I have an index action in rails that can handle quite a few params eg:
params[:first_name] # can be nil or first_name
params[:age] # can be nil or age
params[:country] # can be nil or country
When finding users I would like to AND all the conditions that are not nil. This gives me 8 permutations of the find conditions.
How can I can I keep my code DRY and flexible and not end up with a bunch of if statements just to build the conditions for the find. Keep in mind that if no conditions are specified I just want to return User.all
How about something like:
conditions = params.only(:first_name, :age, :country)
conditions = conditions.delete_if {|key, value| value.blank?}
if conditions.empty?
User.all
else
User.all(:conditions => conditions)
end
I would normally use named scopes for something like this:
class User < ActiveRecord::Base
named_scope :name_like, lambda {|name| {:conditions => ["first_name LIKE ?", "#{name}%"]}}
named_scope :age, lambda {|age| {:conditions => {:age => age}}}
named_scope :in_country, lambda {|country| {:conditions => {:country => country}}}
end
class UsersController < ActionController
def index
root = User
root = root.name_like(params[:first_name]) unless params[:first_name].blank?
root = root.age(params[:age]) unless params[:age].blank?
root = root.country(params[:country]) unless params[:age].blank?
#users = root.paginate(params[:page], :order => "first_name")
end
end
That's what I normally do.
This seems to work quite nicely:
conditions = params.slice(:first_name, :age, :country)
hash = conditions.empty? ? {} : {:conditions => conditions}
#users = User.all hash
Using James Healy answer, I modify the code to be used in Rails 3.2 (in case anyone out there need this).
conditions = params.slice(:first_name, :age, :country)
conditions = conditions.delete_if {|key, value| value.blank?}
#users = User.where(conditions)
You could try Ambition, or a number of other ActiveRecord extensions.
This works for me too
conditions = params[:search] ? params[:search].keep_if{|key, value| !value.blank?} : {}
User.all(:conditions => conditions)
If you happen to be on an ancient project (Rails 2.x) and very messy, you could do something like the following for adding new fields to the original query.
Original code:
User.find(:all,
:conditions => ['first_name LIKE ? AND age=? AND country=?',
"#{name}%", age, country]
Adding a new dynamic condition on zip_code field:
zip_code = params[:zip_code] # Can be blank
zip_query = "AND zip_code = ?" unless zip_code.blank?
User.find(:all,
:conditions => ['first_name LIKE ? AND age=? AND country=? #{zip_query}',
"#{name}%", age, country, zip_code].reject(&:blank?)
Adding a reject(&:blank?) to the conditions arrays will filter the nil value.
Note: The other answers are much better if you are coding from zero, or refactoring.
Related
No hair left on my head (and I have had lots :) ), I have been pulling out my hair and for the life of me I can't figure this out.
I have a one to many relations between 2 tables. I have installed the Datagrid Gem for reporting. I need to get the report from one model based on the other one.
Please have a look at my code.
reports_grid.rb
class ReportsGrid
include Datagrid
scope do
Land.includes(:estate)
end
filter(:estate, :enum, :select => proc { Estate.group("title").select("title").map {|c| [c.title] }})
column(:id, :header => "Land ID")
column(:current_stage, :header => "Stage")
column(:price)
column(:status)
end
reports_controller.rb
class ReportsController < ApplicationController
def index
#grid = ReportsGrid.new(params[:reports_grid]) do |scope|
if params[:reports_grid].present?
if params[:reports_grid][:estate].present?
scope.joins(:estate).where("estates.title = ? ",params[:reports_grid][:estate]).page(params[:page])
**# when I get the #grid.assets here all good and return correct number of rows**
else
scope.page(params[:page])
end
else
scope.page(params[:page])
end
end
end
end
Land.rb
belongs_to :estate
estate.rb
has_many :lands
Now when I go to /reports and try to run the filter I get the following error
PG::UndefinedColumn: ERROR: column lands.estate does not exist LINE 1: ..._id" WHERE (estates.title = 'Olive Gardens' ) AND "lands"."e... ^ : SELECT COUNT(*) FROM "lands" INNER JOIN "estates" ON "estates"."id" = "lands"."estate_id" WHERE (estates.title = 'Olive Gardens' ) AND "lands"."estate" = 'Olive Gardens'
Why is the Gem tries to add "lands"."estate" = 'Olive Gardens' to the query when I have defined it at the instance.
Please let me know if you need me to add anything. Thank you in advance.
Edit:
This is what I have done and worked in the Filter:
I have done this:
filter(:estate_id, :enum,
:select => lambda {Estate.all.map {|p| [p.title, p.id]}},
:multiple => false,
:include_blank => true
) do |value|
self.where(:lands => {:estate_id => value})
end
Do you it is a good approach?
I guess in the scope I could say Land.joins(:estate) then use the scope.all.map... in the query.
Datagrid filter designed to filter data but not to just be by default.
If you have some reason why estate should not filter data by itself then add :dummy => true option:
filter(:estate, :enum, :select => ..., :dummy => true)
But I'would recommend it. Do this instead and your hair will start growing instantly:
filter(:estate, :enum, :select => ...) do |scope, value|
scope.joins(:estate).where("estates.title = ? ", value)
end
It seems obvious from documentation here:
https://github.com/bogdan/datagrid/wiki/Filters#filter-block
Try using references
Land.includes(:estate).references(:estates)
So I'm trying to update few things in my user for it's role and its plan_id .. I've came up with something dirty in my console but everytime I'm trying to use update_all similar way I'm getting no where. I think I'm missing something.. here's my original console way;
expired_subscription_user_ids = Subscription.where("expiry_date < ?", Time.now.beginning_of_day).pluck(:user_id)
User.where(:id => cancelled_subscription).each do |user|
user.role = 'cancelled'
user.plan_id = 'cancelled'
user.save
end
Here's the same thing but using update all that's not working out for me.
User.where(:id => cancelled_subscription).each do |user|
user.update_all(:role => 'subscriber', :plan_id => 'subscriber')
end
So pretty much all users with cancelled_subscription will have their role and plan_id chanced.
You have to use the .update_all method on an ActiveRecord::Relation object, like this:
scope = User.where(:id => cancelled_subscription)
scope.update_all(:role => 'subscriber', :plan_id => 'subscriber')
Documentation: http://apidock.com/rails/ActiveRecord/Relation/update_all
An interesting comment in the documentation, from "openface":
Note that ActiveRecord will not update the timestamp fields (updated_at/updated_on) when using update_all().
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.
There is a search action in RoR that can handle some params e.g.:
params[:name] # can be nil or first_name
params[:age] # can be nil or age
params[:city] # can be nil or country
params[:tag] # can be nil or country
The model name is Person. It also has_many :tags.
When finding persons I need like to AND all the conditions that are present. Of course, it not rational and not DRY.
What I tried to do:
conditions = []
conditions << [ "name like ?", params[:name]+"%" ] if params[:name].present?
conditions << [ "age = ?", params[:age] ] if params[:age].present?
conditions << [ "city = like ?", params[:city]+"%" ] if params[:city].present?
#persons = Person.all(:conditions => conditions )
#What about tags? How do include them if params[:tag].present?
Of course, I want my code to be DRY. Now it's not. Even more, it will cause an exception if params[:age] and params[:name] and params[:city] are not present.
How can I solve? And how do I include tags for persons filtered by tag.name=params[:tag] (if params[:tag].present?) ?
You should do something like this:
lets say filters parameters include this:
filters = {
:name_like => "Grienders",
:age_equal => 15
}
Now you define methods for each
class Person
def search_with_filters(filters)
query = self.scoped
filters.each do |key, values|
query = query.send(key, values)
end
return query
end
def name_like(name)
where("name like ?", name)
end
def age_equal(age)
where(:age => age
end
end
Do you see the method search_with_filters will be the "controlling" method that will take a set of query conditions (name_like, age_equal, etc...) and pass them out to matching method name using the send method, and along with that we also pass the condition which will be the parameter of the method.
The reason why this way is good is because you can scale to any number of conditions (your filter lets say get huge) and also the code is very clean because all you have to do is populate your filters parameter. The method is very readable and very modular and also easy to test
To include the tags condition in your query:
if params[:tag].present?
#persons = Person.all(:conditions => conditions).includes(:tags).where("tags.name = ?", params[:tag])
else
#persons = Person.all(:conditions => conditions)
end
As for there error you are getting when params[:age] .. is not present - This is very strange because it is supposed to return false incase the key is not set in params. Could you please paste the error you are getting?
I would work extensively with scopes for this. Starting with default scope, merge other scopes based on conditions.
Write scopes (or class methods):
class Person << AR::Base
...
NAME_PARTS = ['first_name', 'last_name']
scope :by_name, lambda { |q| where([NAME_PARTS.join(' LIKE :q OR ') + ' LIKE :q', { :q => "%#{q}%" }]) }
scope :by_email, lambda { |q| joins(:account).where(["accounts.email LIKE :q", { :q => "%#{q}%" }]) }
scope :by_age, where(["people.age = ?", q])
scope :tagged, lambda { |q| joins(:tags).where(["tags.name LIKE :q", { :q => "%#{q}%" }]) }
end
Refer:
Scopes in Rails 3
Scopes overhaul section in How Rails 3 Makes Your Life Better
Now, merge the scopes only when the condition is met. As I understand your condition, is the value for a particular search item is nil (like, age is not given), do not search for that scope.
...
def search(object)
interested_fields = ['name', 'age', 'email', 'tags']
criteria = object.attributes.extract!(*interesting_fields) # returns { :age => 20, ... }
scope = object.class.scoped
build(criteria).each do |k, v|
scope = scope.send(k.to_sym, v)
end
scope.all
end
# This method actually builds the search criteria.
# Only keep param which has value and reject the rest.
def build(params)
required = ['name', 'age', 'email', 'tags']
params.delete_if { |k, v| required.include?(k) && v.blank? }
params
end
...
Refer:
extract!
I have a few places in a model that does stuff like
def ServerInfo.starttime(param)
find(:all, :conditions => "name ='#{param}_started'", :select => "date").first.date.to_datetime
end
Now, for reasons not relevant to the question, it can happen that this particular row is not in the database at all and the code above fails with NoMethodError (undefined method `date' for nil:NilClass):. My current fix is
res = find(:all, :conditions => "name ='#{param}_started'", :select => "date")
check_time = res.first.nil? ? 0 : res.first.date.to_datetime
This works find, but I feel it's not right to sprinkle that code all over the place. Is there some more ruby-ish / rail-ish way to prevent dereferencing nil?
In order to avoid the NoMethodError for nil, you should define a begin rescue block,
def ServerInfo.starttime(param)
begin
find(:all, :conditions => "foo").first.date.to_datetime
rescue
0
end
end
I also like the Rails try method:
find(:all, :conditions => "foo").first.try(:date).try(:to_datetime) || 0
maybe this is cleaner:
check_time = res.first.date.to_datetime if res.first
btw, don't use:
:conditions => "name ='#{param}_started'" # SQL injection vulnerability.
use this one instead:
:conditions => ["name = ?", "#{param}_started"] # This is safer. Pure clean Ruby
it's safer
You may also define a scope. For instance in a Rails3 app you should try:
In your ServerInfo.rb model:
scope :starttime, lambda{|param|
if self.has_attribute?(param+'_started')
where("name = ?", param+'_started' ).select('date')
else
false
end
}
// Remember to never put your params directly in your sql query, that is bad practice since you risk some sql injection //
Then in a controller:
res = ServerInfo.starttime('a_param')
check_time = res.first.date.to_datetime if res
I didn't try that code, then you may need to adapt it to your need (or to your Rails2 app)