HL7v2.Message (HL7v2 v3.10.1)

Programmatic HL7v2 message construction.

Low-level message constructor for building HL7v2 messages from typed segment structs. The MSH segment is auto-populated with sensible defaults (field separator, encoding characters, processing ID, version, timestamp, control ID) and can be overridden via opts.

Note: This is an append-only builder — it does not enforce segment ordering or required-segment presence. Use HL7v2.validate/1 after building to check structural conformance.

Examples

msg =
  HL7v2.Message.new("ADT", "A01",
    sending_application: "PHAOS",
    sending_facility: "HOSP"
  )
  |> HL7v2.Message.add_segment(%HL7v2.Segment.PID{
    patient_identifier_list: [%HL7v2.Type.CX{id: "12345"}],
    patient_name: [%HL7v2.Type.XPN{family_name: %HL7v2.Type.FN{surname: "Smith"}, given_name: "John"}]
  })

wire = HL7v2.Message.encode(msg)

Summary

Types

t()

Functions

add_segment(msg, segment)

Adds a segment to the message.

encode(msg)

Encodes the message to HL7v2 wire format binary.

new(message_code, trigger_event, opts \\ [])

Creates a new message with MSH auto-populated.

segment(msg, module)

Returns the first segment of a given type, or nil.

segments(msg, module)

Returns all segments of a given type.

to_raw(message)

Converts to a RawMessage for encoding.

Types

t()

@type t() :: %HL7v2.Message{msh: HL7v2.Segment.MSH.t(), segments: [struct()]}

Functions

add_segment(msg, segment)

@spec add_segment(
  t(),
  struct()
) :: t()

Adds a segment to the message.

Segments are appended in order. MSH is managed separately and cannot be added via this function.

encode(msg)

@spec encode(t()) :: binary()

Encodes the message to HL7v2 wire format binary.

Converts to a RawMessage and delegates to HL7v2.Encoder.

new(message_code, trigger_event, opts \\ [])

@spec new(binary(), binary(), keyword()) :: t()

Creates a new message with MSH auto-populated.

Options

:sending_application -- string or %HD{} (default nil)
:sending_facility -- string or %HD{} (default nil)
:receiving_application -- string or %HD{} (default nil)
:receiving_facility -- string or %HD{} (default nil)
:date_time -- %TS{} or %DTM{} (default: current UTC time)
:message_control_id -- string (default: auto-generated)
:processing_id -- string (default: "P")
:version_id -- string (default: "2.5.1")

segment(msg, module)

@spec segment(t(), module()) :: struct() | nil

Returns the first segment of a given type, or nil.

Examples

HL7v2.Message.segment(msg, HL7v2.Segment.PID)
#=> %HL7v2.Segment.PID{...}

segments(msg, module)

@spec segments(t(), module()) :: [struct()]

Returns all segments of a given type.

Examples

HL7v2.Message.segments(msg, HL7v2.Segment.OBX)
#=> [%HL7v2.Segment.OBX{...}, %HL7v2.Segment.OBX{...}]

to_raw(message)

@spec to_raw(t()) :: HL7v2.RawMessage.t()

Converts to a RawMessage for encoding.