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index.js
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index.js
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'use strict'
const DatLibrarian = require('dat-librarian')
const fs = require('fs')
const hexTo32 = require('hex-to-32')
const http = require('http')
const hyperdriveHttp = require('hyperdrive-http')
const path = require('path')
const Websocket = require('websocket-stream')
const { URL } = require('url')
const DAT_LOCALHOST_NAME = 'dat.localhost'
const IS_LOCALHOST_REGEX = /(localhost|\[?::1\]?|127(\.[0-9]{1,3}){3})$/
const BASE_32_KEY_LENGTH = 52
const ERR_404 = 'Not found'
const ERR_500 = 'Server error'
function log () {
const msg = arguments[0]
arguments[0] = '[dat-gateway] ' + msg
if (process.env.DEBUG || process.env.LOG) {
console.log.apply(console, arguments)
}
}
module.exports =
class DatGateway extends DatLibrarian {
constructor ({ dir, dat, loopback, max, net, period, ttl, redirect, domain }) {
dat = dat || {}
if (typeof dat.sparse === 'undefined') {
dat.sparse = dat.sparse || true // only download files requested by the user
}
if (typeof dat.temp === 'undefined') {
dat.temp = dat.temp || true // store dats in memory only
}
log('Creating new gateway with options: %j', { dir, dat, max, net, period, ttl })
super({ dir, dat, net })
this.domain = domain
this.domainRegex = new RegExp(`.+.${this.domain}$`)
this.loopback = loopback || DAT_LOCALHOST_NAME
this.max = max
this.period = period
this.redirect = redirect
this.ttl = ttl
this.lru = {}
if (this.ttl && this.period) {
this.cleaner = setInterval(() => {
log('Checking for expired archives...')
const tasks = Object.keys(this.dats).filter((key) => {
const now = Date.now()
const lastRead = this.lru[key]
const isExpired = (lastRead && ((now - lastRead) > this.ttl))
log('Archive %s expired? %s', key, isExpired)
return isExpired
}).map((key) => {
log('Deleting expired archive %s', key)
delete this.lru[key]
return this.remove(key)
})
return Promise.all(tasks)
}, this.period)
}
}
load () {
log('Setting up...')
return this.getHandler().then((handler) => {
log('Setting up server...')
this.server = http.createServer(handler)
const websocketHandler = this.getWebsocketHandler()
this.websocketServer = Websocket.createServer({
perMessageDeflate: false,
server: this.server
}, websocketHandler)
}).then(() => {
log('Loading pre-existing archives...')
// load pre-existing archives
return super.load()
})
}
/**
* Promisification of server.listen()
* @param {Number} port Port to listen on.
* @return {Promise} Promise that resolves once the server has started listening.
*/
listen (port, host) {
return new Promise((resolve, reject) => {
this.server.listen(port, host, (err) => {
if (err) return reject(err)
else return resolve()
})
})
}
async close () {
if (this.cleaner) {
log('Halting cleaner...')
clearInterval(this.cleaner)
}
if (this.server) {
await new Promise(resolve => this.server.close(resolve))
}
return super.close()
}
getIndexHtml () {
return new Promise((resolve, reject) => {
const filePath = path.join(__dirname, 'index.html')
fs.readFile(filePath, 'utf-8', (err, html) => {
if (err) return reject(err)
else return resolve(html)
})
})
}
getWebsocketHandler () {
return (stream, req) => {
stream.on('error', function (e) {
log('getWebsocketHandler has error: ' + e)
})
const urlParts = req.url.split('/')
const address = urlParts[1]
if (!address) {
stream.end('Must provide archive key')
return Promise.resolve()
}
return this.addIfNew(address).then((dat) => {
const archive = dat.archive
const replication = archive.replicate({
live: true
})
// Relay error events
replication.on('error', function (e) {
stream.emit('error', e)
})
stream.pipe(replication).pipe(stream)
}).catch((e) => {
stream.end(e.message)
})
}
}
getHandler () {
return this.getIndexHtml().then((welcome) => {
return (req, res) => {
const start = Date.now()
const requestURL = `http://${req.headers.host}${req.url}`
const urlParts = new URL(requestURL)
const pathParts = urlParts.pathname.split('/').slice(1)
let hostname = urlParts.hostname
const hostIsOnLoopback = RegExp(IS_LOCALHOST_REGEX).test(hostname)
// normalize loopback interface hostnames
if (hostIsOnLoopback && !hostname.endsWith(this.loopback)) {
hostname = hostname.replace(IS_LOCALHOST_REGEX, DAT_LOCALHOST_NAME)
// redirect to normalized hostname
res.writeHead(302, {
'Access-Control-Allow-Origin': '*',
Location: `http://${hostname}:${urlParts.port}${req.url}`
})
return res.end()
}
// normalized subdomain
const hostParts = hostname.split('.')
let subdomain = null
if (hostIsOnLoopback && hostParts.length >= 3) {
subdomain = hostParts.slice(0, -2).join('.')
} else if (this.domainRegex.test(hostname)) {
const i = hostname.indexOf(this.domain)
subdomain = hostname.slice(0, i - 1)
}
// get Dat archive key from subdomain or path
let datKey = null
if (subdomain) {
if (subdomain.includes('.')) {
datKey = subdomain
} else if (subdomain.length === BASE_32_KEY_LENGTH) {
datKey = hexTo32.decode(subdomain)
}
} else if (pathParts.length >= 1) {
datKey = pathParts[0] // ???
}
const isRedirected = Boolean(subdomain && datKey)
const isRedirecting = Boolean(this.redirect && !subdomain && datKey)
let path = '/'
if (pathParts) {
if (subdomain && isRedirected) {
path = pathParts.join('/')
} else if (pathParts.length >= 2) {
path = pathParts.slice(1).join('/')
}
}
// return index
if (path === '/' && !datKey && !isRedirected && !isRedirecting) {
res.writeHead(200)
return res.end(welcome)
}
// redirect /:key to /:key/
if (!isRedirected && pathParts.length === 1 && !pathParts[0].endsWith('/') && pathParts[0] !== 'favicon.ico') {
res.writeHead(302, {
'Access-Control-Allow-Origin': '*',
Location: `${req.url}/`
})
return res.end()
} else {
res.setHeader('Access-Control-Allow-Origin', '*')
}
const logError = (err, end) => log('[%s] %s %s | ERROR %s [%i ms]', datKey, req.method, path, err.message, end - start)
log('[%s] %s %s', datKey, req.method, path)
// redirect to subdomain
if (isRedirecting) {
return DatLibrarian.resolve(datKey).then((resolvedKey) => {
const encodedDatKey = datKey.includes('.') ? datKey : hexTo32.encode(resolvedKey)
const redirectURL = `http://${encodedDatKey}.${hostname}:${urlParts.port}/${path}${urlParts.search || ''}`
log('Redirecting %s to %s', datKey, redirectURL)
res.setHeader('Location', redirectURL)
res.writeHead(302)
res.end()
}).catch((e) => {
const end = Date.now()
logError(e, end)
res.writeHead(500)
res.end(ERR_500)
})
}
// Return a Dat DNS entry without fetching it from the archive
if (path === '.well-known/dat') {
return DatLibrarian.resolve(datKey).then((resolvedAddress) => {
log('Resolving address %s to %s', datKey, resolvedAddress)
res.writeHead(200)
res.end(`dat://${resolvedAddress}\nttl=3600`)
}).catch((e) => {
const end = Date.now()
logError(e, end)
res.writeHead(500)
res.end(ERR_500)
})
}
// return the archive
return this.addIfNew(datKey).then((dat) => {
// handle it!!
const end = Date.now()
log('[%s] %s %s | OK [%i ms]', datKey, req.method, path, end - start)
req.url = `/${path}${urlParts.search || ''}`
dat.onrequest(req, res)
}).catch((e) => {
const end = Date.now()
logError(e, end)
if (e.message.indexOf('not found') > -1) {
res.writeHead(404)
res.end(ERR_404)
} else {
res.writeHead(500)
res.end(ERR_500)
}
})
}
})
}
addIfNew (address) {
return DatLibrarian.resolve(address).then((key) => {
if (this.keys.indexOf(key) === -1) {
return this.add(address)
} else {
this.lru[key] = Date.now()
return this.get(key)
}
})
}
clearOldest () {
const sortOldestFirst = Object.keys(this.lru).sort((a, b) => {
return this.lru[a] - this.lru[b]
})
const oldest = sortOldestFirst[0]
return this.remove(oldest)
}
add () {
if (this.keys.length >= this.max) {
// Delete the oldest item when we reach capacity and try again
return this.clearOldest().then(() => this.add.apply(this, arguments))
}
return super.add.apply(this, arguments).then((dat) => {
log('Adding HTTP handler to archive...')
if (!dat.onrequest) dat.onrequest = hyperdriveHttp(dat.archive, { live: true, exposeHeaders: true })
return new Promise((resolve) => {
/*
Wait for the archive to populate OR for 3s to pass,
so that addresses for archives which don't exist
don't hold us up all night.
*/
let isDone = false
const done = () => {
if (isDone) return null
isDone = true
const key = dat.archive.key.toString('hex')
this.lru[key] = Date.now()
return resolve(dat)
}
dat.archive.metadata.update(1, done)
setTimeout(done, 3000)
})
})
}
}