ruby on rails - nested forms - ruby-on-rails

I have a form that sets the attributes of a model, however, there is an attribute that I want to set through the code. That is, I want the user to set some attributes, but I want the program to set other attributes.
Is there any way of doing this?
Example:
If I have table with a "text" column and a "user" column, I want the user to enter the text, but I want the "user" column to be set by the program. How would I accomplish this?

Sure. You could do something like this:
def create
#something = Something.new(params[:something])
#something.programmatically_set_attribute = "Some value" #Here's the part that matters
respond_to do |format|
if #host.save
format.html { redirect_to(#something, :notice => 'Something was successfully created.') }
format.xml { render :xml => #something, :status => :created, :location => #something}
else
format.html { render :action => "new" }
format.xml { render :xml => #something.errors, :status => :unprocessable_entity }
end
end
end
In your form, you would just leave out the field that you don't want edited by human hands. You would also have to change the update function, as well.

If you want to ensure that only the text attribute is updateable by the user and none other you may want to use attr_accessible as follows
class MyModel < ActiveRecord::Base
attr_accesssible :text
end
This will ensure that only the text attribute of MyModel can be updated via mass-assignment.

Related

auto-increment text_field number rails 3.2.6

i'v been researching trying to find the answer for this, but am struggeling to work it out. i have a booking_no text_field which i want to be automatically set when a user make a new booking through booking/new. i would like it to be an autonumber which just counts up by 1 evertime starting with 100.
I know it is probably easiest to do this in the model but i'm not sure how.
my booking.rb:
(i havent set the validates yet)
class Booking < ActiveRecord::Base
attr_accessible :booking_no, :car_id, :date, :user_id
belongs_to :car
belongs_to :user
end
EDIT for comment:
#error ArgumentsError in booking_controller#create
wrong number of arguments (1 for 0)
my booking_controller#create
def create
#booking = Booking.new(params[:booking])
respond_to do |format|
if #booking.save
format.html { redirect_to #booking, :notice => 'Booking was successfully created.' }
format.json { render :json => #booking, :status => :created, :location => #booking }
else
format.html { render :action => "new" }
format.json { render :json => #booking.errors, :status => :unprocessable_entity }
end
end
end
It's probably best if you set the booking_no as auto-increment field in the Database table itself..
Otherwise to manage it in your model, you can proceed something like:
before_create :increment_booking_no
def increment_booking_no
self.booking_no = (self.class.last.nil?) ? "0" : ((self.class.last.booking_no.to_i) + 1).to_s
end

Nice way of doing dual column validation

I'm using Rails 3 for this one. I've got a collections model, a user model and an intermediate subscription model. This way a user can subscribe to multiple collections, with a particular role. However, I don't want a user to be able to subscribe to the same collection twice.
So in my Subscription model I've got something like:
validate :subscription_duplicates
def subscription_duplicates
self.errors.add_to_base "This user is already subscribed" if Subscription.where(:user_id => self.user.id, :collection_id => self.collection.id)
end
However this seems ugly. Also, it breaks when I want to do something like the following in my collection controller:
def create
#collection = Collection.new(params[:collection])
#collection.subscriptions.build(:user => current_user, :role => Subscription::ROLES['owner'])
#collection.save
respond_with(#collection)
end
When I do the build the subscription does not have an id so I get a "Called id for nil" error.
Thanks for any guidance!
use validates_uniqueness_of
validates_uniqueness_of :user_id, :scope => :collection_id
First of all, your create action should always test if the object was saved, and if not then handle that (usually by re-rendering the new/edit page and showing the errors to the user).
A standard sort of create action would look like this (for a #post in this case):
def create
#post = Post.new(params[:post])
#created = #post.save
respond_to do |format|
if #created
flash[:notice] = 'Post was successfully created.'
format.html { redirect_to #post }
format.xml { render :xml => #post, :status => :created, :location => #post }
format.js
else
format.html { render :action => :new } #or edit or wherever you got here from
format.xml { render :xml => #post.errors, :status => :unprocessable_entity }
format.js
end
end
end
Shingara's approach to avoiding duplicates should work fine for you.

How to assign value in a RoR object?

I have a order object, which have a create method like this :
def create
#order = Order.new(params[:order])
# #order.status_id = "1"
respond_to do |format|
if #order.save
flash[:notice] = 'Order was successfully created.'
format.html { redirect_to(#order) }
format.xml { render :xml => #order, :status => :created, :location => #order }
else
format.html { render :action => "new" }
format.xml { render :xml => #order.errors, :status => :unprocessable_entity }
end
end
end
I want to set the #order status_id to "1", so I have the
#order.status_id = "1"
But this code is not work, after I uncomment it, it still can't save "1" in the status_id in db, but other attribute can successfully store.
order.rb
class Order < ActiveRecord::Base
has_many :order_items
belongs_to :status
end
You should be able to assign a string value to a relationship key and it will be converted as required. The params always come in as strings, so obviously this needs to occur for anything to be working.
This is the kind of situation where a robust unit test would help narrow down the scope of the problem. It may be one of:
There is an attr_accessor defined for status_id that is blocking the assignment.
There is a status_id= method defined which is blocking the assignment.
The status_id is being reset during a before_validation or before_save call.
You'd want to create a test routine that verifies this works:
def test_status_assignment
order = Order.new
order.status_id = '1'
order.save
assert_equal 1, order.status_id
end
You could have attr_accessible in your model blocking you from assigning to that field. It does this by using a whitelist of approved fields.
Change #order.status_id = "1" to #order.status_id = 1
Ruby may be reading "1" as a string (which it is supposed to do) instead of an integer (what you are probably looking for). When you remove the quotes ruby will interpret it as an integer. If you must leave it as a string, try something like my_string.to_i or "123".to_i.
If this doesn't work, please post whatever error message you are receiving.
This
#order.status_id = "1"
should be
#order.status_id = 1
Or maybe
#order.status = Status.find_by_id(1)
if you have relationships set up nicely

Model types and sorting in Rails?

This is something I've been stuck on for a while now, and I have to apologize in advance for going into so much detail for such a simple problem. I just want to make it clear what I'm trying to do here.
Scenario
So, there's a model Foo, each Foo can either be red, green, or blue. Having URLs like /reds to list all red objects, and /reds/some-red-object to show a certain object. In that "show" view, there should be next/previous links, that would essentially "find the next RedFoo in alphabetical order, and once at the last RedFoo, the next record should be the first GreenFoo, continuing in alphabetical order, and so on".
I've tried implementing this in a couple of ways and mostly ended up at a roadblock somewhere. I did get it working for the most part with single table inheritance though, having something like this:
class Foo < ActiveRecord::Base
class RedFoo < Foo
class GreenFoo < Foo
class BlueFoo < Foo
Each subclass's models and controllers are identical, just replace the model names. So the controllers look something like:
class RedFoosController < ApplicationController
def index
#foos = RedFoo.find(:all, :order => "title ASC")
respond_to do |format|
format.html { render :template => 'foos/index'}
format.xml { render :xml => #foos }
end
end
def show
#foo = RedFoo.find(params[:id])
respond_to do |format|
format.html { render :template => 'foos/show'}
format.xml { render :xml => #foo }
end
end
def new
#foo = RedFoo.new
respond_to do |format|
format.html { render :template => 'foos/new'}
format.xml { render :xml => #foo }
end
end
def edit
#foo = RedFoo.find(params[:id])
respond_to do |format|
format.html { render :template => 'foos/edit'}
end
end
def create
#foo = RedFoo.new(params[:foo])
respond_to do |format|
if #foo.save
flash[:notice] = 'Foo was successfully created.'
format.html { redirect_to(#foo) }
format.xml { render :xml => #foo, :status => :created, :location => #foo }
else
format.html { render :action => "new" }
format.xml { render :xml => #foo.errors, :status => :unprocessable_entity }
end
end
end
def update
#foo = RedFoo.find(params[:id])
respond_to do |format|
if #foo.update_attributes(params[:foo])
flash[:notice] = 'Foo was successfully updated.'
format.html { redirect_to(#foo) }
format.xml { head :ok }
else
format.html { render :action => "edit" }
format.xml { render :xml => #foo.errors, :status => :unprocessable_entity }
end
end
end
def destroy
#foo = RedFoo.find(params[:id])
#foo.destroy
respond_to do |format|
format.html { redirect_to(foos_url) }
format.xml { head :ok }
end
end
end
The models only contain methods for next/previous, which work fine, surprisingly.
class RedFoo < Foo
def next
if self == RedFoo.find(:all, :order => "title ASC").last
GreenFoo.find(:all, :order => "title ASC").first
else
RedFoo.find(:first, :conditions => ["title > ?", self.title], :order => "title ASC")
end
end
def previous
if self == RedFoo.find(:all, :order => "title ASC").first
BlueFoo.find(:all, :order => "title ASC").last
else
RedFoo.find(:first, :conditions => ["title < ?", self.title], :order => "title DESC")
end
end
end
Problem
For whatever reason when I try to create and edit records, none of the attributes get saved in the database. It simply adds a new record with completely empty columns, regardless of what's filled in the form. No errors get returned in the script/server output or in the log files. From the script/console however, everything works perfectly fine. I can create new records and update their attributes no problem.
It's also quite a bad code smell that I have a lot of code duplication in my controllers/models (they're using the same views as the base model, so that's fine though). But I think that's unavoidable here unless I use some meta-goodness.
Any advice or suggestions about tackling this record saving issue would be great, but the reason I posted my setup in detail is because I have a feeling I'm probably going about this whole thing the wrong way. So, I'm open to other approaches if you know of something more practical than using STI. Thanks.
Update
The parameters hash looks about right:
{"commit"=>"Create", "authenticity_token"=>"+aOA6bBSrZP2B6jsDMnKTU+DIAIkhc8fqoSicVxRJls=", "red_foo"=>{"title"=>"Hello world!"}}
But #foo.inspect returns the following RedFoo object (all nil, except for type):
#<RedFoo id: nil, title: nil, type: "RedFoo", created_at: nil, updated_at: nil>
Problem is the params
:red_foo
is the name of the params in the view, whereas you use
params[:foo]
in the controller, I think the best way would be to be use :foo, in the view by using text_field_tag rather than any (what i assume can be) form builders text_field.
You can get out of the controller smell by using a module to do the basic crud stuff, since i assume most of the new/create/edit/update/destroy stuff is the same
OR
you could map all the routes to a foo controller and use some sort of parameter either passed in from the route, or through URI analysis to get the red/green/blue foo
Please take a look at the section called "Single table inheritance" on this page and let us know if it solves your problem.
Must admit, the way I go about STI is to use set_table_name inside a model.
e.g.
class RedFoo < AR::Base
set_table_name "foos"
include FooModule
extend FooClassModule # for self methods
def next; ...; end
end
But anyway, for this situation, what does your logger say when you do a #foo.inspect just before a save, and also what is the SQL that is ran on insert/update?
Right, so #foo.inspect gives you "nil" in the log?
What I mean (if I wasn't clear enough) was:
def create
#foo = RedFoo.new(params[:foo])
logger.error "******************* foo: #{#foo.inspect} **************"
respond_to do |format|
if #foo.save
...
if you do that and tail -f your log you can easily find out what is happening to foo and compare that to the incoming params hash
Infact, that would also be some useful information to have, what is the params hash?

Validating data of a model from another controller in Rails

I have two tables:
Client(id,name,...)
Purchase(id,item,date,client_id,...)
They have their respective Model, with their validations. What I need is to create a new client with a new purchase, all into the create method of Client controller. Something like this:
def create
#client = Client.new(params[:client])
respond_to do |format|
if #client.save
# Add purchase
#sell = Purchase.new
#sell.client_id = #client.id
#sell.date = params[:date]
# Fill another fields
if #sell.save
# Do another stuff...
else
format.html { render :action => "new" }
format.xml { render :xml => #client.errors, :status => :unprocessable_entity }
end
flash[:notice] = 'You have a new client!'
format.html { redirect_to(:action => :show, :id => #evento.id) }
format.xml { render :xml => #client, :status => :created, :location => #client }
else
format.html { render :action => "new" }
format.xml { render :xml => #evento.client, :status => :unprocessable_entity }
end
end
end
In Purchase's model I have:
belongs_to :client
validates_format_of :date, :with => /^20[0-9]{2}[-][0-9]{2}[-][0-9]{2}$/, :message => 'not valid'
validates_presence_of :date
And there is my problem: how can I validate the date input, through validations into the model, from Client controller? And, how can I rollback the new client created when errors?
Yes, I can do the check as the very first instruction in the method, with a regular expression, but I think it's ugly. I feel like might exist a conventional method for doing this validation or even doing all the stuff in another way (i.e. calling create method for Purchase from Client controller).
Can you put me back in the right way?
Thank you in advance.
Take a look at the following page on working with associations.
Rails provides you with a bunch of handy methods on your objects.
Like the following:
Client.purchases.empty?
Client.purchases.size,
Client.purchases
Client.purchases<<(purchase)
Client.purchases.delete(purchase)
Client.purchases.find(purchases_id)
Client.purchases.find_all(conditions)
Client.purchases.build
Client.purchases.create
When using these methods, you're taking advantage of the validations on each of the models.
Hop into your Rails console and create a new client and try any of the above methods. You'll quickly learn how powerful they are and you'll be on your way in no time.
Edit: Here's a much better guide on Rails associations!
Depends a little on the situation, but you can use validates_associated to run the validations on associated objects. Then you can create the user (but don't save), create the purchase (but don't save) and try to save the user. If you've done it right the user will fail to save with a validation error on the associated object.

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