import { createHmac } from 'node:crypto' import { extractUrls } from '../lib/md.js' import { isJob } from '../lib/item.js' const imgProxyEnabled = process.env.NODE_ENV === 'production' || (process.env.NEXT_PUBLIC_IMGPROXY_URL && process.env.IMGPROXY_SALT && process.env.IMGPROXY_KEY) if (!imgProxyEnabled) { console.warn('IMGPROXY_* env vars not set, imgproxy calls are no-ops now') } const IMGPROXY_URL = process.env.NEXT_PUBLIC_IMGPROXY_URL const IMGPROXY_SALT = process.env.IMGPROXY_SALT const IMGPROXY_KEY = process.env.IMGPROXY_KEY const cache = new Map() // based on heuristics. see https://stacker.news/items/266838 const imageUrlMatchers = [ u => u.host === 'i.postimg.cc', u => u.host === 'pbs.twimg.com', u => u.host === 'i.ibb.co', u => u.host === 'nostr.build' || u.host === 'cdn.nostr.build', u => u.host === 'www.zapread.com' && u.pathname.startsWith('/i'), u => u.host === 'i.imgflip.com', u => u.host === 'i.redd.it', u => u.host === 'media.tenor.com', u => u.host === 'i.imgur.com' ] const exclude = [ u => u.protocol === 'mailto:', u => u.host.endsWith('.onion') || u.host.endsWith('.b32.ip') || u.host.endsWith('.loki'), u => ['twitter.com', 'x.com', 'nitter.it', 'nitter.at'].some(h => h === u.host), u => u.host === 'stacker.news', u => u.host === 'news.ycombinator.com', u => u.host === 'www.youtube.com' || u.host === 'youtu.be', u => u.host === 'github.com' ] function matchUrl (matchers, url) { try { return matchers.some(matcher => matcher(new URL(url))) } catch (err) { console.log(url, err) return false } } function decodeOriginalUrl (imgproxyUrl) { const parts = imgproxyUrl.split('/') const b64Url = parts[parts.length - 1] const originalUrl = Buffer.from(b64Url, 'base64url').toString('utf-8') return originalUrl } export function imgproxy ({ models }) { return async function ({ data: { id, forceFetch = false } }) { if (!imgProxyEnabled) return console.log('running imgproxy job', id) const item = await models.item.findUnique({ where: { id } }) let imgproxyUrls = {} try { if (item.text) { imgproxyUrls = await createImgproxyUrls(id, item.text, { forceFetch }) } if (item.url && !isJob(item)) { imgproxyUrls = { ...imgproxyUrls, ...(await createImgproxyUrls(id, item.url, { forceFetch })) } } } catch (err) { console.log('[imgproxy] error:', err) // rethrow for retry throw err } console.log('[imgproxy] updating item', id, 'with urls', imgproxyUrls) await models.item.update({ where: { id }, data: { imgproxyUrls } }) } } export const createImgproxyUrls = async (id, text, { forceFetch }) => { const urls = extractUrls(text) console.log('[imgproxy] id:', id, '-- extracted urls:', urls) // resolutions that we target: // - nHD: 640x 360 // - qHD: 960x 540 // - HD: 1280x 720 // - HD+: 1600x 900 // - FHD: 1920x1080 // - QHD: 2560x1440 // reference: // - https://en.wikipedia.org/wiki/Graphics_display_resolution#High-definition_(HD_and_derivatives) // - https://www.browserstack.com/guide/ideal-screen-sizes-for-responsive-design const resolutions = ['640x360', '960x540', '1280x720', '1600x900', '1920x1080', '2560x1440'] const imgproxyUrls = {} for (let url of urls) { if (!url) continue console.log('[imgproxy] id:', id, '-- processing url:', url) if (url.startsWith(IMGPROXY_URL)) { console.log('[imgproxy] id:', id, '-- proxy url, decoding original url:', url) // backwards compatibility: we used to replace image urls with imgproxy urls url = decodeOriginalUrl(url) console.log('[imgproxy] id:', id, '-- original url:', url) } if (!(await isImageURL(url, { forceFetch }))) { console.log('[imgproxy] id:', id, '-- not image url:', url) continue } imgproxyUrls[url] = {} for (const res of resolutions) { const [w, h] = res.split('x') const processingOptions = `/rs:fit:${w}:${h}` imgproxyUrls[url][`${w}w`] = createImgproxyUrl(url, processingOptions) } } return imgproxyUrls } const createImgproxyUrl = (url, processingOptions) => { const b64Url = Buffer.from(url, 'utf-8').toString('base64url') const target = `${processingOptions}/${b64Url}` const signature = sign(target) return `${IMGPROXY_URL}${signature}${target}` } async function fetchWithTimeout (resource, { timeout = 1000, ...options } = {}) { const controller = new AbortController() const id = setTimeout(() => controller.abort(), timeout) const response = await fetch(resource, { ...options, signal: controller.signal }) clearTimeout(id) return response } const isImageURL = async (url, { forceFetch }) => { if (cache.has(url)) return cache.get(url) if (!forceFetch && matchUrl(imageUrlMatchers, url)) { return true } if (!forceFetch && matchUrl(exclude, url)) { return false } let isImage // first run HEAD with small timeout try { // https://stackoverflow.com/a/68118683 const res = await fetchWithTimeout(url, { timeout: 1000, method: 'HEAD' }) const buf = await res.blob() isImage = buf.type.startsWith('image/') } catch (err) { console.log(url, err) } // For HEAD requests, positives are most likely true positives. // However, negatives may be false negatives if (isImage) { cache.set(url, true) return true } // if not known yet, run GET request with longer timeout try { const res = await fetchWithTimeout(url, { timeout: 10000 }) const buf = await res.blob() isImage = buf.type.startsWith('image/') } catch (err) { console.log(url, err) } cache.set(url, isImage) return isImage } const hexDecode = (hex) => Buffer.from(hex, 'hex') const sign = (target) => { // https://github.com/imgproxy/imgproxy/blob/master/examples/signature.js const hmac = createHmac('sha256', hexDecode(IMGPROXY_KEY)) hmac.update(hexDecode(IMGPROXY_SALT)) hmac.update(target) return hmac.digest('base64url') }