Action show to find value from hash instead of id - ruby-on-rails

I am still learning rails and have done a lot of readings, but I am not very clear about how params, 'show' actions work yet.
For example we have UsersController, 'index' action is showing all the users with the code #user = User.all, and 'show' action is looking into each users, by using the code #user = User.find(params[:id])
I understand that they are all from the database, where User is a model.
However in my scenario, what if the data I am showing in views, doesn't go through database, instead in the 'index' action it is something like this -
#user = [{name => "alex"}, {name => "peter"}, {name => "john"}]
and in my 'show' action, how can I write the code so that it finds the users by name?

In your Rails app, the data that you show in your views, do not necessarily have to come from/through the database. You can always show any data you want in your views.
For example, in your index action, if you have this:
#users = [{name => "alex"}, {name => "peter"}, {name => "john"}]
Then, in your index view, you can show only those users by looping through the #users instance variable.
Same for show page as well.
If you want to show the users by name in your show page, you have to set the users by name in an instance variable e.g. #users_by_name:
#users_by_name = User.find_by(name: user_name)
# or you can hard code the values if you want like index action
and then this #users_by_name instance variable will be available in your show view so that you can loop through that and show the user names.
Originally, the show page is designed for showing a particular user related information, but you can show whatever information you want going against the conventions.
To be able to have a route like this: localhost:3000/users/alex that will show the user alex's information, you can add a route in your routes.rb file:
get 'users/:name', to: "users#show"
And, in your controller's show action, something like this:
def show
#user = User.find(params[:name])
end
Then, show the #user information in your view page.
P.S. This is not a good idea to find user by name as there might be more than one user with same name in the database and it will create conflict/ or give wrong data in such situations.

In show action , we search the user specific record not all.
So , we have to provide some unique identifiers as parameters to find the specific record.
For eg. Your view should be similar to the params we are passing as below:
<% #user.each do |user| %><br>
<%= link_to user.name, user_show_path+"?name="+user.name %><br>
<% end %><br>
In show action , write the code
def show
#user = User.find_by(:name => params[:name])
end
Also in routes.rb , write the below code:
get 'users/:name', to: "users#show"
For the above solution, make sure that name field will be unique.

My original question is that if it is possible for 'show' action not to go through database
Sure.
Your show action can be the following if you wanted it to:
#app/controllers/users_controller.rb
class UsersController < ApplicationController
def show
#user = "me"
end
end
You really don't have to do anything specific in your application, Rails is just a framework and has certain conventions if you want it to work efficiently.
What you're asking is if you can populate your #user object from a third party set of data...
... Yes you can ...
The way to do it would be in the model, not the controller:
#app/models/user.rb
class User < ActiveRecord::Base
# populates from Hash
end
You'd then be able to populate the data in the controller from the model again:
#app/controllers/users_controller.rb
class UsersController < ApplicationController
def show
#user = User.__________ #-> pull from your hash
end
end
finds the users by name
That's simple - just pass the name through the url: url.com/users/marine_lorphelin
This will set the :id parameter to marine_lorphelin, with which you'll be able to look up the name through your model:
#app/controllers/users_controller.rb
class UsersController < ApplicationController
def show
#user = User._______
end
end
If you were using a database with your user model, you'd be able to use the following:
def show
#user = User.find_by name: params[:id]
end
Since you're not, you'll have to attach your XML hash to your model somehow. This, I don't know without specifics such as where you're getting your data from, how you're accessing it, and which routes you're going to send to invoke it.

Related

Rails 4 - Couldn't find User without an ID

I'm new to rails, so any explanation & advise would much appreciated.
i have a webpage in which i would like any user to view that page not just the current_user, but i am unsure how to correctly define the instance variable #user in my controller
in my static_pages_controller.rb i have the below action recruiterpg
static_pages_controller.rb
def recruiterpg
#user = User.find(params[:user_id])
#adverts = #user.adverts
#applications = #user.forms
end
in my controller, i have defined user as #user = User.find(params[:user_id]) but this breaks my code in the views; views/static_pages/recruiterpg.html.erb
when i define user as #user = current_user my code in the views works perfectly fine
what am trying to do is: for my views, the recruiterpg.html.erb, i would like
any user to be able to view the page not only the current_user to
view the page. Could one kindly advise me and explain to me how to
define #user correctly in my status_pages_controller.rb. i also
tried #user = User.find(params[:id]) but my code still breaks in the
views - i get the error message
Couldn't find User without an ID
You need to make sure you are passing a user_id to the recruiterpg action. For example, try this url in your browser (set user_id to a known id in the users table):
http://localhost:3000/dashboard?user_id=1
A suggested modification to your action:
def recruiterpg
#user = User.find params.require(:user_id)
#adverts = #user.adverts
#applications = #user.forms
end
If params[:user_id] isn't defined, you want to find a way to make visible what is being defined.
If you throw the following statements into your controller...
def recruiterpg
...
puts params
...
end
...you should see something like the following get spit out in your console when you load the page...
{"controller"=>"static_pages", "action"=>"recruiterpg", "id"=>"49"}
Take a look at the Rails guide for parameters. They can get defined in one of three ways.
One: As a query string similar to Sean's answer above.
Two: Routing parameters. See section 4.3 in the Rails guide. In your case, that would mean you should have something like the following in routes.rb:
get '/dashboard/:user_id' => 'staticpages#recruiterpg'
Note that there's nothing magic about :user_id in that string.
Three: From a form which it doesn't seem like applies here, since a user isn't submitting data.
Since you're new, here is some information for you:
User Story
Firstly, the best way to resolve errors is to identify your user story.
A "user story" is a software principle in which you put the "user's perspective" first -- explaining how the software should work in conditions defined from how the user engages with it.
One of the main issues you have with your question is your user story is very weak; it's hard to decifer what you're trying to achieve.
Next time you ask a question, you should try your hardest to describe how the user should see your app, before providing code snippets :)
Controller
Your main issue is an antipattern.
An antipattern is basically a "hack" which will likely break another part of your app in future. Kind of like duct tape for software):
#app/controllers/static_pages_controller.rb
class StaticPagesController < ApplicationController
def recruiterpg
#user = User.find(params[:user_id])
#adverts = #user.adverts
#applications = #user.forms
end
end
So you're showing a static page but yet you want to populate it with data?
Hmm...
What you should be doing is something like the following:
#config/routes.rb
resources :users do
resources :recruiters, only: :index #-> url.com/users/:user_id/recruiters
end
#app/controllers/recruiters_controller.rb
class RecruitersController < ApplicationController
def index
#user = User.find params[:user_id]
#adverts = #user.adverts
#applications = #user.forms
end
end
This will allow you to populate the following view:
#app/views/recruiters/index.html.erb
<%= #adverts %>
--
It's important to note the structure of the controller / routes here.
The issue you have is that you're calling a "static page" and expecting to have params available to find a User. This can only happen if you have params available...
Params
Rails is not magic, and as such if you want to look up a user, you have to provide the parameters to do so.
This is why you're able to look up current_user -- the params are already set for this user.
As such, you'll need to use something called nested routes in order to attain a user ID other than that of current_user:
#config/routes.rb
resources :users do
resources :recruiters #-> url.com/users/:user_id/recruiters
end

Only getting the index for the current user

I have a pretty basic app. I've managed to install devise. The idea is to have users who have created challenges (1 to many relationship).
I want the logged in user to be able to see all the challenges they have created.
I order to do this am I correct in thinking that I can pass the current user id as a parameter to just get the challenges of the current user as follows (assuming the view is set up correctly)
<%= link_to challenges_path(user_id: current_user.id), class: 'expandable' %>
challenges controller
def index
#challenges = Challenge.all
render :layout => false
end
If this is the default behaviour you want for the index of the challenges, then you can simply change your controller action directly, and no need to modify your link_to to add user_id
challenges controller
def index
#challenges = Challenge.where(user: current_user)
end
Now if you want to change the behavior only if the user_id GET param is set, you can keep your link_to like this and modify your controller this way
def index
#challenges = params[:user_id] ? Challenge.where(user: current_user) : Challenge.all
end

Ruby on Rails controller design

When I look at examples of Rails controllers, I usually see something like this:
class WidgetController < ActionController::Base
def new
#widget = Widget.new
end
def create
#widget = Widget.new(params[:id])
if #widget.save
redirect_to #widget
else
render 'new'
end
end
end
This works, but there's a couple problems:
Routes
If I add widgets to my routes.rb file:
Example::Application.routes.draw do
resources :widgets
end
GET /widgets/new will route to new and POST /widgets will route to create.
If the user enters incorrect information on the new widget page and submits it, their browser will display a URL with /widgets, but the new template will be rendered. If the user bookmarks the page and returns later or refreshes the page, the index action will be called instead of the new action, which isn't what the user expects. If there's no index action or if the user doesn't have permission to view it, the response will be a 404.
Duplication of code
As a contrived example, let's say I had some tricky logic in my new method:
def new
#widget = Widget.new
do_something_tricky()
end
Using the current approach, I'd duplicate that logic in new and create. I could call new from create, but then I'd have to modify new to check if #widget is defined:
def new
#widget ||= Widget.new
do_something_tricky()
end
Plus, this feels wrong because it reduces the orthogonality of the controller actions.
What to do?
So what's the Rails way of resolving this problem? Should I redirect to new instead of rendering the new template? Should I call new inside of create? Should I just live with it? Is there a better way?
I don't think this is a problem in "the rails way" and there is no builtin functionality to allow this without getting your hands dirty. What does a user expects when bookmarking a form they just submitted and had errors? Users don't know better, and they shouldn't bookmark a failed form.
I think redirecting to new_widget_path is the cleanest solution. Yet, you should keep the errors and display them on the form. For this I recommend you keep the params in session (which I expect to be smaller than a serialized Widget object).
def new
#widget = widget_from_session || Widget.new
end
def widget_from_session
Widget.new(session.delete(:widget_params)) if session[:widget_params].present?
end
private :widget_from_session
# Before the redirect
session[:widget_params] = params
The code is self explanatory, Widget.new will only be called when widget_from_session returns nil, this is when session[:widget_params] is present. Calling delete on a hash will return de deleted value and delete it from the original hash.
UPDATE Option 2
What about submitting the form using ajax? Your controller could benefit from:
respond_to :html, :json
...
def create
#widget = Widget.new params[:widget]
#widget
respond_with #widget, location: nil
end
Based on the response code (which is set by Rails: 201 Created or 422 Unprocessable Entity), you could show the errors (available in the body of the response when validations fail) or redirect the user to #widget
This is how StackOverflow does it: https://stackoverflow.com/questions/ask. They submit the form asynchronously.
In general, I think the Rails way of solving the problem would be to put the tricky method onto the model or as a helper method, so the controller stays "thin" and you don't have to make sure to add custom behavior to both #new and #create.
EDIT: For further reading, I'd recommend the "Rails AntiPatterns" book, as they go through a lot of these common design issues and give potential solutions.
you put do_something_tricky() in its own method and call it inside the create action (but only when you're rendering the new template, ie when validation fails).
As for the bookmark issue, I don't know a good way to prevent that but to modify the routes and set the create action to the new action but using POST
get '/users/new' => 'users#new'
post '/users/new' => 'users#create'
UPDATE: using resources
resources :platos, except: :create do
post '/new' => 'plates#create', on: :collection, as: :create
end
then you can use create_platos_path in your forms
You don't need to write same function in two action , use before_filter instead.
If you want to have "widget_new_url" after incorrect submission then in your form add url of new widget path something like :url => widget_new_path .
Rails takes the url from Form .
I have this problem before, so I use edit action instead.
Here is my code.
Routes:
resources :wines do
collection do
get :create_wine, as: :create_wine
end
end
Controller:
def create_wine
#wine = Wine.find_uncomplete_or_create_without_validation(current_user)
redirect_to edit_wine_path(#wine)
end
def edit
#wine = Wine.find(params[:id])
end
def update
#wine = Wine.find(params[:id])
if #wine.update_attributes(params[:wine])
redirect_to #wine, notice: "#{#wine.name} updated"
else
render :edit
end
end
Model:
def self.find_uncomplete_or_create_without_validation(user)
wine = user.wines.uncomplete.first || self.create_without_validation(user)
end
def self.create_without_validation(user)
wine = user.wines.build
wine.save(validate: false)
wine
end
View:
= simple_form_for #wine, html: { class: 'form-horizontal' } do |f|
= f.input :complete, as: :hidden, input_html: { value: 'true' }
What I did is create a new action 'create_wine' with get action.
If user request 'create_wine', it will create a new wine without validation and redirect to edit action with a update form for attributes and a hidden field for compele .
If user has create before but gave up saving the wine it will return the last uncompleted wine.
Which means whether use save it or not, the url will be the same to /wines/:id.
Not really good for RESTful design, but solve my problem. If there is any better solution please let me know.

Redirecting to different actions without using a query string

I am trying to figure out the best way to do the following (there are a few ways I can think of, but I want to know what the best way to handle it is):
A user is putting together a shipment, and then clicks the "Send" link, which sends him to the /shipments/:id/confirm page. The confirm action checks to see if the user has a completed ShippingAddress; if not, it sends him to the ShippingAddress#new. (If he does, it render the confirm page.
I want the user to be able to complete the ShippingAddress#new page, submit it, and then be redirect back to the /shipments/:id/confirm. How can I do that? How can I pass the :id to the ShippingAddress#new page without doing something like redirect_to new_shipping_address_path(shipment_id: #shipment.id) in the Shipment#confirm action? Or is that the best way to do that?
class ShipmentsController < ApplicationController
def confirm
#shipment = Shipment.where(id: params[:id]).first
unless current_user.has_a_shipping_address?
# Trying to avoid having a query string, but right now would do the below:
# in reality, there's a bit more logic in my controller, handling the cases
# where i should redirect to the CardProfiles instead, or where I don't pass the
# shipment_id, and instead use the default shipment.
redirect_to new_shipping_address_path(shipment_id: #shipment.id)
end
end
end
class ShippingAddressesController < ApplicationController
def new
#shipment = Shipment.where(id: params[:shipment_id]).first
end
def create
#shipment = Shipment.where(id: params[:shipment_id]).first
redirect_to confirm_shipment_path(#shipment)
end
end
[In reality, there is also a CardProfiles#new page that needs to be filled out after the shipping address is].
Try calling render instead of redirect_to, and set the id into an instance variable. Adjust the view logic to pull that instance variable if it exists.
#shipment_id = #shipment.id
render new_shipping_address_path
In the view
<%= form_for #shipment_address do |f| %>
<% if #shipment_id %>
<%= hidden_field_tag :shipment_id, #shipment_id %>
<% end %>
I don't know your view logic entirely, but giving an example.

How do I use instance variables, defined in the controller, in the view with ActiveAdmin?

I have this:
ActiveAdmin.register User do
controller do
def show
#user = User.find(params[:id])
show!
end
end
show do
attributes_table do
row "User" do
link_to #user.display_name, user_path(#user.slug)
end
end
end
end
But when I load the page, I get an error saying:
undefined method `display_name' for nil:NilClass
which means that #user is nil. I am positive that #user is set appropriately (meaning the finder is getting appropriate data that exists in the db). I'm thinking it has something to with how ActiveAdmin works that I'm unfamiliar with. Any thoughts?
Also, I know I could do show do |user|, but there are more complicated things I am using this for and need access to the user object in the controller.
Just in case someone else stumbles upon this:
controller.instance_variable_get(:#user)
should work as well.
There is controller in active admin, despite this you can not pass instance variable to arbre part. But you can use params hash for this:
ActiveAdmin.register User do
controller do
def show
params[:user] = User.find(params[:id])
show!
end
end
show do
attributes_table do
row "User" do
link_to params[:user].display_name, user_path(params[:user].slug)
end
end
end
end
P.S.: If you don't want to change params, then all instance variables are stored in #arbre_context.assigns. You may also do like:
link_to #arbre_context.assigns[:user].display_name, user_path(#arbre_context.assigns[:user].slug)
Instance variables are defined as helper methods. If you have that defined in your controller, you can access it. Alternatively, you can simply call resource, which will have reference to the active record object.
ActiveAdmin.register User do
controller do
def show
#user = User.find(params[:id])
show!
end
end
show do
attributes_table do
row "User" do
# note that your have access to `user` as a method.
link_to user.display_name, user_path(user.slug)
end
end
end
end
It seems does not work that way in activeadmin. The only instance variable available inside "form" block is #config.
The best way to solve this issue is to use partials as described in "Customizing the Form"
http://activeadmin.info/docs/5-forms.html
Not entirely sure how selects the correct instance variable on the model, but, you could give pretty much any name to the instance variable, i test some cases and it seems that just looks for the one that haves the same model type when you don't specify it, to answer your other question, you have many ways to do it
the simples one, just the same name as your instance variable,
in your case,
row :attr do
link_to user.display_name, admin_user_path(user)
end
the you have
row :attr do |any_name|
link_to any_name.display_name, admin_user_path(any_name)
end
and the last method i know, you have two escenarios, one for your active_admin files(.rb)
#eg: admin/user.rb
#arbre_context.assigns[:user]
or in custom .arb views, like a form for a custom collection_action(same but direct access)
assigns[:user]
eg:
#views/admin/users/new_invitation.html.arb(arbre) or html.erb
active_admin_form_for assigns[:user], :url => send_invitation_admin_users_path do |user|
....
end
form_for assigns[:user], :url => send_invitation_admin_users_path do |user|
....
end
semantic_form_for assigns[:user], :url => send_invitation_admin_users_path do |user|
.....
Like i say, i'm not sure how active_admin deals with instance variables, but a least you have multiple options, regards
If your goal is to set #user for the show action template, it's not necessary to do so, because active admin is already doing this for you.
If you use member_action, the #user object is there for you, it's called resource.
You can define a singleton method on your resource, it would be available in the view. This could make sense in some cases.
This is another way to pass information from the controller to the view.
member_action :show, method: :get do
resource.instance_eval do
define_singleton_method('language') do
'English'
end
end
end
show do
attributes_table do
row :name
row :email
row :id
row :language
end
end

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