With the goal of creating a JSON string, the requirement is to use an existing attribute and assign it, in the JSON output, with the attribute name id.
#valids = Destination.limit(10).select(:name, :long_name, :other_code).as_json(except: :id)
except: :id is being invoked to avoid confusion, as other_code attribute is intended to be the id in the generated JSON.
this will then be transformed into valid JSON via
#valids.to_json
how can other_code be output as id ?
You can do this like that with a simple string instead of symbols.
Destination
.limit(10)
.select('name, long_name, other_code as id')
.as_json
Honestly am new to Ruby on rails but very experience with json and frontend application responses
You can try this. if it work, you can now try it with your database responses. Ensure that column id exist in that your database
def your_definition_here
respond_to do |format|
#valids='999'
format.json do
render json: {id: #valids}.to_json
#render json: {id: #valids.id}.to_json
end
end
end
I've been using the same pattern for returning json code (see example below). I'm getting a collection of photos and storing it in the variable. If tag param is present, I'm getting a more specific collection and reassigning it to the same variable. Then returning it as json. What would be a better design pattern to achieve the same thing?
photos = collection_of_photos
if params[:tag]
photos = photos.find_all {|photo| some condition}
end
render json: photos
If the photos are ActiveRecord objects you should use a scope to generate the appropriate query for the exact data you need. Otherwise, Rails will load all of the photos instead of the subset you need. Assuming your photos records have a single tag attribute, you can do something like the following:
class Photo < ApplicationRecord
scope :with_tag, (tag) -> { where(tag: tag) }
end
In your controller you'd only need the call that scope since ActiveRecord scopes return an #all scope if no parameters are provided:
render json: Photo.with_tag(params[:tag])
# Equivalent when params[:tag] is nil
render json: Photo.all
Now say you're not dealing with ActiveRecord objects. Say you have an array of hashes:
photos = [{ name: '1.jpg', tag: 'flower'}, ... ]
You can create a helper method to perform the filtering:
class PhotosController < ApplicationController
def index
photos = [{ name: '1.jpg', tag: 'flower'}, ... ]
render json: select_photos_by_tag(photos, params[:tag])
end
private
def select_photos_by_tag(photos, tag)
if tag
photos.select { |photo| photo[:tag] == tag }
else
photos
end
end
end
I am trying to send the serialized version of a model to a view as a param, using the gem active_model_serializers
#app/serializers/admin_serializer.rb
class AdminSerializer < ActiveModel::Serializer
attributes :id, :email, :access_locked?
end
#app/controllers/dashboard/admins_controller.rb
def index
#search = Admin.search(params[:q])
#admins = #search.result(:distinct => true).page(params[:page]).per(10)
#page_entries_info = view_context.page_entries_info #admins
# render json: #admins
respond_to do |format|
format.html
format.js
format.json {render json: #admins}
end
end
#app/views/dashboard/admins/index.html.erb
<%= debug (ActiveModel::Serializer::Adapter.adapter_class(:json_api).new(ActiveModel::Serializer.serializer_for(#admins.first).new(#admins.first),{}).to_json) %>
<%= debug (#admins.all.map{|admin| AdminSerializer.new(admin).to_json}) %>
Above debugs are yielding the below response:
--- '{"data":{"id":"1","type":"admins","attributes":{"email":"tech#bluesapling.com","access_locked?":false}}}' //returned by the first debug
---
- '{"object":{"id":36,"email":"aubrey_schmitt#feeneykoch.io","created_at":"2016-03-28T05:15:17.546Z","updated_at":"2016-03-28T05:15:17.546Z"},"instance_options":{},"root":null,"scope":null}'
- '{"object":{"id":20,"email":"alysa_johnston#thompson.io","created_at":"2016-03-28T05:15:16.304Z","updated_at":"2016-03-28T05:15:16.304Z"},"instance_options":{},"root":null,"scope":null}'
- '{"object":{"id":22,"email":"kristofer.langosh#kunzeluettgen.com","created_at":"2016-03-28T05:15:16.459Z","updated_at":"2016-03-28T05:15:16.459Z"},"instance_options":{},"root":null,"scope":null}'
- '{"object":{"id":37,"email":"beryl_keler#wiza.biz","created_at":"2016-03-28T05:15:17.624Z","updated_at":"2016-03-28T05:15:17.624Z"},"instance_options":{},"root":null,"scope":null}'
- '{"object":{"id":5,"email":"wilhelmine_buckridge#crona.io","created_at":"2016-03-28T05:15:15.139Z","updated_at":"2016-03-28T05:15:15.139Z"},"instance_options":{},"root":null,"scope":null}'
- '{"object":{"id":14,"email":"edward_wisoky#corkery.net","created_at":"2016-03-28T05:15:15.838Z","updated_at":"2016-03-28T05:15:15.838Z"},"instance_options":{},"root":null,"scope":null}'
- '{"object":{"id":27,"email":"leonor#jerde.biz","created_at":"2016-03-28T05:15:16.848Z","updated_at":"2016-03-28T05:15:16.848Z"},"instance_options":{},"root":null,"scope":null}'
- '{"object":{"id":2,"email":"carley#wyman.net","created_at":"2016-03-28T05:15:14.873Z","updated_at":"2016-03-28T05:15:14.873Z"},"instance_options":{},"root":null,"scope":null}'
- '{"object":{"id":10,"email":"ervin.gleichner#cremin.org","created_at":"2016-03-28T05:15:15.527Z","updated_at":"2016-03-28T05:15:15.527Z"},"instance_options":{},"root":null,"scope":null}'
- '{"object":{"id":15,"email":"lonzo.dickens#johnscole.name","created_at":"2016-03-28T05:15:15.916Z","updated_at":"2016-03-28T05:15:15.916Z"},"instance_options":{},"root":null,"scope":null}'
In the first debug I am serializing only one object, while in the second one I am trying to do it for an array of objects.
The first debug is correctly returning the serialized version of the object(in json_api format) while second debug is not.
Tried ArraySerializer as well, with no success: ActiveModel::Serializer::ArraySerializer.new(#admins, each_serializer: AdminSerializer).as_json
how do I achieve the desired serialization. Moreover, if achieved, can I used some other simplified version of this? As this debug statement is way too verbose.
Tried all the solutions mentioned here - How do you initialize an ActiveModel::Serializer class with an ActiveRecord::Relation array?
The basic problem which I am trying to solve is, in the index method of the Admin controller, the Admin object is passed as a PORO to the index.html file. But I want the serialized json version of this object so that I can pass it to my react components as a prop
index method is rendering proper json on firing http://dashboard.localhost.com:3000/admins.json
UPDATE#1 for the index method
def index
#search = Admin.search(params[:q])
#admins_array = #search.result(:distinct => true).to_a
if params[:page]
#admins = #search.result(:distinct => true).page(params[:page][:number]).per(10)
#admins_json_array = Kaminari.paginate_array(#admins_array).page(params[:page][:number]).per(10)
else
#admins = #search.result(:distinct => true).page(1).per(10)
#admins_json_array = Kaminari.paginate_array(#admins_array).page(1).per(10)
end
#admins_json = ActiveModel::SerializableResource.new(#admins_json_array.to_a)
...
...
...
end
I have a controller that I need to specify the serializer in, due to wanting different attributes from the default serializer.
In Controller:
def index
search = User.ransack(search_params)
render json: search.result, each_serializer: MembershipRenewalSerializer::MemberSerializer
end
So, just to get things working, what happens if you specify the each_serializer option?
Edits:
Outside Controller:
ActiveModel::SerializableResource.new(
User.first(2),
each_serializer: MembershipRenewalSerializer::MemberSerializer
).to_json
Note, that without specifying each_serializer, SerializableResource would use the UserSerializer.
Edit #2,
It looks like there is something weird happening with the #admins data.
Try converting to an array:
ActiveModel::SerializableResource.new(#admins.to_a).to_json
Edit #3
To paginate your array, try the following:
#search = Admin.search(params[:q])
#results = #search.result(:distinct => true).to_a
#admins = Kaminari.paginate_array(#results).page(params[:page]).per(10)
Follow the guide: Serializing before controller render
You could use ActiveModel::SerializableResource.new(#admins, adapter: :json_api).to_json
in index.html.erb
<%= debug (ActiveModel::SerializableResource.new(#posts, adapter: :json_api).to_json) %>
below is the output(using posts)
'{"data":[{"id":"1","type":"posts","attributes":{"title":"first post","body":null}},{"id":"2","type":"posts","attributes":{"title":"second post","body":null}}],"links":{}}
I create a concern with some API helper methods and there you can check if its a collection pass find the appropiate serializer and pass it to the collection serializer.
def api_response(data)
render json: wrap_answer(data)
end
def wrap_answer(data)
if data.respond_to?(:each)
ActiveModel::Serializer::CollectionSerializer.new(data, each_serializer: ActiveModel::Serializer.serializer_for(data.first))
else
data
end
end
should have made that into string and use json.stringify to make that as a string and make your life easy
I'm using jQuery autocomplete in a few areas. It makes a call to this method:
def index
#schools = School.order(:name).where("name like ?", "%#{params[:term]}%").limit(10)
render json: #schools.map(&:name)
end
Initially I didn't handle case sensitivity well, so I have some duplicate names in differing cases (ie. "Rutgers" and "rutgers".
I'd like to change the above method to return only unique values, ignoring the case, so only one "Rutgers" result will be returned.
I'm going to clean up the DB but a quick temp fix for this would be great!
I guess it depends on which DB you are using, but you can try doing something like this:
def index
#school_names = School.order("lower(name)")
.where("name ilike ?", "%#{params[:term]}%")
.distinct.limit(10).pluck("lower(name)")
render json: #school_names.map(&:downcase)
end
The above will work with POSTGRESQL, for Sqlite, this will work:
def index
#school_names = School.order("lower(name)")
.where("lower(name) LIKE lower(?)", "%#{params[:term]}%")
.distinct.limit(10).pluck("lower(name)")
render json: #school_names.map(&:downcase)
end
I am aware that ActiveRecord provides a to_json method which allows fields to be filtered out of the JSON output using :only and :except.
At present I am using the following to format an array from a find as JSON:
#customers = Customer.find(:all)
...
format.js { render :json => #customers}
How would I be able to select the fields to be output in the objects in the array? Is there a shortcut or do I need to do this by hand?
Cheers,
Adam
I think you answered your own question. With Rails 2.3.x you could use the following:
#customers = Customer.all #Shortcut for to Customer.find(:all)
respond_to do |format|
format.js { render :json => #customers.to_json(:only=>[:column_one, :column_two]}
end
You can overwrite the to_json method of the model class if you want to globally apply the change for the model.
For example, to exclude null values from the rendered JSON you could overwrite the original ActiveRecord method to_json
def to_json(options)
hash = Serializer.new(self, options).serializable_record
hash = { self.class.model_name => hash } if include_root_in_json
ActiveSupport::JSON.encode(hash)
end
with this in your model class:
def to_json(options)
hash = Serializer.new(self, options).serializable_record.reject {|key, value| value.nil? }
hash = { self.class.model_name => hash } if include_root_in_json
ActiveSupport::JSON.encode(hash)
end
If you peep into the ActionController::Base class, you'll see that it calls to_json on your collection immediately (no extra options used), so you've got to have it already prepared. So if in your action you don't use the attributes that are not rendered to json, you can replace your find with
#customers = Customer.find(:all, :select => ["id", ...])
to select only the ones that you need.