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@@ -1,330 +0,0 @@
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-import { v4 as uuid } from 'uuid'
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-import { fetchRange } from './features/pdf-preview/util/pdf-caching'
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-const OError = require('@overleaf/o-error')
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-
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-// VERSION should get incremented when making changes to caching behavior or
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-// adjusting metrics collection.
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-// Keep in sync with PdfJsMetrics.
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-const VERSION = 3
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-
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-const CLEAR_CACHE_REQUEST_MATCHER = /^\/project\/[0-9a-f]{24}\/output$/
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-const COMPILE_REQUEST_MATCHER = /^\/project\/[0-9a-f]{24}\/compile$/
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-const PDF_REQUEST_MATCHER =
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- /^(\/zone\/.)?(\/project\/[0-9a-f]{24}\/.*\/output.pdf)$/
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-const PDF_JS_CHUNK_SIZE = 128 * 1024
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-
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-// Each compile request defines a context (essentially the specific pdf file for
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-// that compile), requests for that pdf file can use the hashes in the compile
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-// response, which are stored in the context.
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-
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-const CLIENT_CONTEXT = new Map()
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-
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-/**
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- * @param {string} clientId
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- */
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-function getClientContext(clientId) {
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- let clientContext = CLIENT_CONTEXT.get(clientId)
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- if (!clientContext) {
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- const cached = new Set()
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- const pdfs = new Map()
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- const metrics = {
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- version: VERSION,
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- id: uuid(),
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- epoch: Date.now(),
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- failedCount: 0,
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- tooLargeOverheadCount: 0,
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- tooManyRequestsCount: 0,
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- cachedCount: 0,
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- cachedBytes: 0,
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- fetchedCount: 0,
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- fetchedBytes: 0,
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- requestedCount: 0,
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- requestedBytes: 0,
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- compileCount: 0,
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- }
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- clientContext = { pdfs, metrics, cached }
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- CLIENT_CONTEXT.set(clientId, clientContext)
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- // clean up old client maps
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- expirePdfContexts()
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- }
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- return clientContext
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-}
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-
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-/**
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- * @param {string} clientId
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- * @param {string} path
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- * @param {Object} pdfContext
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- */
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-function registerPdfContext(clientId, path, pdfContext) {
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- const clientContext = getClientContext(clientId)
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- const { pdfs, metrics, cached, clsiServerId } = clientContext
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- pdfContext.metrics = metrics
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- pdfContext.cached = cached
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- if (pdfContext.clsiServerId !== clsiServerId) {
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- // VM changed, this invalidates all browser caches.
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- clientContext.clsiServerId = pdfContext.clsiServerId
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- cached.clear()
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- }
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- // we only need to keep the last 3 contexts
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- for (const key of pdfs.keys()) {
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- if (pdfs.size < 3) {
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- break
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- }
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- pdfs.delete(key) // the map keys are returned in insertion order, so we are deleting the oldest entry here
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- }
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- pdfs.set(path, pdfContext)
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-}
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-
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-/**
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- * @param {string} clientId
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- * @param {string} path
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- */
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-function getPdfContext(clientId, path) {
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- const { pdfs } = getClientContext(clientId)
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- return pdfs.get(path)
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-}
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-
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-function expirePdfContexts() {
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- // discard client maps for clients that are no longer connected
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- const currentClientSet = new Set()
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- self.clients.matchAll().then(function (clientList) {
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- clientList.forEach(client => {
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- currentClientSet.add(client.id)
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- })
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- CLIENT_CONTEXT.forEach((map, clientId) => {
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- if (!currentClientSet.has(clientId)) {
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- CLIENT_CONTEXT.delete(clientId)
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- }
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- })
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- })
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-}
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-
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-/**
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- * @param {FetchEvent} event
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- */
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-function onFetch(event) {
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- const url = new URL(event.request.url)
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- const path = url.pathname
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-
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- if (path.match(COMPILE_REQUEST_MATCHER)) {
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- return processCompileRequest(event)
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- }
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-
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- const match = path.match(PDF_REQUEST_MATCHER)
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- if (match) {
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- const ctx = getPdfContext(event.clientId, match[2])
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- if (ctx) {
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- return processPdfRequest(event, ctx)
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- }
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- }
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-
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- if (
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- event.request.method === 'DELETE' &&
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- path.match(CLEAR_CACHE_REQUEST_MATCHER)
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- ) {
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- return processClearCacheRequest(event)
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- }
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-
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- // other request, ignore
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-}
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-
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-/**
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- * @param {FetchEvent} event
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- */
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-function processClearCacheRequest(event) {
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- CLIENT_CONTEXT.delete(event.clientId)
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- // use default request proxy.
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-}
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-
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-/**
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- * @param {FetchEvent} event
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- */
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-function processCompileRequest(event) {
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- event.respondWith(
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- fetch(event.request).then(response => {
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- if (response.status !== 200) return response
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-
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- return response.json().then(body => {
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- handleCompileResponse(event, response, body)
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-
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- // Send the service workers metrics to the frontend.
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- const { metrics } = getClientContext(event.clientId)
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- metrics.compileCount++
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- body.serviceWorkerMetrics = metrics
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-
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- return new Response(JSON.stringify(body), response)
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- })
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- })
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- )
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-}
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-
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-/**
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- * @param {Request} request
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- * @param {Object} file
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- * @return {Response}
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- */
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-function handleProbeRequest(request, file) {
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- // PDF.js starts the pdf download with a probe request that has no
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- // range headers on it.
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- // Upon seeing the response headers, it decides whether to upgrade the
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- // transport to chunked requests or keep reading the response body.
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- // For small PDFs (2*chunkSize = 2*128kB) it just sends one request.
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- // We will fetch all the ranges in bulk and emit them.
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- // For large PDFs it sends this probe request, aborts that request before
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- // reading any data and then sends multiple range requests.
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- // It would be wasteful to action this probe request with all the ranges
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- // that are available in the PDF and serve the full PDF content to
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- // PDF.js for the probe request.
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- // We are emitting a dummy response to the probe request instead.
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- // It triggers the chunked transfer and subsequent fewer ranges need to be
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- // requested -- only those of visible pages in the pdf viewer.
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- // https://github.com/mozilla/pdf.js/blob/6fd899dc443425747098935207096328e7b55eb2/src/display/network_utils.js#L43-L47
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- const pdfJSWillUseChunkedTransfer = file.size > 2 * PDF_JS_CHUNK_SIZE
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- const isRangeRequest = request.headers.has('Range')
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- if (!isRangeRequest && pdfJSWillUseChunkedTransfer) {
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- const headers = new Headers()
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- headers.set('Accept-Ranges', 'bytes')
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- headers.set('Content-Length', file.size)
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- headers.set('Content-Type', 'application/pdf')
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- return new Response('', {
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- headers,
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- status: 200,
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- statusText: 'OK',
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- })
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- }
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-}
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-
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-/**
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- *
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- * @param {FetchEvent} event
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- * @param {Object} file
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- * @param {string} clsiServerId
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- * @param {string} compileGroup
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- * @param {Date} pdfCreatedAt
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- * @param {Object} metrics
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- * @param {Set} cached
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- */
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-function processPdfRequest(
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- event,
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- { file, clsiServerId, compileGroup, pdfCreatedAt, metrics, cached }
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-) {
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- const response = handleProbeRequest(event.request, file)
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- if (response) {
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- return event.respondWith(response)
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- }
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-
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- const rangeHeader =
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- event.request.headers.get('Range') || `bytes=0-${file.size - 1}`
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- const [start, last] = rangeHeader
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- .slice('bytes='.length)
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- .split('-')
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- .map(i => parseInt(i, 10))
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- const end = last + 1
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-
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- return event.respondWith(
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- fetchRange({
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- url: event.request.url,
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- start,
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- end,
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- file,
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- pdfCreatedAt,
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- metrics,
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- cached,
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- })
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- .then(blob => {
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- return new Response(blob, {
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- status: 206,
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- headers: {
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- 'Accept-Ranges': 'bytes',
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- 'Content-Length': end - start,
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- 'Content-Range': `bytes ${start}-${last}/${file.size}`,
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- 'Content-Type': 'application/pdf',
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- },
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- })
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- })
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- .catch(error => {
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- metrics.failedCount++
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- reportError(event, OError.tag(error, 'failed to compose pdf response'))
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- return fetch(event.request)
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- })
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- )
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-}
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-
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-/**
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- * @param {FetchEvent} event
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- * @param {Response} response
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- * @param {Object} body
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- */
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-function handleCompileResponse(event, response, body) {
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- if (!body || body.status !== 'success') return
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-
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- for (const file of body.outputFiles) {
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- if (file.path !== 'output.pdf') continue // not the pdf used for rendering
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- if (file.ranges?.length) {
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- const { clsiServerId, compileGroup } = body
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- registerPdfContext(event.clientId, file.url, {
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- file,
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- clsiServerId,
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- compileGroup,
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- })
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- }
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- break
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- }
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-}
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-
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-/**
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- * @param {FetchEvent} event
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- */
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-function onFetchWithErrorHandling(event) {
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- try {
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- onFetch(event)
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- } catch (error) {
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- reportError(event, OError.tag(error, 'low level error in onFetch'))
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- }
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-}
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-// allow fetch event listener to be removed if necessary
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-const controller = new AbortController()
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-// listen to all network requests
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-self.addEventListener('fetch', onFetchWithErrorHandling, {
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- signal: controller.signal,
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-})
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-
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-// complete setup ASAP
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-self.addEventListener('install', event => {
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- event.waitUntil(self.skipWaiting())
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-})
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-self.addEventListener('activate', event => {
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- event.waitUntil(self.clients.claim())
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-})
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-self.addEventListener('message', event => {
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- if (event.data && event.data.type === 'disable') {
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- controller.abort() // removes the fetch event listener
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- }
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-})
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-
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-/**
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- *
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- * @param {FetchEvent} event
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- * @param {Error} error
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- */
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-function reportError(event, error) {
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- self.clients
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- .get(event.clientId)
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- .then(client => {
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- if (!client) {
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- // The client disconnected.
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- return
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- }
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- client.postMessage(
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- JSON.stringify({
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- extra: { url: event.request.url, info: OError.getFullInfo(error) },
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- error: {
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- name: error.name,
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- message: error.message,
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- stack: OError.getFullStack(error),
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- },
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- })
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- )
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- })
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- .catch(() => {})
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-}
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Jakob Ackermann