Active Record Query ignoring nil values - ruby-on-rails

Takes a query using some methods like code bellow. How can I ignore the nil values? For example: if the method date returns nil I wanna that the query use just array_one and array_to.
def array_one
...
end
def array_two
...
end
def date
...
end
Record.where(array_one: array_one, array_two: array_two, date: date)

You can chain your queries together (it's called lazy loading). They won't actually be executed until the first thing that calls query. This allows you to 'build' the query
query = Record.where(array_one: array_one, array_two: array_two)
query = query.where(date: date) if date.present?
query.each do |row| # now the query is executed
# do stuff
end

Record.where({ array_one: array_one, array_two: array_two, date: date }.compact)

I would do something like this:
scope = Record.scope
scope = scope.where(array_one: array_one) if array_one
scope = scope.where(array_two: array_two) if array_two
scope = scope.where(date: date) if date
scope

Related

Finding the months between two dates in rails

I can currently set a time range like so:
start_date: "2018-09-11"
end_date: "2018-11-19"
How can I do this for start to end of months? Examples:
time_range = ["2018-09-11".."2018-09-30"]
time_range = ["2018-10-01".."2018-10-31"]
time_range = ["2018-11-01".."2018-11-19"]
I'm not sure what's exactly your desired outcome but, given start date and end date as Date objects, you can perform
(start_date..end_date).to_a.group_by(&:month).values
and at the end what you get is a three element array, and each element contains an array with all the dates in that range for a month
I do not know if I understand very well what you asked, but I'll try to help you.
The Date class has several methods that will help you to work with dates.
Date < Object
Examples
my_date_range_array = [Date.today.beginning_of_year..Date.today.end_of_year]
my_date_time_range_array = [Time.now.beginning_of_year..Time.now.end_of_year]
my_date_range_array = [6.months.ago..Date.today]
YourModel.where date: Date.today.beginning_of_month..Date.today
YourModel.where date: 6.months.ago..Date.today
If you need every single date in the range, you can use something like this:
(Date.today.beginning_of_year..Date.today.end_of_year).map{ |date| date }
I hope that my answer helps you
This is a pure Ruby solution, but I believe (though I don't know Rails) it can be simplified slightly by replacing my methods first_day_of_month and first_day_of_month with Rails methods beginning_of_month and end_of_month, respectively. I designed the method for efficiency over simplicity.
require 'date'
DATE_FMT = "%Y-%m-%d"
def date_ranges(start_date_str, end_date_str)
start_date = Date.strptime(start_date_str, DATE_FMT)
end_date = Date.strptime(end_date_str, DATE_FMT)
return [start_date_str..end_date_str] if
[start_date.year, start_date.month] == [end_date.year, end_date.month]
d = start_date
ranges = [start_date_str..last_day_of_month(d)]
loop do
d = d >> 1
break if [d.year, d.month] == [end_date.year, end_date.month]
ranges << (first_day_of_month(d)..last_day_of_month(d))
end
ranges << (first_day_of_month(d)..end_date_str)
end
def first_day_of_month(d)
(d - d.day + 1).strftime(DATE_FMT)
end
def last_day_of_month(d)
((d >> 1)-d.day).strftime(DATE_FMT)
end
date_ranges("2018-09-11", "2019-02-11")
#=> ["2018-09-11".."2018-09-30", "2018-10-01".."2018-10-31",
# "2018-11-01".."2018-11-30", "2018-12-01".."2018-12-31",
# "2019-01-01".."2019-01-31", "2019-02-01".."2019-02-11"]
date_ranges("2018-09-08", "2018-09-23")
#=> ["2018-09-08".."2018-09-23"]
With the information provided by the OP, this is what I understand he is looking for.
Given a set range for example:
time_range = "2018-09-11".."2018-09-19"
new_range_min = time_range.min.to_date.beginning_of_month
new_range_max = time_range.max.to_date.end_of_month
new_range = new_range_min..new_range_max

Too many checks for empty params. How to optimize queries to ActiveRecord in Rails5?

I'm doing checks for empty parameters before do the query.
There is only 1 check for params[:car_model_id]. I can imagine if I will add more checks for other params, then there will be a mess of if-else statements. It doesn't look nice and I think it can be optimized. But how? Here is the code of controller:
class CarsController < ApplicationController
def search
if params[:car_model_id].empty?
#cars = Car.where(
used: ActiveRecord::Type::Boolean.new.cast(params[:used]),
year: params[:year_from]..params[:year_to],
price: params[:price_from]..params[:price_to],
condition: params[:condition]
)
else
#cars = Car.where(
used: ActiveRecord::Type::Boolean.new.cast(params[:used]),
car_model_id: params[:car_model_id],
year: params[:year_from]..params[:year_to],
price: params[:price_from]..params[:price_to],
condition: params[:condition]
)
end
if #cars
render json: #cars
else
render json: #cars.errors, status: :unprocessable_entity
end
end
end
The trick would be to remove the blank values, do a little bit of pre-processing (and possibly validation) of the data, and then pass the params to the where clause.
To help with the processing of the date ranges, you can create a method that checks both dates are provided and are converted to a range:
def convert_to_range(start_date, end_date)
if start_date && end_date
price_from = Date.parse(price_from)
price_to = Date.parse(price_to)
price_from..price_to
end
rescue ArgumentError => e
# If you're code reaches here then the user has invalid date and you
# need to work out how to handle this.
end
Then your controller action could look something like this:
# select only the params that are need
car_params = params.slice(:car_model_id, :used, :year_from, :year_to, :price_from, :price_to, :condition)
# do some processing of the data
year_from = car_params.delete(:year_from).presence
year_to = car_params.delete(:year_to).presence
car_params[:price] = convert_to_range(year_from, year_to)
price_from = car_params.delete(:price_from).presence
price_to = car_params.delete(:price_to).presence
car_params[:price] = convert_to_range(price_from, price_to)
# select only params that are present
car_params = car_params.select {|k, v| v.present? }
# search for the cars
#cars = Car.where(car_params)
Also, I'm pretty sure that the used value will automatically get cast to boolean for you when its provided to the where.
Also, #cars is an ActiveRecord::Relation which does not have an errors method. Perhaps you mean to give different results based on whether there are any cars returned?
E.g: #cars.any? (or #cars.load.any? if you don't want to execute two queries to fetch the cars and check if cars exist)
Edit:
As mentioned by mu is too short you can also clean up your code by chaining where conditions and scopes. Scopes help to move functionality out of the controller and into the model which increases re-usability of functionality.
E.g.
class Car > ActiveRecord::Base
scope :year_between, ->(from, to) { where(year: from..to) }
scope :price_between, ->(from, to) { where(price: from..to) }
scope :used, ->(value = true) { where(used: used) }
end
Then in your controller:
# initial condition is all cars
cars = Cars.all
# refine results with params provided by user
cars = cars.where(car_model_id: params[:car_model_id]) if params[:car_model_id].present?
cars = cars.year_between(params[:year_from], params[:year_to])
cars = cars.price_between(params[:price_from], params[:price_to])
cars = cars.used(params[:used])
cars = cars.where(condition: params[:condition]) if params[:condition].present?
#cars = cars

Rails: Attempting to query created_at

I have the following action in my controller:
def find_by_registration_date
#registration_date = params[:registration_date]
#registrations = Registration.where(:created_at => #registration_date)
end
...were params[:registration_date] is a simple date (no time) like:
"registration_date"=>"2014-07-16"
...and my created_at date looks like...
created_at: "2014-07-16 15:50:52"
How can a search based on Y-M-D?
If its mysql, you can do
#registrations = Registration.where("DATE(created_at) = ? ", #registration_date)
For other databases, find the equivalent date function

Add extra filter parameters in RoR

Suppose I have a method in a controller:
def my_find(is_published, count)
items = Idea.where(published: is_published)
#......
end
Sometimes I want to pass some extra filter arguments
def my_find(is_published, count, some_extra_filter = nil)
items = Idea.where(published: is_published) #.where (some_extra_filter)
#......
end
where some_extra_filter can be lambda or just an plain sql "where" string and it can also be nil or "".
So how do I concatenate .where(published: is_published) with where (some_extra_filter) to get what I need?
This is actually very easy using scopes:
def my_find
#items = Idea.scoped
#items = #items.where(published: is_published) unless is_published.nil?
#items = #items.where(other: other_param) if other_params < 10
# etc, etc
end

Using scope to return results within multiple DateTime ranges in ActiveRecord

I've got a Session model that has a :created_at date and a :start_time date, both stored in the database as :time. I'm currently spitting out a bunch of results on an enormous table and allowing users to filter results by a single date and an optional range of time using scopes, like so:
class Session < ActiveRecord::Base
...
scope :filter_by_date, lambda { |date|
date = date.split(",")[0]
where(:created_at =>
DateTime.strptime(date, '%m/%d/%Y')..DateTime.strptime(date, '%m/%d/%Y').end_of_day
)
}
scope :filter_by_time, lambda { |date, time|
to = time[:to]
from = time[:from]
where(:start_time =>
DateTime.strptime("#{date} #{from[:digits]} #{from[:meridian]}", '%m/%d/%Y %r')..
DateTime.strptime("#{date} #{to[:digits]} #{to[:meridian]}", '%m/%d/%Y %r')
)
}
end
The controller looks more or less like this:
class SessionController < ApplicationController
def index
if params.include?(:date) ||
params.include?(:time) &&
( params[:time][:from][:digits].present? && params[:time][:to][:digits].present? )
i = Session.scoped
i = i.filter_by_date(params[:date]) unless params[:date].blank?
i = i.filter_by_time(params[:date], params[:time]) unless params[:time].blank? || params[:time][:from][:digits].blank? || params[:time][:to][:digits].blank?
#items = i
#items.sort_by! &params[:sort].to_sym if params[:sort].present?
else
#items = Session.find(:all, :order => :created_at)
end
end
end
I need to allow users to filter results using multiple dates. I'm receiving the params as a comma-separated list in string format, e.g. "07/12/2012,07/13/2012,07/17/2012", and need to be able to query the database for several different date ranges, and time ranges within those date ranges, and merge those results, so for example all of the sessions on 7/12, 7/13 and 7/17 between 6:30 pm and 7:30 pm.
I have been looking everywhere and have tried several different things but I can't figure out how to actually do this. Is this possible using scopes? If not what's the best way to do this?
My closest guess looks like this but it's not returning anything so I know it's wrong.
scope :filter_by_date, lambda { |date|
date = date.split(",")
date.each do |i|
where(:created_at =>
DateTime.strptime(i, '%m/%d/%Y')..DateTime.strptime(i, '%m/%d/%Y').end_of_day
)
end
}
scope :filter_by_time, lambda { |date, time|
date = date.split(",")
to = time[:to]
from = time[:from]
date.each do |i|
where(:start_time =>
DateTime.strptime("#{i} #{from[:digits]} #{from[:meridian]}", '%m/%d/%Y %r')..
DateTime.strptime("#{i} #{to[:digits]} #{to[:meridian]}", '%m/%d/%Y %r')
)
end
}
Another complication is that the start times are all stored as DateTime objects so they already include a fixed date, so if I want to return all sessions started between 6:30 pm and 7:30 pm on any date I need to figure something else out too. A third party is responsible for the data so I can't change how it's structured or stored, I just need to figure out how to do all these complex queries. Please help!
EDIT:
Here's the solution I've come up with by combining the advice of Kenichi and Chuck Vose below:
scope :filter_by_date, lambda { |dates|
clauses = []
args = []
dates.split(',').each do |date|
m, d, y = date.split '/'
b = "#{y}-#{m}-#{d} 00:00:00"
e = "#{y}-#{m}-#{d} 23:59:59"
clauses << '(created_at >= ? AND created_at <= ?)'
args.push b, e
end
where clauses.join(' OR '), *args
}
scope :filter_by_time, lambda { |times|
args = []
[times[:from], times[:to]].each do |time|
h, m, s = time[:digits].split(':')
h = (h.to_i + 12).to_s if time[:meridian] == 'pm'
h = '0' + h if h.length == 1
s = '00' if s.nil?
args.push "#{h}:#{m}:#{s}"
end
where("CAST(start_time AS TIME) >= ? AND
CAST(start_time AS TIME) <= ?", *args)
}
This solution allows me to return sessions from multiple non-consecutive dates OR return any sessions within a range of time without relying on dates at all, OR combine the two scopes to filter by non-consecutive dates and times within those dates. Yay!
An important point I overlooked is that the where statement must come last -- keeping it inside of an each loop returns nothing. Thanks to both of you for all your help! I feel smarter now.
something like:
scope :filter_by_date, lambda { |dates|
clauses = []
args = []
dates.split(',').each do |date|
m, d, y = date.split '/'
b = "#{y}-#{m}-#{d} 00:00:00"
e = "#{y}-#{m}-#{d} 23:59:59"
clauses << '(start_time >= ? AND start_time <= ?)'
args.push b, e
end
where clauses.join(' OR '), *args
}
and
scope :filter_by_time, lambda { |dates, time|
clauses = []
args = []
dates.split(',').each do |date|
m, d, y = date.split '/'
f = time[:from] # convert to '%H:%M:%S'
t = time[:to] # again, same
b = "#{y}-#{m}-#{d} #{f}"
e = "#{y}-#{m}-#{d} #{t}"
clauses << '(start_time >= ? AND start_time <= ?)'
args.push b, e
end
where clauses.join(' OR '), *args
}
So, the easy part of the question is what to do about datetimes. The nice thing about DateTimes is that they can be cast to times really easily with this:
CAST(datetime_col AS TIME)
So you can do things like:
i.where("CAST(start_time AS TIME) IN(?)", times.join(", "))
Now, the harder part, why aren't you getting any results. The first thing to try is to use i.to_sql to decide whether the scoped query looks reasonable. My guess is that when you print it out you'll find that all those where are chaining together with AND. So you're asking for objects with a date that is on 7/12, 7/13, and 7/21.
The last part here is that you've got a couple things that are concerning: sql injections and some overeager strptimes.
When you do a where you should never use #{} in the query. Even if you know where that input is coming from your coworkers may not. So make sure you're using ? like in the where I did above.
Secondly, strptime is extremely expensive in every language. You shouldn't know this, but it is. If at all possible avoid parsing dates, in this case you can probably just gsub / into - in that date and everything will be happy. MySQL expects dates in m/d/y form anyways. If you're still having trouble with it though and you really need a DateTime object you can just as easily do: Date.new(2001,2,3) without eating your cpu.

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