I'm using rails 4.1 and the new enum functionality to include an array of enums in my model class e.g:
class Campaign < ActiveRecord::Base
enum status: [:pending, :active, :paused, :complete]
end
I want to query campaigns and list a count by status e.g:
Campaign.all.group("status").count
This simple query works fine however returns the integer value of the enum from the DB. Is there an easy rails way to convert this to the string representation?
Just map numbers to related string values:
Campaign.all.group(:status).count.map { |k, v| [Campaign.statuses.key(k), v] }.to_h
if you want status wise count
campaigns = Campaign.all.group(:status).count
#campaigns = Campaign.statuses.map { |k, v| [k , campaigns[v] || 0] }
it will give output like
{"pending"=>0, "active"=>1, "paused"=>0, "complete"=>0}
Also you can use rails #transform_keys method:
Campaign.all.group(:status).count.transform_keys { |k| Campaign.statuses.key(k) }
Related
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
I have a JSON string as pulled from some API
[{"_id"=>"56aefb3b653762000b400000",
"checkout_started_at"=>"2016-02-01T07:32:09.120+01:00",
"created_at"=>"2016-02-01T07:29:15.695+01:00", ...}]
I want to filter data in this string based on created_at, e.g. letting the user chose a specific date-range and then only show the data from this range.
E.g.
#output = my_json.where(created_at: start_date..end_date)
My first thought was to somehow transfer the JSON string to Hashie, to interact with JSON as the data were objects:
my_json = (my_json).map { |hash| Hashie::Mash.new(hash) }
but that didn't work out
undefined method `where' for Array:0x007fd0bdeb84e0
How can I filter out data from a JSON string based on specific criteria or even SQL queries?
This simplest possible way would be to use Enumberable#select directly on the array of hashes:
require 'time'
myjson.select { |o| Time.iso8601(o["created_at"]).between?(start_date, end_date) }
If you want a fancy interface surrounding the raw data:
require 'time' # not needed in rails
class Order < Hashie::Mash
include Hashie::Extensions::Coercion
coerce_key :created_at, ->(v) do
return Time.iso8601(v)
end
end
class OrderCollection
def initialize(json)
#storage = json.map { |j| Order.new(j) }
end
def between(min, max)
#storage.select { |t| t.created_at.between?(min, max) }
end
end
orders = OrderCollection.new(myjson)
orders.between(Time.yesterday, Time.now)
I am listing products and I want to be able to pass a hash as my where clause so I can do something like:
filter = {}
filter[:category_id] = #category.id
filter[:is_active] = true
#products = Products.where(filter)
Is it possible to do this somehow?
I also need to add something like this in my where clause:
WHERE price > 100
How could I add that to a filter?
The reason I want to do this is because in the UI I will have a set of optional filters, so then I will use if clauses in my controller to set each filter.
You can pass a hash to where exactly like you did:
filter = {
category_id: #category_id,
is_active: true
}
#products = Product.where(filter)
Using a hash only works for equality (e.g. category_id = 123), so you can't put something like price > 100 in there. To add that criteria, just add another where to the chain:
#product = Product.where(filter).where('price > 100')
Or...
#product = Product.where(filter)
if params[:min_price]
#product = #product.where('price > ?', min_price)
end
You could have a bit of fun with scopes: write a scope that's actually a mini predicate builder, sanitizing and pattern-matching strings, and delegating to the standard predicate builder for other scalar types. E.g.
# app/models/concerns/searchable.rb
module Searchable
extend ActiveSupport::Concern
included do
scope :search, ->(params) {
params.inject(self) do |rel, (key, value)|
next rel if value.blank?
case value
when String
rel.where arel_table[key].matches '%%%s%%' % sanitize_sql_like(value)
when Range, Numeric, TrueClass, FalseClass
rel.where key => value
else
raise ArgumentError, "unacceptable search type"
end
end
}
end
end
# app/models/product.rb
class Product < ApplicationRecord
include Searchable
then you can
filter = { name: 'cheese', description: 'aged', age: 42.. }
Product.search(filter) #=> SELECT "products".* FROM products WHERE "products"."name" ILIKE '%cheese%' AND "products"."description" ILIKE '%aged%' AND "products"."age" >= 42
I have the following snippet of code to fetch certain columns from the db:
#data = Topic.select("id,name").where("id in (?)",#question.question_topic.split(",")).map(&:attributes)
In the resulting Array of Hashes which is :
Current:
#data = [ { "id" => 2, "name" => "Sports" }]
To be changed to:
#data = [ { "id" => "2", "name" => "Sports" }]
I want to convert "id" to string from fixnum. Id is integer in the db. What is the cleanest way to do this?
Note: After using .map(&:attributes) it is not an active record relation.
You can do it with proper map usage:
topics = Topic.select("id,name").where("id in (?)",#question.question_topic.split(","))
#data = topics.map do |topic|
{
'id' => topic.id.to_s,
'name' => topic.name
}
end
What you're looking for is simply
#data.each { |obj| obj["id"] = obj["id"].to_s }
There isn't really a simpler way (I think that's straightforward enough anyway).
Going by the title which implies a different question - converting every value in the hash to a string you can do this:
#data.each do |obj|
obj.map do |k, v|
{k => v.to_s}
end
end
Just leaving that there anyway.
You can use Ruby's #inject here:
#data.map do |datum|
new_datum = datum.inject({}) do |converted_datum, (key, value)|
converted_datum[key] = value.to_s
converted_datum
end
end
This will work to convert all values to strings, regardless of the key.
If you are using Rails it can be even cleaner with Rails' #each_with_object:
#data.map do |datum|
datum.each_with_object({}) do |(key, value), converted_datum|
converted_datum[key] = value.to_s
end
end
This will iterate all the key names in the hash and replace the value with the #to_s version of the datum associated with the key. nil's converted to empty strings. Also, this assumes you don't have complex data within the hash like embedded arrays or other hashes.
def hash_values_to_string(hash)
hash.keys.each {|k| hash[k]=hash[k].to_s}; hash
end
I have this in models_name:
model_names = Object.constants.collect { |sym| Object.const_get(sym) }.select { |constant| constant.class == Class && constant.include?(Mongoid::Document) }.collect { |klass| klass.name }
the result is:
["Model_name1","Model_name2","Model_name3"]
I need something like:
[{"Model1":"Count"},{"Model2":"Count"},{"Model3":"Count"}]
I need show in a chart all models and object counter inside each model is working with morris.js
You can see the example:
http://jsbin.com/uzosiq/2/embed?javascript,live
Thank you very much!
that last one:
collect { |klass| klass.name }
rewrite it as
collect { |klass| [klass.name, klass.count] }
this should return an array of arrays of 2 elements (classname and count). If the variable to which this is assigned is called a, just do this:
Hash[a]
now you have a hash at your disposal. Now you can do this:
Hash[a].map do |k, v|
{k => v}
end
and now you have an array of hashes of only one key-value assoc each. Which I think it is what you want.
module Foo
end
class Bar
include Foo
end
1.upto(5) { Bar.new }
model_names = Object.constants.collect { |sym| Object.const_get(sym) }.
select { |constant| constant.class == Class && constant.include?(Foo) }.
inject({}) do |m,klass|
m.update klass.name => ObjectSpace.each_object(klass).to_a.size
end
p model_names
{"Bar"=>5}
Will work only on MRI based rubies, so no jRuby nor Runbinius.
Here is a live demo