Rails "param is missing or the value is empty" error - ruby-on-rails

Question

I have this link_to helper passing an :email_sequence instance and an extra :set_active params.
I then try to update the :email_sequence instance in the controller using strong params but I'm getting an error saying:
param is missing or the value is empty: email_sequence
link_to:
<%= link_to "Activate", admin_email_sequence_path(base_email.email_sequence, set_active: :true), method: :patch %>
Controller:
class Admin::EmailSequencesController < AdminController
before_action :set_email_sequence
def update
if #email_sequence.update(active: email_sequence_params[:set_active])
flash[:success] = "Sequence updated succesfully"
redirect_to_forwarder_or(params[:forwarding_uri], admin_account_emails_path)
end
end
private
def set_email_sequence
#email_sequence = current_account.email_sequences.find(params[:id])
end
def email_sequence_params
params.require(:email_sequence).permit(:set_active)
end
end
This is what gets sent in the params:
{"_method"=>"patch", "authenticity_token"=>"[FILTERED]", "set_active"=>"false", "id"=>"1"}
Can anybody tell me what am I doing wrong?

Answer 1

By params.require(:email_sequence).permit(:set_active) you expect parameters to be { email_sequence: {set_active: "ANY SCALAR VALUE HERE"} } but you pass only set_active you can fix it by permitting the only one parameter
params.permit(:set_active)

Answer 2

You don't need strong parameters here in the first place. Contrary to popular belief strong parameters does not magically sanitize the parameters. It just prevent mass assignment vulnerabilities by requiring that you whitelist the parameters when passing a hash of parameters. Since you are only using a single parameter there is no mass assignment vulnerability:
class Admin::EmailSequencesController < AdminController
before_action :set_email_sequence
def update
if #email_sequence.update(active: params[:set_active])
flash[:success] = "Sequence updated succesfully"
redirect_to_forwarder_or(params[:forwarding_uri], admin_account_emails_path)
else
# provide an error response!
end
end
private
def set_email_sequence
#email_sequence = current_account.email_sequences.find(params[:id])
end
end
If you later want to use multiple parameters nested in a hash the use of link_to is pretty questionable even if it can be done.
<%= link_to "Activate",
admin_email_sequence_path(
base_email.email_sequence,
"email_sequence[set_active]" => true,
"email_sequence[foo]" => "bar"
),
method: :patch
%>
Use button_to or form_with/form_for to create a form element and style the button to look the way you want instead as this places the parameters in request body instead of the query string.