I'm submitting a simple form with variables that are named in the database.
I am trying to:
Store the submitted variables in the database (which works fine)
Run a calculation, then store that value into the database
No matter what I try I either get an error or 'nil' (upon #kcmil.inspect) as my result for #kcmil. I'm assuming in my current code i'm not passing the variables to the model, but it doesn't work even when it's in the controller.
I'm at a loss here. My variables that are submitted in the form store just fine as expected. I just want to be able to use submitted variables from a form (that are also database items that get stored upon submission) and before saving to the database (or after, should it matter?) run a calculation and store the result in a database item (that is not previously called in or saved from the form). Does that make sense? Any help or hints are GREATLY APPRECIATED!!
Here are my current calculators_controller create and edit actions:
def create
#calculator = Calculator.new(calc_params)
if #calculator.save
flash[:notice] = "Calculation created successfully."
redirect_to(:action => 'index')
else
render('new')
end
end
def update
#calculator = Calculator.find(params[:id])
if #calculator.update_attributes(calc_params)
flash[:notice] = "Calculation updated successfully."
redirect_to(:action => 'index', :id => #calculator.id)
else
render('edit')
end
end
private
def calc_params
params.require(:calculator).permit(:subsection, :amps, :volts, :distance, :vdrop, :phase, :kcmil, :section_id)
end
Here's my model
class Calculator < ActiveRecord::Base
before_create :kcmil_calc
def kcmil_calc
if #phase == 1
self.kcmil = ((13 * #distance.to_i * #amps.to_i ) / #vdrop.to_i).round(2)
else
self.kcmil = ((12.9 * #distance.to_i * #amps.to_i ) / #vdrop.to_i).round(2)
end
end
end
I HAVE IT! I HAVE IT!
before_update :defaults
def defaults
if self.phase == 1
self.kcmil = ((12.9 * distance * amps) / vdrop).round(2)
else
self.kcmil = ((13 * distance * amps) / vdrop).round(2)
end
end
solved it! I had to call self.phase instead of #phase and change before_create to before_update to get it to work . No change in the controller required. Dang - one simple #! I also removed the to_i because it's not needed since my views prevent me from submitting anything other than integers.
Related
I had a previous question that helped me loop through all users where a certain question is met.
However, I'm realizing I can't hard code that condition. I need to somehow get that data from the submitted form, which doesn't seem to be possible in the mailer.
In other words, I'm trying to loop through all users where the user's state is equal to the home_state of the candidate being entered. Basically when the candidate is created, I want to get the home_state of that candidate, and then loop through all users, and for each user that has same state as that candidate, I want to send them the email via this mailer.
Here's my candidate_mailer.rb file
class CandidateMailer < ApplicationMailer
default from: 'wesleycreations#gmail.com'
def self.send_request(row)
#candidate = Candidate.new(candidate_params) # if I can access this here, how to I create the
# following array?
emails = []
User.where(state: #candidate.home_state).each do |u|
emails << u.email # To insert the user email into the array
end
emails.each do |email|
new_request(email,row).deliver_now
end
end
def new_request(email, row)
#candidate = row
mail(to: email, subject: 'New request')
end
end
But the
#candidate = Candidate.new(candidate_params)
obviously doesn't work because the params aren't available in the mailer.
Here in the candidates_controller.rb I have this
def create
#candidate = Candidate.new(candidate_params) #of course here I can access params
if #candidate.save
row = #candidate
CandidateMailer.send_request(row)
else
render('new')
end
end
SO the question is, how do I access params in rails mailer? And if I can't, then how do I refactor my code so that the lines that check if the user meets certain condition is done in the controller?
I was able to figure this out by doing this. after I saved the candidate, I saved the candidate to a global variable. and THEN I send the mailer.
def create
#candidate = Candidate.new(candidate_params)
if #candidate.save
row = #candidate
$candidate = #candidate
end
CandidateMailer.send_request(row)
else
end
end
This way the mailer had access to the new candidate that been created, and I was able to check my condition in there.
So in my mailer, when I use $candidate.home_state, it returned the correct state, mail went out, and made me very happy :)
emails = []
User.where(state: $candidate.home_state).each do |u|
emails << u.email # To insert the user email into the array
end
I currently generate a user's profile page using their serial ID, like so:
get '/users/:id' do
#user = User.get(params[:id])
end
This works great, until a number is entered that doesn't exist in the database.
I'm aware I can change User.get to User.get! to return an ObjectNotFoundError error if the record isn't found, but I'm not sure how I can use this to my aid.
I used to use .exists? when using RoR.
Any suggestions?
Thanks in advance!
Edit: I'm going to leave the question unanswered, as I haven't actually found a solution to what I asked in the title; however, I did manage to solve my own problem by checking to see if the :id entered is higher than the amount of users that exist in the database, like so:
if params[:id].to_i > User.count
"This user does not exist."
else
#users_id = User.get(params[:id])
erb(:'users/id')
end
You already have the correct code:
#user = User.get(params[:id])
If no user exists with the given id, then #get will return nil. Then you can just do a conditional:
#user = User.get params[:id]
if #user
# user exists
else
# no user exists
end
This is a very common pattern in Ruby which takes advantage of the "truthiness" of anything other than false or nil. i.e. you can say if 0 or if [] and the condition will evaluate to true
You can recreate a .exists? method:
class User
def self.exists?(id_or_conditions)
if id_or_conditions.is_a? Integer
!! User.get id_or_conditions
else
!! User.first id_or_conditions
end
end
end
#get is similar to #find in rails, except it doesn't raise an error if the record is not found. #first is similar to #find_by in rails.
Just to show you how I got to this point:
Every user has many profiles. Every profile has type recognized by single table inheritance(amateur, professional, and some other). I need to store current_profile somewhere and somehow.
Professionals Controller
class ProfessionalsController < ApplicationController
def create
#professional = Professional.new(professional_params)
#user = current_user
#professional.user_id = current_user.id
#update_current_profile = User.update(#user, {:current_profile => #professional.id})
if #professional.save
...
else
...
end
end
private
def professional_params
params.require(:professional).permit(:id, :username, :user_id)
end
end
This is meant to update current_profile of user to the newly created professional profile and do some staff then.
When the profile is created current_profile is set(updated) to NULL. If I change :
#update_current_profile = User.update(#user, {:current_profile => #professional.id})
to something different, for example:
#update_current_profile = User.update(#user, {:current_profile => #professional.user_id})
or
#update_current_profile = User.update(#user, {:current_profile => 3})
it stores data in User.current_profile perfectly.
I was trying #professional without an .id too. Why is this doing so?
Another question is. Is this the best way to store current_profile of user? Would you recommend me any better/safer/more efficient solution?
Thanks all of you guys.
#professional is a new, unsaved record and therefore does not have an id yet. Can only update the current_profile once the #professional record was saved.
Just reorder the lines a bit and it should work:
def create
#professional = Professional.new(professional_params)
#user = current_user
#professional.user_id = current_user.id
if #professional.save
#update_current_profile = User.update(#user, {:current_profile => #professional.id})
# ...
else
# ...
end
end
Just another tip: You use many instance variables (the one with the #) in this method. I do not know enough about your code, but I would suggest to look if some of them can be replaced with local variables. Rule of thumb: Only use instance variables in controllers when you want to share that variable with another method or the view.
I'm trying to do a simple calculation with two submitted form variables then store all three variables in the database. Each variable is a column in my database.
E.G.
somedbfield = ( item_1 * item_2 ) + 2
How would I upon form submit, somedbfield, item_1, item_2 save in the Test database? all three items are being validated with validates_numericality_of in the model and they should all be integers. Here's just my basic code to find the test.id from the form submitted, but I don't know how to create a calculation using the form values and then submit all three values to the database:
class Test_Controller < ApplicationController
def update
#test = Test.find(params[:id])
respond_to do |format|
if #test.update(test_params)
format.html { redirect_to('index', :notice => 'User was successfully updated.') }
format.json { respond_with_bip(#test) }
else
format.html { render :action => "edit" }
format.json { respond_with_bip(#test) }
end
end
private
def test_params
params.require(:test).permit(:item_1, :item_2, :somedbfield)
end
end
This is a much more simpler version of a question that I previously asked but couldn't get any answers for, so i'm trying just to simplify and work forward from there.
Thank you!!
The way I see it, your update method simply retrieves an instance of the model and saves it without doing anything.
To update the database, you would need to pass in the parameters to the instance and then save it:
item_1 = params[:item_1]
item_2 = params[:item_2]
somedbfield = ( item_1 * item_2 ) + 2
#test.update(:item_1 => item_1, :item_2 => item_2, :somedbfield => somedbfield)
you should use the params[:symbol] syntax for this. You can use:
#test.item_1=params[:item_1]
#test.item_2=params[:item_2]
#test.somedbfield=params[:item_1]*params[:item_2]+2
#test.save
Let me know if this helps.
controller/makenew.rb
class MakeController < Controller
map '/makenew'
#require 'model/debate'
def debate
if request.post? #this line is potentially dangerous!
#---> 1/3 fetch postdata
data = request.subset(:question, :type, :category, :assertion)
data['user_id'] = user.id #id = request.params['id']
#---> 2/3 check permissions
if user.points < 40
flash[:error] = 'You don\'t have enough points to make a debate.'
redirect_referrer
else
debate = Debate.new
end
#---> 3/3 modify database
begin
debate.save(data)
flash[:success] = success
flash[:form_data] = debate
redirect 'debates'
rescue => e
Ramaze::Log.error(e)
#flash[:form_errors] = debate.errors
#flash[:error] = data
flash[:error] = e
#flash[:error] = 'Failure whilst saving. Contact technical support!'
redirect 'debates' #redirect_referrer
end
#|
end #closes posting conditional
end #closes makesave
end
The error I get is.
SQLite3::ConstraintException: debates.question may not be NULL
I have checked the postdata for data.question and it is not null.
What is going on?
You need to pass 'data' to #update. Thus:
debate.save(data)
is wrong, you have to do:
debate.update(data)
debate.save
If you don't do this, your debate object has no member assigned and thus its question member is nil, violating your DB constraints.
See the differences between #save and #update here:
Update : http://sequel.rubyforge.org/rdoc/classes/Sequel/Model/InstanceMethods.html#method-i-update
Save : http://sequel.rubyforge.org/rdoc/classes/Sequel/Model/InstanceMethods.html#method-i-save
In a nutshell: #save will save the current model instance to the database, while #update will change a bunch of instance attributes in one operation.
But you have to remember that changing a model instance's attributes DOES NOT write them to the database. You always have to call #save explicitly.
Are you sure that your model accepts mass assignment of primary keys?
Try calling Debate.unrestrict_primary_key
You can check the rules in the Sequel documentation.