I am getting an empty active record when i initialize new model object.
2.3.0 :030 > user = User.new
=> #<User >
2.3.0 :031 >
when i access the attributes present in the model it returns an error like
2.3.0 :031 > user.UsersName
NoMethodError: undefined method `UsersName' for #<User >
User Model:
class User < ActiveRecord::Base
attr_accessible :UserName, :Password, :RoleId, :EmployeeId, :Password_confirmation
end
Please be sure either one of these is true:
Your model User is inherited from ActiveRecord::Base and you have a column UserName inside your users table. Though, by convention, we should not have attribute names started with capital letter.
EDIT- You can skip 'User' from 'UserName' as it is redundant and replace it with user.name. For that you should have column name inside users table and nothing else need to be defined inside model.
If above is not the case, then you must have an attr_accessor :UserName Or
you must have a method def UserName. Not sure if capital letters work here.
Also, i suggest you to define all your fields starting with lowercase letters.
Your model declares that UserName is accessible yet you're calling UsersName (user.UsersName).
Have you tried user.UserName?
Related
I have set up a simple has-many and belongs-to association using DataMapper with Sinatra. My User model has many 'peeps', and my Peep model belongs to user. See below for the classes....
I am able to successfully create a new peep which belongs to a particular user, by passing the user_id directly into the peep on initialization, like this:
Method 1
new_peep = Peep.create(content: params[:content], user_id: current_user.id)
This adds 1 to Peep to Peep.count.
However, my understanding is that I should be able to create the association by assigning the current_user to new_peep.user. But when I try that, the peep object won't save.
I've tried this:
Method 2
new_peep = Peep.create(content: params[:content], user: current_user)
Current user here is User.get(session[:current_user_id])
The resulting new_peep has an id of nil, but does have user_id set to the current_user's id. New_peep looks exactly like the new_peep that successfully gets created using Method 1, except it has no id because it hasn't successfully saved. I've tried calling new_peep.save separately, but I still get the below for the peep object:
<Peep #id=nil #content="This is a test peep" #created_at=#<DateTime: 2016-05-08T12:42:52+01:00 ((2457517j,42172s,0n),+3600s,2299161j)> #user_id=1>, #errors={}
Note that there are no validation errors. Most problems other people seem to have had with saving records come down to a validation criteria not being met.
I assumed this was something to do with the belongs_to association not working, but I can (after creating new_peep using Method 1 above) still call new_peep.user and access the correct user. So it seems to me the belongs_to is working as a reader but not a setter.
This problem also means I cannot create a peep by adding one into the user.peeps collection then saving user, which means there's virtually no point in peep belonging to user.
I've seen other people have had problems saving records that don't have any changes to save - but this is a completely new record, so all its attributes are being updated.
I'd really like to know what's going on - this has baffled me for too long!
Here are my classes:
class Peep
include DataMapper::Resource
property :id, Serial
property :content, Text
property :created_at, DateTime
belongs_to :user, required: false
def created_at_formatted
created_at.strftime("%H:%M, %A %-d %b %Y")
end
end
class User
include DataMapper::Resource
include BCrypt
attr_accessor :password_confirmation
attr_reader :password
property :id, Serial
property :email, String, unique: true, required: true
property :username, String, unique: true, required: true
property :name, String
property :password_hash, Text
def self.authenticate(params)
user = first(email: params[:email])
if user && Password.new(user.password_hash) == params[:password]
user
else
false
end
end
def password=(actual_password)
#password = actual_password
self.password_hash = Password.create(actual_password)
end
validates_confirmation_of :password
validates_presence_of :password
has n, :peeps
end
When you create the Peep you don't create it through User, maybe that's why it has no primary id, since it belongs to User. Also you're assigning it the foreign key user_id as if you have a property defined as such. Although the database has it, in DataMapper you don't pass in the foreign key id, it does it for you.
Try replacing
new_peep = Peep.create(content: params[:content], user: current_user)
with:
new_peep = current_user.peeps.create(content: params[:content], created_at: Time.now)
I have two classes:
class User
include Mongoid::Document
has_one :preference
attr_accessible :name
field :name, type: String
end
class Preference
include Mongoid::Document
belongs_to :user
attr_accessible :somepref
field :somepref, type: Boolean
end
And I have two factories:
FactoryGirl.define do
factory :user do
preference
name 'John'
end
end
FactoryGirl.define do
factory :preference do
somepref true
end
end
After I create a User both documents are saved in the DB, but Preference document is missing user_id field and so has_one relation doesn't work when I read User from the DB.
I've currently fixed it by adding this piece of code in User factory:
after(:create) do |user|
#user.preference.save! #without this user_id field doesn't get saved
end
Can anyone explain to me why is this happening and is there a better fix?
Mongoid seems to be lacking support here.
When FactoryGirl creates a user, it first has to create the preference for that new user. As the new user does not have an id yet, the preference can't store it either.
In general, when you try create parent & child models in one operation, you need two steps:
create the parent, persist to database so it get's an id.
create the child for the parent and persist it.
Step two would end up in an after(:create) block. Like this:
FactoryGirl.define do
factory :user do
name 'John'
after(:create) do |user|
preference { create(:preference, user: user) }
end
end
end
As stated in this answer:
To ensure that you can always immediately read back the data you just
wrote using Mongoid, you need to set the database session options
consistency: :strong, safe: true
neither of which are the default.
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 have a simple user model
class User < ActiveRecord::Base
has_one :user_profile
end
And a simple user_profile model
class UserProfile < ActiveRecord::Base
belongs_to :user
end
The issue is when I call the following build method, without calling the save method, I end up with a new record in the database (if it passes validation)
class UserProfilesController < ApplicationController
def create
#current_user = login_from_session
#user_profile = current_user.build_user_profile(params[:user_profile])
##user_profile.save (even with this line commented out, it still save a new db record)
redirect_to new_user_profile_path
end
Anyyyyyy one have anyyy idea what's going on.
The definition of this method says the following but it's still saving for me
build_association(attributes = {})
Returns a new object of the associated type that has been instantiated with attributes and linked to this object through a foreign key, but has not yet been saved.
http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html#method-i-has_one
Ok, I'm sure experienced vets already know this, but as a rookie I had to figure it out the long way...let me see if I can explain this without screwing it up
Although I was not directly saving the user_profile object, I noticed in my logs that something was updating the user model's last_activity_time (and the user_profile model) each time I submitted the form (the user model's last_activity date was also updated when the logged in user did various other things too - I later realized this was set in the Sorcery gem configuration).
Per http://api.rubyonrails.org/classes/ActiveRecord/AutosaveAssociation.html
AutosaveAssociation is a module that takes care of automatically saving associated records when their parent is saved. In my case, the user mode is the parent and the scenario they provide below mirrors my experience.
class Post
has_one :author, :autosave => true
end
post = Post.find(1)
post.title # => "The current global position of migrating ducks"
post.author.name # => "alloy"
post.title = "On the migration of ducks"
post.author.name = "Eloy Duran"
post.save
post.reload
post.title # => "On the migration of ducks"
post.author.name # => "Eloy Duran"
The following resolutions resolved my problem
1. Stopping Sorcery (config setting) from updating the users last_activity_time (for every action)
or
2. Passing an ':autosave => false' option when I set the association in the user model as follows
class User < ActiveRecord::Base
has_one :user_profile, :autosave => false
end
I am following Michael Hartl's RoR tutorial, and it is covering the basics of password encryption. This is the User model as it currently stands:
class User < ActiveRecord::Base
attr_accessor :password
attr_accessible :name, :email,: password, :password_confirmation
email_regex = /^[A-Za-z0-9._+-]+#[A-Za-z0-9._-]+\.[A-Za-z0-9._-]+[A-Za-z]$/
#tests for valid email addresses.
validates :name, :presence => true,
:length => {:maximum => 50}
validates :email, :presence => true,
:format => {:with => email_regex},
:uniqueness => {:case_sensitive => false}
validates :password, :presence => true,
:length => {:maximum => 20, :minimum => 6},
:confirmation => true
before_save :encrypt_password
private
def encrypt_password
self.encrypted_password = encrypt(password)
end
def encrypt(string)
string
end
end
I posted a previous question about before_save not working, and it turns out that what I had accidentally done is written my encrypt_password as:
def encrypt_password
#encrypted_password = encrypt(password)
end
I understand that if self.encrypted_password sets the encrypted_password attribute, but why does #encrypted_password not do that as well? In the response to the previous post about before_save not working someone said that the instance variable was "forgotten" after the method ended with the way I had originally coded it -- why was this the case? Can someone please explain how self and # work differently in the context of the code above?
NOTE: I already took a look at the posts here and here, but they both say that "self" is calling the attribute = method, and I don't even understand how that method could exist here since I never created it or declared the encrypted_password w/ attr_accessor. So I am still confused, and this is not a re-posting of those questions.
The accessors for encrypted_password have been automatically added by Rails for you because a field by that name exists in the users table.
Any field you add to a table will be automatically made available via self.field_name.
Here is where Michael Hartl's tutorial creates the encrypted_password field in the users table.
Also look at the user_spec.rb (Listing 7.3) in the linked page, where the author is testing for the presence of the encrypted_password field.
UPDATED:
As #mu points out, the # is used for Ruby instance variables (aka "iv"). But encrypted_password is an "attribute" defined by Rails, and is not an instance variable.
If you run User.find(1).instance_variables, you will see that there is an iv called #attributes, which is of type Hash.
Inside that iv is where the encrypted_password is stored. Rails has defined accessor methods for encrypted_password, which gets/sets the data for that
attribute in the #attributes Hash.
Note that you could also get/set the data via #attributes["encrypted_password"] called from within the User class (but the accessor methods are convenient way to do just that).
If you let me, I'd like to rephrase the answer.
I explained in this post, that as soon as you create a (rails-) Model with the same (singular) name as one of the (plural) tablenames of your database, the "magic" of rails will create setters and getters in order to modify your table's records.
This is because your model inherits all methods from the ActiveRecord::Base Class, which defines basic CRUD accessors (Create, Read, Update, Delete).
The key point related to your question, is that you don't know how rails implements the instance variable related to your database table column, And you shouldn't. :) All you have to know is that at that point, you have setters and getters available to CRUD (create, read, update, delete) your database column "encrypted_password".
In your example, maybe rails uses an instance variable called #encrypted_password, maybe rails uses an hash-instance-variable called #attributes["encrypted_password"], or maybe rails uses an instance variable called #you_will_never_guess_encrypted_password.
-
And that's a good point you don't know about the internal rails behavior with instance variables. In 2019 Rails further development may lead the framework to use #complicated-hash-instance-variable to store the encrypted_password value.
In fact the best approach is to let rails manage its "private" "affair" ;) with instance variables, and just use the getter and setter methods it provides to you.
So your application will still work with encrypted_password in the next century (I hope so ^^).
So if you use #encrypted_password it may work with some "imaginary" version of rails and it won't work anymore with other rails versions. Actually with a current version of rails it doesn't work.
-
The second key point is that when you want to use the getter "encrypted_password" Rails created for your encrypted_password database table column, you prefix it with "self" in order to tells Ruby : "ok I want to use the encrypted_password method of my User instance variable."
In Ruby, a method is called by passing its name to a receiver.
You write it like this :
my_receiver.my_method
In your case we pass the method encrypted_password to the User instance variable. But we don't know how this instance variable will be named, so we use the word self to tell Ruby : "I'm talking about any instance variable of the User class that calls the encrypted_password method".
For instance we could have named our instance variable "toto" :
toto = User.new
so toto.encrypted_password would display the encrypted password, and self in this very case in our code would reference toto.
However, thanks to Ruby, if you don't give any receiver when calling a method, Ruby will assume you pass it to self.
Reference : Pragmatic Programmer's guide
So in your example, you even don't need to put "self." as prefix.
You could have it written like this :
class User < ActiveRecord::Base
def encrypt_password
encrypted_password = encrypt(password)
end
end
I hope this helps to clarify this interesting subject.
TL;DR -
Always write self.widget_count = 123 if you intend to save widget_count back to the database.
(But please do read the long answers, as the reason why is valuable to know.)