < ActiveRecord::Base
has_many :books
end
Very simple. But, for whatever reason, you need to override the author= method on Book. As I'm new to Rails, I've followed the Sam Ruby's suggestion on Agile Web Development with Rails: use attribute_writer private method. So, my first try was:
class Book < ActiveRecord::Base
belongs_to :author
def author=(author)
author = Author.find_or_initialize_by_name(author) if author.is_a? String
self.write_attribute(:author, author)
end
end
Unfortunately, this does not work. That's what I get from console:
>> book = Book.new(:name => "Alice's Adventures in Wonderland", :pub_year => 1865)
=> #<Book id: nil, name: "Alice's Adventures in Wonderland", pub_year: 1865, author_id: nil, created_at: nil, updated_at: nil>
>> book.author = "Lewis Carroll"
=> "Lewis Carroll"
>> book
=> #<Book id: nil, name: "Alice's Adventures in Wonderland", pub_year: 1865, author_id: nil, created_at: nil, updated_at: nil>
>> book.author
=> nil
It seems that Rails does not recognize it is an object and makes nothing: after the attribuition, author is still nil! Of course, I could try write_attribute(:author_id, author.id), but it does not help when the author is not saved yet (it still has no id!) and I need the objects be saved together (author must be saved only if book is valid).
After search a lot for a solution (and try many other things in vain), I found this message: http://groups.google.com/group/rubyonrails-talk/browse_thread/thread/4fe057494c6e23e8, so finally I could had some working code:
class Book < ActiveRecord::Base
belongs_to :author
def author_with_lookup=(author)
author = Author.find_or_initialize_by_name(author) if author.is_a? String
self.author_without_lookup = author
end
alias_method_chain :author=, :lookup
end
This time, the console was nice to me:
>> book = Book.new(:name => "Alice's Adventures in Wonderland", :pub_year => 1865)
=> #<Book id: nil, name: "Alice's Adventures in Wonderland", pub_year: 1865, author_id: nil, created_at: nil, updated_at: nil>
>> book.author = "Lewis Carroll"=> "Lewis Carroll"
>> book
=> #<Book id: nil, name: "Alice's Adventures in Wonderland", pub_year: 1865, author_id: nil, created_at: nil, updated_at: nil>
>> book.author
=> #<Author id: nil, name: "Lewis Carroll", created_at: nil, updated_at: nil>
The trick here is the alias_method_chain, that creates an interceptor (in this case author_with_lookup) and an alternative name to the old setter (author_without_lookup). I confess it took some time to understand this arrangement and I'd be glad if someone care to explain it in detail, but what surprised me was the lack of information about this kind of problem. I have to google a lot to find just one post, that by the title seemed initially unrelated to the problem. I'm new to Rails, so what do you think guys: is this a bad practice?
I recommend creating a virtual attribute instead of overriding the author= method.
class Book < ActiveRecord::Base
belongs_to :author
def author_name=(author_name)
self.author = Author.find_or_initialize_by_name(author_name)
end
def author_name
author.name if author
end
end
Then you could do cool things like apply it to a form field.
<%= f.text_field :author_name %>
Would this work for your situation?
When you override the accessor, you have to set an actual DB attribute for write_attribute and self[:the_attribute]=, and not the name of the association-generated attribute you're overriding. This works for me.
require 'rubygems'
require 'active_record'
ActiveRecord::Base.establish_connection(:adapter => "sqlite3", :dbfile => ":memory:")
ActiveRecord::Schema.define do
create_table(:books) {|t| t.string :title }
create_table(:authors) {|t| t.string :name }
end
class Book < ActiveRecord::Base
belongs_to :author
def author=(author_name)
found_author = Author.find_by_name(author_name)
if found_author
self[:author_id] = found_author.id
else
build_author(:name => author_name)
end
end
end
class Author < ActiveRecord::Base
end
Author.create!(:name => "John Doe")
Author.create!(:name => "Tolkien")
b1 = Book.new(:author => "John Doe")
p b1.author
# => #<Author id: 1, name: "John Doe">
b2 = Book.new(:author => "Noone")
p b2.author
# => #<Author id: nil, name: "Noone">
b2.save
p b2.author
# => #<Author id: 3, name: "Noone">
I strongly recommend doing what Ryan Bates suggests, though; create a new author_name attribute and leave the association generated methods as they are. Less fuzz, less confusion.
I solved this problem using alias_method
class Book < ActiveRecord::Base
belongs_to :author
alias_method :set_author, :author=
def author=(author)
author = Author.find_or_initialize_by_name(author) if author.is_a? String
set_author(author)
end
end