Effective DataTables

Use a high level DSL and just one ruby file to create a Datatables jQuery table for any ActiveRecord class or Array.

Powerful server-side searching, sorting and filtering of ActiveRecord classes, with belongs_to and has_many relationships.

Does the right thing with searching sql columns as well as computed values from both ActiveRecord and Array collections.

Displays links to associated edit/show/destroy actions based on current_user authorized actions.

Other features include aggregate (total/average) footer rows, bulk actions, show/hide columns, responsive collapsing columns and Google charts.

This gem includes the jQuery DataTables assets.

Works with postgres, mysql, sqlite3 and arrays.

effective_datatables 4.0

This is the 4.0 series of effective_datatables.

This requires Twitter Bootstrap 4 and Rails 5.1+

Please check out Effective Datatables 3.x for more information using this gem with Bootstrap 3.

Getting Started

gem 'haml-rails'            # or try using gem 'hamlit-rails'
gem 'effective_datatables'

Run the bundle command to install it:

bundle install

Install the configuration file:

rails generate effective_datatables:install

The generator will install an initializer which describes all configuration options.

Make sure you have Twitter Bootstrap 4 installed.

Require the javascript on the asset pipeline by adding the following to your application.js:

//= require effective_datatables

Require the stylesheet on the asset pipeline by adding the following to your application.css:

*= require effective_datatables

Quick Start

All logic for the table exists in its own model file. Once that's built, we initialize in the controller, render in the view.

The Model

Start by creating a new datatable.

This model exists at /app/datatables/posts_datatable.rb:

class PostsDatatable < Effective::Datatable
  datatable do
    col :created_at
    col :title
    col :user      # Post belongs_to :user
    col :comments  # Post has_many :comments

    actions_col
  end

  collection do
    Post.all
  end
end

The Controller

We're going to display this DataTable on the posts#index action.

class PostsController < ApplicationController
  def index
    @datatable = PostsDatatable.new(self)
  end
end

The View

Here we just render the datatable:

<h1>All Posts</h1>
<%= render_datatable(@datatable) %>

Usage

Once your controller and view are set up to render a datatable, the model is the central point to configure all behaviour.

Here is an advanced example:

The Model

This model exists at /app/datatables/posts_datatable.rb:

class PostsDatatable < Effective::Datatable

  # The collection block is the only required section in a datatable
  # It has access to the attributes and filters Hashes, representing the current state
  # It must return an ActiveRecord::Relation or an Array of Arrays
  collection do
    scope = Post.all.joins(:user).where(created_at: filters[:start_date]...filters[:end_date])
    scope = scope.where(user_id: attributes[:user_id]) if attributes[:user_id]
    scope
  end

  # Everything in the filters block ends up in a single form
  # The form is submitted by datatables javascript as an AJAX post
  filters do
    # Scopes are rendered as a single radio button form field (works well with effective_form_inputs gem)
    # The scopes only work when your collection is an ActiveRecord class, and they must exist on the model
    # The current scope is automatically applied by effective_datatables to your collection
    # You don't have to consider the current scope when writing your collection block
    scope :all, default: true
    scope :approved
    scope :draft
    scope :for_user, (attributes[:user_id] ? User.find(attributes[:user_id]) : current_user)

    # Each filter has a name and a default value and the default can be nil
    # Each filter is displayed on the front end form as a single field
    # The filters are NOT automatically applied to your collection
    # You are responsible for considering filters in your collection block
    filter :start_date, Time.zone.now-3.months, required: true
    filter :end_date, Time.zone.now.end_of_day
  end

  # These are displayed as a dropdown menu next to the datatables built-in buttons.
  bulk_actions do
    # bulk_action is just passthrough to link_to(), but the action of POST is forced
    # POSTs to the given url with params[:ids], an Array of ids for all selected rows
    # These actions are assumed to change the underlying collection
    bulk_action 'Approve all', bulk_approve_posts_path, data: { confirm: 'Approve all selected posts?' }
    bulk_action_divider
    bulk_action 'Destroy all', bulk_destroy_posts_path, data: { confirm: 'Destroy all selected posts?' }
  end

  # Google Charts
  # https://developers.google.com/chart/interactive/docs/quick_start
  # effective_datatables does all the javascript boilerplate. Just return an Array of Arrays.
  # Charts are updated whenever the current filters and search change
  charts do
    chart :posts_per_day, 'LineChart', label: 'Posts per Day', legend: false do |collection|
      collection.group_by { |post| post.created_at.beginning_of_day }.map do |date, posts|
        [date.strftime('%F'), posts.length]
      end
    end
  end

  # Datatables
  # https://datatables.net/
  # Each column header has a form field controlled by the search: { as: :string } option
  # The user's selected filters, search, sort, length, column visibility and pagination settings are saved between visits
  # on a per-table basis and can be Reset with a button
  datatable do
    length 25  # 5, 10, 25, 50, 100, 500, :all
    order :updated_at, :desc

    # Renders a column of checkboxes to select items for any bulk_actions
    bulk_actions_col

    col :id, visible: false
    col :updated_at, visible: false

    col :created_at, label: 'Created' do |post|
      time_ago_in_words(post.created_at)
    end

    # This is a belongs_to column
    # effective_datatables will try to put in an edit or show link, depending on the current_user's authorization
    # It will also initialize the search field with PostCategory.all
    col :post_category, action: :edit

    if attributes[:user_id].nil?  # Show all users, otherwise this table is meant for one user only
      col :user, search: { collection: User.authors }

      col 'user.first_name'  # Using the joined syntax
    end

    if can?(:index, Comment)
      col :comments
    end

    col :category, search: { collection: Post::CATEGORY } do |survey|
      Post::CATEGORY.invert[post.category]
    end

    # This is a computed method, not an attribute on the post database table.
    # The first block takes the object from the collection do ... end block and does some work on it.
    # It computes some value. A val.
    # The first block returns a Float/Integer.  All sorting/ordering is then performed on this number.
    # The second block formats the number and returns a String
    val :approval_rating do |post|
      post.approvals.sum { |a| a.rating }
    end.format do |rating|
      number_to_percentage(rating, precision: 2)
    end

    # In a col there is only one block, the format block.
    # A col takes the value as per the collection do ... end block and just formats it
    # All sorting/ordering is performed as per the original value.
    col :approved do |post|
      if post.approved?
        content_tag(:span, 'Approved', 'badge badge-approved')
      else
        content_tag(:span, 'Draft', 'badge badge-draft')
      end
    end

    # Will add a Total row to the table's tfoot
    # :average is also supported, or you can do a custom block
    aggregate :total

    # Uses effective_resources gem to discover the resource path and authorization actions
    # Puts in icons to show/edit/destroy actions, if authorized to those actions.
    # Use the actions_col block to add additional actions
    actions_col show: false do |post|
      if !post.approved? && can?(:approve, Post)
        link_to 'Approve', approve_post_path(post) data: { method: :post, confirm: 'Really approve?'}
      end
    end
  end

end

The Controller

Any options used to initialize a datatable become the attributes. Use these to configure datatables behavior.

In the above example, when attributes[:user_id] is present, the table displays information for just that user.

class PostsController < ApplicationController
  def index
    @datatable = PostsDatatable.new(self, user_id: current_user.id)
  end
end

The View

Render the datatable with its filters and charts, all together:

<h1>All Posts</h1>
<%= render_datatable(@datatable) %>

or, the datatable, filter and charts may be rendered individually:

<h1>All Posts</h1>
<p>
  <%= render_datatable_filters(@datatable) %>
</p>

<p>
  <%= render_datatable_charts(@datatable) %>
</p>

<p>
<%= render_datatable(@datatable, charts: false, filters: false) %>
</p>

or, to render a simple table, (without filters, charts, pagination, sorting, searching, export buttons, per page, or default visibility):

<%= render_datatable(@datatable, simple: true) %>

DSL

The effective_datatables DSL is made up of 5 sections: collection, datatable, filters bulk_actions, charts

As well, a datatable can be initialized with attributes.

attributes

When initialized with a Hash, that hash is available throughout the entire datatable as attributes.

You can call the attributes from within the datatable as attributes or within a partial/view as @datatable.attributes.

These attributes are serialized and stored in an encrypted cookie. Objects won't work. Keep it simple.

Attributes cannot be changed by search, filter, or state in any way. They're guaranteed to be the same as when first initialized.

class PostsController < ApplicationController
  def index
    @datatable = PostsDatatable.new(self, user_id: current_user.id, admin: true)
  end
end

Use attributes to restrict the collection scope, exclude columns or otherwise tweak the table.

An example of using attributes[:user_id] to make a user specific posts table is above.

Here we do something similar with attributes[:admin]:

class PostsDatatable < Effective::Datatable
  collection do
    attributes[:admin] ? Post.all : Post.where(draft: false)
  end

  datatable do
    col :title

    if attributes[:admin]
      col :user
    end

    col :post_category
    col :comments
  end
end

collection

The collection do ... end block must return an ActiveRecord relation or an Array of Arrays.

collection do
  Post.all
end

or

collection do
  scope = Post.includes(:user).where(created_at: filters[:start_date]...filters[:end_date])
  scope = scope.where(user_id: attributes[:user_id]) if attributes[:user_id]
  scope
end

or

collection do
  [
    ['June', 'Huang', '[email protected]'],
    ['Leo', 'Stubbs', '[email protected]'],
    ['Quincy', 'Pompey', '[email protected]'],
    ['Annie', 'Wojcik', '[email protected]'],
  ]
end

or

collection do
  time_entries = TimeEntry.where(date: filter[:start_date].beginning_of_year...filter[:end_date].end_of_year)
    .group_by { |time_entry| "#{time_entry.client_id}_#{time_entry.created_at.strftime('%b').downcase}" }

  Client.all.map do |client|
    [client] + [:jan, :feb, :mar, :apr, :may, :jun, :jul, :aug, :sep, :oct, :nov, :dec].map do |month|
      entries = time_entries["#{client.id}_#{month}"] || []

      calc = TimeEntryCalculator.new(entries)

      [calc.duration, calc.bill_duration, calc.overtime, calc.revenue, calc.cost, calc.net]
    end
  end
end

The collection block is responsible for applying any attribute and filters logic.

When an ActiveRecord collection, the current_scope, will be applied automatically by effective_datatables.

All searching and ordering is also done by effective_datatables.

Your collection method should not contain a .order(), or implement search in any way.

Sometimes it's handy to call .reorder(nil) on a scope.

datatable

The datatable do ... end block configures a table of data.

Initialize the datatable in your controller or view, @datatable = PostsDatatable.new(self), and render it in your view <%= render_datatable(@datatable) %>

col

This is the main DSL method that you will interact with.

col defines a 1:1 mapping between the underlying SQL database table column or Array index to a frontend jQuery Datatables table column. It creates a column.

Each column's search and sorting is performed on its underlying value, as per the collection.

It accepts one optional block used to format the value after any search or sorting is done.

The following options are available:

action: :show|:edit|false  # :resource and relation columns only. generate links to this action. edit -> show by default
as: :string|:integer|etc   # Sets the type of column initializing defaults for search, sort and format
col_class: 'col-green'     # Sets the html class to use on this column's td and th
label: 'My label'          # The label for this column
partial: 'posts/category'  # Render this column with a partial. The local will be named resource
partial_as: 'category'     # The name of the object's local variable, otherwise resource
responsive: 10000          # Controls how columns collapse https://datatables.net/reference/option/columns.responsivePriority

# Configure the search behavior. Autodetects by default.
search: false
search: :string
search: { as: :string, fuzzy: true }
search: { as: :select, collection: User.all, multiple: true }

sort: true|false           # Should this column be orderable. true by default
sql_column: 'posts.rating' # The sql column to search/sort on. Only needed when doing custom selects or tricky joins.
visible: true|false        # Show/Hide this column by default

The :as setting determines a column's search, sort and format behaviour.

It is auto-detected from an ActiveRecord collection's SQL datatype, and set to :string for any Array-based collections.

Valid options for :as are as follows:

:boolean, :currency, :datetime, :date, :decimal, :duration, :email, :float, :integer, :percentage, :price, :resource, :string, :text

These settings are loosely based on the regular datatypes, with some custom effective types thrown in:

• :currency expects the underlying datatype to be a Float.
• :duration expects the underlying datatype to be an Integer representing the number of minutes. 120 == 2 hours
• :email expects the underlying datatype to be a String
• :percentage expects the underlying datatype to be an Integer or a Float. 75 == 0.75 == 75%
• :price expects the underlying datatype to be an Integer representing the number of cents. 5000 == $50.00
• :resource can be used for an Array based collection which includes an ActiveRecord object

The column will be formatted as per its as: setting, unless a custom format block is present:

col :approved do |post|
  if post.approved?
    content_tag(:span, 'Approved', 'badge badge-approved')
  else
    content_tag(:span, 'Draft', 'badge badge-draft')
  end
end

You can also set custom search and sort on a per-column basis. See Advanced Search and Sort below.

If the column name matches a belongs_to, has_many or other association on your collection class, like col :user, the column will be created as a resource column.

A resource column will try to link to the show/edit/destroy actions of its objects, based on permissions and routes. You can alter this behaviour with the action: variable.

You can also use the joined syntax, col 'user.email' to create a column for just this one field.

This feature is only working with belongs_to and you need to add the .joins(:user) to the collection do ... end block yourself.

val

Shorthand for value, this command also creates a column on the datatable.

It accepts all the same options as col with the additional requirement of a "compute" block.

val :approval_rating do |post|
  post.approvals.sum { |a| a.rating }
end.format do |rating|
  number_to_percentage(rating, precision: 2)
end

So, val yields the object from the collection to the first/compute block, and stores the result.

All searching and sorting for this column will be performed on this computed value.

This is implemented as a full Array search/sort and is much slower for large datasets than a paginated SQL query

The .format do ... end block can then be used to apply custom formatting.

bulk_actions_col

Creates a column of checkboxes for use with the bulk_actions section.

Each input checkbox has a value equal to its row object.to_param and gets submitted as an Array of ids, params[:ids]

Use these checkboxes to select all / none / one or more rows for the bulk_actions do ... end section (below).

You can only have one bulk_actions_col per datatable.

actions_col

When working with an ActiveRecord based collection, this column will consider the current_user's authorization, and generate glyphicon links to edit, show and destroy actions for any collection class.

The authorization method is configured via the config/initializers/effective_datatables.rb initializer file.

There are just a few options:

show: true|false|:authorize
edit: true|false|:authorize
destroy: true|false|:authorize

visible: true|false

When the show, edit and destroy actions are true (default), the permission check will be made just once, authorizing the class. When set to :authorize, permission to each individual object will be checked.

Use the block syntax to add additional actions

actions_col show: false do |post|
  (post.approved? ? link_to('Approve', approve_post_path(post)) : '') +
  glyphicon_to('print', print_ticket_path(ticket), title: 'Print')
end

The glyphicon_to helper is part of the effective_resources gem, which is a dependency of this gem.

length

Sets the default number of rows per page. Valid lengths are 5, 10, 25, 50, 100, 250, 500, :all

When not specified, effective_datatables uses the default as per the config/initializers/effective_datatables.rb or 25.

length 100

order

Sets the default order of table rows. The first argument is the column, the second the direction.

The column must exist as a col or val and the direction is either :asc or :desc.

When not specified, effective_datatables will sort by the first defined column.

order :created_at, :asc|:desc

aggregate

The aggregate command inserts a row in the table's tfoot.

The only option available is :label.

You can only have one aggregate per datatable. (Unfortunately, this is a limit of the jQuery Datatables)

There is built in support for automatic :total and :average aggregates:

aggregate :total|:average

or write your own:

aggregate :average_as_percentage do |values, column|
  if column[:name] == :first_name
    'Average'
  elsif values.present?
    average = values.map { |value| value.presence || 0 }.sum / [values.length, 1].max
    content_tag(:span, number_to_percentage(average, precision: 1))
  end
end

You can also override an individual columns aggregate calculation as follows:

col :created_at, label: 'Created' do |post|
  time_ago_in_words(post.created_at)
end.aggregate { |values, column| distance_of_time_in_words(values.min, values.max) }

In the above example, values is an Array containing all row's values for one column at a time.

filters

Creates a single form with fields for each filter and a single radio input field for all scopes.

The form is submitted by an AJAX POST action, or, in some advanced circumstances (see Dynamic Columns below) as a regular POST or even GET.

Initialize the datatable in your controller or view, @datatable = PostsDatatable.new(self), and render its filters anywhere with <%= render_datatable_filters(@datatable) %>.

scope

All defined scopes are rendered as a single radio button form field. Works great with the effective_form_inputs gem.

Only supported for ActiveRecord based collections. They must exist as regular scopes on the model.

The currently selected scope will be automatically applied. You shouldn't consider it in your collection block.

filters do
  scope :approved
  scope :for_user, current_user
end

Must match the scopes in your app/models/post.rb:

class Post < ApplicationRecord | ActiveRecord::Base
  scope :approved, -> { where(draft: false) }
  scope :for_user, Proc.new { |user| where(user: user) }
end

filter

Each filter has a name and a default/fallback value. If the form is submitted blank, the default values are used.

effective_datatables looks at the default value, and tries to cast the incoming (String) value into that datatype.

This ensures that calling filters[:name] always return a value. The default can be nil.

You can override the parsing on a per-filter basis.

Unlike scopes, the filters are NOT automatically applied to your collection. You are responsible for considering filters in your collection block.

filters do
  filter :start_date, Time.zone.now-3.months, required: true
  filter :end_date, nil, parse: -> { |term| Time.zone.local(term).end_of_day }
  filter :user, current_user, as: :select, collection: User.all
  filter :year, 2018, as: :select, collection: [2018, 2017], label: false, include_blank: false
  filter :reports, '2018', as: :grouped_select, collection: [['Years', [['2017', '2017'], ['2018', '2018']]], ['Months', [['January', '1'], ['February', '2']]]], group_method: :last
end

and apply these to your collection do ... end block by calling filters[:start_date]:

collection do
  scope = Post.includes(:post_category, :user).where('created_at > ?', filters[:start_date])

  if filters[:end_date].present?
    scope = scope.where('created_at < ?', filters[:end_date])
  end

  scope
end

The filter command has the following options:

as: :select|:date|:boolean      # Passed to SimpleForm
label: 'My label'               # Label for this form field
parse: -> { |term| term.to_i }  # Parse the incoming term (string) into whatever datatype
required: true|false            # Passed to SimpleForm

Any other option given will be yielded to SimpleForm as input_html options.

bulk_actions

Creates a single dropdown menu with a link to each action, download or content.

Along with this section, you must put a bulk_actions_col somewhere in your datatable do ... end section.

bulk_action

Creates a link that becomes clickable when one or more checkbox/rows are selected as per the bulk_actions_col column.

A controller action must be created to accept a POST with an array of selected ids, params[:ids].

This is a pass-through to link_to and accepts all the same options, except that the method POST is used by default.

You can also specify data-method: :get to instead make a GET request with the selected ids and redirect the browser link a normal link.

bulk_actions do
  bulk_action 'Approve all', bulk_approve_posts_path, data: { confirm: 'Approve all selected posts?' }
end

In your routes file:

resources :posts do
  collection do
    post :bulk_approve
  end
end

In your PostsController:

def bulk_approve
  @posts = Post.where(id: params[:ids])

  # You should probably write this inside a transaction.  This is just an example.
  begin
    @posts.each { |post| post.approve! }
    render json: { status: 200, message: "Successfully approved #{@posts.length} posts." }
  rescue => e
    render json: { status: 500, message: 'An error occured while approving a post.' }
  end
end

or if using effective_resources:

include Effective::CrudController

collection_action :bulk_approve

and in your model

def approve!
  update_attributes!(status: :approved)
end

bulk_action_divider

Inserts a menu divider <li class='divider' role='separator'></li>

bulk_download

So it turns out there are some http issues with using an AJAX action to download a file.

A workaround for these issues is included via the jQuery File Download Plugin

The use case for this feature is to download a csv report generated for the selected rows.

bulk_actions do
  bulk_download 'Export Report', bulk_export_report_path
end

def bulk_export_report
  authorize! :export, Post

  @posts = Post.where(id: params[:ids])

  Post.transaction do
    begin
      cookies[:fileDownload] = true

      send_data(PostsExporter.new(@posts).export,
        type: 'text/csv; charset=utf-8; header=present',
        filename: 'posts-export.csv'
      )

      @posts.update_all(exported_at: Time.zone.now)
      return
    rescue => e
      cookies.delete(:fileDownload)
      raise ActiveRecord::Rollback
    end
  end

  render json: { error: 'An error occurred' }
end

bulk_action_content

Blindly inserts content into the dropdown.

bulk_actions do
  bulk_action_content do
    content_tag(:li, 'Something')
  end
end

Don't actually use this.

charts

Create a Google Chart based on your searched collection, filters and attributes.

No javascript required. Just use the chart do ... end block and return an Array of Arrays.

charts do
  chart :breakfast, 'BarChart' do |collection|
    [
      ['Bacon', 10],
      ['Eggs', 20],
      ['Toast', 30]
    ]
  end

  chart :posts_per_day, 'LineChart', label: 'Posts per Day', legend: false do |collection|
    collection.group_by { |post| post.created_at.beginning_of_day }.map do |date, posts|
      [date.strftime('%F'), posts.length]
    end
  end
end

And then render each chart in your view:

<%= render_datatable_chart(@datatable, :breakfast) %>
<%= render_datatable_chart(@datatable, :posts_per_day) %>

or all together

<%= render_datatable_charts(@datatable) %>

All options passed to chart are used to initialize the chart javascript.

By default, the only package that is loaded is corechart, see the config/initializers/effective_datatables.rb file to add more packages.

Extras

The following commands don't quite fit into the DSL, but are present nonetheless.

simple

To render a simple table, without pagination, sorting, filtering, export buttons, per page, and default visibility:

<%= render_datatable(@datatable, simple: true) %>

index

If you just want to render a datatable and nothing else, there is a quick way to skip creating a view:

class PostsController < ApplicationController
  def index
    render_datatable_index PostsDatatable.new(self)
  end
end

will render views/effective/datatables/index with the assigned datatable.

Advanced Search and Sort

The built-in search and ordering can be overridden on a per-column basis.

The only gotcha here is that you must be aware of the type of collection.

With ActiveRecord collection

In the case of a col and an ActiveRecord collection:

collection do
  Post.all
end

datatable do
  col :post_category do |post|
    content_tag(:span, post.post_category, "badge-#{post.post_category}")
  end.search do |collection, term, column, sql_column|
    # collection is an ActiveRecord scoped collection
    # term is the incoming PostCategory ID as per the search
    # column is this column's options Hash
    # sql_column is the column[:sql_column]
    categories = current_user.post_categories.where(id: term.to_i)

    collection.where(post_category_id: categories)  # Must return an ActiveRecord scope
  end.sort do |collection, direction, column, sql_column|
    collection.joins(:post_category).order(:post_category => :title, direction)
  end
end

If you run into issues where collection here is an Array, you're probably using some joins in your collection do ... end block.

If column[:sql_column].blank? then this col has fallen back to being a val.

Try adding col :post_category, sql_column: 'post_categories.title'

With Array collection

And in the case of a col with an Array collection, or any val:

collection do
  Client.all.map do |client|
    [client, client.first_name client.last_name, client.purchased_time()]
  end
end

datatable do
  col :client
  col :first_name
  col :last_name

  col :purchased_time do |duration|
    number_to_duration(duration)
  end.search do |collection, term, column, index|
    # collection is an Array of Arrays
    # term is the incoming value as per the search. "3h30m"
    # column is the column's attributes Hash
    # index is this column's index in the collection
    (hours, minutes) = term.to_s.gsub(/[^0-9|h]/, '').split.map(&:to_i)
    duration = (hours.to_i * 60) + minutes.to_i

    collection.select! { |row| row[index] == duration }  # Must return an Array of Arrays
  end.sort do |collection, term, column, index|
    collection.sort! do |x, y|
      x[index] <=> y[index]
    end
  end
end

The search and sort for each column will be merged together to form the final results.

Default search collection

When using a col :comments type belongs_to or has_many column, a search collection for that class will be loaded.

Add the following to your related model to customize the search collection:

class Comment < ApplicationRecord
  scope :datatables_filter, -> { includes(:user) }
end

Datatables will look for a datatables_filter scope, or sorted scope, or fallback to all.

If there are more than 500 max records, the filter will fallback to a as: :string.

Dynamic Column Count

There are some extra steps to be taken if you want to change the number of columns based on filters.

Unfortunately, the DataTables jQuery doesn't support changing columns, so submitting filters needs to be done via POST instead of AJAX.

The following example displays a client column, and one column per month for each month in a date range:

class TimeEntriesPerClientReport < Effective::Datatable

  filters do
    # This instructs the filters form to use a POST, if available, or GET instead of AJAX
    # It posts to the current controller/action, and there are no needed changes in your controller
    changes_columns_count

    filter :start_date, (Time.zone.now - 6.months).beginning_of_month, required: true, label: 'For the month of: ', as: :effective_date_picker
    filter :end_date, Time.zone.now.end_of_month, required: true, label: 'upto and including the whole month of', as: :effective_date_picker
  end

  datatable do
    length :all

    col :client

    selected_months.each do |month|
      col month.strftime('%b %Y'), as: :duration
    end

    actions_col
  end

  collection do
    time_entries = TimeEntry.where(date: filter[:start_date].beginning_of_month...filter[:end_date].end_of_month)
      .group_by { |time_entry| "#{time_entry.client_id}_#{time_entry.created_at.strftime('%b')}" }

    Client.all.map do |client|
      [client] + selected_months.map do |month|
        entries = time_entries["#{client.id}_#{month.strftime('%b')}"] || []

        entries.map { |entry| entry.duration }.sum
      end
    end
  end

  # Returns an array of 2016-Jan-01, 2016-Feb-01 datetimes
  def selected_months
    @selected_months ||= [].tap do |months|
      each_month_between(filter[:start_date].beginning_of_month, filter[:end_date].end_of_month) { |month| months << month }
    end
  end

  # Call with each_month_between(start_date, end_date) { |date| puts date }
  def each_month_between(start_date, end_date, &block)
    while start_date <= end_date
      block.call(start_date)
      start_date = start_date + 1.month
    end
  end
end

Additional Functionality

There are a few other ways to customize the behaviour of effective_datatables

Checking for Empty collection

Check whether the datatable has records by calling @datatable.present? and @datatable.blank?.

Override javascript options

The javascript options used to initialize a datatable can be overriden as follows:

render_datatable(@datatable, input_js: { dom: "<'row'<'col-sm-12'tr>>", autoWidth: true })

render_datatable(@datatable, input_js: { buttons_export_columns: ':visible:not(.col-actions)' })

Please see datatables options for a list of initialization options.

You don't want to actually do this!

Get access to the raw results

After all the searching, sorting and rendering of final results is complete, the server sends back an Array of Arrays to the front end jQuery DataTable

The finalize method provides a hook to process the final collection as an Array of Arrays just before it is convered to JSON.

This final collection is available after searching, sorting and pagination.

As you have full control over the table_column presentation, I can't think of any reason you would actually need or want this:

def finalize(collection)
  collection.each do |row|
    row.each do |column|
      column.gsub!('horse', 'force') if column.kind_of?(String)
    end
  end
end

Authorization

All authorization checks are handled via the config.authorization_method found in the config/initializers/effective_datatables.rb file.

It is intended for flow through to CanCan or Pundit, but neither of those gems are required.

This method is called by the controller action with the appropriate action and resource

Action will be :index

The resource will be the collection base class, such as Post. This can be overridden:

def collection_class
  NotPost
end

The authorization method is defined in the initializer file:

# As a Proc (with CanCan)
config.authorization_method = Proc.new { |controller, action, resource| authorize!(action, resource) }

# As a Custom Method
config.authorization_method = :my_authorization_method

and then in your application_controller.rb:

def my_authorization_method(action, resource)
  current_user.is?(:admin) || EffectivePunditPolicy.new(current_user, resource).send('#{action}?')
end

or disabled entirely:

config.authorization_method = false

If the method or proc returns false (user is not authorized) an Effective::AccessDenied exception will be raised

You can rescue from this exception by adding the following to your application_controller.rb:

rescue_from Effective::AccessDenied do |exception|
  respond_to do |format|
    format.html { render 'static_pages/access_denied', :status => 403 }
    format.any { render :text => 'Access Denied', :status => 403 }
  end
end

License

MIT License. Copyright Code and Effect Inc.

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Bonus points for test coverage
6. Create new Pull Request