HL7v2.MLLP (HL7v2 v3.10.1)

MLLP (Minimal Lower Layer Protocol) framing for HL7v2 messages.

MLLP wraps each HL7v2 message in a simple frame:

<SB>message<EB><CR>

Where:

SB (Start Block) = 0x0B
EB (End Block) = 0x1C
CR (Carriage Return) = 0x0D

See HL7 Implementation Technology Specification — Minimal Lower Layer Protocol.

Summary

Functions

extract_messages(buffer)

Extracts complete MLLP messages from a buffer.

frame(message)

Wraps a message binary in an MLLP frame.

unframe(arg1)

Extracts the message from an MLLP frame.

Functions

extract_messages(buffer)

@spec extract_messages(binary()) :: {[binary()], binary()}

Extracts complete MLLP messages from a buffer.

Returns {messages, remaining_buffer} where messages is a list of extracted message binaries (without MLLP framing) and remaining_buffer contains any incomplete data that needs more bytes.

Examples

iex> HL7v2.MLLP.extract_messages(<<0x0B, "MSG1", 0x1C, 0x0D, 0x0B, "MSG2", 0x1C, 0x0D>>)
{["MSG1", "MSG2"], <<>>}

iex> HL7v2.MLLP.extract_messages(<<0x0B, "MSG1", 0x1C, 0x0D, 0x0B, "partial">>)
{["MSG1"], <<0x0B, "partial">>}

frame(message)

@spec frame(binary()) :: binary()

Wraps a message binary in an MLLP frame.

Examples

iex> HL7v2.MLLP.frame("MSH|...")
<<0x0B, "MSH|...", 0x1C, 0x0D>>

unframe(arg1)

@spec unframe(binary()) :: {:ok, binary()} | {:error, :invalid_frame}

Extracts the message from an MLLP frame.

Returns {:ok, message} when the binary starts with SB and ends with EB+CR. Returns {:error, :invalid_frame} otherwise.

Examples

iex> HL7v2.MLLP.unframe(<<0x0B, "MSH|...", 0x1C, 0x0D>>)
{:ok, "MSH|..."}

iex> HL7v2.MLLP.unframe("bad")
{:error, :invalid_frame}