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118 lines
3.1 KiB
JavaScript
118 lines
3.1 KiB
JavaScript
'use strict'
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const Archive = require('archiver')
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const BPromise = require('bluebird')
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const fs = require('fs')
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const core = require('overleaf-editor-core')
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const Snapshot = core.Snapshot
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const OError = require('@overleaf/o-error')
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const assert = require('./assert')
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// The maximum safe concurrency appears to be 1.
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// https://github.com/overleaf/issues/issues/1909
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const FETCH_CONCURRENCY = 1 // number of files to fetch at once
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const DEFAULT_ZIP_TIMEOUT = 25000 // ms
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class DownloadError extends OError {
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constructor(hash) {
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super(`ProjectArchive: blob download failed: ${hash}`, { hash })
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}
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}
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ProjectArchive.DownloadError = DownloadError
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class ArchiveTimeout extends OError {
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constructor() {
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super('ProjectArchive timed out')
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}
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}
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ProjectArchive.ArchiveTimeout = ArchiveTimeout
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/**
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* @constructor
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* @param {Snapshot} snapshot
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* @param {?number} timeout in ms
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* @classdesc
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* Writes the project snapshot to a zip file.
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*/
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function ProjectArchive(snapshot, timeout) {
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assert.instance(snapshot, Snapshot)
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this.snapshot = snapshot
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this.timeout = timeout || DEFAULT_ZIP_TIMEOUT
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}
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/**
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* Write zip archive to the given file path.
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*
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* @param {BlobStore} blobStore
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* @param {string} zipFilePath
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*/
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ProjectArchive.prototype.writeZip = function projectArchiveToZip(
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blobStore,
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zipFilePath
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) {
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const snapshot = this.snapshot
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const timeout = this.timeout
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const startTime = process.hrtime()
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const archive = new Archive('zip')
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// Convert elapsed seconds and nanoseconds to milliseconds.
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function findElapsedMilliseconds() {
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const elapsed = process.hrtime(startTime)
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return elapsed[0] * 1e3 + elapsed[1] * 1e-6
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}
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function addFileToArchive(pathname) {
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if (findElapsedMilliseconds() > timeout) {
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throw new ProjectArchive.ArchiveTimeout()
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}
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const file = snapshot.getFile(pathname)
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return file.load('eager', blobStore).then(function () {
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const content = file.getContent()
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if (content === null) {
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return streamFileToArchive(pathname, file).catch(function (err) {
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throw new ProjectArchive.DownloadError(file.getHash()).withCause(err)
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})
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} else {
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archive.append(content, { name: pathname })
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}
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})
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}
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function streamFileToArchive(pathname, file) {
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return new BPromise(function (resolve, reject) {
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blobStore
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.getStream(file.getHash())
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.then(stream => {
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stream.on('error', reject)
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stream.on('end', resolve)
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archive.append(stream, { name: pathname })
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})
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.catch(reject)
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})
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}
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const addFilesToArchiveAndFinalize = BPromise.map(
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snapshot.getFilePathnames(),
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addFileToArchive,
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{ concurrency: FETCH_CONCURRENCY }
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).then(function () {
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archive.finalize()
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})
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const streamArchiveToFile = new BPromise(function (resolve, reject) {
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archive.on('error', reject)
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const stream = fs.createWriteStream(zipFilePath)
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stream.on('error', reject)
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stream.on('finish', resolve)
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archive.pipe(stream)
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})
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return BPromise.join(streamArchiveToFile, addFilesToArchiveAndFinalize)
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}
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module.exports = ProjectArchive
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