In the process of drying my Rails app code, I have created the following concern that is used to generate the contents of an index method.
define_method(:generate_index) do |string, scope|
instance_variable_set( "##{string}", string.camelize.constantize.public_send(scope))
end
I use this code to generate something like the following:
def index
generate_index("foo", "all")
# #foo = Foo.all
end
What I'd like to do is to have the define method accept a number of scopes. I tried passing in an array of scopes but that results in an error.
Any ideas?
Thanks
You could use the splash * operator:
define_method(:generate_index) do |klass, *scopes|
scope = klass.to_s.camelize.constantize
scopes.each { |s| scope = scope.send(s) }
instance_variable_set("##{string}", scope)
end
def index
generate_index(:foo, :all, :where_not_test)
# #foo = Foo.all.where_not_test
end
Related
How can I use Ransack with "find_by_sql"?
I generally do this:
def index
#m = Mymodel.ransack(params[:q])
#mymodels = #m.result.page(params[:page])
end
Can I use Ransack when doing a custom query?:
#mymodels = Mymodel.find_by_sql(["SELECT ... ", current_user])
If I get it correctly, this is want you want:
def index
#m = Mymodel.ransack(params[:q])
#mymodels = #m.result.page(param[:page]).where(user: current_user)
end
To answer your question directly though, you can convert it to an SQL string, but you won't (or would be hard) be able to use current_user as an argument:
def index
#m = Mymodel.ransack(params[:q])
sql = #m.result.page(param[:page]).to_sql
#mymodels = Mymodel.find_by_sql(sql, current_user)
# the line just above won't work immediately because you'll need to
# modify the `sql` variable manually by inserting the `?` that you'll
# need to map that to the `current_user` that you passed as an argument
end
I have model Places and I have the index method in a controller. I need to get all places via request
/places
And filter places via request with query
/places?tlat=xxxx&tlong=xxxx&blat=xxxxx&blong=xxxx
What the best way to get this records? Should I check an existence of each param or are there Rails way?
#places = if params[tlat]&¶ms[blat]....
Places.all.where("lat > ? AND long > ? AND lat < ? AND long < ?", tlat, tlong, blat, blong)
else
Places.all
If you want to set WHERE clauses depending on params, you can use Ursus' code which is fine.
However, if you need to apply those WHERE clauses only if a set of params are present, you can use the following:
#places = Place.all
if params[:blat].present? && params[:tlat].present?
#places = #places.where(blat: params[:blat], tlat: params[:tlat])
end
# etc.
You could use an array of arrays to pair the associated params, kind of like what Ursus did.
I'd do something like this if possible. Important to note the this is just one query, composed dynamically.
#places = Place.all
%i(tlat tlong blat blong).each do |field|
if params[field].present?
#places = #places.where(field => params[field])
end
end
IMO, truly the "Rails way" (but actually just the "Ruby way") would be to extract this long conditional, and the query itself, out to their own private method. It becomes much easier to understand what's going on in the index action
class MyController < ApplicationController
def index
#places = Place.all
apply_geo_scope if geo_params_present?
end
private
def geo_params_present?
!!(params[:tlat] && params[:blat] && params[:tlong] && params[:blong])
end
# A scope in the model would be better than defining this in the controller
def apply_geo_scope
%i(tlat tlong blat blong).each do |field|
#places = #places.where(field => params[field])
end
end
end
I am using rails to make a datatable that paginates with Ajax, and I am following railscast #340 to do so.
This episode makes use of a normal ActiveModel Class called ProductsDatatable or in my case OrdersDatatable to create and configure the table. My question has to do with ruby syntax in this class. I am trying to pass a collection of orders to the OrdersDatatable object, from the controller. I want to access this collection in the fetch_orders method.
I create the table object like this in order.rb:
#datatable = OrdersDatatable.new(view_context)
#datatable.shop_id = #current_shop.id
#datatable.orders_list = #orders # which is Order.in_process
And my OrdersDatatable class looks like this: (the important parts which probably need to change is the second line in initialize and the first line in fetch_orders)
class OrdersDatatable
include Rails.application.routes.url_helpers
include ActionView::Helpers::DateHelper
include ActionView::Helpers::TagHelper
delegate :params, :h, :link_to, :number_to_currency, to: :#view
attr_accessor :shop_id, :orders_list
def initialize(view)
#view = view
#orders_list = self.orders_list
end
def current_shop
Shop.find(shop_id)
end
def as_json(options = {})
{
sEcho: params[:sEcho].to_i,
iTotalRecords: orders.count,
iTotalDisplayRecords: orders.count,
aaData: data
}
end
private
def data
orders.map do |order|
[
order.id,
order.name,
h(time_tag(order.date_placed.in_time_zone)),
order.state,
order.source,
order.payment_status,
h(order.delivered? ? 'shipped' : 'unshipped'),
h(number_to_currency order.final_total, unit: order.currency.symbol),
h(link_to 'details', edit_admin_shop_order_path(current_shop, order)),
h(link_to 'delete', admin_shop_order_path(current_shop, order), method: :delete, data: { confirm: 'Are you sure?' } ),
]
end
end
def orders
#orders ||= fetch_orders
end
def fetch_orders
orders = orders_list.order("#{sort_column} #{sort_direction}")
orders = orders.page(page).per_page(per_page)
if params[:sSearch].present?
orders = orders.where("title like :search", search: "%#{params[:sSearch]}%")
end
orders
end
def page
params[:iDisplayStart].to_i/per_page + 1
end
def per_page
params[:iDisplayLength].to_i > 0 ? params[:iDisplayLength].to_i : 10
end
def sort_column
columns = %w[id name date_placed state source payment_status delivered final_total]
columns[params[:iSortCol_0].to_i]
end
def sort_direction
params[:sSortDir_0] == "desc" ? "desc" : "asc"
end
end
When I change the first line in fetch_orders to this
orders = Order.in_process.order("#{sort_column} #{sort_direction}")
which is the hard-coded equivalent, it does work. So I just need the correct syntax
Short answer: If you've got an array, and want to sort it, use the sort_by method:
orders = orders_list.sort_by{|order| "#{order.sort_column} #{order.sort_direction}"}
Long answer: The reason your original code doesn't work is that in this case
Order.in_process.order("#{sort_column} #{sort_direction}")
you are building a query. in_process is a named scope (passing in some conditions), and .order tells rails what to order the query by. Then, when it runs out of chained methods, the query executes (runs some sql) and gets the records out of the DB to build a collection of objects.
Once you are working with a collection of objects, you can't call the .order method on it, as that's just used to assemble an sql query. You need to use Array#sort_by instead. sort_by takes a code block, into which is passed each object in the collection (as order in my example but you could call it anything, it's just a variable name).
BTW, if you just want to call a method on all the objects to sort them, you can use a "shortcut syntax" like .sort_by(&:methodname). This uses a little trick of ruby called Symbol#to_proc (http://railscasts.com/episodes/6-shortcut-blocks-with-symbol-to-proc).
So, for example, if there was a method in Order like so
def sort_string
"#{self.sort_column} #{self.sort_direction}"
end
then you could change your code to
orders = orders_list.sort_by(&:sort_string)
which is neat.
If you have an array, then you can sort like this.
orders = orders_list.sort! {|a,b| a.sort_column <=> b.sort_direction}
What I'm trying to do: I have a model "Recipe" in which I defined a method "search" that takes an array of strings from checkboxes (I call them tags), and a single string. The idea is to search the db for recipes that has anything in it's 'name' or 'instructions' that contains the string, AND also has any of the tags matching it's 'tags' property.
Problem: The search method return all the recipes in my db, and doesn't seem to work at all at finding by the specific parameters.
The action method in the controller:
def index
#recipes = Recipe.search(params[:search], params[:tag])
if !#recipes
#recipes = Recipe.all
end
respond_to do |format|
format.html
format.json { render json: #recipe }
end
end
The search method in my model:
def self.search(search, tags)
conditions = ""
search.present? do
# Condition 1: recipe.name OR instruction same as search?
conditions = "name LIKE ? OR instructions LIKE ?, '%#{search[0].strip}%', '%#{search[0].strip}%'"
# Condition 2: if tags included, any matching?
if !tags.empty?
tags.each do |tag|
conditions += "'AND tags LIKE ?', '%#{tag}%'"
end
end
end
# Hämtar och returnerar alla recipes där codition 1 och/eller 2 stämmer.
Recipe.find(:all, :conditions => [conditions]) unless conditions.length < 1
end
Any ideas why it return all records?
if you are using rails 3, then it is easy to chain find conditions
def self.search(string, tags)
klass = scoped
if string.present?
klass = klass.where('name LIKE ? OR instructions LIKE ?', "%#{string}%", "%#{string}%")
end
if tags.present?
tags.each do |tag|
klass = klass.where('tags LIKE ?', "%#{tag}%")
end
end
klass
end
When you do
search.present? do
...
end
The contents of that block are ignored - it's perfectly legal to pass a block to a function that doesn't expect one, however the block won't get called unless the functions decides to. As a result, none of your condition building code is executed. You probably meant
if search.present?
...
end
As jvnill points out, it is in general much nicer (and safer) to manipulate scopes than to build up SQL fragments by hand
I have done this in Rails 2.3.10 and 3.0.3 and it works
def self.find(*args)
records = super
# Manipulate Records here.
end
I am looking for a base finder function in Rails 3 which I can replace for this functionality to be applied to Post.all, Post.first, Post.last etc.
My advice ... make a scope or a class method to do this instead:
e.g.
scope :my_scope, lambda {|...| ...}
then to apply
TheClass.my_scope.all
TheClass.my_scope.first
TheClass.my_scope.last
all, first, and last are all just wrappers for find so redefining find should affect all of those. Take a look at how they're implemented in ActiveRecord::FinderMethods.
I believe you are looking for this:
# File activerecord/lib/active_record/relation/finder_methods.rb, line 95
def find(*args)
return to_a.find { |*block_args| yield(*block_args) } if block_given?
options = args.extract_options!
if options.present?
apply_finder_options(options).find(*args)
else
case args.first
when :first, :last, :all
send(args.first)
else
find_with_ids(*args)
end
end
end
This will do what the original question was asking.
def self.find_by_sql(*args)
records = super
# Manipulate Records here
return records
end