HL7

Overview

This is a fork of Davin Hills' Go Level 7 library for creation/manipulation of HL7 files.

HL7 segment specs can be found here: https://hl7-definition.caristix.com/v2/HL7v2.4/Segments

Features

Decode HL7 messages
Multiple message support with Split
Unmarshal into Go structs
Simple query syntax
Message validation

Note: Message building is not currently working for MSH segments. Coming soon...

Installation

go get github.com/borisrodman/hl7

Usage

Data Location Syntax

segment-name.field-sequence-number.component.subcomponent
Segments are specified using the three letter name (MSH)
Fields are specifified by the sequence number of the HL7 specification (Field 0 is always the segment name)
Components and Subcomponents are 0 based indexes
"" returns the message
"PID" returns the PID segment
"PID.5" returns the 5th field of the PID segment
"PID.5.1" returns the 1st component of the 5th field of the PID segment
"PID.5.1.2" returns the 2nd subcomponent of the 1st component of the 5th field of the PID

Message building

type MSHSegment struct {
	FieldSeparator     string `hl7:"MSH.1" hl7default:"^~\\&"`
	EncodingCharacters string `hl7:"MSH.2" hl7default:""`
    SendingApp        string `hl7:"MSH.3"`
    SendingFacility   string `hl7:"MSH.4"`
    ReceivingApp      string `hl7:"MSH.5"`
    ReceivingFacility string `hl7:"MSH.6"`
    MsgDate           string `hl7:"MSH.7"`
    MessageType       string `hl7:"MSH.9"`
    ControlID         string `hl7:"MSH.10"`
    ProcessingID      string `hl7:"MSH.11"`
	VersionID          string `hl7:"MSH.12" hl7default:"2.4"`
}

type PIDSegment struct {
    FirstName string `hl7:"PID.5.1"`
    LastName  string `hl7:"PID.5.0"`
}

type PV1Segment struct {
	SetID                   string `hl7:"PV1.1"`
	PatientClass            string `hl7:"PV1.2"`
	AssignedPatientLocation string `hl7:"PV1.3"`
	AdmissionType           string `hl7:"PV1.4"`
}

func CreateHL7() {
    msh := MSHSegment{
        SendingApp:        "MyApp",
        SendingFacility:   "MyPlace",
        ReceivingApp:      "EMR",
        ReceivingFacility: "MedicalPlace",
        MessageType:       "ORM^001",
        MsgDate:           "20151209154606",
        ControlID:         "MSGID1",
        ProcessingID:      "P",
        VersionID:         "2.4",
    }
    pid := PIDSegment{FirstName: "Davin", LastName: "Hills"}
    pv1 := datamodel.PV1Segment{SetID: "0001", PatientClass: "I", AdmissionType: "O"}

    file, err := os.OpenFile("test.hl7", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
    defer os.close(file)

    err = hl7.NewEncoder(file).Encode(&msh)
    err = hl7.NewEncoder(file).Encode(&pid)
    err = hl7.NewEncoder(file).Encode(&pv1)
}

Data Extraction / Unmarshal

data := []byte(...) // raw message
type PIDSegment struct {
	FirstName string `hl7:"PID.5.1"`
	LastName  string `hl7:"PID.5.0"`
}
ps := PIDSegment{}

err := hl7.Unmarshal(data, &ps)

// from an io.Reader

hl7.NewDecoder(reader).Decode(&ps)

Message Query

msg, err := hl7.NewDecoder(reader).Message()

// First matching value
val, err := msg.Find("PID.5.1")

// All matching values
vals, err := msg.FindAll("PID.11.1")

Message Validation

Message validation is accomplished using the IsValid function. Create a slice of Validation structs and pass them, with the message, to the IsValid function. The first return value is a pass / fail bool. The second return value returns the Validation structs that failed.

A number of validation slices are already defined and can be combined to build custom validation criteria. The NewValidMSH24() function is one example. It returns a set of validations for the MSH segment for version 2.4 of the HL7 specification.

val := []hl7.Validation{
	Validation{Location: "MSH.0", VCheck: SpecificValue, Value: "MSH"},
	Validation{Location: "MSH.1", VCheck: HasValue},
	Validation{Location: "MSH.2", VCheck: HasValue},
}
msg, err := hl7.NewDecoder(reader).Message()
valid, failures := msg.IsValid(val)

# README

HL7