81 lines
2.3 KiB
JavaScript
81 lines
2.3 KiB
JavaScript
// adpated from https://github.com/sebastianseilund/node-json-socket
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import {StringDecoder} from 'string_decoder'
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import EventEmitter from 'events'
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const decoder = new StringDecoder()
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export default class JsonStream extends EventEmitter{
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constructor(opts={}){
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super()
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this._contentLength = null
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this._buffer = ''
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this._delimeter = opts.delimiter || '#'
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this.onData = this.onData.bind(this)
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}
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onData (data) {
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data = decoder.write(data)
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try {
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this._handleData(data)
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} catch (e) {
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this.emit('error', { error: e })
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}
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}
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serialize(message) {
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var messageData = JSON.stringify(message)
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var length = Buffer.byteLength(messageData, 'utf8')
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var data = length + this._delimeter + messageData
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return data
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}
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_handleData (data) {
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this._buffer += data
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if (this._contentLength == null) {
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var i = this._buffer.indexOf(this._delimeter)
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//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
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if (i !== -1) {
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var rawContentLength = this._buffer.substring(0, i)
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this._contentLength = parseInt(rawContentLength)
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if (isNaN(this._contentLength)) {
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this._contentLength = null
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this._buffer = ''
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var err = new Error('Invalid content length supplied ('+rawContentLength+') in: '+this._buffer)
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err.code = 'E_INVALID_CONTENT_LENGTH'
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throw err
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}
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this._buffer = this._buffer.substring(i+1)
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}
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}
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if (this._contentLength != null) {
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var length = Buffer.byteLength(this._buffer, 'utf8')
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if (length == this._contentLength) {
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this._handleMessage(this._buffer)
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} else if (length > this._contentLength) {
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var message = this._buffer.substring(0, this._contentLength)
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var rest = this._buffer.substring(this._contentLength)
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this._handleMessage(message)
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this.onData(rest)
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}
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}
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}
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_handleMessage (data) {
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this._contentLength = null
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this._buffer = ''
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var message
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try {
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message = JSON.parse(data)
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} catch (e) {
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var err = new Error('Could not parse JSON: '+e.message+'\nRequest data: '+data)
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err.code = 'E_INVALID_JSON'
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throw err
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}
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message = message || {}
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this.emit('message', message)
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}
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}
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