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Issue #70: Add simple HTTP fetch caching.
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Required us to remove the abbreviated express type imports, because
we have to distinguish between the built-in fetch Response type and
the express framework Response type.
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@ccxvii
ccxvii committed Apr 25, 2024
1 parent 8468e9b commit d4a7c80
Showing 1 changed file with 58 additions and 29 deletions.
87 changes: 58 additions & 29 deletions examples/rest-server/src/server.ts
View file
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
import cors from 'cors'
import express, { Request, Response } from 'express'
import express from 'express'
import * as fs from 'fs'
import * as mupdf from 'mupdf'
import path from 'path'
Expand All @@ -8,6 +8,9 @@ const app = express()
const PORT = 8080
const HOST = 'http://localhost'

// cache fetched documents in memory for at least 5 minutes
const FETCH_CACHE_EXPIRES = 5 * 60 * 1000

app.use(cors())
app.use(express.json())
app.use(express.static('public'))
Expand All @@ -16,15 +19,41 @@ app.listen(PORT, () => {
console.log(`Server started on ${PORT}`)
})

const fetch_cache: Map<string, { promise: Promise<Response>, expires: number }> = new Map()
function cached_fetch(url: string): Promise<Response> {
let item = fetch_cache.get(url)
if (!item) fetch_cache.set(url, item = { promise: fetch(url), expires: Date.now() + FETCH_CACHE_EXPIRES })
return item.promise
}

const response_cache: Map<string, { promise: Promise<ArrayBuffer>, expires: number }> = new Map()
function cached_response_arrayBuffer(url: string, res: Response): Promise<ArrayBuffer> {
let item = response_cache.get(url)
if (!item) response_cache.set(url, item = { promise: res.arrayBuffer(), expires: Date.now() + FETCH_CACHE_EXPIRES })
return item.promise
}

setInterval(function () {
let now = Date.now()
fetch_cache.forEach((value, key, map) => {
if (value.expires > now)
map.delete(key)
})
response_cache.forEach((value, key, map) => {
if (value.expires > now)
map.delete(key)
})
}, FETCH_CACHE_EXPIRES)

// Helper function to load document from URL
async function loadDocumentFromUrl(url: string): Promise<mupdf.Document> {
const response = await fetch(url)
const buffer = await response.arrayBuffer()
return mupdf.Document.openDocument(new Uint8Array(buffer), 'application/pdf')
const response = await cached_fetch(url)
const buffer = await cached_response_arrayBuffer(url, response)
return mupdf.Document.openDocument(buffer, 'application/pdf')
}

// GET /document/needs-password
app.get('/document/needs-password', async (req: Request, res: Response) => {
app.get('/document/needs-password', async (req: express.Request, res: express.Response) => {
const { url } = req.query
if (!url) {
return res.status(400).send('URL is required')
Expand All @@ -38,7 +67,7 @@ app.get('/document/needs-password', async (req: Request, res: Response) => {
// POST /document/authenticate-password
app.post(
'/document/authenticate-password',
async (req: Request, res: Response) => {
async (req: express.Request, res: express.Response) => {
const { url, password } = req.body
if (!url || !password) {
return res.status(400).send('URL and password are required')
Expand All @@ -51,7 +80,7 @@ app.post(
)

// GET /document/metadata
app.get('/document/metadata', async (req: Request, res: Response) => {
app.get('/document/metadata', async (req: express.Request, res: express.Response) => {
const { url } = req.query
if (!url) {
return res.status(400).send('URL is required')
Expand All @@ -67,7 +96,7 @@ app.get('/document/metadata', async (req: Request, res: Response) => {

// TODO: SetMetaData is not working
// POST /document/metadata
app.post('/document/metadata', async (req: Request, res: Response) => {
app.post('/document/metadata', async (req: express.Request, res: express.Response) => {
const { url, key, value } = req.body
if (!url || !key || !value) {
return res.status(400).send('URL, key, and value are required')
Expand All @@ -82,7 +111,7 @@ app.post('/document/metadata', async (req: Request, res: Response) => {
})

// GET /document/page-count
app.get('/document/page-count', async (req: Request, res: Response) => {
app.get('/document/page-count', async (req: express.Request, res: express.Response) => {
const { url } = req.query
if (!url) {
return res.status(400).send('URL is required')
Expand All @@ -94,7 +123,7 @@ app.get('/document/page-count', async (req: Request, res: Response) => {
})

// GET /document/page/:pageNumber
app.get('/document/page/:pageNumber', async (req: Request, res: Response) => {
app.get('/document/page/:pageNumber', async (req: express.Request, res: express.Response) => {
const { url } = req.query
if (!url) {
return res.status(400).send('URL is required')
Expand All @@ -107,7 +136,7 @@ app.get('/document/page/:pageNumber', async (req: Request, res: Response) => {
})

// GET /document/structured-text
app.get('/document/structured-text', async (req: Request, res: Response) => {
app.get('/document/structured-text', async (req: express.Request, res: express.Response) => {
const { url } = req.query
if (!url) {
return res.status(400).send('URL is required')
Expand All @@ -127,7 +156,7 @@ app.get('/document/structured-text', async (req: Request, res: Response) => {
})

// GET /document/images
app.get('/document/images', async (req: Request, res: Response) => {
app.get('/document/images', async (req: express.Request, res: express.Response) => {
const { url } = req.query
if (!url) {
return res.status(400).send('URL is required')
Expand All @@ -154,7 +183,7 @@ app.get('/document/images', async (req: Request, res: Response) => {
})

// GET /document/annotations
app.get('/document/annotations', async (req: Request, res: Response) => {
app.get('/document/annotations', async (req: express.Request, res: express.Response) => {
const { url } = req.query
if (!url) {
return res.status(400).send('URL is required')
Expand All @@ -174,7 +203,7 @@ app.get('/document/annotations', async (req: Request, res: Response) => {
})

// POST /document/bake
app.post('/document/bake', async (req: Request, res: Response) => {
app.post('/document/bake', async (req: express.Request, res: express.Response) => {
const { url } = req.body
if (!url) {
return res.status(400).send('URL is required')
Expand All @@ -190,7 +219,7 @@ app.post('/document/bake', async (req: Request, res: Response) => {
})

// POST /document/search
app.post('/document/search', async (req: Request, res: Response) => {
app.post('/document/search', async (req: express.Request, res: express.Response) => {
const { url, searchTerm } = req.body
if (!url || !searchTerm) {
return res.status(400).send('URL and searchTerm are required')
Expand All @@ -210,7 +239,7 @@ app.post('/document/search', async (req: Request, res: Response) => {
})

// GET /document/links
app.get('/document/links', async (req: Request, res: Response) => {
app.get('/document/links', async (req: express.Request, res: express.Response) => {
const { url } = req.query
if (!url) {
return res.status(400).send('URL is required')
Expand All @@ -230,7 +259,7 @@ app.get('/document/links', async (req: Request, res: Response) => {
})

// POST /document/embed-file
app.post('/document/embed-file', async (req: Request, res: Response) => {
app.post('/document/embed-file', async (req: express.Request, res: express.Response) => {
const { url, embedUrl } = req.body
if (!url || !embedUrl) {
return res.status(400).send('URL and embedUrl are required')
Expand Down Expand Up @@ -265,7 +294,7 @@ app.post('/document/embed-file', async (req: Request, res: Response) => {
// GET /document/page/:pageNumber/bounds
app.get(
'/document/page/:pageNumber/bounds',
async (req: Request, res: Response) => {
async (req: express.Request, res: express.Response) => {
const { url } = req.query
if (!url) {
return res.status(400).send('URL is required')
Expand All @@ -283,7 +312,7 @@ app.get(
// GET /document/page/:pageNumber/pixmap
app.get(
'/document/page/:pageNumber/pixmap',
async (req: Request, res: Response) => {
async (req: express.Request, res: express.Response) => {
const { url } = req.query
if (!url) {
return res.status(400).send('URL is required')
Expand All @@ -308,7 +337,7 @@ app.get(
// GET /document/page/:pageNumber/structured-text
app.get(
'/document/page/:pageNumber/structured-text',
async (req: Request, res: Response) => {
async (req: express.Request, res: express.Response) => {
const { url } = req.query
if (!url) {
return res.status(400).send('URL is required')
Expand All @@ -326,7 +355,7 @@ app.get(
// GET /document/page/:pageNumber/images
app.get(
'/document/page/:pageNumber/images',
async (req: Request, res: Response) => {
async (req: express.Request, res: express.Response) => {
const { url } = req.query
if (!url) {
return res.status(400).send('URL is required')
Expand Down Expand Up @@ -355,7 +384,7 @@ app.get(
// POST /document/page/:pageNumber/add-text
app.post(
'/document/page/:pageNumber/add-text',
async (req: Request, res: Response) => {
async (req: express.Request, res: express.Response) => {
const { url, text, x, y, fontFamily, fontSize } = req.body
if (!url || !text || !x || !y || !fontFamily || !fontSize) {
return res
Expand Down Expand Up @@ -395,7 +424,7 @@ app.post(
// POST /document/page/:pageNumber/add-image
app.post(
'/document/page/:pageNumber/add-image',
async (req: Request, res: Response) => {
async (req: express.Request, res: express.Response) => {
const { url, imageUrl, x, y, width, height } = req.body
if (!url || !imageUrl || !x || !y || !width || !height) {
return res
Expand Down Expand Up @@ -440,7 +469,7 @@ app.post(
// POST /document/page/:pageNumber/copy
app.post(
'/document/page/:pageNumber/copy',
async (req: Request, res: Response) => {
async (req: express.Request, res: express.Response) => {
const { url } = req.body
if (!url) {
return res.status(400).send('URL is required')
Expand All @@ -462,7 +491,7 @@ app.post(
// DELETE /document/page/:pageNumber/delete
app.delete(
'/document/page/:pageNumber/delete',
async (req: Request, res: Response) => {
async (req: express.Request, res: express.Response) => {
const { url } = req.body
if (!url) {
return res.status(400).send('URL is required')
Expand All @@ -482,7 +511,7 @@ app.delete(
// POST /document/page/:pageNumber/rotate
app.post(
'/document/page/:pageNumber/rotate',
async (req: Request, res: Response) => {
async (req: express.Request, res: express.Response) => {
const { url, degrees } = req.body
if (!url || !degrees) {
return res.status(400).send('URL and degrees are required')
Expand All @@ -508,7 +537,7 @@ app.post(
// POST /document/page/:pageNumber/crop
app.post(
'/document/page/:pageNumber/crop',
async (req: Request, res: Response) => {
async (req: express.Request, res: express.Response) => {
const { url, x, y, width, height } = req.body

if (!url || x === undefined || y === undefined || !width || !height) {
Expand All @@ -531,7 +560,7 @@ app.post(
)

// POST /document/split
app.post('/document/split', async (req: Request, res: Response) => {
app.post('/document/split', async (req: express.Request, res: express.Response) => {
const { url } = req.body
if (!url) {
return res.status(400).send('URL is required')
Expand All @@ -554,7 +583,7 @@ app.post('/document/split', async (req: Request, res: Response) => {
})

// POST /document/merge
app.post('/document/merge', async (req: Request, res: Response) => {
app.post('/document/merge', async (req: express.Request, res: express.Response) => {
const { urls } = req.body
if (!urls || !Array.isArray(urls) || urls.length < 2) {
return res.status(400).send('At least two URLs are required')
Expand Down

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