Creates a Flow that handles decoding a stream of unstructured byte chunks into a stream of frames where the incoming chunk stream uses a specific byte-sequence to mark frame boundaries.

The decoded frames will not include the separator sequence.

If there are buffered bytes (an incomplete frame) when the input stream finishes and allowTruncation is set to false then this Flow will fail the stream reporting a truncated frame.

Declaration

public static Flow<ByteString, ByteString, NotUsed> Delimiter(ByteString delimiter, int maximumFrameLength, bool allowTruncation = false)

Parameters

Type	Name	Description
ByteString	delimiter	The byte sequence to be treated as the end of the frame.
int	maximumFrameLength	The maximum length of allowed frames while decoding. If the maximum length is exceeded this Flow will fail the stream.
bool	allowTruncation	If false, then when the last frame being decoded contains no valid delimiter this Flow fails the stream instead of returning a truncated frame.

Returns

Type	Description
Flow<ByteString, ByteString, NotUsed>	TBD

| Edit this page View Source

LengthField(int, int, int, ByteOrder)

Creates a Flow that decodes an incoming stream of unstructured byte chunks into a stream of frames, assuming that incoming frames have a field that encodes their length.

If the input stream finishes before the last frame has been fully decoded, this Flow will fail the stream reporting a truncated frame.

Declaration

public static Flow<ByteString, ByteString, NotUsed> LengthField(int fieldLength, int maximumFramelength, int fieldOffset = 0, ByteOrder byteOrder = ByteOrder.LittleEndian)

Parameters

Type	Name	Description
int	fieldLength	The length of the "Count" field in bytes
int	maximumFramelength	The maximum length of allowed frames while decoding. If the maximum length is exceeded this Flow will fail the stream. This length includes the header (i.e the offset and the length of the size field)
int	fieldOffset	The offset of the field from the beginning of the frame in bytes
ByteOrder	byteOrder	The ByteOrder to be used when decoding the field

Returns

Type	Description
Flow<ByteString, ByteString, NotUsed>	TBD

Exceptions

Type	Condition
ArgumentException	This exception is thrown when the specified `fieldLength` is not equal to either 1, 2, 3 or 4.

| Edit this page View Source

LengthField(int, int, int, ByteOrder, Func<IReadOnlyList<byte>, int, int>)

Creates a Flow that decodes an incoming stream of unstructured byte chunks into a stream of frames, assuming that incoming frames have a field that encodes their length.

If the input stream finishes before the last frame has been fully decoded, this Flow will fail the stream reporting a truncated frame.

Declaration

public static Flow<ByteString, ByteString, NotUsed> LengthField(int fieldLength, int fieldOffset, int maximumFrameLength, ByteOrder byteOrder, Func<IReadOnlyList<byte>, int, int> computeFrameSize)

Parameters

Type	Name	Description
int	fieldLength	The length of the "Count" field in bytes
int	fieldOffset	The offset of the field from the beginning of the frame in bytes.
int	maximumFrameLength	The maximum length of allowed frames while decoding. If the maximum length is exceeded this Flow will fail the stream. This length includes the header (i.e the offset and the length of the size field)
ByteOrder	byteOrder	The ByteOrder to be used when decoding the field.
Func<IReadOnlyList<byte>, int, int>	computeFrameSize	This function can be supplied if frame size is varied or needs to be computed in a special fashion. For example, frame can have a shape like this: `[offset bytes][body size bytes][body bytes][footer bytes]`. Then computeFrameSize can be used to compute the frame size: `(offset bytes, computed size) => (actual frame size)`. "Actual frame size" must be equal or bigger than sum of `fieldOffset` and `fieldLength`, the operator fails otherwise.

Returns

Type	Description
Flow<ByteString, ByteString, NotUsed>	TBD

Exceptions

Type	Condition
ArgumentException	This exception is thrown when the specified `fieldLength` is not equal to either 1, 2, 3 or 4.

| Edit this page View Source

SimpleFramingProtocol(int)

Returns a BidiFlow that implements a simple framing protocol. This is a convenience wrapper over LengthField(int, int, int, ByteOrder) and simply attaches a length field header of four bytes (using big endian encoding) to outgoing messages, and decodes such messages in the inbound direction. The decoded messages do not contain the header.

This BidiFlow is useful if a simple message framing protocol is needed (for example when TCP is used to send individual messages) but no compatibility with existing protocols is necessary.

The encoded frames have the layout {{{ [4 bytes length field, Big Endian][User Payload] }}} The length field encodes the length of the user payload excluding the header itself.

Declaration

public static BidiFlow<ByteString, ByteString, ByteString, ByteString, NotUsed> SimpleFramingProtocol(int maximumMessageLength)

Parameters

Type	Name	Description
int	maximumMessageLength	Maximum length of allowed messages. If sent or received messages exceed the configured limit this BidiFlow will fail the stream. The header attached by this BidiFlow are not included in this limit.

Returns

Type	Description
BidiFlow<ByteString, ByteString, ByteString, ByteString, NotUsed>	TBD

| Edit this page View Source

SimpleFramingProtocolDecoder(int)

Protocol decoder that is used by SimpleFramingProtocol(int)

Declaration

public static Flow<ByteString, ByteString, NotUsed> SimpleFramingProtocolDecoder(int maximumMessageLength)

Parameters

Type	Name	Description
int	maximumMessageLength	TBD

Returns

Type	Description
Flow<ByteString, ByteString, NotUsed>	TBD

| Edit this page View Source

SimpleFramingProtocolEncoder(int)

Protocol encoder that is used by SimpleFramingProtocol(int)

Declaration

public static Flow<ByteString, ByteString, NotUsed> SimpleFramingProtocolEncoder(int maximumMessageLength)

Parameters

Type	Name	Description
int	maximumMessageLength	TBD

Returns

Type	Description
Flow<ByteString, ByteString, NotUsed>	TBD