h1. hydra-batch-edit

Batch Editing Functionality for Hydra Heads

*This is Alpha Software!*  While working on a specific Hydra Head with specific content & use cases, we added batch editing functionality.  We wrote the code as a separate gem so that others can use this as a starting point, but _you will have to modify the code_ to get this to work.  If other Hydra partners start using the gem, it will become more immediately useful & configurable out of the box.  At that point, someone will delete this message.

As far as we can tell, the code is sufficiently "test-coveraged" and html/javascript is "fall-backable".

The initial code for this gem was written by "MediaShelf":http://yourmediashelf.com on behalf of Northwestern University.  It is used in the NWU Digital Image Library (DIL) Hydra Head.  As with all Hydra code, this software is distributed under the "Apache 2 License":http://www.apache.org/licenses/LICENSE-2.0.

h2. Features

The main thrust of the re-usable functionality this gem aims to provide:

# Jackie User constructs a batch of objects from Blacklight/Hydra search results
# When Jackie has selected everything for the batch, she clicks a button to proceed to the next step
# (Might want to have a sanity check page here where Jackie sees all of the objects she has selected.  We skipped that step for now.)
# Before displaying the next step, a before_filter in the controller makes sure Jackie has edit permissions for each of the objects, filtering out the non-editable content and notifying Jackie that they've been removed from her batch
# Jackie sees a form for specifying what changes to apply to the batch
# Jackie submits her changes and they are applied to each of the objects in the batch
# Before applying the submitted updates, the before_filter in the controller checks (again) that Jackie has edit permissions for everything in the batch
# The BatchUpdatesController#update method applies Jackie's changes to each of the objects in the batch

*Note* As of version 1.0.0 The batches are tracke using the batches behavior in hydra-collections.  They are not persisted between page changes and only exist on the current page.

*Note* Version 0.3.1 and previous The batches are tracked as a list of pids _in the user session_.  They are not persisted.

h2. Installing

In your Gemfile, add

<pre>gem 'hydra-batch-edit'</pre> 

# Call batch_edit_tools view helper in your search result page template.  We recommend putting it in catalog/_sort_and_per_page.html.erb
# Call batch_edit_continue in the search result page template.  We put it in catalog/index.html
# Call batch_edit_select(document) [passing in the solr document] on the index partial that's rendered for each search result
# Add routes to config/routes.rb 
<pre>
  Hydra::BatchEdit.add_routes(self)
</pre>
# Add javascript to app/assets/javascripts/application.js
<pre>
  //= require batch_edit
</pre>
# Add css to app/assets/stylesheets/application.css
<pre>
  *= require batch_edit
</pre>
  



h2. Dependencies

hydra-head
hydra-collections
bootstrap
blacklight.js
coffeescript & scss

  
h2. Customizing

*This is Alpha Software* These instructions assume that you know how to work with rails and are familiar with Hydra

h3. What you will need to do

You will *definitely* need to override the edit form.
You will probably need to override BatchEditController#update 
You might need to override BatchEditController#edit

h3. Extend Hydra::BatchEditController update and/or edit methods

Example app/controllers/batch_updates_controller.rb

<pre>
  class BatchEditController < ApplicationController
    include Hydra::BatchEditBehavior
    def update
      batch.each do |doc_id|
        obj = ActiveFedora::Base.find(doc_id, :cast=>true)
        type = obj.class.to_s.underscore.to_sym
        obj.update_attributes(params[type])
        obj.do_something_special
        obj.save
      end
      flash[:notice] = "Batch update complete"
      clear_batch!
      redirect_to catalog_index_path
    end
  end
</pre>

h3. Override Edit View

Example app/views/batch_edit/edit.html.erb

<pre>
  <%= form_for MyModel.new, :url=>batch_edit_path, :method=>:put do |f| %>

    <%= f.label :title, "Title:"  %>
    <%= f.text_field :title %>

    <%= f.label :description, "Description:"  %>
    <%= f.text_field :description %>

    <%= f.label :license, "License:"  %>
    <%= f.text_field :license %>
    
    <%= f.label :access_policy, "Access Policy:"  %>
    <%= f.select :access_policy, ... %>

    <%# note the class submits-batches causes the batch ids to be returned with the updates %>
    <%= f.submit "Save changes", :class=>'submits-batches btn btn-primary'%>

  <% end %>
</pre>