MongoDbPersistence

Implements: IReferenceable, IUnreferenceable, IConfigurable, IOpenable, ICleanable

Description

The MongoDbPersistence class allows you to create persistence components that store data in MongoDB databases using the official MongoDB driver.

Important points

• This is the most basic persistence component that is only able to store data items of any type.
• Specific CRUD operations over the data items must be implemented in child classes by accessing the _collection property.

Configuration parameters

• collection: (optional) MongoDB collection name

connection(s):

• discovery_key: (optional) key to retrieve the connection from IDiscovery
• host: host name or IP address
• port: port number (default: 27017)
• uri: resource URI or connection string with all parameters in it

credential(s):

• store_key: (optional) key to retrieve the credentials from ICredentialStore
• username: (optional) username
• password: (optional) user’s password

options:

• max_pool_size: (optional) maximum connection pool size (default: 2)
• keep_alive: (optional) enable connection keep alive (default: true)
• connect_timeout: (optional) connection timeout in milliseconds (default: 5000)
• socket_timeout: (optional) socket timeout in milliseconds (default: 360000)
• auto_reconnect: (optional) enable auto reconnection (default: true)
• reconnect_interval: (optional) reconnection interval in milliseconds (default: 1000)
• max_page_size: (optional) maximum page size (default: 100)
• replica_set: (optional) name of replica set
• ssl: (optional) enable SSL connection (default: false)
• auth_source: (optional) authentication source
• debug: (optional) enable debug output (default: false).

References

• *:logger:*:*:1.0 - (optional) ILogger components to pass log messages
• *:discovery:*:*:1.0 - (optional) IDiscovery services
• *:credential-store:*:*:1.0 - (optional) credential stores to resolve credentials

Constructors

Creates a new instance of the persistence component.

MongoDbPersistence([String? collection])

• collection: String? - (optional) collection name.

Fields

Instance methods

clear

Clears a component’s state.

@override

Future clear(String? correlationId)

• correlationId: String? - object to convert from the public partial format.

close

Closes the component and frees used resources.

@override

Future close(String? correlationId)

• correlationId: String? - object to convert from the public partial format.

configure

Closes the component and frees used resources.

@override void configure(ConfigParams config)

• config: ConfigParams - configuration parameters to be set.

convertFromPublic

Converts an object value from public to internal format.

Map<String, dynamic>? convertFromPublic(dynamic item, {bool createUid = false})

• value: dynamic - object in public format to convert.
• createUid: bool - autocreation flag Uid
• returns: Map<String, dynamic>? - converted object in internal format.

convertFromPublicPartial

Converts the given object from the public partial format.

Map<String, dynamic>? convertFromPublicPartial(Map<String, dynamic>? item)

• item: Map<String, dynamic>? - the object to convert from the public partial format.
• returns: Map<String, dynamic>? - the initial object.

convertToPublic

Converts and object value from internal to public format.

dynamic convertToPublic(Map<String, dynamic>? item)

• value: dynamic - object in internal format to convert.
• returns: Map<String, dynamic>? - converted object in public format.

create

Creates a data item.

Future<T?> create(String? correlationId, T? item)

• correlationId: String? - (optional) transaction id used to trace execution through the call chain.
• item: T? - item to be created.
• returns: Future<T?> - created item

deleteByFilter

This method shall be called by a public deleteByFilter method from the child class that receives FilterParams and converts them into a filter function.

Future deleteByFilterEx(String? correlationId, Map<String, dynamic> filter)

• correlationId: String? - (optional) transaction id used to trace execution through the call chain.
• filter: Map<String, dynamic> - (optional) filter function used to filter items.

ensureIndex

Adds index definition to create it on opening.

void ensureIndex(keys, {String key, bool unique = false, bool sparse = false, bool background = false, bool dropDups = false, Map<String, dynamic> partialFilterExpression, String name})

• keys: dynamic - index keys (fields)
• key: String - index options
• unique: bool - TODO: add description
• sparse: bool - TODO: add description
• background: bool - TODO: add description
• dropDups: bool - TODO: add description
• partialFilterExpression: Map<String, dynamic> - TODO: add description
• name: String - TODO: add description

getCountByFilter

Gets a number of data items retrieved by a given filter.

This method shall be called by a public getCountByFilter method from the child class that receives FilterParams and converts them into a filter function.

Future<int> getCountByFilterEx(String? correlationId, Map<String, dynamic>? filter)

• correlationId: String? - (optional) transaction id usedto trace execution through the call chain.
• filter: Map<String, dynamic>? - (optional) filter JSON object
• returns: Future<int> - number of filtered items.

getListByFilter

Gets a list of data items retrieved by a given filter and sorted according to sort parameters.

This method shall be called by a public getListByFilter method from the child class that receives FilterParams and converts them into a filter function.

Future<List<T>> getListByFilterEx(String? correlationId, Map<String, dynamic>? filter, Map<String, dynamic>? sort)

• correlationId: String? - (optional) transaction id used to trace execution through the call chain.
• filter: Map<String, dynamic>? - (optional) filter function used to filter items
• sort: Map<String, dynamic>? - (optional) sorting parameters
• returns: Future<List<T>> - data list of results by filter.

getOneRandom

Gets a random item from items that match to a given filter.

This method shall be called by a public getOneRandom method from the child class that receives FilterParams and converts them into a filter function.

Future<T?> getOneRandom(String? correlationId, Map<String, dynamic> filter)

• correlationId: String? - (optional) transaction id used to trace execution through the call chain.
• filter: Map<String, dynamic> - fileter JSON object.
• returns: Future<T?> - random item.

getPageByFilter

Gets a page of data items retrieved by a given filter and sorted according to sort parameters.

This method shall be called by a public getPageByFilter method from the child class that receives FilterParams and converts them into a filter function.

Future<DataPage<T>> getPageByFilterEx(String? correlationId, Map<String, dynamic> filter, PagingParams paging, Map<String, dynamic> sort)

• correlationId: String? - (optional) transaction id used to trace execution through the call chain.
• filter: Map<String, dynamic> - (optional) filter JSON object
• paging: PagingParams - (optional) paging parameters
• sort: Map<String, dynamic> - (optional) sorting JSON object
• returns: Future<DataPage<T>> - data page obtained by filtering

Examples

class MyMongoDbPersistence extends MongoDbPersistence<MyData> {
  MyMongoDbPersistence():base('mydata');

  Future<MyData> getByName(String? correlationId, String name) {
      var filter = {'name': name};
      var query = mngquery.SelectorBuilder();
      var selector = <String, dynamic>{};
      selector[r'$query'] = filter;
      query.raw(selector);
      var item = await collection.findOne(filter);
      if (item == null) {
        return null;
      }
      item = convertToPublic(item);
      var instance = MyData.fromJson(item);
      return instance;
  });

  Future<MyData> set(String correlatonId, MyData item) {
    if (item == null) {
      return null;
    }
    var jsonMap = json.decode(json.encode(item));
    // Assign unique id
    if (jsonMap['id'] == null) {
      jsonMap['id'] = IdGenerator.nextLong();
    }
    convertFromPublic(jsonMap);
    var filter = {r'$query': {'name': jsonMap['name']}};
    var result = await collection.findAndModify(
        query: filter, update: jsonMap, returnNew: true, upsert: true);
    if (result != null) {
        convertToPublic(result);
        var newItem = MyData.fromJson(result);;
        return newItem;
    }
    return null;
  }
}

var persistence = MyMongoDbPersistence();
persistence.configure(ConfigParams.fromTuples([
    'host', 'localhost',
    'port', 27017
]));

await persitence.open('123');
await persistence.set('123', { name: 'ABC' });
var item = await persistence.getByName('123', 'ABC');
print(item);         // Result: { name: 'ABC' }