bigbluebutton-Github/bbb-export-annotations/workers/collector.js
2022-07-18 17:32:51 +02:00

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const Logger = require('../lib/utils/logger');
const config = require('../config');
const fs = require('fs');
const redis = require('redis');
const { Worker, workerData, parentPort } = require('worker_threads');
const path = require('path');
const { execSync } = require("child_process");
const jobId = workerData;
const logger = new Logger('presAnn Collector');
logger.info("Collecting job " + jobId);
const kickOffProcessWorker = (jobId) => {
return new Promise((resolve, reject) => {
const worker = new Worker('./workers/process.js', { workerData: jobId });
worker.on('message', resolve);
worker.on('error', reject);
worker.on('exit', (code) => {
if (code !== 0)
reject(new Error(`PresAnn Process Worker stopped with exit code ${code}`));
})
})
}
const dropbox = path.join(config.shared.presAnnDropboxDir, jobId);
// Takes the Job from the dropbox
let job = fs.readFileSync(path.join(dropbox, 'job'));
let exportJob = JSON.parse(job);
// Collect the annotations from Redis
(async () => {
const client = redis.createClient({
host: config.redis.host,
port: config.redis.port,
password: config.redis.password
});
client.on('error', (err) => logger.info('Redis Client Error', err));
await client.connect();
let presAnn = await client.hGetAll(exportJob.jobId);
// Remove annotations from Redis
await client.DEL(jobId);
client.disconnect();
let annotations = JSON.stringify(presAnn);
let whiteboard = JSON.parse(annotations);
let pages = JSON.parse(whiteboard.pages);
fs.writeFile(path.join(dropbox, 'whiteboard'), annotations, function(err) {
if(err) { return logger.error(err); }
});
// Collect the Presentation Page files (PDF / PNG / JPEG) from the presentation directory
let presentationFile = path.join(exportJob.presLocation, exportJob.presId);
let pdfFile = `${presentationFile}.pdf`
if (fs.existsSync(pdfFile)) {
for (let p of pages) {
let pageNumber = p.page;
let outputFile = path.join(dropbox, `slide${pageNumber}`);
// CairoSVG doesn't handle transparent SVG and PNG embeds properly, e.g., in rasterized text.
// So textboxes may get a black background when downloading/exporting repeatedly.
// To avoid that, we take slides from the uploaded file, but later probe the dimensions from the SVG
// so it matches what was shown in the browser.
let extract_png_from_pdf = [
'pdftocairo',
'-png',
'-f', pageNumber,
'-l', pageNumber,
'-scale-to', config.collector.pngWidthRasterizedSlides,
'-singlefile',
'-cropbox',
pdfFile, outputFile,
].join(' ')
execSync(extract_png_from_pdf);
}
}
// If PNG file already available
else if (fs.existsSync(`${presentationFile}.png`)) {
fs.copyFileSync(`${presentationFile}.png`, path.join(dropbox, 'slide1.png'));
}
// If JPEG file available
else if (fs.existsSync(`${presentationFile}.jpeg`)) {
fs.copyFileSync(`${presentationFile}.jpeg`, path.join(dropbox, 'slide1.jpeg'));
}
else {
return logger.error(`Could not find whiteboard presentation file for job ${exportJob.jobId}`);
}
kickOffProcessWorker(exportJob.jobId);
})()
parentPort.postMessage({ message: workerData })