// @ts-check const reg = require("../../matrix/read-registration") const userRegex = reg.namespaces.users.map(u => new RegExp(u.regex)) const assert = require("assert").strict /** @type {import("xxhash-wasm").XXHashAPI} */ // @ts-ignore let hasher = null // @ts-ignore require("xxhash-wasm")().then(h => hasher = h) const BLOCK_ELEMENTS = [ "ADDRESS", "ARTICLE", "ASIDE", "AUDIO", "BLOCKQUOTE", "BODY", "CANVAS", "CENTER", "DD", "DETAILS", "DIR", "DIV", "DL", "DT", "FIELDSET", "FIGCAPTION", "FIGURE", "FOOTER", "FORM", "FRAMESET", "H1", "H2", "H3", "H4", "H5", "H6", "HEADER", "HGROUP", "HR", "HTML", "ISINDEX", "LI", "MAIN", "MENU", "NAV", "NOFRAMES", "NOSCRIPT", "OL", "OUTPUT", "P", "PRE", "SECTION", "SUMMARY", "TABLE", "TBODY", "TD", "TFOOT", "TH", "THEAD", "TR", "UL" ] const NEWLINE_ELEMENTS = BLOCK_ELEMENTS.concat(["BR"]) /** * Determine whether an event is the bridged representation of a discord message. * Such messages shouldn't be bridged again. * @param {string} sender */ function eventSenderIsFromDiscord(sender) { // If it's from a user in the bridge's namespace, then it originated from discord // This includes messages sent by the appservice's bot user, because that is what's used for webhooks // TODO: It would be nice if bridge system messages wouldn't trigger this check and could be bridged from matrix to discord, while webhook reflections would remain ignored... // TODO that only applies to the above todo: But you'd have to watch out for the /icon command, where the bridge bot would set the room avatar, and that shouldn't be reflected into the room a second time. if (userRegex.some(x => sender.match(x))) { return true } return false } /** * @param {string} mxc * @returns {string?} */ function getPublicUrlForMxc(mxc) { const avatarURLParts = mxc?.match(/^mxc:\/\/([^/]+)\/(\w+)$/) if (avatarURLParts) return `${reg.ooye.server_origin}/_matrix/media/r0/download/${avatarURLParts[1]}/${avatarURLParts[2]}` else return null } /** * Event IDs are really big and have more entropy than we need. * If we want to store the event ID in the database, we can store a more compact version by hashing it with this. * I choose a 64-bit non-cryptographic hash as only a 32-bit hash will see birthday collisions unreasonably frequently: https://en.wikipedia.org/wiki/Birthday_attack#Mathematics * xxhash outputs an unsigned 64-bit integer. * Converting to a signed 64-bit integer with no bit loss so that it can be stored in an SQLite integer field as-is: https://www.sqlite.org/fileformat2.html#record_format * This should give very efficient storage with sufficient entropy. * @param {string} eventID */ function getEventIDHash(eventID) { assert(hasher, "xxhash is not ready yet") if (eventID[0] === "$" && eventID.length >= 13) { eventID = eventID.slice(1) // increase entropy per character to potentially help xxhash } const unsignedHash = hasher.h64(eventID) const signedHash = unsignedHash - 0x8000000000000000n // shifting down to signed 64-bit range return signedHash } class MatrixStringBuilder { constructor() { this.body = "" this.formattedBody = "" } /** * @param {string} body * @param {string} [formattedBody] * @param {any} [condition] */ add(body, formattedBody, condition = true) { if (condition) { if (formattedBody == undefined) formattedBody = body this.body += body this.formattedBody += formattedBody } return this } /** * @param {string} body * @param {string} [formattedBody] * @param {any} [condition] */ addLine(body, formattedBody, condition = true) { if (condition) { if (formattedBody == undefined) formattedBody = body if (this.body.length && this.body.slice(-1) !== "\n") this.body += "\n" this.body += body const match = this.formattedBody.match(/<\/?([a-zA-Z]+[a-zA-Z0-9]*)[^>]*>\s*$/) if (this.formattedBody.length && (!match || !NEWLINE_ELEMENTS.includes(match[1].toUpperCase()))) this.formattedBody += "
" this.formattedBody += formattedBody } return this } /** * @param {string} body * @param {string} [formattedBody] * @param {any} [condition] */ addParagraph(body, formattedBody, condition = true) { if (condition) { if (formattedBody == undefined) formattedBody = body if (this.body.length && this.body.slice(-1) !== "\n") this.body += "\n\n" this.body += body formattedBody = `

${formattedBody}

` this.formattedBody += formattedBody } return this } get() { return { msgtype: "m.text", body: this.body, format: "org.matrix.custom.html", formatted_body: this.formattedBody } } } /** * Context: Room IDs are not routable on their own. Room permalinks need a list of servers to try. The client is responsible for coming up with a list of servers. * ASSUMPTION 1: The bridge bot is a member of the target room and can therefore access its power levels and member list for calculation. * ASSUMPTION 2: Because the bridge bot is a member of the target room, the target room is bridged. * https://spec.matrix.org/v1.9/appendices/#routing * https://gitdab.com/cadence/out-of-your-element/issues/11 * @param {string} roomID * @param {{[K in "getStateEvent" | "getJoinedMembers"]: import("../../matrix/api")[K]}} api */ async function getViaServers(roomID, api) { const candidates = [] const {joined} = await api.getJoinedMembers(roomID) // Candidate 0: The bot's own server name candidates.push(reg.ooye.server_name) // Candidate 1: Highest joined non-sim non-bot power level user in the room // https://github.com/matrix-org/matrix-react-sdk/blob/552c65db98b59406fb49562e537a2721c8505517/src/utils/permalinks/Permalinks.ts#L172 try { /** @type {{users?: {[mxid: string]: number}}} */ const powerLevels = await api.getStateEvent(roomID, "m.room.power_levels", "") if (powerLevels.users) { const sorted = Object.entries(powerLevels.users).sort((a, b) => b[1] - a[1]) // Highest... for (const power of sorted) { const mxid = power[0] if (!(mxid in joined)) continue // joined... if (userRegex.some(r => mxid.match(r))) continue // non-sim non-bot... const match = mxid.match(/:(.*)/) assert(match) if (!candidates.includes(match[1])) { candidates.push(match[1]) break } } } } catch (e) { // power levels event not found } // Candidates 2-3: Most popular servers in the room /** @type {Map} */ const servers = new Map() // We can get the most popular servers if we know the members, so let's process those... Object.keys(joined) .filter(mxid => !mxid.startsWith("@_")) // Quick check .filter(mxid => !userRegex.some(r => mxid.match(r))) // Full check .slice(0, 1000) // Just sample the first thousand real members .map(mxid => { const match = mxid.match(/:(.*)/) assert(match) return match[1] }) .filter(server => !server.match(/([a-f0-9:]+:+)+[a-f0-9]+/)) // No IPv6 servers .filter(server => !server.match(/[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}/)) // No IPv4 servers // I don't care enough to check ACLs .forEach(server => { const existing = servers.get(server) if (!existing) servers.set(server, 1) else servers.set(server, existing + 1) }) const serverList = [...servers.entries()].sort((a, b) => b[1] - a[1]) for (const server of serverList) { if (!candidates.includes(server[0])) { candidates.push(server[0]) if (candidates.length >= 4) break // Can have at most 4 candidate via servers } } return candidates } /** * Context: Room IDs are not routable on their own. Room permalinks need a list of servers to try. The client is responsible for coming up with a list of servers. * ASSUMPTION 1: The bridge bot is a member of the target room and can therefore access its power levels and member list for calculation. * ASSUMPTION 2: Because the bridge bot is a member of the target room, the target room is bridged. * https://spec.matrix.org/v1.9/appendices/#routing * https://gitdab.com/cadence/out-of-your-element/issues/11 * @param {string} roomID * @param {{[K in "getStateEvent" | "getJoinedMembers"]: import("../../matrix/api")[K]}} api * @returns {Promise} */ async function getViaServersQuery(roomID, api) { const list = await getViaServers(roomID, api) const qs = new URLSearchParams() for (const server of list) { qs.append("via", server) } return qs } module.exports.BLOCK_ELEMENTS = BLOCK_ELEMENTS module.exports.eventSenderIsFromDiscord = eventSenderIsFromDiscord module.exports.getPublicUrlForMxc = getPublicUrlForMxc module.exports.getEventIDHash = getEventIDHash module.exports.MatrixStringBuilder = MatrixStringBuilder module.exports.getViaServers = getViaServers module.exports.getViaServersQuery = getViaServersQuery