Rails Query a List for a CRON Job - ruby-on-rails

I'm a complete novice with CRON jobs but I think I have that set up correctly.
Ultimately what I'm trying to do is send an email every day at 8:00 am to users (and a couple others) that have not logged in within the last 3 days, have not received the email, AND are marked as active OR temp as a status.
So from querying the db in console I know that I can do:
first = User.where(status: 'active').or(User.where(status: 'temp'))
second = first.where("last_login_at < ? ", Time.now-3.days)
third = second.where(notified: false)
That's not certainly clean but I was struggling with finding a contained query that grabbed all that data. Is there a cleaner way to do this query?
I believe I have my cron job set up correctly using a runner. I have whenever installed and in my schedule.rb I have:
every 1.day, at: '8:00 am' do
runner 'ReminderMailer.agent_mailer.deliver'
end
So under app > mailer I created ReminderMailer
class ReminderMailer < ApplicationMailer
helper ReminderHelper
def agent_reminder(user)
#user = user
mail(to: email_recipients(user), subject: 'This is your reminder')
end
def email_recipients(agent)
email_address = ''
email_addresses += agent.notification_emails + ',' if agent.notification_emails
email_addresses += agent.manager
email_address += agent.email
end
end
Where I'm actually struggling is where I should put my queries to send to the mailer, which is why I built a ReminderHelper.
module ReminderHelper
def applicable_agents(user)
agent = []
first = User.where(status: 'active').or(User.where(status: 'temp'))
second = first.where("last_login_at < ? ", Time.now-3.days)
third = second.where(notified: false)
agent << third
return agent
end
end
EDIT: So I know I could in theory do a chain of where queries. There's gotta be a better way right?
So what I need help on is: do I have the right structure in place? Is there a cleaner way to query this data in ActiveRecord for the CRON job? Is there a way to test this?

Try combining them together as if understand the conditions correct
Have not logged in within the last 3 days,
Have not received the email
Are marked as active OR temp as a status
User.where("last_login_at < ? ", 3.days.ago).
where(notified: false).
where(status: ['active', temp])
module ReminderHelper
def applicable_agents(user)
User.where("last_login_at < ? ", 3.days.ago).
where(notified: false).
where(status: ['active', temp])
end
end
You don't need to add/ assign them to array. Because this relation is already like an array. You can use .to_a if you need array. If you just want to iterate over them then users.each should work fine.
Update
class User
scope :not_notified, -> { where(notified: false) }
scope :active_or_temp, -> { where(status: ['active', 'temmp']) }
scope :last_login_in, -> (default_days = 3) { where("last_login_at < ?", default_days.days.ago) }
end
and then use
User.not_notified.active_or_temp.last_login_in(3)
Instead of Time.now-3.days it's better to use 3.days.ago because it keeps time zone also in consideration and avoids unnecessary troubles and failing test cases.
Additionally you can create small small scopes and combine them. More read on scopes https://guides.rubyonrails.org/active_record_querying.html

Related

attr_accessor not updating value from rails model

I have the following model
class Job < ActiveRecord::Base
attr_accessor :incentive
end
I want to be able to store a temporary column in my model via attr_accessor.
I want to be able to do something like this
job = Job.last
job.incentive = {id: 1}
and i expect if i do job.incentive, it should return {id: 1}
I also tried doing this as well
def incentive =(val)
#incentive = val
end
def incentive
#incentive
end
But that also didn't work. How can i be able to store temporary column values in rails 4
You script is fine, you'll find the below script working perfectly in your rails console:
job = Job.last
job.incentive = { id: 1 }
p job.incentive # returns { id: 1 }
If you restart or refresh your console (or webpage) this information is gone, since it is only set in memory and not stored to the database.

Ignore parameters that are null in active record Rails 4

I created a simple web form where users can enter some search criteria to look for venues e.g. a price range. When a user clicks "find" I use active record to query the database. This all works very well if all fields are filled in. Problems occur when one or more fields are left open and therefore have a value of null.
How can I work around this in my controller? Should I first check whether a value is null and create a query based on that? I can imagine I end up with many different queries and a lot of code. There must be a quicker way to achieve this?
Controller:
def search
#venues = Venue.where("price >= ? AND price <= ? AND romance = ? AND firstdate = ?", params[:minPrice], params[:maxPrice], params[:romance], params[:firstdate])
end
You may want to filter out all of the blank parameters that were sent with the request.
Here is a quick and DRY solution for filtering out blank values, triggers only one query of the database, and builds the where clause with Rails' ActiveRecord ORM.
This approach safeguards against SQL-injection, as pointed out by #DanBrooking. Rails 4.0+ provides "strong parameters." You should use the feature.
class VenuesController < ActiveRecord::Base
def search
# Pass a hash to your query
#venues = Venue.where(search_params)
end
private
def search_params
params.
# Optionally, whitelist your search parameters with permit
permit(:min_price, :max_price, :romance, :first_date).
# Delete any passed params that are nil or empty string
delete_if {|key, value| value.blank? }
end
end
I would recommend to make method in Venue
def self.find_by_price(min_price, max_price)
if min_price && max_price
where("price between ? and ?", min_price, max_price)
else
all
end
end
def self.find_by_romance(romance)
if romance
where("romance = ?", romance)
else
all
end
end
def self.find_by_firstdate(firstdate)
if firstdate
where("firstdate = ?", firstdate)
else
all
end
end
And use it in your controller
Venue
.find_by_price(params[:minPrice], params[:maxPrice])
.find_by_romance(params[:romance])
.find_by_firstdate(params[:firstdate])
Another solution to this problem, and I think a more elegant one, is using scopes with conditions.
You could do something like
class Venue < ActiveRecord::Base
scope :romance, ->(genre) { where("romance = ?", genre) if genre.present? }
end
You can then chain those, which would work as an AND if there is no argument present, then it is not part of the chain.
http://guides.rubyonrails.org/active_record_querying.html#scopes
Try below code, it will ignore parameters those are not present
conditions = []
conditions << "price >= '#{params[:minPrice]}'" if params[:minPrice].present?
conditions << "price <= '#{params[:maxPrice]}'" if params[:maxPrice].present?
conditions << "romance = '#{params[:romance]}'" if params[:romance].present?
conditions << "firstdate = '#{params[:firstdate]}'" if params[:firstdate].present?
#venues = Venue.where(conditions.join(" AND "))

Optional time where clause

I have an optional time where clause.
Namely where('created_at < ?', params[:infinite_scroll_time_buffer]).
This is included in a series of calls.
I realized that where could take a hash, and if the hash is empty, or is missing any attributes, they won't be included. This sounds great, as I could avoid checking if the params[:infinite_scroll_time_buffer] is there, and just include the where clause and let Rails take care of the rest.
The problem is the following:
def action
options = {}
options[:created_at] = params[:infinite_scroll_time_buffer]
Post.method.another_method.where(options).another_method
end
That would work, except the SQL Query checks that post.created_at = ? instead of post.created_at < ? (rightfully so).
I could have a range of times, but I can't for the life of me find a way for Time to reference the beginning of all time, or something like Time::THE_BEGINNING_OF_EVERYTHING_AS_WE_KNOW_IT_DUN_DUN_DUN
so that I could then have a range from that to the params[:infinite_scroll_time_buffer]. Is there another way to accomplish this?
Create a scope inside your post.rb:
scope :created_before, ->(time) { where('created_at < ?', time) }
Now:
def action
options = {}
Post.method.another_method.where(options).
created_before(params[:infinite_scroll_time_buffer]).
another_method
end
If you don't have the params[:infinite_scroll_time_buffer] present then don't make the query in the first place:
def action
options = {}
# more operation on options hash here
posts = Post.method.another_method.where(options)
posts = posts.created_before(params[:infinite_scroll_time_buffer]) if params[:infinite_scroll_time_buffer].present?
posts = posts.some_another_method
end

How to test the number of database calls in Rails

I am creating a REST API in rails. I'm using RSpec. I'd like to minimize the number of database calls, so I would like to add an automatic test that verifies the number of database calls being executed as part of a certain action.
Is there a simple way to add that to my test?
What I'm looking for is some way to monitor/record the calls that are being made to the database as a result of a single API call.
If this can't be done with RSpec but can be done with some other testing tool, that's also great.
The easiest thing in Rails 3 is probably to hook into the notifications api.
This subscriber
class SqlCounter< ActiveSupport::LogSubscriber
def self.count= value
Thread.current['query_count'] = value
end
def self.count
Thread.current['query_count'] || 0
end
def self.reset_count
result, self.count = self.count, 0
result
end
def sql(event)
self.class.count += 1
puts "logged #{event.payload[:sql]}"
end
end
SqlCounter.attach_to :active_record
will print every executed sql statement to the console and count them. You could then write specs such as
expect do
# do stuff
end.to change(SqlCounter, :count).by(2)
You'll probably want to filter out some statements, such as ones starting/committing transactions or the ones active record emits to determine the structures of tables.
You may be interested in using explain. But that won't be automatic. You will need to analyse each action manually. But maybe that is a good thing, since the important thing is not the number of db calls, but their nature. For example: Are they using indexes?
Check this:
http://weblog.rubyonrails.org/2011/12/6/what-s-new-in-edge-rails-explain/
Use the db-query-matchers gem.
expect { subject.make_one_query }.to make_database_queries(count: 1)
Fredrick's answer worked great for me, but in my case, I also wanted to know the number of calls for each ActiveRecord class individually. I made some modifications and ended up with this in case it's useful for others.
class SqlCounter< ActiveSupport::LogSubscriber
# Returns the number of database "Loads" for a given ActiveRecord class.
def self.count(clazz)
name = clazz.name + ' Load'
Thread.current['log'] ||= {}
Thread.current['log'][name] || 0
end
# Returns a list of ActiveRecord classes that were counted.
def self.counted_classes
log = Thread.current['log']
loads = log.keys.select {|key| key =~ /Load$/ }
loads.map { |key| Object.const_get(key.split.first) }
end
def self.reset_count
Thread.current['log'] = {}
end
def sql(event)
name = event.payload[:name]
Thread.current['log'] ||= {}
Thread.current['log'][name] ||= 0
Thread.current['log'][name] += 1
end
end
SqlCounter.attach_to :active_record
expect do
# do stuff
end.to change(SqlCounter, :count).by(2)

Rails 3 multiple parameter filtering using scopes

Trying to do a basic filter in rails 3 using the url params. I'd like to have a white list of params that can be filtered by, and return all the items that match. I've set up some scopes (with many more to come):
# in the model:
scope :budget_min, lambda {|min| where("budget > ?", min)}
scope :budget_max, lambda {|max| where("budget < ?", max)}
...but what's the best way to use some, none, or all of these scopes based on the present params[]? I've gotten this far, but it doesn't extend to multiple options. Looking for a sort of "chain if present" type operation.
#jobs = Job.all
#jobs = Job.budget_min(params[:budget_min]) if params[:budget_min]
I think you are close. Something like this won't extend to multiple options?
query = Job.scoped
query = query.budget_min(params[:budget_min]) if params[:budget_min]
query = query.budget_max(params[:budget_max]) if params[:budget_max]
#jobs = query.all
Generally, I'd prefer hand-made solutions but, for this kind of problem, a code base could become a mess very quickly. So I would go for a gem like meta_search.
One way would be to put your conditionals into the scopes:
scope :budget_max, lambda { |max| where("budget < ?", max) unless max.nil? }
That would still become rather cumbersome since you'd end up with:
Job.budget_min(params[:budget_min]).budget_max(params[:budget_max]) ...
A slightly different approach would be using something like the following inside your model (based on code from here:
class << self
def search(q)
whitelisted_params = {
:budget_max => "budget > ?",
:budget_min => "budget < ?"
}
whitelisted_params.keys.inject(scoped) do |combined_scope, param|
if q[param].nil?
combined_scope
else
combined_scope.where(whitelisted_params[param], q[param])
end
end
end
end
You can then use that method as follows and it should use the whitelisted filters if they're present in params:
MyModel.search(params)

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