Module: ASModel::CRUD

Defined in:
backend/app/model/ASModel_crud.rb

Overview

Code for converting JSONModels into DB records and back again.

Defined Under Namespace

Modules: ClassMethods

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object 



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# File 'backend/app/model/ASModel_crud.rb', line 8

def self.included(base)
  base.extend(ClassMethods)
  base.include(JSONModel)
  base.extend(JSONModel)
end

.set_audit_fields(json, obj) ⇒ Object 



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# File 'backend/app/model/ASModel_crud.rb', line 17

def self.set_audit_fields(json, obj)
  ['created_by', 'last_modified_by'].each do |field|
    json[field] = obj[field.intern] if obj[field.intern]
  end

  ['system_mtime', 'user_mtime', 'create_time'].each do |field|
    val = obj[field.intern]
    next if !val

    json[field] = val.getutc.iso8601
  end
end

Instance Method Details

#apply_nested_records(json, new_record = false) ⇒ Object

Several JSONModels consist of logical subrecords that are stored as separate models in the database (in separate tables).

When we get a JSON blob for a record with subrecords, we want to create a database record for each subrecords (or, if a URI referencing an existing subrecord was given, use the existing object), then associate those subrecords with the main record.



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# File 'backend/app/model/ASModel_crud.rb', line 60

def apply_nested_records(json, new_record = false)
  self.remove_nested_records if !new_record

  self.class.nested_records.each do |nested_record|
    # Read the subrecords from our JSON blob and fetch or create
    # the corresponding subrecord from the database.
    model = Kernel.const_get(nested_record[:association][:class_name])

    if nested_record[:association][:type] === :one_to_one
      add_record_method = nested_record[:association][:name].to_s
    elsif nested_record[:association][:type] === :many_to_one
      add_record_method = "#{nested_record[:association][:name].to_s.singularize}="
    else
      add_record_method = "add_#{nested_record[:association][:name].to_s.singularize}"
    end

    records = json[nested_record[:json_property]]

    is_array = true
    if nested_record[:association][:type] === :one_to_one || nested_record[:is_array] === false
      is_array = false
      records = [records]
    end

    updated_records = []
    (records or []).each_with_index do |json_or_uri, i|
      next if json_or_uri.nil?

      db_record = nil

      begin
        needs_linking = true

        if json_or_uri.is_a? String
          # A URI.  Just grab its database ID and look it up.
          db_record = model[JSONModel(nested_record[:jsonmodel]).id_for(json_or_uri)]
          updated_records << json_or_uri
        else
          # Create a database record for the JSON blob and return its ID
          subrecord_json = JSONModel(nested_record[:jsonmodel]).from_hash(json_or_uri, true, true)

          # The value of subrecord_json can be mutated by the various
          # transformations performed by the model layer.  Make sure we
          # keep the modified version of the JSON here.
          updated_records << subrecord_json

          if model.respond_to? :ensure_exists
            # Give our classes an opportunity to provide their own logic here
            db_record = model.ensure_exists(subrecord_json, self)
          else
            extra_opts = {}

            if nested_record[:association][:key]
              extra_opts[nested_record[:association][:key]] = self.id

              # We'll skip the call to the .add method because this step
              # will have already linked the nested record to this one.
              needs_linking = false
            end

            db_record = model.create_from_json(subrecord_json, extra_opts)
          end
        end

        if db_record.system_modified?
          # If the subrecord got changed by the system, mark ourselves as
          # modified too.
          self.mark_as_system_modified
        end

        self.send(add_record_method, db_record) if (db_record && needs_linking)
      rescue Sequel::ValidationFailed => e
        # Modify the exception keys by prefixing each with the path up until this point.
        e.instance_eval do
          if @errors
            prefix = nested_record[:json_property]
            prefix = "#{prefix}/#{i}" if is_array

            new_errors = {}
            @errors.each do |k, v|
              new_errors["#{prefix}/#{k}"] = v
            end

            @errors = new_errors
          end
        end

        raise e
      end
    end

    json[nested_record[:json_property]] = is_array ? updated_records : updated_records[0]
  end
end

#delete ⇒ Object

Delete the current record using Sequel’s delete method, but clean up dependencies first.



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# File 'backend/app/model/ASModel_crud.rb', line 224

def delete
  object_graph = self.object_graph

  deleted_uris = []

  successfully_deleted_models = []
  last_error = nil
  while true
    progressed = false
    object_graph.each do |model, ids_to_delete|
      next if successfully_deleted_models.include?(model)

      begin
        model.handle_delete(ids_to_delete)
        successfully_deleted_models << model
        progressed = true
      rescue Sequel::DatabaseError
        last_error = $!
        next
      end

      if model.my_jsonmodel(true)
        ids_to_delete.each do |id|
          deleted_model = model.my_jsonmodel(true)

          deleted_uri = deleted_model.uri_for(id, :repo_id => model.active_repository)

          if deleted_uri
            deleted_uris << deleted_uri
          end
        end
      end
    end

    break if object_graph.models.length == successfully_deleted_models.length

    unless progressed
      if last_error && DB.is_retriable_exception(last_error)
        # Give us a chance to retry after a deadlock
        raise last_error
      end

      raise ConflictException.new("Record deletion failed: #{last_error}")
    end
  end


  deleted_uris.each do |uri|
    Tombstone.create(:uri => uri)
    DB.after_commit do
      RealtimeIndexing.record_delete(uri)
    end
  end
end

#eagerly_load! ⇒ Object

Do whatever is necessary to eaglerly load this object from the database.

This is designed to give mixins the options of eagerly loading an entire record and its components.



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# File 'backend/app/model/ASModel_crud.rb', line 48

def eagerly_load!
  # Do nothing by default
end

#map_validation_to_json_property(columns, property) ⇒ Object

When reporting a Sequel validation error against the set of ‘columns’, report it against the JSONModel ‘property’ instead.

For example, an identifier that must be unique to a repository might have a constraint against the columns [:repository, :identifier], but when we report this to the client we just want to tell them that the value for ‘identifier’ was incorrect.



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# File 'backend/app/model/ASModel_crud.rb', line 287

def map_validation_to_json_property(columns, property)
  errors = self.errors.clone

  self.errors.clear

  errors.each do |error, msg|
    if error == columns
      self.errors[property] = msg
    else
      self.errors[error] = msg
    end
  end
end

#mark_as_system_modified ⇒ Object 



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# File 'backend/app/model/ASModel_crud.rb', line 314

def mark_as_system_modified
  @system_modified = true
end

#remove_nested_records ⇒ Object 



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# File 'backend/app/model/ASModel_crud.rb', line 156

def remove_nested_records
  self.class.nested_records.each do |nested_record_defn|
    if [:one_to_one, :one_to_many].include?(nested_record_defn[:association][:type])
      # If the current record "owns" its nested record, delete the nested record.
      model = Kernel.const_get(nested_record_defn[:association][:class_name])

      # Tell the nested record to clear its own nested records
      Array(self.send(nested_record_defn[:association][:name])).each do |nested_record|
        nested_record.delete
      end
    elsif nested_record_defn[:association][:type] === :many_to_many
      # Just remove the links
      self.send("remove_all_#{nested_record_defn[:association][:name]}".intern)
    elsif nested_record_defn[:association][:type] === :many_to_one
      # Just remove the link
      self.send("#{nested_record_defn[:association][:name].intern}=", nil)
    end
  end
end

#system_modified? ⇒ Boolean

that their local copy of the record includes the system-generated data too.

Returns:

  • (Boolean) 


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# File 'backend/app/model/ASModel_crud.rb', line 309

def system_modified?
  @system_modified
end

#update_from_json(json, extra_values = {}, apply_nested_records = true) ⇒ Object 



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# File 'backend/app/model/ASModel_crud.rb', line 177

def update_from_json(json, extra_values = {}, apply_nested_records = true)
  if self.values.has_key?(:suppressed)
    if self[:suppressed] == 1
      raise ReadOnlyException.new("Can't update an object that has been suppressed")
    end

    # No funny business.  If you want to set this you need to do it via the
    # dedicated controller.
    json["suppressed"] = false
  end


  schema_defined_properties = json.class.schema["properties"].map {|prop, defn|
    prop if !defn['readonly']
  }.compact

  # Start by assuming all existing properties were nil, then overlay the
  # updates plus any extra attributes.
  #
  # This has the effect of unsetting (or setting to NULL) any properties that
  # were removed by this update.
  updated = Hash[schema_defined_properties.map {|property| [property, nil]}].
    merge(json.to_hash).
    merge(ASUtils.keys_as_strings(extra_values))

  if updated.has_key?('lock_version') && !updated['lock_version']
    raise ConflictException.new("You must provide a lock_version in your request")
  end

  self.class.strict_param_setting = false

  self.update(self.class.prepare_for_db(json.class, updated).
              merge(:user_mtime => Time.now,
                    :last_modified_by => RequestContext.get(:current_username)))

  if apply_nested_records
    self.apply_nested_records(json)
  end

  self.class.fire_update(json, self)

  self
end

#validate ⇒ Object 



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# File 'backend/app/model/ASModel_crud.rb', line 31

def validate
  # Check uniqueness constraints
  self.class.repo_unique_constraints.each do |constraint|
    validates_unique([:repo_id, constraint[:property]],
                     :message => constraint[:message])
    map_validation_to_json_property([:repo_id, constraint[:property]],
                                     constraint[:json_property])
  end

  super
end