This is a very simple question, but I cannot figure out what is happening here. Here's my simple model:
class User
attr_accessor :first_name, :last_name
end
I can write the first_name and last_name fields for a new User, and when I call that user through the variable I assigned it to, I get this:
> u
=> #<User>
It doesn't show the fields I wrote. But when I do this (for last & first name):
> u.first_name
=> "John"
Why isn't the full object showing up when I call u? Such as => #<User first_name: 'John' last_name: 'Smith'>. What do I have to add to my model to get that output? Thanks in advance.
The method that is used for converting an object to a String is to_s, the method that is used for human-readable debugging output is inspect. Some environments also use other methods, e.g. pry (or some plugin) uses pretty_inspect for "pretty" human-readable debugging output. You need to implement those methods.
Example:
class User
def inspect
"#<#{self.class} first_name: '#{first_name}', last_name: '#{last_name}'>"
end
end
What ruby are you using? For me it works:
class Testtt
attr_accessor :a
end
test = Testtt.new
test.a = 1
> test
=> #<Testtt:0x007fdbca785b60 #a=1>
Related
I'm sending serialized data to a class which need to access a Mongoid document which may or may not be embedded.
In case of embedded document, I'm accepting a variable number of arguments which I reduce to get the embedded document.
The code is pretty simple:
def perform(object, *arguments)
#opts = arguments.extract_options!
#object = arguments.reduce(object){|object, args| object.public_send(*args)}
# [...]
I used public_send because AFAIK I only need to call public methods.
However, when I try to access an embedded document I have some really strange result where #object is an enumerator.
After some debugging, this is what I found that for any root document object and an embedded collection items, I have:
object.items.public_send(:find)
# => #<Enumerator: ...>
object.items.send(:find) # or __send__
# => nil
The method called is not the same at all when I call public_send or send!
How is it even possible?
Is it normal? Is that a bug?
public_send seems to invoke the find method of Array (Enumerable) but send (or __send__) invokes the find method of Mongoid
Edit: simple reproductible case:
require 'mongoid'
class User
include Mongoid::Document
field :name, type: String
embeds_many :groups
end
class Group
include Mongoid::Document
field :name, type: String
embedded_in :user
end
Mongoid.load_configuration({
sessions: {
default: {
database: 'send_find',
hosts: [
'localhost:27017'
]
}
}
})
user = User.create(name: 'john')
user.groups.create(name: 'g1')
user.groups.create(name: 'g2')
puts "public_send :find"
puts user.groups.public_send(:find).inspect
# => #<Enumerator: [#<Group _id: 5530dea57735334b69010000, name: "g1">, #<Group _id: 5530dea57735334b69020000, name: "g2">]:find>
puts "send :find"
puts user.groups.send(:find).inspect
# => nil
puts "__send__ :find"
puts user.groups.__send__(:find).inspect
# => nil
Okay, after a few hours of debugging, I found that it is actually a bug in Mongoid.
The relation is not an array but a proxy around the array, which delegates most methods to the array.
As public_send was also delegated but not send and __send__, the behavior was not the same.
For more information, see my pull request and the associated commit.
I need to search within Mongoid objects that have array attributes. Here are the relevant objects:
class Author
include Mongoid::Document
field :name, type: String
class Book
include Mongoid::Document
field :name, type: String
field :authors, type: Array
I can see that at least one book has a given author:
Book.all.sample.authors
=> [BSON::ObjectId('5363c73a4d61635257805e00'),
BSON::ObjectId('5363c73a4d61635257835e00'),
BSON::ObjectId('5363c73a4d61635257c75e00'),
BSON::ObjectId('5363c73b4d616352574a5f00')]
But I'm unable to find books that have that author.
Book.where(authors: '5363c73a4d61635257805e00').first
=> nil
I've tried the solution listed here: https://groups.google.com/forum/#!topic/mongoid/csNOcugYH0U but it didn't work for me:
Book.any_in(:author => ["5363c73b4d616352574a5f00"]).first
=> nil
I'm not sure what I'm doing wrong. Any ideas? I'd prefer to use Mongoid Origin commands.
This output:
Book.all.sample.authors
=> [BSON::ObjectId('5363c73a4d61635257805e00'),
BSON::ObjectId('5363c73a4d61635257835e00'),
BSON::ObjectId('5363c73a4d61635257c75e00'),
BSON::ObjectId('5363c73b4d616352574a5f00')]
tells us that authors contains BSON::ObjectIds. ObjectIds are often presented as Strings and sometimes you can use a String instead of a full blown ObjectId (such as with Model.find) but they're still not Strings. You are searching the array for a String:
Book.where(authors: '5363c73a4d61635257805e00')
but '5363c73a4d61635257805e00' and ObjectId('5363c73a4d61635257805e00') are not the same thing inside MongoDB. You need to search for the right thing:
Book.where(authors: BSON::ObjectId('5363c73a4d61635257805e00'))
You might want to monkey patch a to_bson_id method into various places. Something like this:
class String
def to_bson_id
BSON::ObjectId.from_string(self)
end
end
module Mongoid
module Document
def to_bson_id
id
end
end
end
module BSON
class ObjectId
def to_bson_id
self
end
end
end
class NilClass
def to_bson_id
self
end
end
Should do the trick. Then you can say things like:
Book.where(authors: '5363c73a4d61635257805e00'.to_bson_id)
Book.where(authors: some_string_or_object_id.to_bson_id)
and The Right Thing happens.
You might want to rename authors to author_ids to make its nature a little clearer.
I am just learning Ruby and datamapper, I have read the docs about associations from the official DataMapper site, but I still have two problems.
First whenever I add associated object, I can not see it when displaying all objects.
I have test class like:
class Test
include DataMapper::Resource
property :id, Serial
property :name, String
has 1, :phonen, :through => Resource
end
And then phonen class like:
class Phonen
include DataMapper::Resource
property :id, Serial
property :number, String
belongs_to :test
end
Then I am creating those 2 objects
#test = Test.create(
:name => "Name here"
)
#phone = Phonen.create(
:number => "Phone number"
)
#test.phonen = #phone
#test.save
And I want to display them like that (I want to return json)
get '/' do
Test.all.to_json
end
What am I doing wrong? maybe its something with the to_json...
I honestly don't know..
But I have one additional question to this topic, lets say I managed to connect those two classes, if I display JSON will I get Phonen { } or just inside class { }?
I know its probably very easy question, but I can't figure it out. That's why I decided to ask you guys. Thanks for help
Test.all
Is returning an active record association in array form, not a hash, when you try to convert to json it's failing.
You can try:
render json: Test.all
As asked in this question:
Ruby array to JSON and Rails JSON rendering
Say I am keeping track of email correspondances. An enquiry (from a customer) or a reply (from a supporter) is embedded in the order the two parties are corresponding about. They share the exact same logic when put into the database.
My problem is that even though I use the same logic, the object classes are different, the model fields I need to call are different, and the method names are different as well.
How do I put methods and objects references in before I actually have to use them? Does a "string_to_method" method exists or something like that?
Sample code with commentaries:
class Email
include Mongoid::Document
field :from, type: String
field :to, type: String
field :subject, type: String
belongs_to :order, :inverse_of => :emails
def start
email = Email.create!(:from => "sender#example.com", :to => "recipient#example.com", :subject => "Hello")
from_or_to = from # This represents the database field from where I later on will fetch the customers email address. It is either from or to.
enquiries_or_replies = enquiries # This represents a method that should later be called. It is either enquiries or replies.
self.test_if_enquiry_or_reply(from_or_to, enquiries_or_replies)
end
def test_if_enquiry_or_reply(from_or_to, enquiries_or_replies)
order = Order.add_enquiry_or_reply(self, from_or_to, enquiries_or_replies)
self.order = order
self.save
end
end
class Order
include Mongoid::Document
field :email_address, type: String
has_many :emails, :inverse_of => :order
embeds_many :enquiries, :inverse_of => :order
embeds_many :replies, :inverse_of => :order
def self.add_enquiry_or_reply(email, from_or_to, enquiries_or_replies)
order = Order.where(:email_address => email.from_or_to).first # from_or_to could either be from or to.
order.enquiries_or_replies.create!(subject: email.subject) # enquiries_or_replies could either be enquiries or replies.
order
end
end
Judging by the question and the code sample, it sounds like you are mixing concerns too much. My first suggestion would be to re-evaluate your method names and object structure. Ambiguous names like test_if_thing1_or_thing2 and from_or_to (it should just be one thing) will make it very hard for others, and your future self, to understand the code laster.
However, without diverging into a debate on separation of concerns, you can change the methods you call by using public_send (or the private aware send). So you can do
order.public_send(:replies).create!
order.public_send(:enquiries).create!
string to method does exist, it's called eval
so, you could do
method_name = "name"
eval(method_name) #calls the name method
I'm writing a few helpers to DRY up my tests. I pictured something like:
class ActiveSupport::TestCase
def self.test_presence_validation_of model, attribute
test "should not save #{model.to_s} with null #{attribute.to_s}", <<-"EOM"
#{model.to_s} = Factory.build #{model.to_sym}, #{attribute.to_sym} => nil
assert !#{model.to_s}.save, '#{model.to_s.capitalize} with null #{attribute.to_s} saved to the Database'
EOM
# Another one for blank attribute.
end
end
So that this:
class MemberTest < ActiveSupport::TestCase
test_presence_validation_of :member, :name
end
Executes exactly this at MemberTest class scope:
test 'should not save member with null name' do
member = Factory.build :member, :name => nil
assert !member.save, 'Member with null name saved to the Database'
end
Is it possible to do it this way (with a few adaptations, of course; I doubt my "picture" works), or do I have to use class_eval?
Have you seen Shoulda? It's great for testing common Rails functionality such as validations, relationships etc. https://github.com/thoughtbot/shoulda-matchers
In this case, it seems class_eval is necessary since I want to interpolate variable names into actual code.
Illustrated here.