Class: Pupa::Processor::Connection::PostgreSQLAdapter

Inherits:
Object
  • Object
show all
Includes:
Concerns::IndifferentAccess
Defined in:
lib/pupa/processor/connection_adapters/postgresql_adapter.rb

Overview

A proxy class to save plain old Ruby objects to PostgreSQL.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(database_url) ⇒ PostgreSQLAdapter

Returns a new instance of PostgreSQLAdapter.

Parameters:

  • database_url (String) —

    the database URL



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# File 'lib/pupa/processor/connection_adapters/postgresql_adapter.rb', line 13

def initialize(database_url)
  @raw_connection = Sequel.connect(database_url)
end

Instance Attribute Details

#raw_connection ⇒ Object (readonly)

Returns the value of attribute raw_connection.



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# File 'lib/pupa/processor/connection_adapters/postgresql_adapter.rb', line 10

def raw_connection
  @raw_connection
end

Instance Method Details

#find(selector) ⇒ Hash?

Finds a document matching the selection criteria.

The selection criteria must set a _type key in order to determine the collection to query.

Parameters:

  • selector (Hash) —

    the selection criteria

Returns:

  • (Hash, nil) —

    the matched document, or nil



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# File 'lib/pupa/processor/connection_adapters/postgresql_adapter.rb', line 25

def find(selector)
  collection_name = collection_name_from_class_name(selector[:_type].camelize)
  if selector.except(:_type).empty?
    raise Errors::EmptySelectorError, "selector is empty during find in collection #{collection_name}"
  end
  collection = raw_connection[collection_name]
  query = collection.filter(symbolize_keys(selector))

  case query.count
  when 0
    nil
  when 1
    stringify_keys(query.first)
  else
    raise Errors::TooManyMatches, "selector matches multiple documents during find in collection #{collection_name}: #{JSON.dump(selector)}"
  end
end

#save(object) ⇒ Array

Inserts or replaces a document in PostgreSQL.

Parameters:

  • object (Object) —

    an object

Returns:

  • (Array) —

    whether the object was inserted and the object's database ID



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# File 'lib/pupa/processor/connection_adapters/postgresql_adapter.rb', line 48

def save(object)
  fingerprint = symbolize_keys(object.fingerprint) # Sequel needs symbols
  selector = if fingerprint.key?(:$or) && fingerprint.size == 1
    Sequel.or(reject_subdocument_criteria(fingerprint[:$or]))
  else
    reject_subdocument_criteria(fingerprint)
  end

  collection_name = collection_name_from_class_name(object.class.to_s)
  if fingerprint.empty?
    raise Errors::EmptySelectorError, "selector is empty during save in collection #{collection_name} for #{object._id}"
  end
  collection = raw_connection[collection_name]
  query = collection.filter(selector)

  # Run query before callbacks to avoid e.g. timestamps in the selector.
  case query.count
  when 0
    object.run_callbacks(:save) do
      object.run_callbacks(:create) do
        collection.insert(object.to_h(persist: true))
        [true, object._id.to_s]
      end
    end
  when 1
    # Make the document available to the callbacks.
    # @see https://github.com/jpmckinney/pupa-ruby/issues/17
    object.document = stringify_keys(query.first)
    object.run_callbacks(:save) do
      query.update(object.to_h(persist: true).except(:_id))
      [false, object.document['_id'].to_s]
    end
  else
    raise Errors::TooManyMatches, "selector matches multiple documents during save in collection #{collection_name} for #{object._id}: #{JSON.dump(selector)}"
  end
end