HackMD/lib/models/revision.js
2018-01-18 11:19:47 +01:00

307 lines
9.8 KiB
JavaScript

'use strict'
// external modules
var Sequelize = require('sequelize')
var async = require('async')
var moment = require('moment')
var childProcess = require('child_process')
var shortId = require('shortid')
// core
var config = require('../config')
var logger = require('../logger')
var dmpWorker = createDmpWorker()
var dmpCallbackCache = {}
function createDmpWorker () {
var worker = childProcess.fork('./lib/workers/dmpWorker.js', {
stdio: 'ignore'
})
if (config.debug) logger.info('dmp worker process started')
worker.on('message', function (data) {
if (!data || !data.msg || !data.cacheKey) {
return logger.error('dmp worker error: not enough data on message')
}
var cacheKey = data.cacheKey
switch (data.msg) {
case 'error':
dmpCallbackCache[cacheKey](data.error, null)
break
case 'check':
dmpCallbackCache[cacheKey](null, data.result)
break
}
delete dmpCallbackCache[cacheKey]
})
worker.on('close', function (code) {
dmpWorker = null
if (config.debug) logger.info('dmp worker process exited with code ' + code)
})
return worker
}
function sendDmpWorker (data, callback) {
if (!dmpWorker) dmpWorker = createDmpWorker()
var cacheKey = Date.now() + '_' + shortId.generate()
dmpCallbackCache[cacheKey] = callback
data = Object.assign(data, {
cacheKey: cacheKey
})
dmpWorker.send(data)
}
module.exports = function (sequelize, DataTypes) {
var Revision = sequelize.define('Revision', {
id: {
type: DataTypes.UUID,
primaryKey: true,
defaultValue: Sequelize.UUIDV4
},
patch: {
type: DataTypes.TEXT('long'),
get: function () {
return sequelize.processData(this.getDataValue('patch'), '')
},
set: function (value) {
this.setDataValue('patch', sequelize.stripNullByte(value))
}
},
lastContent: {
type: DataTypes.TEXT('long'),
get: function () {
return sequelize.processData(this.getDataValue('lastContent'), '')
},
set: function (value) {
this.setDataValue('lastContent', sequelize.stripNullByte(value))
}
},
content: {
type: DataTypes.TEXT('long'),
get: function () {
return sequelize.processData(this.getDataValue('content'), '')
},
set: function (value) {
this.setDataValue('content', sequelize.stripNullByte(value))
}
},
length: {
type: DataTypes.INTEGER
},
authorship: {
type: DataTypes.TEXT,
get: function () {
return sequelize.processData(this.getDataValue('authorship'), [], JSON.parse)
},
set: function (value) {
this.setDataValue('authorship', value ? JSON.stringify(value) : value)
}
}
}, {
classMethods: {
associate: function (models) {
Revision.belongsTo(models.Note, {
foreignKey: 'noteId',
as: 'note',
constraints: false
})
},
getNoteRevisions: function (note, callback) {
Revision.findAll({
where: {
noteId: note.id
},
order: [['createdAt', 'DESC']]
}).then(function (revisions) {
var data = []
for (var i = 0, l = revisions.length; i < l; i++) {
var revision = revisions[i]
data.push({
time: moment(revision.createdAt).valueOf(),
length: revision.length
})
}
callback(null, data)
}).catch(function (err) {
callback(err, null)
})
},
getPatchedNoteRevisionByTime: function (note, time, callback) {
// find all revisions to prepare for all possible calculation
Revision.findAll({
where: {
noteId: note.id
},
order: [['createdAt', 'DESC']]
}).then(function (revisions) {
if (revisions.length <= 0) return callback(null, null)
// measure target revision position
Revision.count({
where: {
noteId: note.id,
createdAt: {
$gte: time
}
},
order: [['createdAt', 'DESC']]
}).then(function (count) {
if (count <= 0) return callback(null, null)
sendDmpWorker({
msg: 'get revision',
revisions: revisions,
count: count
}, callback)
}).catch(function (err) {
return callback(err, null)
})
}).catch(function (err) {
return callback(err, null)
})
},
checkAllNotesRevision: function (callback) {
Revision.saveAllNotesRevision(function (err, notes) {
if (err) return callback(err, null)
if (!notes || notes.length <= 0) {
return callback(null, notes)
} else {
Revision.checkAllNotesRevision(callback)
}
})
},
saveAllNotesRevision: function (callback) {
sequelize.models.Note.findAll({
// query all notes that need to save for revision
where: {
$and: [
{
lastchangeAt: {
$or: {
$eq: null,
$and: {
$ne: null,
$gt: sequelize.col('createdAt')
}
}
}
},
{
savedAt: {
$or: {
$eq: null,
$lt: sequelize.col('lastchangeAt')
}
}
}
]
}
}).then(function (notes) {
if (notes.length <= 0) return callback(null, notes)
var savedNotes = []
async.each(notes, function (note, _callback) {
// revision saving policy: note not been modified for 5 mins or not save for 10 mins
if (note.lastchangeAt && note.savedAt) {
var lastchangeAt = moment(note.lastchangeAt)
var savedAt = moment(note.savedAt)
if (moment().isAfter(lastchangeAt.add(5, 'minutes'))) {
savedNotes.push(note)
Revision.saveNoteRevision(note, _callback)
} else if (lastchangeAt.isAfter(savedAt.add(10, 'minutes'))) {
savedNotes.push(note)
Revision.saveNoteRevision(note, _callback)
} else {
return _callback(null, null)
}
} else {
savedNotes.push(note)
Revision.saveNoteRevision(note, _callback)
}
}, function (err) {
if (err) {
return callback(err, null)
}
// return null when no notes need saving at this moment but have delayed tasks to be done
var result = ((savedNotes.length === 0) && (notes.length > savedNotes.length)) ? null : savedNotes
return callback(null, result)
})
}).catch(function (err) {
return callback(err, null)
})
},
saveNoteRevision: function (note, callback) {
Revision.findAll({
where: {
noteId: note.id
},
order: [['createdAt', 'DESC']]
}).then(function (revisions) {
if (revisions.length <= 0) {
// if no revision available
Revision.create({
noteId: note.id,
lastContent: note.content ? note.content : '',
length: note.content ? note.content.length : 0,
authorship: note.authorship
}).then(function (revision) {
Revision.finishSaveNoteRevision(note, revision, callback)
}).catch(function (err) {
return callback(err, null)
})
} else {
var latestRevision = revisions[0]
var lastContent = latestRevision.content || latestRevision.lastContent
var content = note.content
sendDmpWorker({
msg: 'create patch',
lastDoc: lastContent,
currDoc: content
}, function (err, patch) {
if (err) logger.error('save note revision error', err)
if (!patch) {
// if patch is empty (means no difference) then just update the latest revision updated time
latestRevision.changed('updatedAt', true)
latestRevision.update({
updatedAt: Date.now()
}).then(function (revision) {
Revision.finishSaveNoteRevision(note, revision, callback)
}).catch(function (err) {
return callback(err, null)
})
} else {
Revision.create({
noteId: note.id,
patch: patch,
content: note.content,
length: note.content.length,
authorship: note.authorship
}).then(function (revision) {
// clear last revision content to reduce db size
latestRevision.update({
content: null
}).then(function () {
Revision.finishSaveNoteRevision(note, revision, callback)
}).catch(function (err) {
return callback(err, null)
})
}).catch(function (err) {
return callback(err, null)
})
}
})
}
}).catch(function (err) {
return callback(err, null)
})
},
finishSaveNoteRevision: function (note, revision, callback) {
note.update({
savedAt: revision.updatedAt
}).then(function () {
return callback(null, revision)
}).catch(function (err) {
return callback(err, null)
})
}
}
})
return Revision
}