Rails 4 nested form - nested models not saving - ruby-on-rails-4

Question

I am getting ready to give up on this... I 've searched every question on this, done multiple tests and I can't figure it out.
I am trying to create new records of a model (absences) through nested attributes (classroom -> students).
Here is a hash that I manually created and gets saved when I call
# hash: {"classroom"=>{"rank"=>"aaa", "grade_id"=>"", "students_attributes"=>{"0"=>{"last_name"=>"aaa", "first_name"=>"aaa", "absences_attributes"=>{"0"=>{"class_time"=>"1", "status"=>"valid"}}}}}, "id"=>"26"}
#classroom = Classroom.find(params["id"])
#classroom.update(params["classroom"])
This gives me:
(0.5ms) begin transaction
SQL (1.3ms) UPDATE "classrooms" SET "rank" = ?, "updated_at" = ? WHERE "classrooms"."id" = ? [["rank", "aaa"], ["updated_at", "2016-08-10 21:09:17.883875"], ["id", 26]]
SQL (0.2ms) INSERT INTO "students" ("last_name", "first_name", "classroom_id", "created_at", "updated_at") VALUES (?, ?, ?, ?, ?) [["last_name", "aaa"], ["first_name", "aaa"], ["classroom_id", 26], ["created_at", "2016-08-10 21:09:17.897997"], ["updated_at", "2016-08-10 21:09:17.897997"]]
SQL (0.2ms) INSERT INTO "absences" ("class_time", "status", "student_id", "created_at", "updated_at") VALUES (?, ?, ?, ?, ?) [["class_time", 1], ["status", "Αδικαιολόγητη"], ["student_id", 51], ["created_at", "2016-08-10 21:09:17.902018"], ["updated_at", "2016-08-10 21:09:17.902018"]]
(11.4ms) commit transaction
=> true
HOWEVER
when I get this hash through the form submission the update doesn't happen and no "absences" are getting created. Here is what the console looks like:
Processing by ClassroomsController#update as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"blabla",
"classroom"=>{"students_attributes"=>{"0"=>{"absences_attributes"=>{
"0"=>{"student_id"=>"50", "date"=>"2016/08/17", "class_time"=>"1", "status"=>"valid"},
"1"=>{"student_id"=>"50", "date"=>"2016/08/17", "class_time"=>"2", "status"=>"valid"},
"2"=>{"student_id"=>"50", "date"=>"2016/08/17", "class_time"=>"3", "status"=>"valid"},
"3"=>{"student_id"=>"50", "date"=>"2016/08/17", "class_time"=>"4", "status"=>"valid"},
"4"=>{"student_id"=>"50", "date"=>"2016/08/17", "class_time"=>"5", "status"=>"valid"},
"5"=>{"student_id"=>"50", "date"=>"2016/08/17", "class_time"=>"6", "status"=>"valid"},
"6"=>{"student_id"=>"50", "date"=>"2016/08/17", "class_time"=>"7", "status"=>"valid"}},
"id"=>"50"}}}, "id"=>"27"}
Classroom Load (0.2ms) SELECT "classrooms".* FROM "classrooms" WHERE "classrooms"."id" = ? LIMIT 1 [["id", 27]]
(0.1ms) begin transaction Student Load
(0.3ms) SELECT "students".* FROM "students" WHERE "students"."classroom_id" = ? AND "students"."id" = 50 [["classroom_id", 27]]
(0.1ms) commit transaction
Here is my Classrooms Controller
class ClassroomsController < ApplicationController
def new
#classroom = Classroom.new
#students = 30.times {#classroom.students.build}
end
def create
#classroom = Classroom.new(classroom_params)
if #classroom.save
redirect_to #classroom
else
flash.now[:danger] = "Try again."
render "new"
end
end
def show
#classroom = Classroom.find(params[:id])
end
def data
#classroom = Classroom.find(params[:id])
#classroom.students.each { |student| 7.times { student.absences.build } }
end
def update
#classroom = Classroom.find(params[:id])
#classroom.update_attributes(classroom_params)
redirect_to #classroom
end
private
def classroom_params
params.require(:classroom).permit(:id, :grade_id, :rank, students_attributes:
[:id, :classroom_id, :first_name, :last_name, absences_attributes:
[:id, :student_id, :date, :status, :class_time]])
end
end
Classroom Model
class Classroom < ActiveRecord::Base
# belongs_to :grade
has_many :students, inverse_of: :classroom, dependent: :destroy
accepts_nested_attributes_for :students, allow_destroy: true,
reject_if: proc { |a| [a[:first_name], a[:last_name]].any? {|b| b.blank?}}
has_many :absences, through: :students
accepts_nested_attributes_for :absences, allow_destroy: true,
reject_if: proc { |a| a[:status].blank? }
validates :rank, presence: true
end
Student Model
class Student < ActiveRecord::Base
belongs_to :classroom, inverse_of: :students
has_many :absences, inverse_of: :student
accepts_nested_attributes_for :absences, allow_destroy: true,
reject_if: proc { |a| a[:status].blank? }
# validates :first_name, presence: true
# validates :last_name, presence: true
def full_name
return last_name + " " + first_name
end
end
Absence Model
class Absence < ActiveRecord::Base
belongs_to :student, inverse_of: :absences
# validates :date, presence: true
# validates :class_time, presence: true
# validates :status, presence: true, inclusion: { in: ["valid",
# "invalid", "erased"] }
end
I have turned off all validations as to be sure this is not the reason they are not being saved.
Nested form view
<div id="absences" class="tab-pane fade in active">
<h3>Absences</h3>
<br>
<div class="input-group date col-md-3" id="datepicker">
<input type="text" class="form-control">
<div class="input-group-addon">
<span class="glyphicon glyphicon-th"></span>
</div>
</div>
<%= form_for #classroom do |class_f| %>
<% #classroom.students.each do |student| %>
<div class="student_<%= student.id %>">
<h4><%= student.full_name %></h4>
<div class="absences">
<p>
<% 7.times do |i| %>
<span><%= i + 1 %></span>
<% end %>
</p>
<%= class_f.fields_for :students, student do |student_f| %>
<% student.absences.each_with_index do |absence, i| %>
<div class="school-hour text-center" data-value="<%= i + 1 %>">
<%= fa_icon "plus" %>
<%= fa_stacked_icon "plus", base: "circle-o" %>
<%= fa_icon "minus" %>
<%= student_f.fields_for :absences, absence do |ab_f| %>
<%= ab_f.hidden_field :student_id, value: absence.student_id %>
<%= ab_f.hidden_field :date, class:"input-absence-date" %>
<%= ab_f.hidden_field :class_time, value: i + 1 %>
<%= ab_f.hidden_field :status, class:"input-absence-status" %>
<% end %>
</div>
<% end %>
<% end %>
</div>
</div>
<% end %>
<div class="actions">
<%= button_to "Submit", "#", class:"btn btn-primary"%>
</div>
<% end %>
</div>
The hidden fields without values are getting filled via javascript before form submission. I don't think that relates to the problem though. The params hash comes through, but the absences are not saving.

Answer 1

Without having spent a lot of time looking at this, could this be the problem?
reject_if: proc { |a| a[:status].blank? }
It appears the params are passing in status as "" which .blank? evaluates as true.
Whatever your form is passing in, in your first example you have "status"=>"valid" but in your 2nd example from the form "status"=>""

Answer 2

I found out that the problem was the reject_if on the classroom model.
I was trying to update the absence through the user, I wasn't actually changing the name of the user, and so not passing it as a param. As a result the record didn't pass the reject_if: proc { |a| [a[:first_name], a[:last_name]].any? {|b| b.blank?}} so it didn't reach the absence record at all. I tried putting a :new_record? validation in the reject if along with the other checks, but that didn't work out.
I found the solution in this answer: https://stackoverflow.com/a/13774269/5909738
Awesome and clean. Look at the comments as well.