How to modify params before creating an object - ruby-on-rails

I'm using nested attributes to create a Photo and a Comment object. I would like to set the author on the comment, which is nested inside the photo.
Here are the params:
photo: {
file: 'hi.jpg',
comments_params: [
{ content: "hello world!" }
]
}
But I would like to add the author to the comment.
# ...
comments_params: [
{ content: "hello world!", author: current_user }
]
# ...
What's easiest way to do this? My controller code looks like this.
#photo = Photo.new(photo_params)
#photo.save!
private
def photo_params
params.require(:photo).permit(:file, comments_attributes: [:content])
end
I can do it by manipulating the params after filtering them with strong_parameters (pseudo-code, but the idea stands), but I would rather not.
photo_params[:comments_attributes].each do |comment|
comment[:author] = current_user
end
But this feels a bit wrong.

Instead of messing with params, you could assign author to now-existing objects:
#photo = Photo.new(photo_params)
#photo.comments.select(&:new_record?).each {|c| c.author = current_user }
#photo.save!

I don't think there's anything wrong with the way you'd rather not do it.
You could also perhaps use standard Hash#merge or merge!, or ActiveSupport's deep_merge or deep_merge! in some way.
The fact that comments is an array of potentially many makes it hard to do that nicely though.
I think I would make a copy of the original params rather than editing them in place -- is that what seems wrong to you? ActiveSupport's deep_dup may be be helpful.
How about something like:
photo_params = photo_params.deep_dup
photo_params[:comments_attributes] = photo_params[:comments_attributes].collect {|c| c.merge(:author => :current_user)}
#photo = Photo.new(photo_params)
...
I'm not sure if that is really any better. But maybe it gives you an idea of some of the tools at your disposal.

You can add a hidden field to your comment form.
<%= f.hidden_field :user_id, :value => current_user.id %>

Related

Rails: if record exists then use this record

How do I use the result of an if condition in Rails? Something like:
if #edits.where(:article_id => a.id).first
THIS.body.html_safe
else
a.body.html_safe
end
How on earth do I access the result of that condition? That being the THIS record?
Thanks!
You can do the assignment within the if statement.
if edit = #edits.where(:article_id => a.id).first
edit.body.html_safe
else
a.body.html_safe
end
You could write in one line:
(#edits.where(:article_id => a.id).first || a).body.html_safe
Putting such logic in view or helper is very ugly. It's not View's job to judge these.
Better alternative:
# Article model
def default_edit
edits.first
end
# Articles Controller
def show
article = Article.find(params[:article])
#article = article.default_edit || article
end
# view: no need to do anything, just plain obj
<%= #article.body %>
You can use find_by or find_by_* to avoid the nasty .where().first
if edit = Edit.find_by(article_id: article.id)
edit.body.html_safe
else
article.body.html_safe
end

Can I use AR object as hash key or should I use object_id instead

Because of Ruby awesomeness it is possible to use any object as key
document = Document.find 1
o = Hash.new
o[1] = true
o[:coool] = 'it is'
o[document] = true
# an it works
o[document]
#=> true
but just because it is possible doesn't mean is good practice
However I have situation where in my controller I need to set something similar, so I can loop trough it in view
#controller
#users_with_things = Hash.new
Things.accessible_by(some_curent_user_logic).each do |thing|
#user_with_things[thing.user] ||= Array.new
#user_with_things[thing.user] << thing.id
end
#view
- #users_with_things.each do |user, thing_ids|
%input{type: :checkbox, name: "blank[user_#{user.id}]", value: 1, class: "select_groups", :'data-resource-ids' => "[#{thing_ids.join(',')}]", :'data-user-type' => user.type }
The reason why I want to do it this way is because I don't want to call from my view User.find_by_id (want to make it clean)
#controller
#users_with_things = Hash.new
Things.accessible_by(some_curent_user_logic).each do |thing|
#user_with_things[thing.user.id] ||= Array.new
#user_with_things[thing.user.id] << thing.id
end
#view
- #users_with_things.each do |user_id, thing_ids|
- user = User.find user_id
%input{type: :checkbox, name: "blank[user_#{user.id}]", value: 1, class: "select_groups", :'data-resource-ids' => "[#{thing_ids.join(',')}]", :'data-user-type' => user.type }
So my 1st question is: is it ok to use ActiveRecord object as Hash key in situation like this
I can imagine several scenarios where this may go wrong (sessions, when object changes in model and so on) however this is just for rendering in a view
Alternative !
so this is one way to do it, the other may be like this
#controller
#users_with_things = Hash.new
Things.accessible_by(some_curent_user_logic).each do |thing|
#user_with_things[thing.user.object_id] ||= Array.new
#user_with_things[thing.user.object_id] << thing.id
end
#view
- #users_with_things.each do |user_object_id, thing_ids|
- user = ObjectSpace._id2ref(user_object_id) #this will find user object from object_id
%input{type: :checkbox, name: "blank[user_#{user.id}]", value: 1, class: "select_groups", :'data-resource-ids' => "[#{thing_ids.join(',')}]"", :'data-user-type' => user.type }
...which is even more, hardcore. However it is way around if for some reason hash[ARobject] = :something would create big memory cluster for some reason
question 2 : is it good idea to do it this way ?
to be complete there is also another alternative and that is
# ...
#user_with_thing[ [thing.user.id, thing.user.type] ] << thing_id
# ...
so basically array object will be key
#user_with_thing[ [1, 'Admin'] ]
#=> [1,2,3]
I think to use a hash is a good way to organise in your situation. However, I would advise against using the user or to big an object as hash keys, simply because it renders your hash unreadable and because it is really only this sole object with it's object id that can be used as a key.
o = Object.new
h = { o => 'something' }
h[Object.new] #=> nil
In your situation, this may not be an issue, because you simply need to iterate it. But it may be a shot in the leg as soon as you want to do something else with that hash, or you have different instances of the same Active Record Data (which is very common in Rails applications, unless you are a really paying attention what gets loaded when). Besides that, I think it is good to stick by the widely used convention to use simple objects (strings, symbols) as hash keys to make your code readable and maintainable.
Maybe it would be best to keep a two-dimensional hash, like this:
#users_with_things = Things.accessible_by(some_curent_user_logic).inject({}) do |a, thing|
user_id = thing.user.id
a[user_id] ||= { :user => thing.user, :things => [] }
a[user_id][:thing] << thing
a
end
Then you can iterate over #users_with_things in your view like this:
#users_with_things.each do |user_id, values|
# values[:user] is the user, values[:things] the array of things

Ruby: Formatting table data to JSON

I'm trying to make a timeline for an the bugs and updates for an open source project. I'm new to ruby, but I'm getting some experience gradually.
I've created a table called historical_gems, with the following code in the model:
class HistoricalGem < ActiveRecord::Base
attr_accessible :build_date, :version
belongs_to :ruby_gem, :foreign_key => :gem_id
end
I'm using a JS Plugin (http://almende.github.com/chap-links-library/js/timeline/doc) that requires objects with two field names ('start' for the date and 'content' for the title) in the JSON Array to display the timeline using JS.
I believe I have to do something like this in the controller which defines my timeline method to render the JSON:
def timelinem
#name = params[:id]
#rpm = AbcTable.find_by_name(#name)
respond_to do |format|
format.json { render :json => #rpm.json_timelines }
end
end
Then I probably would have to define a 'json_timelines' method inside my model, maybe something like:
def json_timelines(gems = [])
dates = []
gem_id.each { |p|
gems << p
dates << p.build_date(gems)
end
}
end
I'm only starting out with RoR, and even after hours with guides and tutorials and debugging, I'm not able to put together this code. Can anyone help me out, please? I don't think I'm doing it right.
btw, don't be too harsh if I overlooked something obvious, I'm only 16 :)
The render :json => ... in your code should work fine (but with HistoricalGem instead of AbcTable) as long as json_timelines returns an object that's serializable as JSON (e.g., an Array or a Hash).
Try something like this for your method definition:
def json_timelines(gems = [])
gems.map do |g|
{
:content => g.title,
:date => g.build_date
}
end
end
The above snippet assumes your "historical_gems" table has "title" and "build_date" columns; if not, adjust the code to reflect the fields you actually want represented in your JSON.

Is using Playlist.new(params[:playlist]) ever not ok?

Specifically in my new/create actions. I have #playlist = Playlist.new(params[:playlist]). The thing is I also have sensitive data in attr_accessible that I don't want them to modify (the number of listens on a playlist, which they shouldnt be able to update).
I tried Playlist.new(:title => params[:title], :description => params[:description], etc) but that didn't work. I assume because I need to do params[:playlist][:title] but this looks quite messy. Am I doing this incorrectly?
In the Model you can write a function called for example, new_safe which creates the new object with the params you want and then returns it
like this:
def new_safe(params)
playlist = Playlist.new
playlist.title = params[:title]
playlist.description = params[:description]
playlist.save
playlist
end
Just thinking, similiarly you could write it like this which is a bit cleaner
Controller:
#playlist = Playlist.new
#playlist.input_params(params)
Model:
def input_params(params)
playlist.title = params[:title]
playlist.description = params[:description]
playlist.save
end

metaprogramming for params

How can I update these very similar text fields in a less verbose way? The text fields below are named as given - I haven't edited them for this question.
def update
company = Company.find(current_user.client_id)
company.text11 = params[:content][:text11][:value]
company.text12 = params[:content][:text12][:value]
company.text13 = params[:content][:text13][:value]
# etc
company.save!
render text: ""
end
I've tried using send and to_sym but no luck so far...
[:text11, :text12, :text13].each do |s|
company.send("#{s}=".to_sym, params[:content][s][:value])
end
If they are all incremental numbers, then:
11.upto(13).map{|n| "text#{n}".to_sym}.each do |s|
company.send("#{s}=".to_sym, params[:content][s][:value])
end
I'd consider first cleaning up the params, then move onto dynamically assigning attributes. A wrapper class around your params would allow you to more easily unit test this code. Maybe this helps get you started.
require 'ostruct'
class CompanyParamsWrapper
attr_accessor :text11, :text12, :text13
def initialize(params)
#content = params[:content]
content_struct = OpenStruct.new(#content)
self.text11 = content_struct.text11[:value]
self.text12 = content_struct.text12[:value]
self.text13 = content_struct.text13[:value]
end
end
# Company model
wrapper = CompanyParamsWrapper.new(params)
company.text11 = wrapper.text11
# now easier to use Object#send or other dynamic looping

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