Class: Jason::Subscription

Inherits:
Object
  • Object
show all
Defined in:
lib/jason/subscription.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(id: nil, config: nil) ⇒ Subscription

Returns a new instance of Subscription.



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# File 'lib/jason/subscription.rb', line 5

def initialize(id: nil, config: nil)
  if id
    @id = id
    raw_config = $redis_jason.hgetall("jason:subscriptions:#{id}").map { |k,v| [k, JSON.parse(v)] }.to_h
    raise "Subscription ID #{id} does not exist" if raw_config.blank?
    set_config(raw_config)
  else
    @id = Digest::MD5.hexdigest(config.sort_by { |key| key }.to_h.to_json)
    configure(config)
  end
  @includes_helper = Jason::IncludesHelper.new({ model => self.config['includes'] })
  @graph_helper = Jason::GraphHelper.new(self.id, @includes_helper)

  check_for_missing_keys
end

Instance Attribute Details

#config ⇒ Object

Returns the value of attribute config.



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# File 'lib/jason/subscription.rb', line 2

def config
  @config
end

#graph_helper ⇒ Object (readonly)

Returns the value of attribute graph_helper.



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# File 'lib/jason/subscription.rb', line 3

def graph_helper
  @graph_helper
end

#id ⇒ Object

Returns the value of attribute id.



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# File 'lib/jason/subscription.rb', line 2

def id
  @id
end

#includes_helper ⇒ Object (readonly)

Returns the value of attribute includes_helper.



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# File 'lib/jason/subscription.rb', line 3

def includes_helper
  @includes_helper
end

Class Method Details

.all ⇒ Object 



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# File 'lib/jason/subscription.rb', line 208

def self.all
  $redis_jason.smembers('jason:subscriptions').map { |id| Jason::Subscription.find_by_id(id) }
end

.all_for_model(model_name) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 51

def self.all_for_model(model_name)
  $redis_jason.smembers("jason:models:#{model_name}:all:subscriptions")
end

.conditions_for_model(model_name) ⇒ Object

returns [

{ condition: { post_id: 123 }, subscription_ids: [] }

]



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# File 'lib/jason/subscription.rb', line 66

def self.conditions_for_model(model_name)
  rows = $redis_jason.smembers("jason:models:#{model_name}:conditions").map do |row|
    JSON.parse(row)
  end
  conditions = rows.group_by { |row| row['conditions'] }
  conditions.map do |conditions, rows|
    { 'conditions' => conditions, 'subscription_ids' => rows.map { |row| row['subscription_id'] } }
  end
end

.find_by_id(id) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 40

def self.find_by_id(id)
  self.new(id: id)
end

.for_instance(model_name, id, include_all = true) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 55

def self.for_instance(model_name, id, include_all = true)
  subs = $redis_jason.smembers("jason:models:#{model_name}:#{id}:subscriptions")
  if include_all
    subs += all_for_model(model_name)
  end
  subs
end

.for_instance_with_child(model_name, id, child_model_name, include_all = true) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 44

def self.for_instance_with_child(model_name, id, child_model_name, include_all = true)
  sub_ids = for_instance(model_name, id, include_all = true)
  sub_ids.select do |sub_id|
    find_by_id(sub_id).includes_helper.in_sub(model_name, child_model_name)
  end
end

.for_model(model_name) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 76

def self.for_model(model_name)

end

.remove_ids(model_name, ids) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 189

def self.remove_ids(model_name, ids)
  ids.each do |instance_id|
    for_instance(model_name, instance_id, false).each do |sub_id|
      subscription = find_by_id(sub_id)

      id_changeset = subscription.graph_helper.apply_remove_node("#{model_name}:#{instance_id}")
      subscription.apply_id_changeset(id_changeset)
      subscription.broadcast_id_changeset(id_changeset)
    end
  end

  all_for_model(model_name).each do |sub_id|
    subscription = find_by_id(sub_id)
    ids.each do |id|
      subscription.destroy(model_name, id)
    end
  end
end

.update_ids(changed_model_name, changed_model_id, foreign_model_name, old_foreign_id, new_foreign_id) ⇒ Object

Find and update subscriptions affected by a model changing foreign key comment, comment_id, post, old_post_id, new_post_id



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# File 'lib/jason/subscription.rb', line 82

def self.update_ids(changed_model_name, changed_model_id, foreign_model_name, old_foreign_id, new_foreign_id)
  # There are 4 cases to consider.
  # changed_instance ---/--- foreign_instance
  #                  \--+--- new_foreign_instance
  #
  # foreign instance can either be parent or child for a given subscription
  # 1. Child swap/add: foreign is child
  # 2. Stay in the family: foreign is parent + both old and new foreign instances are part of the sub
  # 3. Join the family: foreign is parent + only new foreign instance are part of the sub
  # 4. Leave the family: foreign is parent + only the old foreign instance is part of the sub

  #########
  # Subs where changed is parent
  sub_ids = for_instance_with_child(changed_model_name, changed_model_id, foreign_model_name, true)
  sub_ids.each do |sub_id|
    subscription = find_by_id(sub_id)

    # If foreign key has been nulled, nothing to add
    add = new_foreign_id.present? ? [
      {
        model_names: [changed_model_name, foreign_model_name],
        instance_ids: [[changed_model_id, new_foreign_id]]
      },
      # Add IDs of child models
      subscription.load_ids_for_sub_models(foreign_model_name, new_foreign_id)
    ] : nil

    id_changeset = subscription.graph_helper.apply_update(
      remove: [{
        model_names: [changed_model_name, foreign_model_name],
        instance_ids: [[changed_model_id, old_foreign_id]]
      }],
      add: add
    )

    subscription.apply_id_changeset(id_changeset)
    subscription.broadcast_id_changeset(id_changeset)
  end

  old_sub_ids = for_instance_with_child(foreign_model_name, old_foreign_id, changed_model_name, true)
  new_sub_ids = for_instance_with_child(foreign_model_name, new_foreign_id, changed_model_name, true)

  #########
  # Subs where changed is child
  # + parent in both old + new
  # this is simple, only the edges need to change - no IDs can be changed
  (old_sub_ids & new_sub_ids).each do |sub_id|
    subscription = find_by_id(sub_id)
    subscription.graph_helper.apply_update(
      remove: [{
        model_names: [changed_model_name, foreign_model_name],
        instance_ids: [[changed_model_id, old_foreign_id]]
      }],
      add: [{
        model_names: [changed_model_name, foreign_model_name],
        instance_ids: [[changed_model_id, new_foreign_id]]
      }]
    )
  end

  #########
  # Subs where changed is child
  # + old parent wasn't in the sub, but new parent is
  # IE the changed instance is joining the sub
  # No edges are removed, just added
  (new_sub_ids - old_sub_ids).each do |sub_id|
    subscription = find_by_id(sub_id)
    id_changeset = subscription.graph_helper.apply_update(
      add: [
        {
          model_names: [changed_model_name, foreign_model_name],
          instance_ids: [[changed_model_id, new_foreign_id]]
        },
        # Add IDs of child models
        subscription.load_ids_for_sub_models(changed_model_name, changed_model_id)
      ]
    )

    subscription.apply_id_changeset(id_changeset)
    subscription.broadcast_id_changeset(id_changeset)
  end

  #########
  # --> Leaving the family
  # Subs where changed is child
  # + old parent was in the sub, but new parent isn't
  # Just need to remove the link, orphan detection will do the rest
  (old_sub_ids - new_sub_ids).each do |sub_id|
    subscription = find_by_id(sub_id)
    id_changeset = subscription.graph_helper.apply_update(
      remove: [
        {
          model_names: [changed_model_name, foreign_model_name],
          instance_ids: [[changed_model_id, old_foreign_id]]
        }
      ]
    )
    subscription.apply_id_changeset(id_changeset)
    subscription.broadcast_id_changeset(id_changeset)
  end

  #########
  # ---> Join the community
  # Subs where changed is parent + parent is an _all_ or _condition_ subscription

end

.upsert_by_config(model, conditions: {}, includes: {}) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 32

def self.upsert_by_config(model, conditions: {}, includes: {})
  self.new(config: {
    model: model,
    conditions: conditions || {},
    includes: includes || {}
  })
end

Instance Method Details

#add(model_name, instance_id) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 439

def add(model_name, instance_id)
  idx = $redis_jason.incr("jason:subscription:#{id}:#{model_name}:idx")
  payload = JSON.parse($redis_jason.get("jason:cache:#{model_name}:#{instance_id}") || '{}')

  payload = {
    id: instance_id,
    model: model_name,
    payload: payload,
    md5Hash: id,
    idx: idx.to_i
  }

  broadcaster.broadcast(payload)
end

#add_consumer(consumer_id) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 368

def add_consumer(consumer_id)
  before_consumer_count = consumer_count
  $redis_jason.sadd("jason:subscriptions:#{id}:consumers", consumer_id)
  $redis_jason.hset("jason:consumers", consumer_id, Time.now.utc)

  if before_consumer_count == 0
    set_ids_for_sub_models(enforce: true)
  end
end

#add_id(model_name, id) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 234

def add_id(model_name, id)
  id_changeset = graph_helper.apply_update(
    add: [
      {
        model_names: [model_name],
        instance_ids: [[id]]
      },
      # Add IDs of child models
      load_ids_for_sub_models(model_name, id)
    ]
  )

  apply_id_changeset(id_changeset)
  broadcast_id_changeset(id_changeset)
end

#apply_id_changeset(changeset) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 257

def apply_id_changeset(changeset)
  changeset[:ids_to_add].each do |model_name, ids|
    commit_ids(model_name, ids)
  end

  changeset[:ids_to_remove].each do |model_name, ids|
    remove_ids(model_name, ids)
  end
end

#broadcast_id_changeset(changeset) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 267

def broadcast_id_changeset(changeset)
  changeset[:ids_to_add].each do |model_name, ids|
    ids.each { |id| add(model_name, id) }
  end

  changeset[:ids_to_remove].each do |model_name, ids|
    ids.each { |id| destroy(model_name, id) }
  end
end

#broadcaster ⇒ Object 



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# File 'lib/jason/subscription.rb', line 21

def broadcaster
  @broadcaster ||= Jason::Broadcaster.new(channel)
end

#channel ⇒ Object 



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# File 'lib/jason/subscription.rb', line 387

def channel
  "jason-#{id}"
end

#check_for_missing_keys ⇒ Object 



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# File 'lib/jason/subscription.rb', line 25

def check_for_missing_keys
  missing_keys = includes_helper.all_models - Jason.schema.keys.map(&:to_s)
  if missing_keys.present?
    raise "#{missing_keys.inspect} are not in the schema. Only models in the Jason schema can be subscribed."
  end
end

#clear_all_ids ⇒ Object 



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# File 'lib/jason/subscription.rb', line 327

def clear_all_ids
  includes_helper.all_models.each do |model_name|
    if model_name == model && conditions.blank?
      $redis_jason.srem("jason:models:#{model_name}:all:subscriptions", id)
    end

    ids = $redis_jason.smembers("jason:subscriptions:#{id}:ids:#{model_name}")
    ids.each do |instance_id|
      $redis_jason.srem("jason:models:#{model_name}:#{instance_id}:subscriptions", id)
    end
    $redis_jason.del("jason:subscriptions:#{id}:ids:#{model_name}")
  end
  $redis_jason.del("jason:subscriptions:#{id}:graph")
end

#clear_id(model_name, id, parent_model_name) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 216

def clear_id(model_name, id, parent_model_name)
  remove_ids(model_name, [id])
end

#commit_ids(model_name, ids) ⇒ Object

Add IDs that aren’t present



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# File 'lib/jason/subscription.rb', line 221

def commit_ids(model_name, ids)
  $redis_jason.sadd("jason:subscriptions:#{id}:ids:#{model_name}", ids)
  ids.each do |instance_id|
    $redis_jason.sadd("jason:models:#{model_name}:#{instance_id}:subscriptions", id)
  end
end

#conditions ⇒ Object 



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# File 'lib/jason/subscription.rb', line 354

def conditions
  @config['conditions']
end

#configure(raw_config) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 358

def configure(raw_config)
  set_config(raw_config)
  $redis_jason.sadd("jason:subscriptions", id)
  $redis_jason.hmset("jason:subscriptions:#{id}", *config.map { |k,v| [k, v.to_json] }.flatten)
end

#consumer_count ⇒ Object 



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# File 'lib/jason/subscription.rb', line 383

def consumer_count
  $redis_jason.scard("jason:subscriptions:#{id}:consumers")
end

#destroy(model_name, instance_id) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 364

def destroy
  raise
end

#get ⇒ Object 



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# File 'lib/jason/subscription.rb', line 397

def get
  includes_helper.all_models.map { |model_name| [model_name, get_for_model(model_name)] }.to_h
end

#get_for_model(model_name) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 401

def get_for_model(model_name)
  instance_jsons, idx = Jason::LuaGenerator.new.get_payload(model_name, id)
  if idx == 'missing'
    # warm cache and then retry
    model_klass(model_name).cache_for(instance_jsons)
    instance_jsons, idx = Jason::LuaGenerator.new.get_payload(model_name, id)
  end

  if instance_jsons.any? { |json| json.blank? }
    raise Jason::MissingCacheError
  end

  payload = instance_jsons.map do |instance_json|
    instance_json ? JSON.parse(instance_json) : {}
  end

  {
    type: 'payload',
    model: model_name,
    payload: payload,
    md5Hash: id,
    idx: idx.to_i
  }
end

#ids(model_name = model) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 342

def ids(model_name = model)
  $redis_jason.smembers("jason:subscriptions:#{id}:ids:#{model_name}")
end

#load_ids_for_sub_models(model_name, ids) ⇒ Object

Take a model name and IDs and return an edge set of all the models that appear and their instance IDs



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# File 'lib/jason/subscription.rb', line 279

def load_ids_for_sub_models(model_name, ids)
  # Limitation: Same association can't appear twice
  includes_tree = includes_helper.get_tree_for(model_name)
  all_models = includes_helper.all_models(model_name)

  relation = model_name.classify.constantize.all.eager_load(includes_tree)
  if model_name == model
    if conditions.blank?
      $redis_jason.sadd("jason:models:#{model_name}:all:subscriptions", id)
      all_models -= [model_name]
    elsif conditions.keys == ['id']
      relation = relation.where(conditions)
    else
      $redis_jason.sadd("jason:models:#{model_name}:conditions", {
        'conditions' => conditions,
        'subscription_id' => self.id
      }.to_json)
      relation = Jason::ConditionsMatcher.new(relation.klass).apply_conditions(relation, conditions)
    end
  else
    raise "Must supply IDs for sub models" if ids.nil?
    return if ids.blank?
    relation = relation.where(id: ids)
  end

  pluck_args = all_models.map { |m| "#{m.pluralize}.id" }
  instance_ids = relation.pluck(*pluck_args)

  # pluck returns only a 1D array if only 1 arg passed
  if all_models.size == 1
    instance_ids = instance_ids.map { |id| [id] }
  end

  return { model_names: all_models, instance_ids: instance_ids }
end

#model ⇒ Object 



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# File 'lib/jason/subscription.rb', line 346

def model
  @config['model']
end

#model_klass(model_name) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 350

def model_klass(model_name)
  model_name.to_s.classify.constantize
end

#remove_consumer(consumer_id) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 378

def remove_consumer(consumer_id)
  $redis_jason.srem("jason:subscriptions:#{id}:consumers", consumer_id)
  $redis_jason.hdel("jason:consumers", consumer_id)
end

#remove_id(model_name, id) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 228

def remove_id(model_name, id)
  id_changeset = graph_helper.apply_remove_node("#{model_name}:#{id}")
  apply_id_changeset(id_changeset)
  broadcast_id_changeset(id_changeset)
end

#remove_ids(model_name, ids) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 250

def remove_ids(model_name, ids)
  $redis_jason.srem("jason:subscriptions:#{id}:ids:#{model_name}", ids)
  ids.each do |instance_id|
    $redis_jason.srem("jason:models:#{model_name}:#{instance_id}:subscriptions", id)
  end
end

#reset!(hard: false) ⇒ Object

To be used as a fallback when some corruption of the subscription has taken place



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# File 'lib/jason/subscription.rb', line 427

def reset!(hard: false)
  # Remove subscription state
  if hard
    clear_all_ids
  end

  set_ids_for_sub_models(enforce: true)
  includes_helper.all_models.each do |model_name|
    broadcaster.broadcast(get_for_model(model_name))
  end
end

#set_config(raw_config) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 212

def set_config(raw_config)
  @config =  raw_config.deep_stringify_keys.deep_transform_values { |v| v.is_a?(Symbol) ? v.to_s : v }
end

#set_ids_for_sub_models(model_name = model, ids = nil, enforce: false) ⇒ Object

‘posts’, [post#1, post#2,…]



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# File 'lib/jason/subscription.rb', line 316

def set_ids_for_sub_models(model_name = model, ids = nil, enforce: false)
  edge_set = load_ids_for_sub_models(model_name, ids)
  # Build the tree
  id_changeset = graph_helper.apply_update(
    add: [edge_set],
    enforce: enforce
  )

  apply_id_changeset(id_changeset)
end

#update(model_name, instance_id, payload, gidx) ⇒ Object 



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# File 'lib/jason/subscription.rb', line 454

def update(model_name, instance_id, payload, gidx)
  idx = Jason::LuaGenerator.new.get_subscription(model_name, instance_id, id, gidx)
  return if idx.blank?

  payload = {
    id: instance_id,
    model: model_name,
    payload: payload,
    md5Hash: id,
    idx: idx.to_i
  }

  broadcaster.broadcast(payload)
end

#user_can_access?(user) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/jason/subscription.rb', line 391

def user_can_access?(user)
  # td: implement the authorization logic here
  return true if Jason.subscription_authorization_service.blank?
  Jason.subscription_authorization_service.call(user, model, conditions, includes_helper.all_models - [model])
end