Develop Reference

How to return a selected value from a database collection in Rails?

So I have a database collection labeled #joe, and I am trying to pass the id variable into a link url path. This is in my index.erb.html file.
<%= select_tag "article", options_from_collection_for_select(#joe, 'id', 'title'),
prompt: "Select Something" %>
In my articles_controller.rb file, I have
def index
#joe = Article.all
end
I made a loop where it grabs each id number and passes it into the article_url path. I was wondering, in the dropdown box that I created above, when I select a certain value, I want to pass that value into the article.id variable. I'm having trouble with this and it outputs x amount of buttons.
<% #joe.each do |article| %>
<%= button_to "SELECT", article_url(article.id), :method => 'get' %>
<% end %>
I was wondering if it is possible to do this or if I can implement JavaScript or jQuery into this. Any help would be appreciated. Thank you!
And here's the rake routes command results:
Prefix Verb URI Pattern Controller#Action
home_index GET /home/index(.:format) home#index
articles GET /articles(.:format) articles#index
POST /articles(.:format) articles#create
new_article GET /articles/new(.:format) articles#new
edit_article GET /articles/:id/edit(.:format) articles#edit
article GET /articles/:id(.:format) articles#show
PATCH /articles/:id(.:format) articles#update
PUT /articles/:id(.:format) articles#update
DELETE /articles/:id(.:format) articles#destroy
root GET / home#index

Let's try this:
ERB
<%= form_tag article_path do %>
<%= select_tag "id", options_from_collection_for_select(#joe, 'id', 'title'), prompt: "Select Something", class: 'select' %>
<%= button_tag 'SELECT', class: 'button' %>
<% end %>
JS
$('.button').on('click', function() {
var path = $('form').attr('action');
var articleId = $('.select').val();
$.get([path, articleId].join('/'));
});

how to make collection_select value as link_to variable

I have the ff:
app/views/reports/index.html.erb
<h1>Reports</h1>
<br>
<legend>Categories</legend>
<div class="row">
<div class="span5">
<ol>
<li><%= link_to 'COMMENDATION', commendations_path(format: 'pdf'), { id: 'commendations_click' } %></li>
<%= collection_select(nil,
:employee_id,
#employees,
:id,
:last_name,
{:prompt => "Select an Employee"},
{:id => 'employees_select'}) %>
<br>
<%= collection_select(nil,
:employee_movement_id,
#employeemovements,
:id,
:position,
{:prompt => "-"},
{:id => 'employee_movements_select'}) %>
<li><%= link_to 'REPORT2', '#' %></li>
<li><%= link_to 'REPORT3', '#' %></li>
</ol>
</div>
</div>
<script type="text/javascript">
$(document).ready(function() {
$('#employees_select').change(function() {
$.ajax({
url: "<%= update_employee_movements_path %>",
data: { employee_id : $('#employees_select').val() },
dataType: "script"
});
});
$('#commendations_click').click(function() {
$.ajax({
url: "<%= commendations_path %>",
data: {
employee_id : $('#employees_select').val(),
employee_movement_id : $('#employee_movements_select').val()
},
dataType: "script"
});
});
});
</script>
app/controllers/reports_controller
class ReportsController < ApplicationController
before_filter :authenticate_user!
# GET /reports
def index
#employees = Employee.all
#employeemovements = EmployeeMovement.distinct_positions
end
def update_employee_movements
if params[:employee_id]
#employeemovements = [].insert(0, "Select Employee Movement")
else
employee = Employee.find(params[:employee_id])
#employeemovements = employee.employee_movements.map{ |a| [a.position, a.id] }.insert(0, "Select Employee Movement")
end
end
def commendations
emdates = EmployeeMovement.last_2_dates_obtained(params[:employee_movement_id])
date_from = emdates[0].date_obtained
date_to = emdates.length == 1 ? nil : emdates[1].date_obtained
emp = Employee.find(params[:employee_id])
#commendations = case date_to.nil?
when true then emp.commendations.this_day_onwards(date_from)
else emp.commendations.within(date_from, date_to)
end
end
end
What I'm trying to do here is, I'm creating a page filled with links and drop down lists that will serve as a Reports center. The idea is, each link will be catered by a controller. Each controller will be responsible in showing my PDF in the browser (through ThinReports, if you're curious).
The #employees_select change event is used for changing the value of the #employee_movements_select collection_select.
Now my problem is, how can i capture the value of both #employees_select and #employee_movements_select and pass them to my commendations action?
I tested link_to by hardcoding values, and it works (code below)
<%= link_to 'COMMENDATION', commendations_path(employee_id: 1, employee_movement_id: 12, format: 'pdf') %>
However, If I use javascript to push the values to my commendations action through the 'click' event, my commendations action will be called twice, thus an error occurs because the params[:employee_id] in the action is now blank.
By the way, I need those values because my commendations action needs it so I can populate my PDF report template.
Please help. Thanks a lot in advance!
UPDATE 1
-> Updated link_to:
<%= link_to 'COMMENDATION', '#', { id: 'commendations_click' } %>
-> Removed dataType: "script" in #commendations_click event handler
-> Updated url: in #commendations_click event handler
url: <%= commendations_path(format: 'pdf') %>
UPDATE 2 (RESOLUTION)
I tweaked my javascript to look something like this:
$('#commendations_click').click(function() {
event.preventdefault();
window.location = "<%=j commendations_path(format: 'pdf') %>" + "?employee_id=" + $('#employees_select').val() + "&employee_movement_id=" + $('#employee_movements_select').val();
});
Works perfect now.

Two things come to mind. You can wrap the two select lists within a form element and just do a submit. Everything inside the form will be submitted to your server and you can process the request and handle the redirect on the server side. The other thing you can do is to handle the commendations click event on the client side using jquery or something. Just bind to the click event of that link, grab the values of the two select lists and do whatever you want with it. Remember, link_to just gets rendered as plain old html links on the view. For e.g.
link_to "Profile", profile_path(#profile) gets rendered as Profile

How to add random button to form

I want to provide users a 'random' option so they can select a previous created date idea to use from the database (inside the letsgos table). There’s a “Let’s Go...” section that users can fill out a form and propose a date they would like to go on. There are going to be users who won’t be able to come up with a date idea on their own. So for those users who cannot create their own date I want to provide a ‘random’ button that with each click will insert a date (that’s from the database) into the form. The dates in the database from the letsgos table have content and tag assign to them. When a user clicks on random it should populate the form with the content and tag (each random click should show new data from the database). I don't have any javascript experience so I am not sure if I am doing it the right way.
/views/letsgos/_form.html.erb:
<%= form_for(#letsgo) do |f| %>
<div class="field">
<%= f.text_area :content, placeholder: "Propose new date..." %>
</div>
<%= f.select :tag, options_for_select( [["Select One", ""], "Eat/Drink", "Listen/Watch", "Play", "Explore", "Other"]) %>
Click here for a Random letsgo
<%= f.submit "Post" %>
<% end %>
/views/layouts/application.html.erb
<head>
<script src="http://code.jquery.com/jquery-2.0.3.min.js"></script>
<script>
$(document).ready(function() {
$('.ajax').click(function() {
$.get(this.href, function(response) {
console.log(response);
$('body').html(response);
});
});
});
<script>
</head>
letsgo controller:
def create
#letsgo = current_user.letsgos.build(letsgo_params)
if #letsgo.save
flash[:success] = "Date posted!"
redirect_to root_url
else
flash[:error] = "Date was not posted!"
redirect_to root_url
end
end
def destroy
#letsgo.destroy
redirect_to root_url
end
def random
#letsgo = Letsgo.random.first
if request.xhr?
end
end
private
def letsgo_params
params.require(:letsgo).permit(:content, :tag)
end
def correct_user
#letsgo = current_user.letsgos.find_by(id: params[:id])
redirect_to root_url if #letsgo.nil?
end
Caching columns migration:
rails g migration add_ids_count
def self.up
add_column :letsgos, :ids_count, :integer, :default => 0
Letsgo.reset_column_information
Letsgo.all.each do |l|
l.update_attribute :id_count, l.id.length
end
end
def self.down
remove_column :letsgos, :id_count
end
end

A creative solution to this would be to set up a caching column to store an array of IDs of Letsgo's, if you're worried about the performance on Antarr Byrd's suggestion. Basically, this would cache the Letsgo.pluck(:id) in a single column in the DB. (Maybe do this in a worker in a post-save and/or post-delete hook on Letsgos.) I'd recommend doing this in a buffer of some sort, or maybe as an hourly task.
You could then either pull this in as a JavaScript array (letsgos_ids_array in the example) and create a Math.random() value based on the length of that array and send it to the .find(). Of course you could also just output the array's length directly.
var item_index = Math.floor(Math.random() * letsgos_ids_array_length);
$.get("/letsgos/random", {
"ind" : item_index
}, function(data){
/* do something with the data */
});
Then, this index can be used to pull out the actual ID value from the array from the db.
letsgoarray = Letsgosarray.first # this is the single-column "cached" array of IDs
item_id = letsgosarray[params[:id_index]]
#random_letsgo = Letsgos.find(item_id)
format.json do {
render json: #random_letsgo
}
Array access is fast, and so is single db column querying.

Here you have some good read about random rows:
http://jan.kneschke.de/projects/mysql/order-by-rand/

I've never done this but you can probably do
def random
Letsgos.find(Letsgo.pluck(:id).sample)
end

Rails 4 / Ruby 2: Local variable (FormBuilder) for partial is lost through dynamic update

I have this form that renders a partial for selecting a person's task.
new.html.slim:
= form_for(#person) do |f|
= f.text_field :name
= f.fields_for :assignment do |a|
= a.collection_select :project_id, Project.order(:name), :id, :name
div id="task_list"
= render 'shared/_task_select', a: a
= f.submit 'Save'
shared/_task_select.html.slim:
= a.collection_select :task_id, #tasks, :id, :name
Changing the project triggers a javascript that runs a "create_tasklist"-method in the PersonsController.
new.js:
$(document).ready(function() {
$('#person_assignment_attributes_project_id').change(function() {
var selection = $('#person_assignment_attributes_project_id').val();
$.ajax({
url: "/create_tasklist",
data: {
project_id : selection
},
dataType: "script"
});
});
});
The "create_tasklist"-method triggers a javascript that updates the partial:
create_tasklist.js.erb:
$("#task_list").html("<%= escape_javascript(render 'shared/task_list', a: a) %>");
Now this raises the error:
undefined local variable or method `a' for #<#<Class:0x42cd770>:0x4213ef0>
The same form works well when editing existing persons - until changing the project. Thus, FormBuilder "a" loses its definition through the javascript actions. I have to use a partial here because I want to do more stuff with it in a later stage. Any ideas how to get that variable to keep its defintion?
Edit 1:
I already tried adding this below the third line of new.html.slim:
javascript:
var a = "#{a}";
and then adding: a: a in the "data" declaration of new.js.
Edit 2:
With this the FormBuilder seems to pass through until the "create_tasklist"-method, but I do not know how to access it properly there. If I declare ´#a = params[:a]´ in the "create_tasklist"-method and then use (in create_tasklist.js.erb):
$("#task_list").html("<%= escape_javascript(render 'shared/task_list', a: #a) %>");
I recieve the error:
undefined method `collection_select' for "#<ActionView::Helpers::FormBuilder:0x4760400>":String
So the FormBuilder has become a string but a least it "got through" somehow. How can I leave it intact and is a more efficent way to achieve this?

How can I send an automatically generated ID for a form element to a javascript function?

I am trying to call a javascript function from my form page in a Rails 3 project. I need to send the function the ID of a particular element. Unfortunately I can't get the ID easily since it is automatically generated by a plugin.
I tried doing it this way:
<%= t.select :number_type, #id_types, {}, {:onchange => "has_other_field(' + the_value.id.to_s + "');"} %>
<% if (!the_value.nil?) && (!the_value.number_type.nil?) && !#id_types_sm.include? the_value.number_type) %>
<script type="text/javascript">
setup_other_field("<%= the_value.number_type %>", ###ID WOULD GO HERE###);
</script>
<% end %>
.. But since I don't know the ID of the element, I can't call it from the function.
So now I'm trying to do it this way, by calling the function from an "onload" when the input element loads:
<% if (!the_value.nil?) && (!the_value.number_type.nil?) && (!#id_types_sm.include? the_value.number_type) %>
<%# Call the function from the form helper only if the conditions are met %>
<%= t.select :number_type, #id_types, {}, {:onchange => "has_other_field(this.id);", :onload => "setup_other_field('" + the_value.number_type + "', this.id);"} %>
<% else %>
<%# Use the form helper without calling the function %>
<%= t.select :number_type, #id_types, {}, {:onchange => "has_other_field(this.id);"} %>
<% end %>
BUT I realize that onload does not work for this situation. Is there any workaround for this? How can I either
A) get the element ID from the field to the function in the first option, or
B) call this function from this input element whenever it loads?
... or C) an alternative way to do this?
Thanks in advance and let me know if more details would help.

If you have ID saved in the model, get it with <%= model.id %>
Exception to this rule is when you create object, and it is before it is written to database. If you go to edit or anywhere else it will be ok.
If you have it somewhere on the page :/ then you can use jQuery to get it for you.
< div id="id_of_the_element" attr_with_my_id="15" >ABC< /div >
$("#id_of_the_element").attr('attr_with_my_id')
< input id="id_of_the_element ... >< /input >
$("#id_of_the_element").value