feat: server sends back proper response

* server can now can send the proper response back to the client if it's required. Closes #13
Bugs5382 · Dec 17, 2023 · 681be32 · 681be32
1 parent ab30120
commit 681be32
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Showing 4 changed files with 72 additions and 41 deletions.
diff --git a/__tests__/hl7.server.test.ts b/__tests__/hl7.server.test.ts
@@ -211,9 +211,8 @@ describe('node hl7 server', () => {
         const server = new Server({bindAddress: '0.0.0.0'})
         const IB_ADT = server.createInbound({port: LISTEN_PORT}, async (req, res) => {
           const messageReq = req.getMessage()
-          const messageRes = res.getAckMessage()
-          expect(messageRes.get('MSA.1').toString()).toBe('AA')
           expect(messageReq.get('MSH.12').toString()).toBe('2.7')
+          await res.sendResponse("AA")
         })
 
         await sleep(5)
@@ -257,9 +256,8 @@ describe('node hl7 server', () => {
           })
         const IB_ADT = server.createInbound({port: LISTEN_PORT}, async (req, res) => {
           const messageReq = req.getMessage()
-          const messageRes = res.getAckMessage()
-          expect(messageRes.get('MSA.1').toString()).toBe('AA')
           expect(messageReq.get('MSH.12').toString()).toBe('2.7')
+          await res.sendResponse("AA")
         })
 
         await sleep(5)

diff --git a/src/server/hl7Inbound.ts b/src/server/hl7Inbound.ts
@@ -1,7 +1,7 @@
 import EventEmitter from 'events'
 import net, { Socket } from 'net'
 import tls from 'tls'
-import { Batch, Message, isBatch, isFile, createHL7Date } from 'node-hl7-client'
+import { Batch, Message, isBatch, isFile } from 'node-hl7-client'
 import { ListenerOptions, normalizeListenerOptions } from '../utils/normalize.js'
 import { InboundRequest } from './modules/inboundRequest.js'
 import { Parser } from './modules/parser.js'
@@ -82,8 +82,8 @@ export class Hl7Inbound extends EventEmitter {
     const ipv6 = this._main._opt.ipv6
 
     if (typeof this._main._opt.tls !== 'undefined') {
-      const {key, cert, requestCert, ca} = this._main._opt.tls
-      socket = tls.createServer({key, cert, requestCert, ca},socket => this._onTcpClientConnected(socket))
+      const { key, cert, requestCert, ca } = this._main._opt.tls
+      socket = tls.createServer({ key, cert, requestCert, ca }, socket => this._onTcpClientConnected(socket))
     } else {
       socket = net.createServer(socket => this._onTcpClientConnected(socket))
     }
@@ -134,7 +134,7 @@ export class Hl7Inbound extends EventEmitter {
           allMessage.forEach((message: Message) => {
             const messageParsed = new Message({ text: message.toString() })
             const req = new InboundRequest(messageParsed)
-            const res = new SendResponse(socket, this._createAckMessage(message))
+            const res = new SendResponse(socket, message)
             this._handler(req, res)
           })
         } else if (isFile(data.toString())) {
@@ -145,7 +145,7 @@ export class Hl7Inbound extends EventEmitter {
           // request
           const req = new InboundRequest(parser)
           // response
-          const res = new SendResponse(socket, this._createAckMessage(parser))
+          const res = new SendResponse(socket, parser)
           this._handler(req, res)
         }
       } catch (err) {
@@ -166,29 +166,6 @@ export class Hl7Inbound extends EventEmitter {
     this.emit('client.connect', socket)
   }
 
-  /** @internal */
-  private _createAckMessage (message: Message): Message {
-    const ackMessage = new Message({
-      messageHeader: {
-        msh_9_1: 'ACK',
-        msh_9_2: message.get('MSH.9.2').toString(),
-        msh_10: `ACK${createHL7Date(new Date())}`
-      }
-    })
-
-    ackMessage.set('MSH.3', message.get('MSH.5').toRaw())
-    ackMessage.set('MSH.4', message.get('MSH.6').toRaw())
-    ackMessage.set('MSH.5', message.get('MSH.3').toRaw())
-    ackMessage.set('MSH.6', message.get('MSH.4').toRaw())
-    ackMessage.set('MSH.11', message.get('MSH.11').toRaw())
-
-    const segment = ackMessage.addSegment('MSA')
-    segment.set('1', 'AA')
-    segment.set('2', message.get('MSH.10').toString())
-
-    return ackMessage
-  }
-
   /** @internal */
   private _closeSocket (socket: Socket): void {
     socket.destroy()

diff --git a/src/server/modules/sendResponse.ts b/src/server/modules/sendResponse.ts
@@ -1,24 +1,80 @@
 import { Socket } from 'net'
-import { Message } from 'node-hl7-client'
+import { createHL7Date, Message } from 'node-hl7-client'
 
 /**
  * Send Response
  * @since 1.0.0
  */
 export class SendResponse {
   /** @internal */
-  private readonly _ack: Message
+  private _ack: Message | undefined
+  /** @internal */
+  private readonly _socket: Socket
+  /** @internal */
+  private readonly _message: Message
+  /** @internal */
+  private _ackSent: boolean
 
-  constructor (socket: Socket, ack: Message) {
-    this._ack = ack
-    socket.write(Buffer.from(ack.toString()))
+  constructor (socket: Socket, message: Message) {
+    this._ack = undefined
+    this._ackSent = false
+    this._message = message
+    this._socket = socket
   }
 
   /**
-   * Get Ack Message Object
+   * Send Response back to End User
    * @since 1.0.0
+   * @see {@link https://hl7-definition.caristix.com/v2/HL7v2.1/Tables/0008}
+   * @param type
+   * @example
+   * If you are to confirm to the end user (client) that the message they sent was good and processed successfully.
+   * you would send an "AA" style message (Application Accept).
+   * Otherwise, send an "AR" (Application Reject) to tell the client the data was
+   * no accept.ed/processed.
+   * ```
+   * const server = new Server({bindAddress: '0.0.0.0'})
+   * const IB_ADT = server.createInbound({port: LISTEN_PORT}, async (req, res) => {
+   *  const messageReq = req.getMessage()
+   *  await res.sendResponse("AA")
+   * })
+   * ```
+   * "AE" (Application Error) will be sent if there is a problem creating either an "AA" or "AR" message from the orginial message sent.
    */
-  getAckMessage (): Message {
-    return this._ack
+  async sendResponse (type: 'AA' | 'AR'): Promise<boolean> {
+    try {
+      this._ack = this._createAckMessage(type, this._message)
+      this._socket.write(Buffer.from(this._ack.toString()))
+    } catch (_e: any) {
+      this._ack = this._createAckMessage('AE', this._message)
+      this._socket.write(Buffer.from(this._ack.toString()))
+    }
+
+    this._ackSent = true
+
+    return this._ackSent
+  }
+
+  /** @internal */
+  private _createAckMessage (type: string, message: Message): Message {
+    const ackMessage = new Message({
+      messageHeader: {
+        msh_9_1: 'ACK',
+        msh_9_2: message.get('MSH.9.2').toString(),
+        msh_10: `ACK${createHL7Date(new Date())}`
+      }
+    })
+
+    ackMessage.set('MSH.3', message.get('MSH.5').toRaw())
+    ackMessage.set('MSH.4', message.get('MSH.6').toRaw())
+    ackMessage.set('MSH.5', message.get('MSH.3').toRaw())
+    ackMessage.set('MSH.6', message.get('MSH.4').toRaw())
+    ackMessage.set('MSH.11', message.get('MSH.11').toRaw())
+
+    const segment = ackMessage.addSegment('MSA')
+    segment.set('1', type)
+    segment.set('2', message.get('MSH.10').toString())
+
+    return ackMessage
   }
 }
diff --git a/src/utils/normalize.ts b/src/utils/normalize.ts
@@ -1,6 +1,6 @@
 import { TcpSocketConnectOpts } from 'node:net'
 import type { ConnectionOptions as TLSOptions } from 'node:tls'
-import {assertNumber, randomString, validIPv4, validIPv6} from 'node-hl7-client'
+import { assertNumber, randomString, validIPv4, validIPv6 } from 'node-hl7-client'
 import { HL7ListenerError, HL7ServerError } from './exception.js'
 
 const DEFAULT_SERVER_OPTS = {