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105 lines
2.8 KiB
105 lines
2.8 KiB
// KaTeX rendering server
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// Listens on unix socket, path is provided as first argument
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// Expects JSON lines, each line is a query with the following schema:
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// {
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// formulas: [
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// {
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// tex: string,
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// options?: object
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// }
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// ],
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// options?: object
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// }
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// see https://katex.org/docs/options.html for list of available options
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// If options formulas[].options field is used, the global options field is ignored.
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// For each line, returns one JSON line with the following schema:
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// {
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// results: [
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// { html?: string } | { error?: string }
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// ]
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// } | { error?: string }
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// If one formula is invalid, the error in results is used
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// If the entire query is invalid (couldn't parse JSON, for example), the outer error field is used
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import katex from 'katex'
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import net from 'net'
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import * as readline from 'readline'
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const myArgs = process.argv.slice(2)
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const unixSocketPath = myArgs[0]
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if (!unixSocketPath) {
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console.error('you must specify socket path')
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process.exit(1)
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}
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// This server listens on a Unix socket at /var/run/mysocket
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var unixServer = net.createServer(handleClient);
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unixServer.listen(unixSocketPath);
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function handleExit(signal) {
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// unixServer.emit('close')
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unixServer.close(function () {
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});
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process.exit(0); // put this into the callback to avoid closing open connections
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}
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process.on('SIGINT', handleExit);
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process.on('SIGQUIT', handleExit);
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process.on('SIGTERM', handleExit);
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process.on('exit', handleExit);
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const defaultOptions = {}
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/**
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* @param {net.Socket} socket
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* @returns {Promise<void>}
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* */
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function socketWrite(socket, data) {
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return new Promise((resolve, reject) => {
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socket.write(data, (err) => {
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if (err) {
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reject(err)
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} else {
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resolve()
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}
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})
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})
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}
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/**
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* @param {net.Socket} client
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* */
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async function handleClient(client) {
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const rl = readline.createInterface({ input: client })
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for await (const line of rl) {
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try {
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const query = JSON.parse(line)
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const results = []
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for (const input of query.formulas) {
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const options = input.options ?? query.options ?? defaultOptions
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try {
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const html = katex.renderToString(input.tex, options)
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results.push({ html })
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} catch (e) {
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results.push({ error: String(e) })
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}
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}
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await socketWrite(client, JSON.stringify({ results }, null, query.debug ? ' ' : undefined))
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await socketWrite(client, '\n')
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} catch (e) {
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console.error(e)
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await socketWrite(client, JSON.stringify({ error: String(e) }))
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await socketWrite(client, '\n')
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}
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}
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}
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