pip_services3_postgres 1.0.2

This framework is part of the [Pip.Services](https://github.com/pip-services/pip-services) project. Postgres components for Pip.Services in Dart

example/main.dart

import 'package:pip_services3_commons/pip_services3_commons.dart';
import 'package:pip_services3_postgres/pip_services3_postgres.dart';

void main(List<String> args) async {
  var dbConfig = ConfigParams.fromTuples([
    'connection.uri',
    null,
    'connection.host',
    'localhost',
    'connection.port',
    5432,
    'connection.database',
    'mytestobjects',
    'credential.username',
    'postgres',
    'credential.password',
    'postgres'
  ]);

  // create two type of persistence
  var persistences = [MyPostgresPersistence(), MyPostgresJsonPersistence()];

  // make operations with persistences
  for (var persistence in persistences) {
    persistence.configure(dbConfig);

    await persistence.open(null);
    await persistence.clear(null);

    await makePersistenceOperations(persistence);

    await persistence.close(null);
  }
}

class MyObject implements IStringIdentifiable, ICloneable {
  @override
  String? id;
  String? key;
  String? content;

  MyObject();

  MyObject.from(this.id, this.key, this.content);

  Map<String, dynamic> toJson() {
    return <String, dynamic>{'id': id, 'key': key, 'content': content};
  }

  void fromJson(Map<String, dynamic> json) {
    id = json['id'];
    key = json['key'];
    content = json['content'];
  }

  @override
  MyObject clone() {
    return MyObject.from(id, key, content);
  }
}

abstract class IMyPersistence {
  Future<DataPage<MyObject>> getPageByFilter(
      String? correlationId, FilterParams? filter, PagingParams? paging);

  Future<MyObject?> getOneById(String? correlationId, String id);

  Future<MyObject?> getOneByKey(String? correlationId, String key);

  Future<MyObject?> create(String? correlationId, MyObject? item);

  Future<MyObject?> update(String? correlationId, MyObject? item);

  Future<MyObject?> set(String? correlationId, MyObject? item);

  Future<MyObject?> deleteById(String? correlationId, String? id);
}

class MyPostgresPersistence
    extends IdentifiablePostgresPersistence<MyObject, String> {
  MyPostgresPersistence() : super('myobjects', null) {
    ensureSchema_(
        "CREATE TABLE myobjects (id VARCHAR(32) PRIMARY KEY, key VARCHAR(50), content VARCHAR(255))");
    ensureIndex_("myobjects_key", {'key': 1}, {'unique': true});
  }

  @override
  void defineSchema_() {
    // pass
  }

  String? _composeFilter(FilterParams? filter) {
    filter = filter ?? FilterParams();

    var criteria = [];

    var id = filter.getAsNullableString('id');
    if (id != null) criteria.add("id='" + id + "'");

    var tempIds = filter.getAsNullableString("ids");
    if (tempIds != null) {
      var ids = tempIds.split(",");
      criteria.add("id IN ('" + ids.join("','") + "')");
    }

    var key = filter.getAsNullableString("key");
    if (key != null) criteria.add("key='" + key + "'");

    return criteria.length > 0 ? criteria.join(" AND ") : null;
  }

  Future<DataPage<MyObject>> getPageByFilter(
      String? correlationId, FilterParams? filter, PagingParams? paging) {
    return super.getPageByFilter_(
        correlationId, _composeFilter(filter), paging, null, null);
  }

  Future<MyObject?> getOneByKey(String? correlationId, String key) async {
    var query =
        "SELECT * FROM " + this.quotedTableName_() + " WHERE \"key\"=@1";
    var params = {'1': key};

    var res = await client_!.query(query, substitutionValues: params);

    var resValues = res.isNotEmpty ? res.first[0][1] : null;

    var item = this.convertToPublic_(resValues);

    if (item == null)
      this.logger_.trace(correlationId, "Nothing found from %s with key = %s",
          [this.tableName_, key]);
    else
      this.logger_.trace(correlationId, "Retrieved from %s with key = %s",
          [this.tableName_, key]);

    item = this.convertToPublic_(item);
    return item;
  }
}

class MyPostgresJsonPersistence
    extends IdentifiableJsonPostgresPersistence<MyObject, String> {
  MyPostgresJsonPersistence() : super('myobjects_json', null) {
    clearSchema();
    ensureTable_(idType: "VARCHAR(32)", dataType: "JSONB");
    ensureIndex_(this.tableName_! + '_json_key', {"(data->>'key')": 1},
        {'unique': true});
  }

  @override
  void defineSchema_() {
    // pass
  }

  String? _composeFilter(FilterParams? filter) {
    filter = filter ?? FilterParams();

    var criteria = [];

    var id = filter.getAsNullableString('id');
    if (id != null) criteria.add("data->>'id'='" + id + "'");

    var tempIds = filter.getAsNullableString("ids");
    if (tempIds != null) {
      var ids = tempIds.split(",");
      criteria.add("data->>'id' IN ('" + ids.join("','") + "')");
    }

    var key = filter.getAsNullableString("key");
    if (key != null) criteria.add("data->>'key'='" + key + "'");

    return criteria.length > 0 ? criteria.join(" AND ") : null;
  }

  Future<DataPage<MyObject>> getPageByFilter(
      String? correlationId, FilterParams? filter, PagingParams? paging) {
    return super.getPageByFilter_(
        correlationId, _composeFilter(filter), paging, 'id', null);
  }

  Future<MyObject?> getOneByKey(String? correlationId, String key) async {
    var query =
        "SELECT * FROM " + this.quotedTableName_() + " WHERE data->>'key'=@1";
    var params = {'1': key};

    var res = await client_!.query(query, substitutionValues: params);

    var resValues = res.isNotEmpty ? res.first[0][1] : null;

    var item = this.convertToPublic_(resValues);

    if (item == null)
      this.logger_.trace(correlationId, "Nothing found from %s with key = %s",
          [this.tableName_, key]);
    else
      this.logger_.trace(correlationId, "Retrieved from %s with key = %s",
          [this.tableName_, key]);

    item = this.convertToPublic_(item);
    return item;
  }
}

Future<void> makePersistenceOperations(
    IdentifiablePostgresPersistence persistence) async {
  var myObject1 = MyObject.from('1', 'Key 1', 'Content 1');
  var myObject2 = MyObject.from('2', 'Key 2', 'Content 2');

  // create items
  var item = await persistence.create(null, myObject1);

  assert(myObject1.id == item!.id);

  item = await persistence.create(null, myObject2);

  assert(myObject2.id == item!.id);

  // delete items
  var deleted = await persistence.deleteById(null, myObject1.id);
  assert(myObject1.id == deleted!.id);

  deleted = await persistence.deleteById(null, myObject2.id);
  assert(myObject2.id == deleted!.id);

  // check deleted
  var items = await persistence.getListByFilter_(null, null, null, null);

  assert(items.isEmpty == true);

  print('All operations completed for persistence ' + persistence.toString());
}