Stackedit/server/pandoc.js

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JavaScript
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/* global window */
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const { spawn } = require('child_process');
const fs = require('fs');
const tmp = require('tmp');
const user = require('./user');
const outputFormats = {
asciidoc: 'text/plain',
context: 'application/x-latex',
epub: 'application/epub+zip',
epub3: 'application/epub+zip',
latex: 'application/x-latex',
odt: 'application/vnd.oasis.opendocument.text',
pdf: 'application/pdf',
rst: 'text/plain',
rtf: 'application/rtf',
textile: 'text/plain',
docx: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
};
const highlightStyles = [
'pygments',
'kate',
'monochrome',
'espresso',
'zenburn',
'haddock',
'tango',
];
const readJson = (str) => {
try {
return JSON.parse(str);
} catch (e) {
return {};
}
};
exports.generate = (req, res) => {
let pandocError = '';
const outputFormat = Object.prototype.hasOwnProperty.call(outputFormats, req.query.format)
? req.query.format
: 'pdf';
Promise.all([
user.checkSponsor(req.query.idToken),
user.checkMonetize(req.query.token),
])
.then(([isSponsor, isMonetize]) => {
if (!isSponsor && !isMonetize) {
throw new Error('unauthorized');
}
return new Promise((resolve, reject) => {
tmp.file({
postfix: `.${outputFormat}`,
}, (err, filePath, fd, cleanupCallback) => {
if (err) {
reject(err);
} else {
resolve({
filePath,
cleanupCallback,
});
}
});
});
})
.then(({ filePath, cleanupCallback }) => new Promise((resolve, reject) => {
const options = readJson(req.query.options);
const metadata = readJson(req.query.metadata);
const params = [];
params.push('--latex-engine=xelatex');
params.push('--webtex=http://chart.apis.google.com/chart?cht=tx&chf=bg,s,FFFFFF00&chco=000000&chl=');
if (options.toc) {
params.push('--toc');
}
options.tocDepth = parseInt(options.tocDepth, 10);
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if (!Number.isNaN(options.tocDepth)) {
params.push('--toc-depth', options.tocDepth);
}
options.highlightStyle = highlightStyles.indexOf(options.highlightStyle) !== -1 ? options.highlightStyle : 'kate';
params.push('--highlight-style', options.highlightStyle);
Object.keys(metadata).forEach((key) => {
params.push('-M', `${key}=${metadata[key]}`);
});
let finished = false;
function onError(error) {
finished = true;
cleanupCallback();
reject(error);
}
const binPath = process.env.PANDOC_PATH || 'pandoc';
const format = outputFormat === 'pdf' ? 'latex' : outputFormat;
params.push('-f', 'json', '-t', format, '-o', filePath);
const pandoc = spawn(binPath, params, {
stdio: [
'pipe',
'ignore',
'pipe',
],
});
let timeoutId = setTimeout(() => {
timeoutId = null;
pandoc.kill();
}, 50000);
pandoc.on('error', onError);
pandoc.stdin.on('error', onError);
pandoc.stderr.on('data', (data) => {
pandocError += `${data}`;
});
pandoc.on('close', (code) => {
if (!finished) {
clearTimeout(timeoutId);
if (!timeoutId) {
res.statusCode = 408;
cleanupCallback();
reject(new Error('timeout'));
} else if (code) {
cleanupCallback();
reject();
} else {
res.set('Content-Type', outputFormats[outputFormat]);
const readStream = fs.createReadStream(filePath);
readStream.on('open', () => readStream.pipe(res));
readStream.on('close', () => cleanupCallback());
readStream.on('error', () => {
cleanupCallback();
reject();
});
}
}
});
req.pipe(pandoc.stdin);
}))
.catch((err) => {
const message = err && err.message;
if (message === 'unauthorized') {
res.statusCode = 401;
res.end('Unauthorized.');
} else if (message === 'timeout') {
res.statusCode = 408;
res.end('Request timeout.');
} else {
res.statusCode = 400;
res.end(pandocError || 'Unknown error.');
}
});
};