Normally i do like this
for loops
# app/view/products/index.html.haml
- #products.each do |product|
= product.name
= product.foo
= product.bar
normal scoping
# app/view/products/show.html.haml
= #product.name
= #product.price
= #product.xyz
See in above situation, i am repeating myself. I am using same product word every time. I want it something like which could attach/bind the method as per my context.
I rather prefer to do something like this
For loops i like do something like
- #products.each(context_binding: true) do
= name
= foo
= bar
for scoping
- context_binding #product do
= name
= price
= xyz
I guess that is possible and can be done with method missing i dont know how to do it. Can you give some hints so i can archive such type of things.
Just to give you an idea:
class With
def initialize(obj)
#obj = obj
#str = ''
end
def method_missing(name, *args, &block)
#str += #obj.send(name, *args, &block).to_s
end
end
def with(obj, &block)
With.new(obj).instance_eval(&block).to_s
end
Product = Struct.new(:name, :price)
product = Product.new('apple', '2')
output = with(product) do
name
price
end
puts output
Related
In authors_controller.rb, I have this :
def show
a = Author.find(params[:id])
#author = a.map { |e| e.titlecase }
end
I get an error say that map is an undefined method for Author::0x007fec244142a0.
I also tried this :
def show
#author = Author.find(params[:id])
#author.each { |k, v| v.capitalize }
end
How can I apply the method titlecase to each value of Author.find ?
find(params[:id]) returns not array, not enumerator and not Relation class but just instance of your model. You can't use map or each so just apply titlecase to returned object.
def show
#author = Author.find(params[:id])
#author.name = #author.name.titlecase # if you have column 'name'
end
But better move titlecased name to model's method or just use #author.name.titlecase where it's needed.
You can use where and use map operator with it:
def show
#author = Author.where(id: params[:id])
It's ugly but it works. I'm sure there is a better way to do this stuff.
#author.attributes.map do |k,v|
v = #author.__send__(k).capitalize if #author.__send__(k).respond_to?(:capitalize)
end
#author.save
I must say however that I wouldn't recommend doing things this way. Better to capitalize each field in the model
From I understood. You want to capitalize all fields of record Author.find(params[:id]) right?
First, Author.find(params[:id]) will return a record, not array. That means you can't use each or map for it.
To capitalize all fields of a record. Could u try:
def show
author = Author.find(params[:id])
#author = author.attributes.values.map{|field| field.to_s.capitalize}
end
It will return an array of all field values.
UPDATE 1
For better
def show
author = Author.find(params[:id])
#author_info = author.attributes.values.map{|field| field.is_a?(String) ? field.capitalize : field}
end
I have created Rails application and I have used lots of instance variables and most of them are not required in the views. Do I need to replace the unused instance variables for improving the performance?
Sample code:
def show
custom_fields_data = fetch_custom_field_data
#selected_custom_fields_opt_from_view = []
if custom_fields_data.present?
#listings = #listing.category.listings.where("price_cents!=? AND open= ?",0,true).reject { |l| l.author.main_admin? }
#selected_custom_fields_opt_from_view = custom_fields_data.map do |custom_field_data|
CustomField.find(custom_field_data[0]).options.find(custom_field_data[1])
end
#listings.each do |listing|
# array to store the selected a custom field's option from Database
selected_custom_fields_opt_from_db = []
listing.custom_field_values.each do |custom_field_value|
selected_custom_fields_opt_from_db.push(custom_field_value.selected_options.first)
end
if selected_custom_fields_opt_from_db.uniq.sort == #selected_custom_fields_opt_from_view.uniq.sort || (#selected_custom_fields_opt_from_view - selected_custom_fields_opt_from_db).empty?
similar_listing.push(listing)
end
end
#listings = similar_listing
end
#listing_with_filters = similar_listing.present? ? #listings.first : #listing
#selected_tribe_navi_tab = "home"
unless current_user?(#listing.author)
#listing.increment!(:times_viewed)
end
#current_image = if params[:image]
#listing.image_by_id(params[:image])
else
#listing.listing_images.first
end
#prev_image_id, #next_image_id = if #current_image
#listing.prev_and_next_image_ids_by_id(#current_image.id)
else
[nil, nil]
end
payment_gateway = MarketplaceService::Community::Query.payment_type(#current_community.id)
process = get_transaction_process(community_id: #current_community.id, transaction_process_id: #listing.transaction_process_id)
form_path = new_transaction_path(listing_id: #listing.id)
delivery_opts = delivery_config(#listing.require_shipping_address, #listing.pickup_enabled, #listing.shipping_price, #listing.shipping_price_additional, #listing.currency)
#category = #listing.category
#template_listing = #category.template_listing
if #current_user
# For Pivot table
#selected_custom_field = params[:custom_field] if params[:custom_field]
#listing_for_pivot = Listing.new
#listing_images = #listing.listing_images
#shape = get_shape(#listing.listing_shape_id)
#unit_options = ListingViewUtils.unit_options(#shape[:units], unit_from_listing(#template_listing)).first if #shape
#custom_field_questions = #category.custom_fields
#numeric_field_ids = numeric_field_ids(#custom_field_questions)
#category_tree = CategoryViewUtils.category_tree(
categories: ListingService::API::Api.categories.get(community_id: #current_community.id)[:data],
shapes: get_shapes,
locale: I18n.locale,
all_locales: #current_community.locales
)
if #template_listing.present?
#listing_for_pivot.title = #template_listing.title
#listing_for_pivot.description = #template_listing.description
#listing_images = #template_listing.listing_images if #template_listing.listing_images.present?
#listing_for_pivot.listing_shape_id = #template_listing.listing_shape_id
end
if (#current_user.location != nil)
temp = #current_user.location
temp.location_type = "origin_loc"
#listing_for_pivot.build_origin_loc(temp.attributes)
else
#listing_for_pivot.build_origin_loc(:location_type => "origin_loc")
end
#custom_field_area = CategoryCustomField.where(category_id: #category.id, custom_field_id: #category.custom_fields.pluck(:id))
#row = #category.custom_field_row
#row = #custom_field_area.first.custom_field if #row.nil? && #custom_field_area.first
#column = #category.custom_field_column
#column = #custom_field_area.second.custom_field if #column.nil? && #custom_field_area.second
#filters = #category.custom_field_filters
#filters = #custom_field_area.all.from(1).map { |category_custom_field| category_custom_field.custom_field } if #filters.nil? && #custom_field_area.size > 2
#selected_value_for_filter = []
if #filters.present?
if #selected_custom_field
#filters.each do |filter|
if (#selected_custom_field["#{filter.id.to_s}_"])
#selected_value_for_filter.push(filter.options.find(#selected_custom_field["#{filter.id.to_s}_"]))
else
#selected_value_for_filter.push(filter.options.first)
end
end
else
#filters.each do |filter|
#selected_value_for_filter.push(filter.options.first)
end
end
end
# Pivot table section end
end
#applicant = #category.listings.pluck(:author_id).uniq
#suggested_business_accounts = #category.people.where("people.id NOT IN (?)", #applicant);
if #suggested_business_accounts.present?
#business_locations =
#suggested_business_accounts.map do |person|
person.location
end
#business_locations.compact!
end
render locals: {
form_path: form_path,
payment_gateway: payment_gateway,
# TODO I guess we should not need to know the process in order to show the listing
process: process,
delivery_opts: delivery_opts,
listing_unit_type: #listing.unit_type
}
end
It is not recommended to use instance variables if you don't want to send them to views. The scope of the variables should be narrowest, therefore in your case if you are not using instance variables in the views you should convert them to local.
Using instance variables instead of local variables is a bad idea at least memory-wise.
Instance variable exists while the object that holds it exists. On the contrary, local variable exists only inside method/block it is defined.
Garbage collector does not care whether you use instance variable elsewhere beyond the method or not.
Thus, if you have instance variables, which you only intend to use within the method - change them to local ones.
I want to pull data for each of my users. I grab their person_id from my user table, then use each person's ID to figure out how many days each person has available, and show that in my view.
I'm not sure if I am doing this correctly because I am iterating in my controller then again in my view.
def how_many_days_users_have
#my_group = User.all.pluck(:person_id)
#my_group.each do |v|
#indirect_id_v = Empaccrl.where("person_id = ? and is_active = ?", '#{v]', 'Y').pluck(:a_code).first
#v_range = Empaccrl.where("person_id = ? and is_active = ?", '#{v]', 'Y').pluck(:ac).first
#v_range_taken = Empaccrl.where("person_id = ? and is_active = ?", '#{v]', 'Y').pluck(:taken).first
#total_v_hours = #v_range.to_d - #v_range_taken.to_d
#total_v_days = #total_v_hours / 8
end
Then in my view I use this to show me this data:
%tr.trace-table
-#indirect_id_v.each do |idd|
%tr.trace-table
%td.trace-table{:style => 'border: solid black;'}= idd
-#total_v_days.each do |days|
%tr.trace-table
%td.trace-table{:style => 'border: solid black;'}= days
Okay, first things first, move some of that junk to your model, like so:
class Empaccrl < ActiveRecord::Base
def self.all_people
where(person_id: User.all.pluck(:person_id))
end
def self.active_people
all_people.where(is_active: 'Y')
end
def self.active_vacation_data
active_people.select(:person_id, :ac, :taken)
end
def total_v_hours
ac.to_d - taken.to_d
end
def total_v_days
total_v_hours / 8
end
end
Then you can use:
peoples_vacation_information = Empaccrl.active_vacation_data.all
peoples_vacation_information.map do |person|
p "person #{person.person_id} has #{person.total_v_days} vacation days"
end
Honestly, you don't even need all that, but I'm not sure why you are doing what you are doing, so I figured better be safe and add stuff. Whatever you don't need, just ignore.
I'm trying to generate stats for a character created by a form. The user inputs the name, race, class, alignment, and whether or not the stats will be generated randomly, or prioritized (values being assigned from highest to lowest). The form works flawlessly, as I can see the output in a view.
What I am now trying to do is call a method from a class in /lib in the model that will generate the stats; however, I keep getting the following error (I can't post pictures):
NoMethodError in CharactersController#create
undefined method `[]' for nil:NilClass
Extracted source (around line #14):
12 before_save do
13 generate_stats
14 self.strength = #character_stats[:strength]
15 self.dexterity = #character_stats[:dexterity]
16 self.constitution = #character_stats[:constitution]
17 self.intelligence = #character_stats[:intelligence]
Here is a copy of some of my code:
In controllers\characters_controller.rb
class CharactersController < ApplicationController
def create
#character = Character.new(character_info_params)
#character.name = params[:character][:name].capitalize
#character.alignment = "#{params[:character][:alignment_lr]} #{params[:character][:alignment_ud]}"
if #character.save
redirect_to #character
else
render 'new'
end
end
private
def character_info_params
params.require(:character).permit(:name, :race, :class_, :alignment)
end
end
In models\character.rb
class Character < ActiveRecord::Base
require 'random_stats_generator'
attr_accessor :rand_stat_gen
def generate_stats
if #rand_stat_gen == true
#character_stats_inst = RandomStatGenerator.new
#character_stats = #character_stats_inst.generate
end
end
before_save do
generate_stats
self.strength = #character_stats[:strength]
self.dexterity = #character_stats[:dexterity]
self.constitution = #character_stats[:constitution]
self.intelligence = #character_stats[:intelligence]
self.wisdom = #character_stats[:wisdom]
self.charisma = #character_stats[:charisma]
end
#validation passed this point
end
In initializers\stat_builders.rb
require "./lib/random_stat_generator.rb"
In lib/random_stat_generator.rb
class RandomStatGenerator
def initialize
#strength = :strength
#dexterity = :dexterity
#constitution = :constitution
#intelligence = :intelligence
#wisdom = :wisdom
#charisma = :charisma
#character_stats = HashWithIndifferentAccess.new()
end
def self.generate
roll_stats
end
def roll(stat)
#roll_value_1 = (1 + (rand(6)))
#roll_value_2 = (1 + (rand(6)))
#roll_value_3 = (1 + (rand(6)))
#roll_value_4 = (1 + (rand(6)))
#roll_array = [#roll_value_1,#roll_value_2,#roll_value_3,#roll_value_4]
#roll_array = #roll_array.sort_by {|x| x }
#roll_array = #roll_array.reverse
stat = #roll_array[0] + #roll_array[1] + #roll_array[2]
end
def roll_stats
#strength = roll(#strength)
#dexterity = roll(#dexterity)
#constitution = roll(#constitution)
#intelligence = roll(#intelligence)
#wisdom = roll(#wisdom)
#charisma = roll(#charisma)
#character_stats[:strength] = #strength
#character_stats[:dexterity] = #dexterity
#character_stats[:constitution] = #constitution
#character_stats[:intelligence] = #intelligence
#character_stats[:wisdom] = #wisdom
#character_stats[:charisma] = #charisma
return #character_stats
end
end
To me, it looks like the method isn't returning anything, or isn't being called at all.
I've tried a lot of solutions that I've come across online, none of them working. There may be some things that don't really make sense that are left over from these solutions. I'm only just starting with rails, so I'm still trying to get used to everything.
Thanks a lot for your help.
Ruby has really powerful functions for manipulating both hashes and arrays.
Typing out duplicate assignments like:
self.strength = #character_stats[:strength]
self.dexterity = #character_stats[:dexterity]
self.constitution = #character_stats[:constitution]
Is pretty dull. So instead we can simply rewrite the methods to pass hashes around.
class RandomStatGenerator
# This is just a constant containing all the stats we want to generate.
STATS = [:strength, :dexterity, :constitution, :intelligence, :wisdom, :charisma]
# Create a hash with random roll values for each stat
def self.roll_stats
# This is kind of scary looking but actually just creates an
# hash from an array of keys
Hash[STATS.map {|k| [k, self.roll ] } ]
end
private
def self.roll
# Create an array with 4 elements (nil)
ary = Array.new(4)
# We then replace the nil value with a random value 1-6
ary = ary.map do
(1 + (rand(6)))
end
# sort it and drop the lowest roll. return the sum of all rolls.
ary.sort.drop(1).sum
# a ruby ninja writes it like this
Array.new(4).map { 1 + rand(6) }.sort.drop(1).sum
end
end
Output:
irb(main):032:0> RandomStatGenerator.roll_stats
=> {:strength=>14, :dexterity=>14, :constitution=>14, :intelligence=>13, :wisdom=>10, :charisma=>9}
But if you don't intend to actually create instances of a class, than you should use a module instead.
Rails models can either be created with a hash or you can replace its values with a hash:
Character.new(RandomStatGenerator.roll_stats)
#character.assign_attributes(RandomStatGenerator.roll_stats)
So we can use this in Character#generate_stats:
def generate_stats
assign_attributes(RandomStatGenerator.roll_stats)
end
You should use ActiveModel callbacks with extreme prejudice. It is often quite a challenge to regulate where in your application and when in the model lifetime. Since before_save runs after validations means that any validations like validates_presence_of :constitution will fail.
In your case it might be better to simply do it in the controller or use:
before_validation :generate_stats, if: -> { new_record? && #rand_stat_gen }
I would like to suggest the following organisation fo your library
# Use a module at top level
module RandomStatGenerator
STATS = [:strength, :dexterity, :constitution, :intelligence, :wisdom, :charisma]
# Use a class Stats if you need to but I don't see why...
class Stats
def initialize
RandomStatGenerator::STATS.each do |stat|
# Below line will do #stat = :stat
instance_variable_set("##{stat.to_s}", stat)
#character_stats = HashWithIndifferentAccess.new()
end
def roll_stats
#character_stats = RandomStatGenerator.roll_stats
end
end
module_function
# below lines will be considered as module functions
# => call RandomStatGenerator.function_name
def roll
roll_value_1 = (1 + (rand(6)))
roll_value_2 = (1 + (rand(6)))
roll_value_3 = (1 + (rand(6)))
roll_value_4 = (1 + (rand(6)))
roll_array = [roll_value_1,roll_value_2,roll_value_3,roll_value_4]
roll_array = roll_array.sort_by {|x| x }
roll_array = roll_array.reverse
roll_array[0] + roll_array[1] + roll_array[2]
end
def roll_stats
character_stats = {}
STATS.each do |stat|
character_stats[stat] = RandomStatGenerator.roll
end
return character_stats
end
end
Then in your character.rb
def generate_stats
#character_stats = RandomStatGenerator.roll_stats
end
I have this class:
class Items
def initialize &block
(block.arity < 1 ? (instance_eval &block) : block.call(self)) if block_given?
end
def button_id button_id=nil
unless #button_id.present?
raise "button_id must be supplied" if button_id.nil?
#button_id = button_id
end
#button_id
end
end
Now, when I do this it works:
Items.new do
button_id 1
end
But when I do this, it fails because I think it is not on the same scope:
#button = Button.find(params[:button_id]
Items.new do
button_id #button.id
end
How can fix this to take arguments outside the scope?
Thanks!
Try this:
class Items
def self.dsl
new.tap do |item|
yield item
end
end
def button_id(button_id)
#button_id = button_id
end
end
#button = Button.find(params[:button_id])
item = Items.dsl do |item|
item.button_id(#button.id)
end
puts item.inspect
Turns out all I needed to do was to pass the arguments to the block like this:
Items.new do |item|
item.button_id #button.id
end
Less beautiful DSL but works.
I don't think this is the right use case of DSL, when you can simply assign the attributes by arguments.
class Item
attr_accessor: :button_id
def initialize(args)
button_id = args[:button_id]
end
end
Another problem is in your usage. The instance would be of little value if you don't assign it to a variable
item = Item.new button_id: button_id