IdentifiableJsonPostgresPersistence<T, K>

Inherits: IdentifiablePostgresPersistence<T, K>,

Description

The IdentifiableJsonPostgresPersistence class allows you to create persistence components used to store data in PosgreSQL databases in JSON or JSONB fields and implement a number of CRUD operations over data items with unique ids.

Important points

• The data items must implement the IIdentifiable interface.
• In basic scenarios, child classes shall only override the getPageByFilter, getListByFilter or deleteByFilter operations with a specific filter function.
• All other operations can be used out of the box.
• In complex scenarios, child classes can implement additional operations by accessing this._collection and this._model properties.

Configuration parameters

• collection: (optional) PostgreSQL collection name connection(s):
• discovery_key: (optional) key used 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:

• connect_timeout: (optional) number of milliseconds to wait before timing out when connecting a new client (default: 0)
• idle_timeout: (optional) number of milliseconds a client must sit idle in the pool and not be checked out (default: 10000)
• max_pool_size: (optional) maximum number of clients the pool can contain (default: 10)

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 (ICredentialStore)

Constructors

Creates a new instance of the persistence component.

public IdentifiableJsonPostgresPersistence(string tableName)

• tableName: string - (optional) collection name.

Instance methods

ConvertFromPublic

Converts object value from public to internal format.

protected override AnyValueMap ConvertFromPublic(T value)

• value: T - object in public format to convert.
• returns: AnyValueMap - converted object in internal format.

ConvertToPublic

Converts object value from internal to public format.

protected override T ConvertToPublic(AnyValueMap map)

• map: AnyValueMap - object in internal format to convert.
• returns: T - converted object in public format.

EnsureTable

Adds DML statement to automatically create a JSON(B) table

protected void EnsureTable(string idType = “TEXT”, string dataType = “JSONB”)

• idType: string - type of the id column (default: TEXT)
• dataType: string - type of the data column (default: JSONB)

UpdatePartially

Updates only few selected fields in a data item.

public override Task<T> UpdatePartially(IContext context, K id, AnyValueMap data)

• context: IContext - (optional) a context to trace execution through a call chain.
• id: K - id of the data item to be updated.
• data: AnyValueMap - map with fields to be updated.
• return: Task<T> - updated item

Examples

class MyPostgresPersistence : IdentifiableJsonPostgresPersistence<MyData, string> 
{
    public MyPostgresPersistence(): base("mydata", new MyDataPostgresSchema()) { }

    private List<Func<MyData, bool>> ComposeFilter(FilterParams filter)
    {
        filter = filter ?? new FilterParams();

        var id = filter.GetAsNullableString("id");
        var label = filter.GetAsNullableString("label");
        var udi = filter.GetAsNullableString("udi");

        return new List<Func<MyData, bool>>() {
            (item) =>
            {
                if (id != null && item.Id != id)
                    return false;
                if (label != null && item.Label != label)
                    return false;
                if (udi != null && item.Udi != udi)
                return true;
            }
        };
    }

    public Task<DataPage<MyData>> GetPageByFilterAsync(IContext context, FilterParams filter, PagingParams paging)
    {
        return base.GetPageByFilterAsync(context, ComposeFilter(filter), paging);
    }

var persistence = new MyPostgresPersistence();
persistence.Configure(ConfigParams.FromTuples(
    "host", "localhost",
    "port", 27017
));

persistence.OpenAsync("123");
persistence.CreateAsync("123", MyData());

var result = persistence.GetPageByFilterAsync("123", FilterParams.FromTuples("name", "ABC"), null);
Console.WriteLine(result.Result.Data);
persistence.DeleteByIdAsync("123", "1");