0.1.1

rename package to obj-buffer, change default delimiter and some prop/variable names to make more sense.  Allow custom event (default: decoded)

package.json

@@ -1,12 +1,12 @@
 {
-  "name": "@uci-utils/json-stream",
+  "name": "@uci-utils/obj-buffer",
-  "version": "0.1.0",
+  "version": "0.1.1",
-  "description": "seriaized json stream class for communication in a pipe",
+  "description": "encode and decode a plain object for communication across a stream",
-  "main": "src/json-stream.js",
+  "main": "src/obj-stream.js",
   "type": "module",
   "scripts": {
     "test": "./node_modules/.bin/mocha --timeout 30000",
-    "test:dev": "UCI_ENV=dev ./node_modules/.bin/nodemon --exec './node_modules/.bin/mocha --timeout 3000' || exit 0",
+    "test:dev": "UCI_ENV=dev ./node_modules/.bin/nodemon --exec './node_modules/.bin/mocha --timeout 3000' || exit 1",
     "test:dev:trace": "UCI_LOG_LEVEL='trace' npm run test:dev",
     "test:dev:warn": "UCI_LOG_LEVEL='warn' npm run test:dev",
     "test:log": "UCI_ENV=pro UCI_LOG_PATH=./test/test.log 0 npm run test || exit 0"
@@ -32,12 +32,12 @@
     "await-to-js": "^3.0.0"
   },
   "devDependencies": {
-    "@babel/core": "^7.14.0",
+    "@babel/core": "^7.14.3",
-    "@babel/eslint-parser": "^7.13.14",
+    "@babel/eslint-parser": "^7.14.4",
-    "@babel/preset-env": "^7.14.1",
+    "@babel/preset-env": "^7.14.4",
     "chai": "^4.3.4",
-    "eslint": "^7.26.0",
+    "eslint": "^7.27.0",
-    "eslint-config-standard": "^16.0.2",
+    "eslint-config-standard": "^16.0.3",
     "mocha": "^8.4.0",
     "nodemon": "^2.0.7"
   }

readme.md

@@ -1,6 +1,6 @@
-# uCOMmandIt JSON Stream Utility
+# uCOMmandIt Object Buffer
 
-A calls designed to serialize a js object (JSON) for steaming across a pipe
+Encode/Decode a js object via JSON for steaming.  This allows one to send/receive packets that are a js object between processes or in any stream.
 
 
 

src/obj-buffer.js

@@ -12,20 +12,21 @@ const decoder = new StringDecoder()
  * JsonStream - Description
  * @extends EventEmitter
  */
-class JsonStream extends EventEmitter {
+class ObjBuffer extends EventEmitter {
   // private fields
   #contentLength = null
-  #buffer =''
+  #strData =''
-  #delimiter='#'
+  #delimiter='_%#_'
   #state='online'
   #queue=[]
-  #stream
+  #event = 'decoded'
 
   constructor (opts = {}) {
     super()
     this.#delimiter = opts.delimiter || this.#delimiter
-    this.onData = this.onData.bind(this)
+    this.#event = opts.emit || this.#event
-    this.serialize = this.serialize.bind(this)
+    this.decode = this.decode.bind(this)
+    this.resume = this.resume.bind(this)
   }
 
   get state () { return this.#state }
@@ -39,7 +40,7 @@ class JsonStream extends EventEmitter {
   resume () {
     // emit FIFO
     for (let index = 0; index < this.#queue.length; index++) {
-      this.emit('message', this.#queue[index])
+      this.emit(this.#event, this.#queue[index])
     }
     this.#queue = []
     this.#state = 'online'
@@ -47,88 +48,91 @@ class JsonStream extends EventEmitter {
 
   online () { this.#state = 'online' }
 
-  onData (data) {
+  decode (buf) {
-    data = decoder.write(data)
+    const str = decoder.write(buf)
     try {
-      this.#handleData(data)
+      this.#handleData(str)
     } catch (err) {
       // emit an error
       this.emit('error', err)
     }
   }
 
-  async serialize (message) {
+  async encode (obj) {
     return new Promise((resolve, reject) => {
-      let messageData; let length
+      let json; let length
-      try { messageData = JSON.stringify(message) } catch (err) { reject(err) }
+      try { json = JSON.stringify(obj) } catch (err) { reject(err) }
-      try { length = Buffer.byteLength(messageData, 'utf8') } catch (err) { reject(err) }
+      if (json.indexOf(this.#delimiter) != -1) reject(new Error(`object to serialize contains the buffer delimiter ${this.#delimiter}, set alternative delimiter`))
-      const data = length + this.#delimiter + messageData
+      try { length = Buffer.byteLength(json, 'utf8') } catch (err) { reject(err) }
-      resolve(data)
+      const buf = length + this.#delimiter + json
+      resolve(buf)
     })
   }
 
-  #handleData (data) {
+  #handleData (str) {
-    this.#buffer += data
+    this.#strData += str
     if (this.#contentLength == null) {
-      const i = this.#buffer.indexOf(this.#delimiter)
+      const i = this.#strData.indexOf(this.#delimiter)
-      // Check if the buffer has a this.#opts.delimeter or "#", if not, the end of the buffer string might be in the middle of a content length string
+      if (i !== -1) { // delimiter found
-      if (i !== -1) {
+      // Check if decoded string has delimiter, if not the end of the buffer string might be in the middle of a content length string
-        const rawContentLength = this.#buffer.substring(0, i)
+        const rawContentLength = this.#strData.substring(0, i)
         this.#contentLength = parseInt(rawContentLength)
         if (isNaN(this.#contentLength)) {
           this.#contentLength = null
-          this.#buffer = ''
+          this.#strData = ''
           const err = new Error(
             'Invalid content length supplied (' +
               rawContentLength +
               ') in: ' +
-              this.#buffer
+              this.#strData
           )
           err.code = 'E#INVALID#CONTENT#LENGTH'
           throw err
         }
-        this.#buffer = this.#buffer.substring(i + 1)
+        // remove delimiter
+        this.#strData = this.#strData.substring(i + this.#delimiter.length)
       }
     }
     if (this.#contentLength != null) {
-      const length = Buffer.byteLength(this.#buffer, 'utf8')
+      const length = Buffer.byteLength(this.#strData, 'utf8')
       if (length === this.#contentLength) {
-        this.#handleMessage(this.#buffer)
+        // json to parse is complete
+        this.#makeObj(this.#strData)
       } else if (length > this.#contentLength) {
-        const message = this.#buffer.substring(0, this.#contentLength)
+        const json = this.#strData.substring(0, this.#contentLength)
-        const rest = this.#buffer.substring(this.#contentLength)
+        const more = this.#strData.substring(this.#contentLength)
-        this.#handleMessage(message)
+        this.#makeObj(json)
-        this.onData(rest)
+        this.decode(more)
       }
     }
   }
 
   // private methods
 
-  #handleMessage (data) {
+  #makeObj (json) {
     this.#contentLength = null
-    this.#buffer = ''
+    this.#strData = ''
-    let message
+    let obj
     try {
-      message = JSON.parse(data)
+      obj = JSON.parse(json)
     } catch (e) {
       const err = new Error(
-        'Could not parse JSON: ' + e.message + '\nRequest data: ' + data
+        'Could not parse JSON: ' + e.message + '\nRequest data: ' + json
       )
       err.code = 'E#INVALID#JSON'
       throw err
     }
-    message = message || {}
+    obj = obj || {}
     // console.log('stream message', message, this.#state)
     if (this.#state === 'paused') {
-      this.#queue.push(message)
+      this.#queue.push(obj)
     }
     if (this.#state === 'online') {
       this.#queue = []
-      this.emit('message', message)
+      this.emit(this.#event, obj)
     }
   }
 }
 
-export { JsonStream }
+export { ObjBuffer }
-export default JsonStream
+export default ObjBuffer

test/test.js

@@ -1,36 +1,56 @@
 import { expect } from 'chai'
-import JsonStream from '../src/json-stream.js'
+import ObjBuffer from '../src/obj-buffer.js'
 
-const obj = { cmd: 'test', _header: { name: 'a name', id: '12345' }, arg: 5 }
+const obj = { cmd: 'test', _header: { name: 'a # name', id: 'i12345' }, arg: 5 }
-const ser = '63#{"cmd":"test","_header":{"name":"a name","id":"12345"},"arg":5}'
+const ser = '66_%#_{"cmd":"test","_header":{"name":"a # name","id":"i12345"},"arg":5}'
-const jss = new JsonStream()
+const otb = new ObjBuffer()
+const event = 'decoded'
 
-describe('JSON stream check', function () {
+describe('Object to Buffer encode/decode', function () {
-
+  it('Should stringify and encode a message/object', async function () {
-  it('Should stringify and serialize a message/object', async function () {
+    expect(await otb.encode(obj)).to.equal(ser)
-    expect(await jss.serialize(obj)).to.equal(ser)
   })
 
-  it('Should serialize and decode a message', async function () {
+  it('Should encode and decode a message', function () {
-    jss.on('message', mes => {
+    return new Promise(async (resolve, reject) => {
-      // console.log(mes)
+      otb.once(event, mes => {
-      expect(mes).to.deep.equal(obj)
+        // console.log('message received', mes)
+        expect(mes).to.deep.equal(obj)
+        resolve()
+      })
+      const ser = await otb.encode(obj)
+      // console.log('encoded', ser)
+      otb.decode(ser)
     })
-    const ser = await jss.serialize(obj)
-    jss.onData(ser)
   })
 
-  it('Should queue messages if paused and resumed', async function () {
+  it('encode throws an error if object contains the delmiter', async function () {
-    jss.on('message', mes => {
+    obj._header.name = '_%#_'
-      // console.log('queued message', mes)
+    return otb.encode(obj)
-      expect(mes).to.deep.equal(obj)
+      .then(res => {
+        expect.fail('no error was thrown for')
+      })
+      .catch(error => {
+      // console.log('error', error)
+        expect(error).to.be.an('error')
+      }
+      )
+  })
+
+  it('Should queue message if paused and emit if resumed', function () {
+    return new Promise(async (resolve, reject) => {
+      otb.once(event, mes => {
+        // console.log('queued message', mes)
+        expect(mes).to.deep.equal(obj)
+        resolve()
+      })
+      obj._header.name = 'name'
+      const ser = await otb.encode(obj)
+      otb.pause()
+      otb.decode(ser)
+      // console.log(otb.state, otb.queue[0])
+      expect(otb.queue[0]).to.deep.equal(obj)
+      otb.resume()
     })
-    const ser = await jss.serialize(obj)
-    jss.pause()
-    jss.onData(ser)
-    // console.log(jss.state, jss.queue[0])
-    expect(jss.queue[0]).to.deep.equal(obj)
-    jss.resume()
   })
-
 })