I understand that validating uniqueness of a standard, single field like "username" is easy. However, for something that has an unlimited number of inputs like, for example, "Favorite Movies" where a user can add as many favorite movies, is something I can't figure out.
They can choose to add or remove fields via the builder, but how do I ensure that no two or more entries are duplicates?
I think the easiest way to accomplish something like this is to validate the uniqueness of something in a scope. I can't say for sure how it would fit in your scenario since you did not describe you model associations but here is an example of how it could work in a FavoriteMovie model:
class FavoriteMovie < ActiveRecord::Base
belongs_to :user
validates_uniqueness_of :movie_name, :scope => :user_id
end
This makes sure that there can't be two movie names that are the same for one specific user.
It turns out that when using nested attributes, you can only validate what's already in the database and not new duplicate occurrences. So, a validation extension (below) with memory validation is really the only option, unfortunately.
#user.rb
class User
has_many :favorite_movies
validate :validate_unique_movies
def validate_unique_movies
validate_uniqueness_of_in_memory(
favorite_movies, [:name, :user_id], 'Duplicate movie.')
end
end
#lib/extensions.rb
module ActiveRecord
class Base
def validate_uniqueness_of_in_memory(collection, attrs, message)
hashes = collection.inject({}) do |hash, record|
key = attrs.map {|a| record.send(a).to_s }.join
if key.blank? || record.marked_for_destruction?
key = record.object_id
end
hash[key] = record unless hash[key]
hash
end
if collection.length > hashes.length
self.errors.add_to_base(message)
end
end
end
end
A very un-rails like solution to the problem would be to add a unique key constraint on the columns that in combination are required to be unique:
create unique index names_idx on yourtable (id, name);
you could easly check it like:
params[:user][:favourite_movies].sort.uniq == params[:user][:favourite_movies].sort
or in model:
self.favourite_movies.sort.uniq == self.favourite_movies.sort
irb(main):046:0> movies = ['terminator', 'ninja turtles', 'titanic', 'terminator' ].map {|movie| movie.downcase }
=> ["terminator", "ninja turtles", "titanic", "terminator"]
irb(main):047:0> movies.sort.uniq == movies.sort
=> false
You can try to create virtual attribute and check it uniqueness:
def full_name
[first_name, last_name].joun(' ')
end
def full_name=(name)
split = name.split(' ', 2)
self.first_name = split.first
self.last_name = split.last
end
You can check uniqueness on the database level by fix your migration:
CREATE TABLE properties (
namespace CHAR(50),
name CHAR(50),
value VARCHAR(100),
);
execute <<-SQL
ALTER TABLE properties
ADD CONSTRAINT my_constraint UNIQUE (namespace, name)
SQL
Little more modern approach: validates method
validates :movie_name, :uniqueness => {:scope => : user_id}
Related
I want to generate forms for a resource that has a postgres jsonb column :data, and I want the schema for these forms to be stored in a table in the database. After a lot of research I am 90% there but my method fails in ActiveAdmin forms upon create (not update). Can anyone explain this?
Sorry for the long code snippets. This is a fairly elaborate setup but I think it would be of some interest since if this works one could build arbitrary new schemas dynamically without hard-coding.
I am following along this previous discussion with Rails 6 and ActiveAdmin 2.6.1 and ruby 2.6.5.
I want to store Json Schemas in a table SampleActionSchema that belong_to SampleAction (using the json-schema gem for validation)
class SampleActionSchema < ApplicationRecord
validates :category, uniqueness: { case_sensitive: false }, allow_nil: false, allow_blank: true
validate :schema_is_json_schema
private
def schema_is_json_schema
metaschema = JSON::Validator.validator_for_name("draft4").metaschema
unless JSON::Validator.validate(metaschema, schema)
errors.add :schema, 'not a compliant json schema'
end
end
end
class SampleAction < ActiveRecord::Base
belongs_to :sample
validate :is_sample_action
validates :name, uniqueness: { case_sensitive: false }
after_initialize :add_field_accessors
before_create :add_field_accessors
before_update :add_field_accessors
def add_store_accessor field_name
singleton_class.class_eval {store_accessor :data, field_name.to_sym}
end
def add_field_accessors
num_fields = schema_properties.try(:keys).try(:count) || 0
schema_properties.keys.each {|field_name| add_store_accessor field_name} if num_fields > 0
end
def schema_properties
schema_arr=SampleActionSchema.where(category: category)
if schema_arr.size>0
sc=schema_arr[0]
if !sc.schema.empty?
props=sc.schema["properties"]
else
props=[]
end
else
[]
end
end
private
def is_sample_action
sa=SampleActionSchema.where(category: category)
errors.add :category, 'not a known sample action' unless (sa.size>0)
errors.add :base, 'incorrect json format' unless (sa.size>0) && JSON::Validator.validate(sa[0].schema, data)
end
end
This all works correctly; For example, for a simple schema called category: "cleave", where :data looks like data: {quality: "good"}, I can create a resource as follows in the rails console:
sa=SampleAction.new(sample_id: 6, name: "test0", data: {}, category: "cleave" )
=> #<SampleAction id: nil, name: "test0", category: "cleave", data: {}, created_at: nil, updated_at: nil, sample_id: 6>
sa.quality = "good" => true
sa.save => true
To make this system work in AA forms, I call the normal path (new or edit)_admix_sample_action_form with params: {category: "cleave"} and then I generate permit_params dynamically:
ActiveAdmin.register SampleAction, namespace: :admix do
permit_params do
prms=[:name, :category, :data, :sample_id, :created_at, :updated_at]
#the first case is creating a new record (gets parameter from admix/sample_actions/new?category="xxx"
#the second case is updating an existing record
#falls back to blank (no extra parameters)
categ = #_params[:category] || (#_params[:sample_action][:category] if #_params[:sample_action]) || nil
cat=SampleActionSchema.where(category: categ)
if cat.size>0 && !cat[0].schema.empty?
cat[0].schema["properties"].each do |key, value|
prms+=[key.to_sym]
end
end
prms
end
form do |f|
f.semantic_errors
new=f.object.new_record?
cat=params[:category] || f.object.category
f.object.category=cat if cat && new
f.object.add_field_accessors if new
sas=SampleActionSchema.where(category: cat)
is_schema=(sas.size>0) && !sas[0].schema.empty?
if session[:active_sample]
f.object.sample_id=session[:active_sample]
end
f.inputs "Sample Action" do
f.input :sample_id
f.input :name
f.input :category
if !is_schema
f.input :data, as: :jsonb
else
f.object.schema_properties.each do |key, value|
f.input key.to_sym, as: :string
end
end
end
f.actions
end
Everything works fine if I am editing an existing resource (as created in the console above). The form is displayed and all the dynamic fields are updated upon submit. But when creating a new resource where e.g. :data is of the form data: {quality: "good"} I get
ActiveModel::UnknownAttributeError in Admix::SampleActionsController#create
unknown attribute 'quality' for SampleAction.
I have tried to both add_accessors in the form and to override the new command to add the accessors after initialize (these should not be needed because the ActiveRecord callback appears to do the job at the right time).
def new
build_resource
resource.add_field_accessors
new!
end
Somehow when the resource is created in the AA controller, it seems impossible to get the accessors stored even though it works fine in the console. Does anyone have a strategy to initialize the resource correctly?
SOLUTION:
I traced what AA was doing to figure out the minimum number of commands needed. It was necessary to add code to build_new_resource to ensure that any new resource AA built had the correct :category field, and once doing so, make the call to dynamically add the store_accessor keys to the newly built instance.
Now users can create their own original schemas and records that use them, without any further programming! I hope others find this useful, I certainly will.
There are a couple ugly solutions here, one is that adding the parameters to the active admin new route call is not expected by AA, but it still works. I guess this parameter could be passed in some other way, but quick and dirty does the job. The other is that I had to have the form generate a session variable to store what kind of schema was used, in order for the post-form-submission build to know, since pressing the "Create Move" button clears the params from the url.
The operations are as follows: for a model called Move with field :data that should be dynamically serialized into fields according to the json schema tables, both
admin/moves/new?category="cleave" and admin/moves/#/edit find the "cleave" schema from the schema table, and correctly create and populate a form with the serialized parameters. And, direct writes to the db
m=Move.new(category: "cleave") ==> true
m.update(name: "t2", quality: "fine") ==> true
work as expected. The schema table is defined as:
require "json-schema"
class SampleActionSchema < ApplicationRecord
validates :category, uniqueness: { case_sensitive: false }, allow_nil: false, allow_blank: true
validate :schema_is_json_schema
def self.schema_keys(categ)
sas=SampleActionSchema.find_by(category: categ)
schema_keys= sas.nil? ? [] : sas[:schema]["properties"].keys.map{|k| k.to_sym}
end
private
def schema_is_json_schema
metaschema = JSON::Validator.validator_for_name("draft4").metaschema
unless JSON::Validator.validate(metaschema, schema)
errors.add :schema, 'not a compliant json schema'
end
end
end
The Move table that employs this schema is:
class Move < ApplicationRecord
after_initialize :add_field_accessors
def add_field_accessors
if category!=""
keys=SampleActionSchema.schema_keys(category)
keys.each {|k| singleton_class.class_eval{store_accessor :data, k}}
end
end
end
Finally, the working controller:
ActiveAdmin.register Move do
permit_params do
#choice 1 is for new records, choice 2 is for editing existing
categ = #_params[:category] || (#_params[:move][:category] if #_params[:move]) || ""
keys=SampleActionSchema.schema_keys(categ)
prms = [:name, :data] + keys
end
form do |f|
new=f.object.new_record?
f.object.category=params[:category] if new
if new
session[:current_category]=params[:category]
f.object.add_field_accessors
else
session[:current_category] = ""
end
keys=SampleActionSchema.schema_keys(f.object.category)
f.inputs do
f.input :name
f.input :category
keys.each {|k| f.input k}
end
f.actions
end
controller do
def build_new_resource
r=super
r.assign_attributes(category: session[:current_category])
r.add_field_accessors
r
end
end
end
I have one problem when I try to save some data into my database, imported from a CSV file (uploaded).
My environment is about a classroom reservation. I have the following code for my model Reservation:
class Reservation < ActiveRecord::Base
require 'csv'
belongs_to :classroom
validates :start_date, presence: true
validates :end_date, presence: true
validates :classroom_id, presence: true
validate :validate_room
scope :filter_by_room, ->(room_id) { where 'classroom_id = ?' % room_id }
def self.import(file)
CSV.foreach(file, headers: true ) do |row|
room_id = Classroom.where(number: row[0]).pluck(:id)
Reservation.create(classroom_id: room_id, start_date: row[1], end_date: row[2])
end
end
private
def validate_room
if Reservation.filter_by_room(classroom_id).nil?
errors.add(:classroom_id, ' has already booked')
end
end
end
The CSV file comes with these three headers: "classroom number", "start date", "end date".
Note that "classroom number" header came from a column of classroom table.
My job is to get the classroom.id using the "number" and create the row in the database of the reservation table.
Ok, but the problem is when I get the classroom_id in "self.import" method and print on the console, he exists. When I use the scope to filter the classroom_id, he is empty.
Expect I've expressed myself like I want.
Sorry for my bad English :/
Edit: Discovered that classroom_id before Reservation.create become nil when I use inside the create method. If I use row[0] works, but I need to use classroom_id.
{ where 'classroom_id = ?' % room_id }
Should be
{ where 'classroom_id = ?', room_id }
The answer is simple, I forgot to use .first after pluck(:id) method.
The pluck method returns a value wrapped in an array:
room_id = Classroom.where(number: row[0]).pluck(:id).first
For example in my Car model i have such fields:
color, price, year
and in form partial i generate form with all this fields. But how to code such logic:
user could enter color and year and i must find with this conditions, user could enter just year or all fields in same time...
And how to write where condition? I could write something like:
if params[:color].present?
car = Car.where(color: params[:color])
end
if params[:color].present? && params[:year].present?
car = Car.where(color: params[:color], year: params[:year])
end
and so over....
But this is very ugly solution, i'm new to rails, and want to know: how is better to solve my problem?
Check out the has_scope gem: https://github.com/plataformatec/has_scope
It really simplifies a lot of this:
class Graduation < ActiveRecord::Base
scope :featured, -> { where(:featured => true) }
scope :by_degree, -> degree { where(:degree => degree) }
scope :by_period, -> started_at, ended_at { where("started_at = ? AND ended_at = ?", started_at, ended_at) }
end
class GraduationsController < ApplicationController
has_scope :featured, :type => :boolean
has_scope :by_degree
has_scope :by_period, :using => [:started_at, :ended_at], :type => :hash
def index
#graduations = apply_scopes(Graduation).all
end
end
Thats it from the controller side
I would turn those into scopes on your Car model:
scope :by_color, lambda { |color| where(:color => color)}
scope :by_year, lambda { |year| where(:year => year)}
and in your controller you would just conditionally chain them like this:
def index
#cars = Car.all
#cars = #cars.by_color(params[:color]) if params[:color].present?
#cars = #cars.by_year(params[:year]) if params[:year].present?
end
user_params = [:color, :year, :price]
cars = self
user_params.each do |p|
cars = cars.where(p: params[p]) if params[p].present?
end
The typical (naive, but simple) way I would do this is with a generic search method in my model, eg.
class Car < ActiveRecord::Base
# Just pass params directly in
def self.search(params)
# By default we return all cars
cars = all
if params[:color].present?
cars = cars.where(color: params[:color])
end
if params[:price1].present? && params[:price2].present?
cars = cars.where('price between ? and ?', params[:price1], params[:price2])
end
# insert more fields here
cars
end
end
You can easily keep chaining wheres onto the query like this, and Rails will just AND them all together in the SQL. Then you can just call it with Car.search(params).
I think you could use params.permit
my_where_params = params.permit(:color, :price, :year).select {|k,v| v.present?}
car = Car.where(my_where_params)
EDIT: I think this only works in rails 4, not sure what version you're using.
EDIT #2 excerpt from site I linked to:
Using permit won't mind if the permitted attribute is missing
params = ActionController::Parameters.new(username: "john", password: "secret")
params.permit(:username, :password, :foobar)
# => { "username"=>"john", "password"=>"secret"}
as you can see, foobar isn't inside the new hash.
EDIT #3 added select block to where_params as it was pointed out in the comments that empty form fields would trigger an empty element to be created in the params hash.
I have Users Bands and Codes.
A user creates a code and that code has a user_id and a band_id.
I have a before save callback generating the code.
before_create :generate_code
private
def generate_code
self.code = SecureRandom.hex(3)
end
I need to add a check, if code exists with user_id and band_id, return false
That way a user will only have one code per band
thoughts?
if you want to keep generating until you get a valid code, try:
def generate_code
begin
self.code = SecureRandom.hex(3)
end while User.exists?(:code => self[:code])
end
if you just want to try one code, and return false, try:
def generate_code
self.code = SecureRandom.hex(3)
return false if User.exists?(:code => self[:code])
end
Note: change "User" to whatever your relation you're checking the collision in :)
Alternatively, you could just try validates :code, :uniqueness => true or something similar :)
How can I prevent users from adding new tags which don't already exist in the tags db?
I want them to be able to add any tags that already exist to another model which they can fully edit, but not be able to create new tags if they don't yet exist?
I'm using declarative_auth so some users with permissions should be create to add whatever tags they want.
user.rb
acts_as_tagger
post.rb
acts_as_taggable_on :features
https://github.com/mbleigh/acts-as-taggable-on
UPDATE:
This seems to do it except I can't get the error message variable to work:
validates :feature_list, :inclusion => {
:in => SomeModel.tag_counts_on(:features).map(&:name),
:message => "does not include {s}" }
I havn't used acts_as_taggable, but can you pass normal rails validations?
# LIKE is used for cross-database case-insensitivity
validates_inclusion_of :name => lambda { find(:all, :conditions => ["name LIKE ?", name]) }
Could probably be more robust and rails validation like but this works:
validate :valid_feature_tag
def valid_feature_tag
invalid_tags = false
feature_list.each do |tag|
list = SomeModel.tag_counts_on(:features).map(&:name)
unless list.include?(tag)
invalid_tags = true
end
end
unless invalid_tags == false
errors.add(:feature_list, 'cannot contain new tags, please suggest new tags to us')
return false
else
return true
end
end
Here's an efficient and clean way to enforce allowed tags:
validate :must_have_valid_tags
def must_have_valid_tags
valid_tags = ActsAsTaggableOn::Tag.select('LOWER(name) name').where(name: tag_list).map(&:name)
invalid_tags = tag_list - valid_tags
if invalid_tags.any?
errors.add(:tag_list, "contains unknown tags: [#{invalid_tags.join(', ')}]")
end
end