Node.js client library for creating a HL7 Server which can accept incoming a properly formatted HL7 message(s), and then parses the HL7 message. Once the message has been parsed you can then do something with the final result that you so desire.
npm install node-hl7-serverBenefits:
- No other main dependencies (other than the sister app called node-hl7-client which also uses no other external dependencies), making this ultra-fast.
- Automatically re-connect, re-subscribe, or retry sending
- Written in typescript and published with heavily commented type definitions
- Intuitive API with named parameters instead of positional
- TLS/SSL Support for clients connecting, if you want.
- Typescript, CommonJS, ESM formats all available in one package.
1. Acknowledgements
2. Keyword Definitions
3. Basic Install
4. License
This NPM is designed to support medical applications with potential impact on patient care and diagnoses, this package documentation, and it's peer package [node-hl7-server]() follow these definitions when it comes to the documentation.
Keywords such as "MUST", "MUST NOT", "REQUIRED",
"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL".
These are standardized terms for technology documentation interoperability.
These words should have these meaning when you are reading them.
They might be sans uppercase throughout the documentation, but they would have the same meaning regardless.
* MUST - This word, or the terms "REQUIRED" or "SHALL", mean that the definition is an absolute requirement of the specification.
* MUST NOT - This phrase, or the phrase "SHALL NOT", mean that the definition is an absolute prohibition of the specification.
* SHOULD - This word, or the adjective "RECOMMENDED", mean that there may exist valid reasons in particular circumstances to ignore a particular item, but the full implications must be understood and carefully weighed before choosing a different course.
* SHOULD NOT - This phrase, or the phrase "NOT RECOMMENDED", mean that there may exist valid reasons in particular circumstances when the particular behavior is acceptable or even useful. The full implications should be understood and the case carefully weighed before implementing any behavior described with this label.
* MAY - This word, or the adjective "OPTIONAL", mean that an item is truly optional. Any implementation which does not include a particular option MUST be prepared to interoperate with another implementation which does include the option, though perhaps with reduced functionality. In the same vein, an implementation which does include a particular option MUST be prepared to interoperate with another implementation, which does not include the option (except, of course, for the feature the option provides.)
Install using NPM into your package:
``
npm install node-hl7-server
It has one external dependency of `node-hl7-client`
as it uses this package to generate the acknowledgement message back to the client
and also parse the informing message for the server.
Non-TLS:
`ts
import { Server } from 'node-hl7-server'
const server = new Server()
const IB = server.createInbound({port: 3000}, async (req, res) => {
const messageReq = req.getMessage()
const messageRes = res.getAckMessage()
// do your code here
})
`
This will start a basic server on port 3000 with basic functionally.
Before your app shuts down, you should run:
`ts`
await IB.close()
To end the connections.
An HL7 server is designed to be up ready to accept connections at any time, so shutting it down shouldn't really happen.
Your app needs to be responsible for memory leaks.
The server does close the connection once it's finished a reply to the client.
TLS:
`ts
import { Server } from 'node-hl7-server'
const server = new Server(
{
tls:
{
key: fs.readFileSync(path.join('certs/', 'server-key.pem')), // where your certs are
cert: fs.readFileSync(path.join('certs/', 'server-crt.pem')), // where your certs are
rejectUnauthorized: false
}
})
`
When you get a message, you can then parse any segment of the message and do you need to in order for your app to work.
`ts`
const IB_ADT = server.createInbound({port: LISTEN_PORT}, async (req, res) => {
const messageReq = req.getMessage()
const messageRes = res.getAckMessage()
const hl7Version = messageReq.get('MSH.12').toString()
})
In this case... `res.getAckMessage()` returns a Message object from `node-hl7-client`.`
Then you can query the segment MSH.12` in this instance and get its result.
Please consult node-hl7-client documentation for further ways to parse the message segment.
Individual response MSH segment fields can be overridden by passing the optional mshOverrides prop to server.createInbound.
Each field's override can be specified either directly or as a callback that takes the inbound message as an argument
and returns the field value.
For example:
`ts`
const listener = server.createInbound({ port: 3000, mshOverrides: {
// set MSH.7 to formatted timestamp representing time of response creation
'7': () => format(new Date(), 'yyyyMMddHHmmssxx'),
// set MSH.9.3 to "ACK"
'9.3': 'ACK',
// copy MSH.12 value from inbound message to response
'12': (message: Message) => message.get('MSH.12').toString()
}}, async (req, res) => {})
Once you finish processing the received message, you should send an ACK message as a confirmation. You can choose what MSA1
value should be sent depending on the validity of the inbound message received.
For example:
`ts
const IB_ADT = server.createInbound({port: LISTEN_PORT}, async (req, res) => {
const messageReq = req.getMessage()
const messageRes = res.getAckMessage()
const hl7Version = messageReq.get('MSH.12').toString(),
await res.sendResponse("AA");
})
`
If the message is valid, we send AA or CA.
IMPORTANT: Notice CA, CE and CR can only be sent for HL7 versions > 2.1
If hl7Version is 2.1 and any of the aforementioned is sent, the response automatically sends an AE.
If yuu try t send something back that is not what the client can accept,
the server will also throw a sever fault only when sending a response back,
but your overall application should continue to work.
`
npm run docker:build
This package, if you download from source,
comes with a DockerFile to build a simple docker image with a basic node-hl7-server running.
All the server does is respond "success" to all properly formatted HL7 messages.
If you want more a custom instance of this server, download the GIT,
and modify `docker/server.js`` to your liking and then build the docker image and run it.
Suggestions? Open a PR!
GitHub pages now has mostly full listing of all methods, classes, etc., but only for the most recent release.
You can view it here.
- Code Design/Auto Re-Connect/Resend, Inspiration: node-rabbitmq-client
- My Wife, Baby Girl, and Baby Boy.
Licensed under MIT.