Class NpgsqlTypeHandler

Namespace

Npgsql.TypeHandling

Assembly

Npgsql.dll

Base class for all type handlers, which read and write CLR types into their PostgreSQL binary representation. Type handler writers shouldn't inherit from this class, inherit NpgsqlTypeHandler or NpgsqlSimpleTypeHandler<TDefault> instead.

public abstract class NpgsqlTypeHandler

Inheritance

object

NpgsqlTypeHandler

Derived

ArrayHandler

RangeHandler

NpgsqlTypeHandler<TDefault>

Inherited Members

object.GetType()

object.MemberwiseClone()

object.ToString()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

Constructors

NpgsqlTypeHandler()

protected NpgsqlTypeHandler()

Methods

CreateArrayHandler(PostgresType)

Creates a type handler for arrays of this handler's type.

public abstract ArrayHandler CreateArrayHandler(PostgresType arrayBackendType)

Parameters

arrayBackendType PostgresType

Returns

ArrayHandler

CreateConversionButNoParamException(Type)

Used to create an exception when the provided type can be converted and written, but an instance of NpgsqlParameter is required for caching of the converted value (in ConvertedValue.

protected Exception CreateConversionButNoParamException(Type clrType)

Parameters

clrType Type

Returns

Exception

CreateRangeHandler(PostgresType)

Creates a type handler for ranges of this handler's type.

public abstract RangeHandler CreateRangeHandler(PostgresType rangeBackendType)

Parameters

rangeBackendType PostgresType

Returns

RangeHandler

Read<TAny>(NpgsqlReadBuffer, int, bool, FieldDescription)

Reads a value of type TAny with the given length from the provided buffer, using either sync or async I/O.

protected abstract ValueTask<TAny> Read<TAny>(NpgsqlReadBuffer buf, int len, bool async, FieldDescription fieldDescription = null)

Parameters

buf NpgsqlReadBuffer

The buffer from which to read.

len int

The byte length of the value. The buffer might not contain the full length, requiring I/O to be performed.

async bool

If I/O is required to read the full length of the value, whether it should be performed synchronously or asynchronously.

fieldDescription FieldDescription

Additional PostgreSQL information about the type, such as the length in varchar(30).

Returns

ValueTask<TAny>

The fully-read value.

Type Parameters

TAny

ValidateAndGetLength<TAny>(TAny, ref NpgsqlLengthCache, NpgsqlParameter)

Called to validate and get the length of a value of a generic NpgsqlParameter<T>.

protected abstract int ValidateAndGetLength<TAny>(TAny value, ref NpgsqlLengthCache lengthCache, NpgsqlParameter parameter)

Parameters

value TAny

lengthCache NpgsqlLengthCache

parameter NpgsqlParameter

Returns

int

Type Parameters

TAny

ValidateObjectAndGetLength(object, ref NpgsqlLengthCache, NpgsqlParameter)

Responsible for validating that a value represents a value of the correct and which can be written for PostgreSQL - if the value cannot be written for any reason, an exception shold be thrown. Also returns the byte length needed to write the value.

protected abstract int ValidateObjectAndGetLength(object value, ref NpgsqlLengthCache lengthCache, NpgsqlParameter parameter)

Parameters

value object

The value to be written to PostgreSQL

lengthCache NpgsqlLengthCache

If the byte length calculation is costly (e.g. for UTF-8 strings), its result can be stored in the length cache to be reused in the writing process, preventing recalculation.

parameter NpgsqlParameter

The NpgsqlParameter instance where this value resides. Can be used to access additional information relevant to the write process (e.g. Size).

Returns

int

The number of bytes required to write the value.

WriteObjectWithLength(object, NpgsqlWriteBuffer, NpgsqlLengthCache, NpgsqlParameter, bool)

Writes a value to the provided buffer, using either sync or async I/O.

protected abstract Task WriteObjectWithLength(object value, NpgsqlWriteBuffer buf, NpgsqlLengthCache lengthCache, NpgsqlParameter parameter, bool async)

Parameters

value object

The value to write.

buf NpgsqlWriteBuffer

The buffer to which to write.

lengthCache NpgsqlLengthCache

parameter NpgsqlParameter

The NpgsqlParameter instance where this value resides. Can be used to access additional information relevant to the write process (e.g. Size).

async bool

If I/O is required to read the full length of the value, whether it should be performed synchronously or asynchronously.

Returns

Task