import fs from 'fs'
import get from 'lodash-es/get.js'
import debounce from 'lodash-es/debounce.js'
import merge from 'lodash-es/merge.js'
import now2str from 'wsemi/src/now2str.mjs'
import genID from 'wsemi/src/genID.mjs'
import evem from 'wsemi/src/evem.mjs'
import haskey from 'wsemi/src/haskey.mjs'
import isestr from 'wsemi/src/isestr.mjs'
import isobj from 'wsemi/src/isobj.mjs'
import iseobj from 'wsemi/src/iseobj.mjs'
import isfun from 'wsemi/src/isfun.mjs'
import j2o from 'wsemi/src/j2o.mjs'
import o2j from 'wsemi/src/o2j.mjs'
import genEmit from './genEmit.mjs'
/**
* 伺服器端之資料同步器
*
* @class
* @param {Object} instWConverServer 輸入通訊服務實體物件，可使用例如WConverhpServer等建立
* @param {Object} [opt={}] 輸入設定物件，預設{}
* @param {String} [opt.fpTableTags='tableTags.json'] 輸入儲存各資料表時間戳檔案路徑串，預設'./tableTags.json'
* @param {Function} [opt.genTag=()=>'{random string}'] 輸入產生不重複識別碼函數，預設()=>'{random string}'
* @returns {Object} 回傳後端資料同步物件，可監聽事件changeTableTags、error，可使用函數readTableTags、writeTableTags、initTableTags、setTableTags、getTableTags、updateTableTag、clearSync。監聽器須為同步函數，其同步拋錯時轉為error事件通知，本套件自發之error若無監聽者則改以console.error輸出，不會使行程崩潰。同一事件物件只能建立一個本同步器，重建前須先呼叫clearSync；上層掛於ORM等外部物件之監聽須由上層自行移除
* @example
*
* //前後端共用範例
* import w from 'wsemi'
* import WSyncWebdataServer from './src/WSyncWebdataServer.mjs'
* import WSyncWebdataClient from './src/WSyncWebdataClient.mjs'
*
* let ms = []
*
* let ntg = 0
* let genTag = () => {
* ntg++
* return `tag-${ntg}`
* }
*
* //-------- 後端 ---------
*
* //EventEmitter, 模擬後端推播至前端
* let ee = w.evem()
*
* //instWConverServer
* let instWConverServer = w.evem()
*
* //wsds
* let wsds = new WSyncWebdataServer(
* instWConverServer,
* {
* // fpTableTags: 'tableTags-sync-webdata.json',
* genTag,
* },
* )
*
* //tableTagsSrv
* let tableTagsSrv = {
* tabA: 'tag-0-a',
* tabB: 'tag-0-b',
* }
*
* //initTableTags
* wsds.initTableTags(tableTagsSrv)
*
* //readTableTags
* console.log('server: nowTableTags', wsds.readTableTags())
* ms.push({ 'server nowTableTags': JSON.stringify(wsds.readTableTags()) })
*
* //updateTableTag
* setTimeout(() => {
* wsds.updateTableTag('tabA')
* ms.push({ 'server updateTableTag': 'tabA' })
* }, 500)
* setTimeout(() => {
* wsds.updateTableTag('tabB')
* ms.push({ 'server updateTableTag': 'tabB' })
* }, 750)
* setTimeout(() => {
* wsds.updateTableTag('tabA')
* ms.push({ 'server updateTableTag': 'tabA' })
* }, 1000)
*
* //changeTableTags
* wsds.on('changeTableTags', (nowTableTags) => {
* console.log('server: changeTableTags', nowTableTags)
*
* //server push
* console.log('server: push')
* ms.push({ 'server changeTableTags': JSON.stringify(nowTableTags) })
* ee.emit('push', nowTableTags)
*
* })
*
* //error
* wsds.on('error', (err) => {
* console.log('server: error', err)
* })
*
* //getAPIData, 模擬後端提供API
* let tabsCount = {
* tabA: 0,
* tabB: 0,
* }
* async function getAPIData(tableName) {
* ms.push({ 'server call getAPIData before': tableName })
* return new Promise((resolve, reject) => {
* setTimeout(() => {
* tabsCount[tableName] += 1
* ms.push({ 'server call getAPIData after': `table[${tableName}] = ${tabsCount[tableName]}` })
* resolve(`table[${tableName}] = ${tabsCount[tableName]}`)
* }, 100)
* })
* }
*
* //-------- 前端 ---------
*
* //instWConverClient
* let instWConverClient = w.evem()
*
* //wsdc
* let wsdc = new WSyncWebdataClient(instWConverClient, {})
*
* //tableTagsCl
* let tableTagsCl = {
* tabA: 'tag-0-a',
* tabB: 'tag-0-b',
* }
*
* //setTableTags, 模擬前端將tableTags預先或有變更即儲存至localStorage, 啟動時有既有tableTags
* wsdc.setTableTags(tableTagsCl)
* ms.push({ 'clinet setTableTags': JSON.stringify(tableTagsCl) })
*
* //push, 模擬前端接收後端推播有變更tableTags
* ee.on('push', (nowTableTags) => {
*
* //updateTableTags
* wsdc.updateTableTags(nowTableTags)
* ms.push({ 'clinet updateTableTags': JSON.stringify(nowTableTags) })
*
* })
*
* //refreshState
* wsdc.on('refreshState', (msg) => {
* console.log('client: refreshState needToRefresh', msg.needToRefresh)
* })
*
* //refreshTable
* wsdc.on('refreshTable', (input) => {
* // console.log('client: refreshTable', input)
*
* //收到有變更tableTags, 模擬呼叫後端API
* console.log('client: getAPIData before: ' + input.tableName)
* ms.push({ 'clinet call getAPIData before': input.tableName })
* getAPIData(input.tableName)
* .then((data) => {
* console.log('client: getAPIData after: ' + data)
* ms.push({ 'clinet call getAPIData after': data })
* input.pm.resolve(data) //Use pm.resolve to retrieve the data, and pm.reject the message when get an error.
* })
* .catch((err) => {
* input.pm.reject(err)
* })
*
* })
*
* //getData
* wsdc.on('getData', (data) => {
* console.log('client: getData', data)
* //前端取得數據
* })
*
* //beforeUpdateTableTags, afterUpdateTableTags
* wsdc.on('beforeUpdateTableTags', (msg) => {
* // console.log('client: beforeUpdateTableTags', msg)
* })
* wsdc.on('afterUpdateTableTags', (msg) => {
* // console.log('client: afterUpdateTableTags', msg)
* })
*
* //error
* wsdc.on('error', (err) => {
* console.log('client: error', err)
* })
*
* setTimeout(() => {
* console.log('ms', ms)
* }, 2000)
*
* // server: nowTableTags { tabA: 'tag-0-a', tabB: 'tag-0-b' }
* // server: changeTableTags { tabA: 'tag-1', tabB: 'tag-0-b' }
* // server: push
* // client: refreshState needToRefresh true
* // client: getAPIData before: tabA
* // client: getAPIData after: table[tabA] = 1
* // client: getData { tableName: 'tabA', timeTag: 'tag-1', data: 'table[tabA] = 1' }
* // server: changeTableTags { tabA: 'tag-1', tabB: 'tag-2' }
* // server: push
* // client: refreshState needToRefresh true
* // client: getAPIData before: tabB
* // client: getAPIData after: table[tabB] = 1
* // client: getData { tableName: 'tabB', timeTag: 'tag-2', data: 'table[tabB] = 1' }
* // server: changeTableTags { tabA: 'tag-3', tabB: 'tag-2' }
* // server: push
* // client: refreshState needToRefresh true
* // client: getAPIData before: tabA
* // client: getAPIData after: table[tabA] = 2
* // client: getData { tableName: 'tabA', timeTag: 'tag-3', data: 'table[tabA] = 2' }
* // ms [
* // { 'server nowTableTags': '{"tabA":"tag-0-a","tabB":"tag-0-b"}' },
* // { 'clinet setTableTags': '{"tabA":"tag-0-a","tabB":"tag-0-b"}' },
* // { 'server updateTableTag': 'tabA' },
* // { 'server changeTableTags': '{"tabA":"tag-1","tabB":"tag-0-b"}' },
* // { 'clinet updateTableTags': '{"tabA":"tag-1","tabB":"tag-0-b"}' },
* // { 'clinet call getAPIData before': 'tabA' },
* // { 'server call getAPIData before': 'tabA' },
* // { 'server updateTableTag': 'tabB' },
* // { 'server call getAPIData after': 'table[tabA] = 1' },
* // { 'clinet call getAPIData after': 'table[tabA] = 1' },
* // { 'server changeTableTags': '{"tabA":"tag-1","tabB":"tag-2"}' },
* // { 'clinet updateTableTags': '{"tabA":"tag-1","tabB":"tag-2"}' },
* // { 'clinet call getAPIData before': 'tabB' },
* // { 'server call getAPIData before': 'tabB' },
* // { 'server updateTableTag': 'tabA' },
* // { 'server call getAPIData after': 'table[tabB] = 1' },
* // { 'clinet call getAPIData after': 'table[tabB] = 1' },
* // { 'server changeTableTags': '{"tabA":"tag-3","tabB":"tag-2"}' },
* // { 'clinet updateTableTags': '{"tabA":"tag-3","tabB":"tag-2"}' },
* // { 'clinet call getAPIData before': 'tabA' },
* // { 'server call getAPIData before': 'tabA' },
* // { 'server call getAPIData after': 'table[tabA] = 2' },
* // { 'clinet call getAPIData after': 'table[tabA] = 2' }
* // ]
*
*/
function WSyncWebdataServer(instWConverServer, opt = {}) {
let nowTableTags = {}
let isCleared = false
let isDirty = false //記憶體之時間戳有尚未落檔之變更
let lastWritten = null //本實體最後寫入檔案之內容, 釋放時據以判斷檔案是否已由其他實體接手
//check
if (!iseobj(instWConverServer)) {
console.log('instWConverServer is not an effective object, and set instWConverServer to an EventEmitter')
instWConverServer = evem()
}
if (!haskey(instWConverServer, 'emit')) {
throw new Error(`instWConverServer is not an EventEmitter`)
}
//fpTableTags
let fpTableTags = get(opt, 'fpTableTags', '')
if (!isestr(fpTableTags)) {
fpTableTags = './tableTags.json'
}
//genTag
let genTag = get(opt, 'genTag')
if (!isfun(genTag)) {
genTag = () => {
return now2str() + '|' + genID(6)
}
}
//eeEmit, 監聽器之同步拋錯一律攔截轉為error事件
let { emit: eeEmit, emitNow: eeEmitNow, clear: clearEmit } = genEmit(instWConverServer, () => isCleared)
/**
* 讀取各資料表時間資料
*
* @memberof WSyncWebdataServer
* @returns {Object} 回傳各資料表時間戳物件
* @example
*
* let tableTags = wsds.readTableTags()
*
*/
function readTableTags() {
let r = {}
try {
if (fs.existsSync(fpTableTags)) {
let c = fs.readFileSync(fpTableTags, 'utf8')
let o = j2o(c)
if (iseobj(o)) {
r = o
}
}
}
catch (err) {
eeEmit('error', {
msg: 'readTableTags catch',
err,
})
}
return r
}
//writeTableTagsCore, 將記憶體之時間戳寫入檔案, 回傳錯誤或null; 序列化失敗(例如genTag回傳不可序列化之值)時不寫檔, 以免截空既有檔案
let writeTableTagsCore = () => {
let r = o2j(nowTableTags, false, { returnWithStateAndMsg: true })
if (get(r, 'state') !== 'success') {
return new Error(`can not serialize tableTags: ${get(r, 'msg')}`)
}
try {
fs.writeFileSync(fpTableTags, r.msg, 'utf8')
}
catch (err) {
return err
}
lastWritten = r.msg
isDirty = false
return null
}
/**
* 儲存各資料表時間資料，將目前之各資料表時間戳寫入檔案，失敗時發出error事件
*
* @memberof WSyncWebdataServer
* @returns {Undefined} 無回傳
* @example
*
* wsds.writeTableTags()
*
*/
function writeTableTags() {
//check
if (isCleared) {
return
}
//writeTableTagsCore
let err = writeTableTagsCore()
if (err) {
eeEmit('error', {
msg: 'writeTableTags catch',
err,
})
}
}
/**
* 初始化各資料表時間資料
*
* @memberof WSyncWebdataServer
* @param {Object} tableTags 輸入各資料表時間戳物件，null視同{}，其他非物件則發出error事件且不作用；mode為'useInputOnly'時傳入之物件將直接作為內部狀態(之後之更新會就地修改該物件)
* @param {String} [mode='useInputFirst'] 輸入使用設定方式字串，可有'useInputFirst'代表使用傳入設定優先再與既有JSON檔設定合併，為預設值，'useStorageFirst'代表使用既有JSON檔設定優先再與傳入設定合併，'useInputOnly'代表只使用傳入設定，'useStorageOnly'代表只使用既有JSON檔設定
* @returns {Undefined} 無回傳
* @example
*
* let tableTags = {...}
* let mode = ''
* wsds.initTableTags(tableTags, mode)
*
*/
function initTableTags(tableTags = {}, mode = 'useInputFirst') {
// mode可有:
// useInputFirst
// useStorageFirst
// useInputOnly
// useStorageOnly
//check
if (isCleared) {
return
}
//check, null視同{}, 其他非物件無法作為各表時間戳
if (tableTags === null) {
tableTags = {}
}
if (!isobj(tableTags)) {
eeEmit('error', {
msg: 'invalid tableTags for initTableTags',
err: tableTags,
})
return
}
//mode
if (mode === 'useInputOnly') {
nowTableTags = tableTags
}
else if (mode === 'useStorageOnly') {
nowTableTags = readTableTags()
}
else if (mode === 'useInputFirst') {
nowTableTags = merge(readTableTags(), tableTags)
}
else if (mode === 'useStorageFirst') {
nowTableTags = merge(tableTags, readTableTags())
}
else {
throw new Error(`invalid mode[${mode}]`)
}
//writeTableTags
writeTableTags()
}
/**
* 直接設定各資料表時間資料
*
* @memberof WSyncWebdataServer
* @param {Object} tableTags 輸入各資料表時間戳物件，null視同{}，其他非物件則發出error事件且不作用
* @returns {Undefined} 無回傳
* @example
*
* let tableTags = {...}
* wsds.setTableTags(tableTags)
*
*/
function setTableTags(tableTags = {}) {
//check
if (isCleared) {
return
}
//check, null視同{}, 其他非物件無法合併
if (tableTags === null) {
tableTags = {}
}
if (!isobj(tableTags)) {
eeEmit('error', {
msg: 'invalid tableTags for setTableTags',
err: tableTags,
})
return
}
//merge
nowTableTags = merge(nowTableTags, tableTags)
//writeTableTags
writeTableTags()
}
/**
* 直接取得各資料表時間資料，回傳者為內部狀態物件本身，不可修改
*
* @memberof WSyncWebdataServer
* @returns {Object} 回傳各資料表時間戳物件
* @example
*
* let tableTags = wsds.getTableTags()
*
*/
function getTableTags() {
return nowTableTags
}
//updateTableTagCore, 避免大量更新時造成大量推播, 通過debounce合併故是回傳nowTableTags; 持續有更新且間隔皆小於200ms時推播會延至更新停止後(無上限)
let updateTableTagCore = debounce(() => {
//writeTableTags
writeTableTags()
//emit
eeEmit('changeTableTags', nowTableTags)
}, 200)
/**
* 更新指定資料表之時間戳，當資料表更新時需調用此函數，200ms內之多次更新合併為一次寫檔與推播；持續有更新且間隔皆小於200ms時，推播會延至更新停止後
*
* @memberof WSyncWebdataServer
* @param {String} tableName 輸入欲更新指定資料表名稱字串，非有效字串時發出error事件且不作用
* @returns {Undefined} 無回傳
* @example
*
* let tableName = '...'
* wsds.updateTableTag(tableName)
*
*/
function updateTableTag(tableName) {
//check
if (isCleared) {
return
}
//check
if (!isestr(tableName)) {
eeEmit('error', {
msg: 'invalid tableName',
err: tableName,
})
return
}
//modify
nowTableTags[tableName] = genTag()
isDirty = true
//updateTableTagCore
updateTableTagCore()
}
/**
* 監聽更新資料表事件，當外部監聽收到更新通知時再推播nowTableTags至前端
*
* @memberof WSyncWebdataServer
* @param {Object} nowTableTags 各資料表時間戳物件
* @example
*
* wo.on('changeTableTags', function(nowTableTags) {
* ...
* })
*
*/
function onChangeUpdateTableTag() {} onChangeUpdateTableTag()
/**
* 釋放資源：取消待觸發之寫檔與推播及已排程之事件，並將尚未落檔之時間戳寫入檔案(不推播；檔案內容已非本實體最後寫入者代表已由其他實體接手，不覆寫)，之後各寫入類函數皆不作用且不再派發任何事件，讀取類函數照常，可重複呼叫。落檔失敗時於本函數內同步發出error事件。同一時間戳檔重建實體時，宜先釋放舊實體再建立新實體
*
* @memberof WSyncWebdataServer
* @returns {Undefined} 無回傳
* @example
*
* wsds.clearSync()
*
*/
function clearSync() {
//check
if (isCleared) {
return
}
//cancel, 取消待觸發之寫檔與推播
updateTableTagCore.cancel()
//writeTableTagsCore, 尚未落檔之時間戳須寫入, 否則以讀檔模式重建者會取得舊時間戳而使前端不重拉
let err = null
if (isDirty) {
//c, 檔案目前內容, 讀取失敗時視為無法判斷而不覆寫
let c = null
try {
if (fs.existsSync(fpTableTags)) {
c = fs.readFileSync(fpTableTags, 'utf8')
}
}
catch (e) {
c = undefined
}
//檔案不存在, 或仍為本實體最後寫入之內容者才寫入
if (c === null || c === lastWritten) {
err = writeTableTagsCore()
}
}
//isCleared, 之後各寫入類函數皆不作用, 事件亦不再派發
isCleared = true
clearEmit()
//落檔失敗於此同步通知, 因釋放後不再派發任何事件故不可延後
if (err) {
eeEmitNow('error', {
msg: 'writeTableTags catch',
err,
})
}
}
//save
instWConverServer.readTableTags = readTableTags
instWConverServer.writeTableTags = writeTableTags
instWConverServer.initTableTags = initTableTags
instWConverServer.setTableTags = setTableTags
instWConverServer.getTableTags = getTableTags
instWConverServer.updateTableTag = updateTableTag
instWConverServer.clearSync = clearSync
return instWConverServer
}
export default WSyncWebdataServer