Separating year, month and day in rails forms - ruby-on-rails

Question

Normally, in order to get a date select in rails, I write this:
<%= form_for(:buddy, :url => {:action => :create}) do |f| %>
<%= f.date_select(:dob) %>
<%= f.submit("HI") %>
<% end %>
and get this html as a result:
<form action="/buddy/create" accept-charset="UTF-8" method="post"><input name="utf8" type="hidden" value="✓" /><input type="hidden" name="authenticity_token" value="Qs8RK+6gEt9ZoycMbMHwX4xMyoFpRvjA/El3cLnO30RXddr864WmEXzyAgYtXBe5Y9l0zC3UDw4ggRw1xYW1sg==" />
<select id="buddy_dob_1i" name="buddy[dob(1i)]">
<option value="2010">2010</option>
<!-- ETC -->
<select id="buddy_dob_2i" name="buddy[dob(2i)]">
<option value="1" selected="selected">January</option>
<!-- ETC -->
<select id="buddy_dob_3i" name="buddy[dob(3i)]">
<option value="1">1</option>
<!-- ETC -->
<input type="submit" name="commit" value="HI" />
But now I'm using bootstrap. If I use the bootstrap_form_for gem, I run into the problem that on small screens, the three selects get placed on top of each other, which is unacceptable. So I came up with what I thought was a good solution: to place each of the selects in a different field of a table, which prevents the behaviour. So I have written this code:
<%= form_for(:buddy, {:action => :create, :role => 'form'}) do |f| %>
<div class="form-group">
<label for="buddy_dob">Date of Birth</label>
<table class="table functional-table">
<tr>
<td>
<%= select_year(Date.today, {:start_year => DateTime.now.year, :end_year => DateTime.now.year - 117}, {:name => 'buddy[dob(1i)]', :id => 'buddy_dob_1i', :class => 'form-control'}) %>
</td>
<td>
<%= select_month(Date.today, {}, {:name => 'buddy[dob(2i)]', :id => 'buddy_dob_2i', :class => 'form-control'}) %>
</td>
<td>
<%= select_day(1, {}, {:name => 'buddy[dob(3i)]', :id => 'buddy_dob_3i', :class => 'form-control'}) %>
</td>
</tr>
</table>
</div>
<div class="form-group">
<%= f.submit("HI") %>
</div>
<% end %>
which produces this result:
<form role="form" action="/buddy/new" accept-charset="UTF-8" method="post"><input name="utf8" type="hidden" value="✓" /><input type="hidden" name="authenticity_token" value="6Ek01J6PIgzHl/NLpjI6V+kolUVCpw7jrQTF8eYT3ef98/8Dm6qWwuLG1kHnr92xBr0rCAY1+S1xzK60mli3EQ==" />
<div class="form-group">
<label for="buddy_dob">Date of Birth</label>
<table class="table functional-table">
<tr>
<td>
<select id="buddy_dob_1i" name="buddy[dob(1i)]" class="form-control">
<option value="2015" selected="selected">2015</option>
<!-- ETC -->
</td>
</tr>
</table>
<table class="table functional-table">
<tr>
<td>
<select id="buddy_dob_2i" name="buddy[dob(2i)]" class="form-control">
<option value="1" selected="selected">January</option>
<!-- ETC -->
</td>
</tr>
</table>
<table class="table functional-table">
<tr>
<td>
<select id="buddy_dob_3i" name="buddy[dob(3i)]" class="form-control">
<option value="1" selected="selected">1</option>
<!-- ETC -->
</td>
</tr>
</table>
<div class="form-group">
<input type="submit" name="commit" value="HI" />
</div>
</form>
The display for this works exactly as I want, however when I try to submit the form I am redirected to the action :new with no errors registered by rails and no entry created. I never reach :create. I suspect this might be because I've manually separated the date fields which date_select separates and then pieces back together and rails cannot handle this, but I am not sure. How can I fix this and get the form working?

Answer 1

You have nested forms - this is illegal! Most of the browsers will simply ignore the inner form tag, so you'll end up with a DOM structure as presented. The outer form does not specify the action attribute, so browsers will append the current path as an action, in this case - /buddy/new. I'm a little bit surprised you're not getting routing error here - did you by any chance use match /buddy/new without specifying the verb?
Anyway - the solution is to get rid of surrounding form (the one with the role) and instead attach this role to your form_for call:
<%= form_for(:buddy, url: {action: :create}, html: {role: :form) do |f| %>

Answer 2

SOLVED! I just changed form_for to form_tag and it now works as expected. Thanks to BroiSatse for the information about ActionDispatch knowing how to convert the params; it encouraged me to look elsewhere for problems．

Answer 3

Your select names are not "standard". buddy[dob(3i)] is not a valid name.
When the query is sent to Rails, a first module changes all the received names into params. Here, it can't, and fail.
You should set somethink like this : buddy[dob_month].