Rails API Serializer - ruby-on-rails

I want to combine 2 models and sort them out and expose the result on my serializer.
so in my user controller I have
#users_controller.rb
def transactions
#debit = current_user.debits.all
#credit = current_user.credits.all
#history = [#debit, #credit].flatten
#sorted_history = #history.sort_by { |item| item.created_at.strftime('%m/%d/%y') }
render json: UserTransactionSerializer.new(#sorted_history).call
end
and on my serializer I have:
module Api
module V1
class UserTransactionSerializer < BaseSerializer
def call
{
id: object.id,
amount: object.amount,
status: object.status,
created_at: object.created_at.iso8601
}
end
end
end
end
I'm getting this error bellow:
NoMethodError (undefined method `id' for #<Array:0x0055ce49b57b20>)
EDIT: Typo

Your #sorted_history is an array, but UserTransactionSerializer should be passed in an object.
So easy solution would be:
render json: #sorted_history.map{ |trans| UserTransactionSerializer.new(trans).call }

object is an Array, so you have to iterate and return hash for each object in that Array.
def call
object.map do |obj|
{
id: obj.id,
amount: obj.amount,
status: obj.status,
created_at: obj.created_at.iso8601
}
end
end

Related

Rails 5 manage result from monads

I've got Rails 5 app with dry-monads on board. Monads are used to create the Appointment object inside create action in AppointmentsController. They return Success or Failure in the last step with below structure:
# services/appointments/create.rb
(...)
def call
Success(appointment_params: appointment_params)
(...)
.bind(method(:save_appointment))
end
private
def save_appointment(appointment)
if appointment.save
Success(appointment)
else
Failure(failure_appointments: appointment, appointments_errors: appointment.errors.full_messages)
end
end
After each action (success or failure) I want to send an email and display the corresponding json in AppointmentsController:
class Api::AppointmentsController < ApplicationController
def create
succeeded_appointments = []
failure_appointments = []
appointments_errors = []
batch_create_appointments_params[:_json].each do |appointment_params|
appointment = ::Appointments::Create.new(appointment_params).call
if appointment.success?
succeeded_appointments << appointment.value!
else
failure_appointments << appointment.failure[:failure_appointments] &&
appointments_errors << appointment.failure[:appointments_errors]
end
end
if failure_appointments.any?
AppointmentMailer.failed_mail(email, failure_appointments.size, appointments_errors).deliver_now
render json: {
error: appointments_errors.join(', '),
}, status: :bad_request
elsif succeeded_appointments.any?
AppointmentMailer.success_mail(email, succeeded_appointments.size).deliver_now
render json: {
success: succeeded_appointments.map do |appointment|
appointment.as_json(include: %i[car customer work_orders])
end,
}
end
end
I wonder if there is a better, faster way to record these errors than declaring 3 different empty arrays (succeeded_appointments, failure_appointments, appointments_errors) like at the beginning of create action? so far the create action looks heavy.
Create a separate service object for bulk creation:
# services/appointments/bulk_create.rb
class Appointments::BulkCreate
def initialize(bulk_params)
#bulk_params = bulk_params
end
def call
if failed_results.any?
AppointmentMailer.failed_mail(email, failed_results_errors.size, failed_results_errors).deliver_now
Failure(failed_results_errors.join(', '))
else
AppointmentMailer.success_mail(email, success_appointments.size).deliver_now
Success(success_appointments)
end
end
private
attr_reader :bulk_params
def failed_results
results.select(&:failure?)
end
def success_results
results.select(&:success?)
end
def success_appointments
#success_appointments ||= success_results.map do |appointment|
appointment.as_json(include: %i[car customer work_orders])
end
end
def failed_results_errors
#failed_results_errors ||= failed_results.map do |failed_result|
failed_result.failure[:appointments_errors]
end
end
def results
#results ||= bulk_params.map do |appointment_params|
::Appointments::Create.new(appointment_params).call
end
end
end
Then your controller will look like this:
class Api::AppointmentsController < ApplicationController
def create
result = ::Appointments::BulkCreate.new(batch_create_appointments_params[:_json]).call
if result.success?
render json: { success: result.value! }, status: :ok
else
render json: { error: result.failure }, status: :bad_request
end
end
end

Returning resources with different types for rails Restful API

I am working on implementing a search endpoint with ruby based on a json request sent from the client which should have the form GET /workspace/:id/searches? filter[query]=Old&filter[type]=ct:Tag,User,WokringArea&items=5
The controller looks like this
class SearchesController < ApiV3Controller
load_and_authorize_resource :workspace, class: "Company"
load_and_authorize_resource :user, through: :workspace
load_and_authorize_resource :working_area, through: :workspace
def index
keyword = filtered_params[:query].delete("\000")
keyword = '%' + keyword + '%'
if filtered_params[:type].include?('User')
#users = #workspace.users.where("LOWER(username) LIKE LOWER(?)", keyword)
end
if filtered_params[:type].include?('WorkingArea')
#working_areas = #workspace.working_areas.where("LOWER(name) LIKE LOWER(?)", keyword)
end
#resources = #working_areas
respond_json(#resources)
end
private
def filtered_params
params.require(:filter).permit(:query, :type)
end
def ability_klasses
[WorkspaceAbility, UserWorkspaceAbility, WorkingAreaAbility]
end
end
respond_json returns the resources with a json format and it looks like this
def respond_json(records, status = :ok)
if records.try(:errors).present?
render json: {
errors: records.errors.map do |pointer, error|
{
status: :unprocessable_entity,
source: { pointer: pointer },
title: error
}
end
}, status: :unprocessable_entity
return
elsif records.respond_to?(:to_ary)
#pagy, records = pagy(records)
end
options = {
include: params[:include],
permissions: permissions,
current_ability: current_ability,
meta: meta_infos
}
render json: ApplicationRecord.serialize_fast_apijson(records, options), status: status
end
Now the issue is the response is supposed to look like this:
{
data: [
{
id: 32112,
type: 'WorkingArea'
attributes: {}
},
{
id: 33321,
type: 'User',
attributes: {}
},
{
id: 33221,
type: 'Tag'
attributes: {}
}
How can I make my code support responding with resources that have different types?
You can define a model, not in your database, that is based on the results from the API. Then you include some of the ActiveModel modules for more features.
# app/models/workspace_result.rb
class WorkspaceResult
include ActiveModel::Model
include ActiveModel::Validations
include ActiveModel::Serialization
attr_accessor(
:id,
:type,
:attributes
)
def initialize(attributes={})
filtered_attributes = attributes.select { |k,v| self.class.attribute_method?(k.to_sym) }
super(filtered_attributes)
end
def self.from_json(json)
attrs = JSON.parse(json).deep_transform_keys { |k| k.to_s.underscore }
self.new(attrs)
end
end
Then in your API results you can do something like:
results = []
response.body["data"].each do |result|
results << WorkspaceArea.from_json(result)
end
You can also define instance methods on this model, etc.

Active Model Serializers pagination links not showing

I'm using the instructions here: https://github.com/rails-api/active_model_serializers/blob/master/docs/howto/add_pagination_links.md
I have an initializer file with:
ActiveModelSerializers.config.adapter = :json_api
(restarted the server to initialize)
In my model I have:
def packages
#user = User.find(params[:id])
#records = #user.get_records("api").paginate(page: params[:page], per_page: 3)
render json: #records
end
My response is as follows and is not showing the links block:
[
{
created_at: "2016-04-07T18:24:03.216Z",
title: "Record 1"
},
{
created_at: "2016-03-07T18:24:43.245Z",
title: "Record 2"
},
{
created_at: "2016-02-07T18:22:33.236Z",
title: "Record 3"
}
]
I can see in my server log that it's using will_paginate:
[active_model_serializers] Rendered ActiveModel::Serializer::CollectionSerializer with WillPaginate::Collection (0.13ms)
Any ideas why I'm not seeing the links?
Update:
I am paginating an array with will_paginate, therefore I added require 'will_paginate/array' in the controller.
When I try to follow the second method of creating the dictionary in the controller like so...
class Api::V1::UsersController < ActionController::Base
require 'will_paginate/array'
def packages
#user = User.find(params[:id])
#records = #user.get_records("api").paginate(page: params[:page], per_page: 3)
render json: #records,
meta: pagination_dict(#records)
end
def pagination_dict(object)
{
current_page: object.current_page,
next_page: object.next_page,
prev_page: object.prev_page,
total_pages: object.total_pages,
total_count: object.total_count
}
end
end
Then I get:
undefined method `prev_page' for #<WillPaginate::Collection:0x007fced3698d78> Did you mean? previous_page per_page
Which I find also strange.
The function pagination_dict(object) should be in your Base controller and not in the Users Controller

Change Json output, return `icd3_code_id` as `:id`

At the time my controller looks like this:
def search
#icd4 = Icd4Code.search_full(params[:search]).first(20)
render json: { icd: #icd4.as_json(:only => [:bezeichnung, :nummer, :id])}
end
What i would like to change is that my code does not return #icd4.id as :id but instead #icd4.icd3_code_id as :id
So render json: { icd: #icd4 } would look like this:
{"icd":[{"id":6,"nummer":"A00.1","bezeichnung":"Cholera","icd3_code_id":3,"created_at":"2014-02-28T19:38:20.530Z","updated_at":"2014-02-28T19:38:20.530Z"},{"id":7,"nummer":"A00.1","bezeichnung":"El-Tor-Cholera","icd3_code_id":3,"created_at":"2014-02-28T19:38:20.533Z","updated_at":"2014-02-28T19:38:20.533Z"}]}
My actual code render json: { icd: #icd4.as_json(:only => [:bezeichnung, :nummer, :id])} returns this:
{"icd":[{"id":6,"nummer":"A00.1","bezeichnung":"Cholera"},{"id":7,"nummer":"A00.1","bezeichnung":"El-Tor-Cholera"}]}
And i would like this output:
{"icd":[{"id":3,"nummer":"A00.1","bezeichnung":"Cholera"},{"id":7,"nummer":"A00.1","bezeichnung":"El-Tor-Cholera"}]}
How can i achieve this? Thanks
Without a serializer you can iterate through the items and their keys and rename the key when you find yours.
#icd4 = Icd4Code.search_full(params[:search]).first(20)
data = #icd4.as_json(:only => [:bezeichnung, :nummer, :icd3_code_id]).tap do |icd4_json|
icd4_json.each do |icd4_item|
icd4_item.each do |key|
icd4_item[ 'id' ] = icd4_item.delete( key ) if key == 'icd3_code_id'
end
end
end
render json: { icd4: data }
You should definitely take a look at draper and active_model_serializers gems.
http://railscasts.com/episodes/409-active-model-serializers
http://railscasts.com/episodes/286-draper
although I use Draper in a bit different way then Ryan Bates does, usually I do something like this:
render json: item.decorate.as_json
for example as a simplest solution you could have this class:
class Icd4CodeDecorator < Draper::Decorator
decorates :icd4_code
delegate_all
def as_json(options={})
{
id: icd3_code_id,
bezeichnung: bezeichnung,
nummer: nummer
}
end
end
and then in your controller you could just do:
render json: #icd4.decorate.as_json
Although I think it would be better to keep things correct in as_json method and have id value returned for id property and create a decorator class inherited from Draper::CollectionDecorator and define there your custom method, something like:
class Icd4CodesDecorator < Draper::CollectionDecorator
def as_search_json
object.map do |o|
{
id: icd3_code_id,
bezeichnung: bezeichnung,
nummer: nummer
}
end
end
end
and then in your controller you could do:
render json: Icd4CodesDecorator.new(#icd4).as_search_json
This way you can easily create and maintain any number of versions of json output for your models.
The simplest way is to cleverly change the value something like this
def search
#icd4 = Icd4Code.search_full(params[:search]).first(20)
r = icd: #icd4.as_json(:only => [:bezeichnung, :nummer, :icd3_code_id])
final_value = []
r["icd"].each do |h|
f = {}
h.map do |k,v|
if k == 'icd3_code_id'
f["id"] = v
else
f[k] = v
end
end
final_value << f
end
render json: final_value
end

Define several json formats for model

In my rails app i defined a specific JSON-Format in my model:
def as_json(options={})
{
:id => self.id,
:name => self.name + ", " + self.forname
}
end
And in the controller i simply call:
format.json { render json: #patients}
So now im trying to define another JSON-Format for a different action but i dont know how?
How do i have to define another as_json or how can i pass variables to as_json? Thanks
A very ugly method but you can refactor it for better readability:
def as_json(options={})
if options.empty?
{ :id => self.id, :name => self.name + ", " + self.forname }
else
if options[:include_contact_name].present?
return { id: self.id, contact_name: self.contact.name }
end
end
end
Okay, I should give you a better piece of code, here it is:
def as_json(options = {})
if options.empty?
self.default_json
else
json = self.default_json
json.merge!({ contact: { name: contact.name } }) if options[:include_contact].present?
json.merge!({ admin: self.is_admin? }) if options[:display_if_admin].present?
json.merge!({ name: self.name, forname: self.forname }) if options[:split_name].present?
# etc etc etc.
return json
end
end
def default_json
{ :id => self.id, :name => "#{self.name}, #{self.forname}" }
end
Usage:
format.json { render json: #patients.as_json(include_contact: true) }
By defining hash structure by 'as_json' method, in respective model class i.e User model in (Example 1), it becomes the default hash stucture for active record(i.e., user) in json format. It cannot be overridden by any inline definitions as defined in Example: 2
Example 1:
class User < ActiveRecord::Base
.....
def as_json(options={})
super(only: [:id, :name, :email])
end
end
Example: 2
class UserController < ApplicationController
....
def create
user = User.new(params[:user])
user.save
render json: user.as_json( only: [:id, :name] )
end
end
Therefore, in this example when create action is executed 'user' is returned in ("only: [:id, :name, :email]") format not as ("only: [:id, :name]")
So, options = {} are passed to as_json method to specifiy different format for different methods.
Best Practice, is to define hash structure as constant and call it everwhere it is needed
For Example
Ex: models/user.rb
Here, constant is defined in model class
class User < ActiveRecord::Base
...
...
DEFAULT_USER_FORMAT = { only: [:id, :name, :email] }
CUSTOM_USER_FORMAT = { only: [:id, :name] }
end
Ex: controllers/user.rb
class UserController < ApplicationController
...
def create
...
render json: user.as_json(User::DEFAULT_USER_FORMAT)
end
def edit
...
render json: user.as_json(User::CUSTOM_USER_FORMAT)
end
end
Cool!

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