import { createHmac } from 'node:crypto' import { extractUrls } from '../../../lib/md' const IMGPROXY_URL = process.env.NEXT_PUBLIC_IMGPROXY_URL const IMGPROXY_SALT = process.env.IMGPROXY_SALT const IMGPROXY_KEY = process.env.IMGPROXY_KEY 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') } const createImageProxyUrl = url => { const processingOptions = '/rs:fit:600:500:0/g:no' const b64Url = Buffer.from(url, 'utf-8').toString('base64url') const target = `${processingOptions}/${b64Url}` const signature = sign(target) return `${IMGPROXY_URL}${signature}${target}` } const isImageURL = async url => { // https://stackoverflow.com/a/68118683 try { const res = await fetch(url, { method: 'HEAD' }) const buf = await res.blob() return buf.type.startsWith('image/') } catch (err) { console.log(err) return false } } export const proxyImages = async text => { const urls = extractUrls(text) for (const url of urls) { if (url.startsWith(IMGPROXY_URL)) continue if (!(await isImageURL(url))) continue const proxyUrl = createImageProxyUrl(url) text = text.replaceAll(url, proxyUrl) } return text }