Initial deployment of QuickChart service

.dockerignore

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+node_modules

.github/FUNDING.yml

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+github: typpo

.gitignore

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+venv
+
+### Vim ###
+[._]*.s[a-w][a-z]
+[._]s[a-w][a-z]
+*.un~
+Session.vim
+.netrwhist
+*~
+
+
+### OSX ###
+.DS_Store
+.AppleDouble
+.LSOverride
+
+# Icon must end with two \r
+Icon
+
+
+# Thumbnails
+._*
+
+# Files that might appear in the root of a volume
+.DocumentRevisions-V100
+.fseventsd
+.Spotlight-V100
+.TemporaryItems
+.Trashes
+.VolumeIcon.icns
+
+# Directories potentially created on remote AFP share
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
+
+
+### Python ###
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+env/
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib64/
+parts/
+sdist/
+var/
+*.egg-info/
+.installed.cfg
+*.egg
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*,cover
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+target/
+
+
+### Node ###
+# Logs
+logs
+*.log
+npm-debug.log*
+
+# Runtime data
+pids
+*.pid
+*.seed
+
+# Directory for instrumented libs generated by jscoverage/JSCover
+lib-cov
+
+# Coverage directory used by tools like istanbul
+coverage
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+# Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
+.grunt
+
+# node-waf configuration
+.lock-wscript
+
+# Compiled binary addons (http://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directory
+# https://docs.npmjs.com/misc/faq#should-i-check-my-node-modules-folder-into-git
+node_modules
+

.nvmrc

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+v18.16.0

.prettierrc.yaml

@@ -0,0 +1,3 @@
+trailingComma: "all"
+singleQuote: true
+printWidth: 100

.travis.yml

@@ -0,0 +1,5 @@
+language: node_js
+node_js:
+  - 12
+cache: yarn
+

Dockerfile

@@ -0,0 +1,31 @@
+FROM node:18-alpine3.17
+
+ENV NODE_ENV production
+
+WORKDIR /quickchart
+
+RUN apk add --upgrade apk-tools
+RUN apk add --no-cache --virtual .build-deps yarn git build-base g++ python3
+RUN apk add --no-cache --virtual .npm-deps cairo-dev pango-dev libjpeg-turbo-dev librsvg-dev
+RUN apk add --no-cache --virtual .fonts libmount ttf-dejavu ttf-droid ttf-freefont ttf-liberation font-noto font-noto-emoji fontconfig
+RUN apk add --no-cache --repository https://dl-cdn.alpinelinux.org/alpine/edge/community font-wqy-zenhei
+RUN apk add --no-cache libimagequant-dev
+RUN apk add --no-cache vips-dev
+RUN apk add --no-cache --virtual .runtime-deps graphviz
+
+COPY package*.json .
+COPY yarn.lock .
+RUN yarn install --production
+
+RUN apk update
+RUN rm -rf /var/cache/apk/* && \
+    rm -rf /tmp/*
+RUN apk del .build-deps
+
+COPY *.js ./
+COPY lib/*.js lib/
+COPY LICENSE .
+
+EXPOSE 3400
+
+ENTRYPOINT ["node", "--max-http-header-size=65536", "index.js"]

LICENSE

@@ -0,0 +1,661 @@
+                    GNU AFFERO GENERAL PUBLIC LICENSE
+                       Version 3, 19 November 2007
+
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+ Everyone is permitted to copy and distribute verbatim copies
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+  If, pursuant to or in connection with a single transaction or
+arrangement, you convey, or propagate by procuring conveyance of, a
+covered work, and grant a patent license to some of the parties
+receiving the covered work authorizing them to use, propagate, modify
+or convey a specific copy of the covered work, then the patent license
+you grant is automatically extended to all recipients of the covered
+work and works based on it.
+
+  A patent license is "discriminatory" if it does not include within
+the scope of its coverage, prohibits the exercise of, or is
+conditioned on the non-exercise of one or more of the rights that are
+specifically granted under this License.  You may not convey a covered
+work if you are a party to an arrangement with a third party that is
+in the business of distributing software, under which you make payment
+to the third party based on the extent of your activity of conveying
+the work, and under which the third party grants, to any of the
+parties who would receive the covered work from you, a discriminatory
+patent license (a) in connection with copies of the covered work
+conveyed by you (or copies made from those copies), or (b) primarily
+for and in connection with specific products or compilations that
+contain the covered work, unless you entered into that arrangement,
+or that patent license was granted, prior to 28 March 2007.
+
+  Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+  12. No Surrender of Others' Freedom.
+
+  If conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot convey a
+covered work so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you may
+not convey it at all.  For example, if you agree to terms that obligate you
+to collect a royalty for further conveying from those to whom you convey
+the Program, the only way you could satisfy both those terms and this
+License would be to refrain entirely from conveying the Program.
+
+  13. Remote Network Interaction; Use with the GNU General Public License.
+
+  Notwithstanding any other provision of this License, if you modify the
+Program, your modified version must prominently offer all users
+interacting with it remotely through a computer network (if your version
+supports such interaction) an opportunity to receive the Corresponding
+Source of your version by providing access to the Corresponding Source
+from a network server at no charge, through some standard or customary
+means of facilitating copying of software.  This Corresponding Source
+shall include the Corresponding Source for any work covered by version 3
+of the GNU General Public License that is incorporated pursuant to the
+following paragraph.
+
+  Notwithstanding any other provision of this License, you have
+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU General Public License into a single
+combined work, and to convey the resulting work.  The terms of this
+License will continue to apply to the part which is the covered work,
+but the work with which it is combined will remain governed by version
+3 of the GNU General Public License.
+
+  14. Revised Versions of this License.
+
+  The Free Software Foundation may publish revised and/or new versions of
+the GNU Affero General Public License from time to time.  Such new versions
+will be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU Affero General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation.  If the Program does not specify a version number of the
+GNU Affero General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+  If the Program specifies that a proxy can decide which future
+versions of the GNU Affero General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If your software can interact with users remotely through a computer
+network, you should also make sure that it provides a way for users to
+get its source.  For example, if your program is a web application, its
+interface could display a "Source" link that leads users to an archive
+of the code.  There are many ways you could offer source, and different
+solutions will be better for different programs; see section 13 for the
+specific requirements.
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU AGPL, see
+<http://www.gnu.org/licenses/>.

README.md

@@ -1,10 +1,8 @@
 ---
-title: Quickchart
-emoji: 📉
-colorFrom: purple
-colorTo: red
+title: QuickChart
+emoji: 📊
+colorFrom: blue
+colorTo: green
 sdk: docker
-pinned: false
+app_port: 3400
 ---
-
-Check out the configuration reference at https://huggingface.co/docs/hub/spaces-config-reference

index.js

@@ -0,0 +1,492 @@
+const path = require('path');
+
+const express = require('express');
+const javascriptStringify = require('javascript-stringify').stringify;
+const qs = require('qs');
+const rateLimit = require('express-rate-limit');
+const text2png = require('text2png');
+
+const packageJson = require('./package.json');
+const telemetry = require('./telemetry');
+const { getPdfBufferFromPng, getPdfBufferWithText } = require('./lib/pdf');
+const { logger } = require('./logging');
+const { renderChartJs } = require('./lib/charts');
+const { renderGraphviz } = require('./lib/graphviz');
+const { toChartJs, parseSize } = require('./lib/google_image_charts');
+const { renderQr, DEFAULT_QR_SIZE } = require('./lib/qr');
+
+const app = express();
+
+const isDev = app.get('env') === 'development' || app.get('env') === 'test';
+
+app.set('query parser', (str) =>
+  qs.parse(str, {
+    decode(s) {
+      // Default express implementation replaces '+' with space. We don't want
+      // that. See https://github.com/expressjs/express/issues/3453
+      return decodeURIComponent(s);
+    },
+  }),
+);
+
+app.use(
+  express.json({
+    limit: process.env.EXPRESS_JSON_LIMIT || '100kb',
+  }),
+);
+
+app.use(express.urlencoded());
+
+if (process.env.RATE_LIMIT_PER_MIN) {
+  const limitMax = parseInt(process.env.RATE_LIMIT_PER_MIN, 10);
+  logger.info('Enabling rate limit:', limitMax);
+
+  const limiter = rateLimit({
+    windowMs: 60 * 1000,
+    max: limitMax,
+    message:
+      'Please slow down your requests! This is a shared public endpoint. Email support@quickchart.io or go to https://quickchart.io/pricing/ for rate limit exceptions or to purchase a commercial license.',
+    onLimitReached: (req) => {
+      logger.info('User hit rate limit!', req.ip);
+    },
+    keyGenerator: (req) => {
+      return req.headers['x-forwarded-for'] || req.ip;
+    },
+  });
+  app.use('/chart', limiter);
+}
+
+app.get('/', (req, res) => {
+  res.send(
+    'QuickChart is running!<br><br>If you are using QuickChart commercially, please consider <a href="https://quickchart.io/pricing/">purchasing a license</a> to support the project.',
+  );
+});
+
+app.post('/telemetry', (req, res) => {
+  const chartCount = parseInt(req.body.chartCount, 10);
+  const qrCount = parseInt(req.body.qrCount, 10);
+  const pid = req.body.pid;
+
+  if (chartCount && !isNaN(chartCount)) {
+    telemetry.receive(pid, 'chartCount', chartCount);
+  }
+  if (qrCount && !isNaN(qrCount)) {
+    telemetry.receive(pid, 'qrCount', qrCount);
+  }
+
+  res.send({ success: true });
+});
+
+function utf8ToAscii(str) {
+  const enc = new TextEncoder();
+  const u8s = enc.encode(str);
+
+  return Array.from(u8s)
+    .map((v) => String.fromCharCode(v))
+    .join('');
+}
+
+function sanitizeErrorHeader(msg) {
+  if (typeof msg === 'string') {
+    return utf8ToAscii(msg).replace(/\r?\n|\r/g, '');
+  }
+  return '';
+}
+
+function failPng(res, msg, statusCode = 500) {
+  res.writeHead(statusCode, {
+    'Content-Type': 'image/png',
+    'X-quickchart-error': sanitizeErrorHeader(msg),
+  });
+  res.end(
+    text2png(`Chart Error: ${msg}`, {
+      padding: 10,
+      backgroundColor: '#fff',
+    }),
+  );
+}
+
+function failSvg(res, msg, statusCode = 500) {
+  res.writeHead(statusCode, {
+    'Content-Type': 'image/svg+xml',
+    'X-quickchart-error': sanitizeErrorHeader(msg),
+  });
+  res.end(`
+<svg viewBox="0 0 240 80" xmlns="http://www.w3.org/2000/svg">
+  <style>
+    p {
+      font-size: 8px;
+    }
+  </style>
+  <foreignObject width="240" height="80"
+   requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility">
+    <p xmlns="http://www.w3.org/1999/xhtml">${msg}</p>
+  </foreignObject>
+</svg>`);
+}
+
+async function failPdf(res, msg) {
+  const buf = await getPdfBufferWithText(msg);
+  res.writeHead(500, {
+    'Content-Type': 'application/pdf',
+    'X-quickchart-error': sanitizeErrorHeader(msg),
+  });
+  res.end(buf);
+}
+
+function renderChartToPng(req, res, opts) {
+  opts.failFn = failPng;
+  opts.onRenderHandler = (buf) => {
+    res
+      .type('image/png')
+      .set({
+        // 1 week cache
+        'Cache-Control': isDev ? 'no-cache' : 'public, max-age=604800',
+      })
+      .send(buf)
+      .end();
+  };
+  doChartjsRender(req, res, opts);
+}
+
+function renderChartToSvg(req, res, opts) {
+  opts.failFn = failSvg;
+  opts.onRenderHandler = (buf) => {
+    res
+      .type('image/svg+xml')
+      .set({
+        // 1 week cache
+        'Cache-Control': isDev ? 'no-cache' : 'public, max-age=604800',
+      })
+      .send(buf)
+      .end();
+  };
+  doChartjsRender(req, res, opts);
+}
+
+async function renderChartToPdf(req, res, opts) {
+  opts.failFn = failPdf;
+  opts.onRenderHandler = async (buf) => {
+    const pdfBuf = await getPdfBufferFromPng(buf);
+
+    res.writeHead(200, {
+      'Content-Type': 'application/pdf',
+      'Content-Length': pdfBuf.length,
+
+      // 1 week cache
+      'Cache-Control': isDev ? 'no-cache' : 'public, max-age=604800',
+    });
+    res.end(pdfBuf);
+  };
+  doChartjsRender(req, res, opts);
+}
+
+function doChartjsRender(req, res, opts) {
+  if (!opts.chart) {
+    opts.failFn(res, 'You are missing variable `c` or `chart`');
+    return;
+  }
+
+  const width = parseInt(opts.width, 10) || 500;
+  const height = parseInt(opts.height, 10) || 300;
+
+  let untrustedInput = opts.chart;
+  if (opts.encoding === 'base64') {
+    // TODO(ian): Move this decoding up the call stack.
+    try {
+      untrustedInput = Buffer.from(opts.chart, 'base64').toString('utf8');
+    } catch (err) {
+      logger.warn('base64 malformed', err);
+      opts.failFn(res, err);
+      return;
+    }
+  }
+
+  renderChartJs(
+    width,
+    height,
+    opts.backgroundColor,
+    opts.devicePixelRatio,
+    opts.version || '2.9.4',
+    opts.format,
+    untrustedInput,
+  )
+    .then(opts.onRenderHandler)
+    .catch((err) => {
+      logger.warn('Chart error', err);
+      opts.failFn(res, err);
+    });
+}
+
+async function handleGraphviz(req, res, graphVizDef, opts) {
+  try {
+    const buf = await renderGraphviz(req.query.chl, opts);
+    res
+      .status(200)
+      .type(opts.format === 'png' ? 'image/png' : 'image/svg+xml')
+      .end(buf);
+  } catch (err) {
+    if (opts.format === 'png') {
+      failPng(res, `Graph Error: ${err}`);
+    } else {
+      failSvg(res, `Graph Error: ${err}`);
+    }
+  }
+}
+
+function handleGChart(req, res) {
+  // TODO(ian): Move these special cases into Google Image Charts-specific
+  // handler.
+  if (req.query.cht.startsWith('gv')) {
+    // Graphviz chart
+    const format = req.query.chof;
+    const engine = req.query.cht.indexOf(':') > -1 ? req.query.cht.split(':')[1] : 'dot';
+    const opts = {
+      format,
+      engine,
+    };
+    if (req.query.chs) {
+      const size = parseSize(req.query.chs);
+      opts.width = size.width;
+      opts.height = size.height;
+    }
+    handleGraphviz(req, res, req.query.chl, opts);
+    return;
+  } else if (req.query.cht === 'qr') {
+    const size = parseInt(req.query.chs.split('x')[0], 10);
+    const qrData = req.query.chl;
+    const chldVals = (req.query.chld || '').split('|');
+    const ecLevel = chldVals[0] || 'L';
+    const margin = chldVals[1] || 4;
+    const qrOpts = {
+      margin: margin,
+      width: size,
+      errorCorrectionLevel: ecLevel,
+    };
+
+    const format = 'png';
+    const encoding = 'UTF-8';
+    renderQr(format, encoding, qrData, qrOpts)
+      .then((buf) => {
+        res.writeHead(200, {
+          'Content-Type': format === 'png' ? 'image/png' : 'image/svg+xml',
+          'Content-Length': buf.length,
+
+          // 1 week cache
+          'Cache-Control': isDev ? 'no-cache' : 'public, max-age=604800',
+        });
+        res.end(buf);
+      })
+      .catch((err) => {
+        failPng(res, err);
+      });
+
+    telemetry.count('qrCount');
+    return;
+  }
+
+  let converted;
+  try {
+    converted = toChartJs(req.query);
+  } catch (err) {
+    logger.error(`GChart error: Could not interpret ${req.originalUrl}`);
+    res.status(500).end('Sorry, this chart configuration is not supported right now');
+    return;
+  }
+
+  if (req.query.format === 'chartjs-config') {
+    // Chart.js config
+    res.writeHead(200, {
+      'Content-Type': 'application/json',
+    });
+    res.end(javascriptStringify(converted.chart, undefined, 2));
+    return;
+  }
+
+  renderChartJs(
+    converted.width,
+    converted.height,
+    converted.backgroundColor,
+    1.0 /* devicePixelRatio */,
+    '2.9.4' /* version */,
+    undefined /* format */,
+    converted.chart,
+  ).then((buf) => {
+    res.writeHead(200, {
+      'Content-Type': 'image/png',
+      'Content-Length': buf.length,
+
+      // 1 week cache
+      'Cache-Control': isDev ? 'no-cache' : 'public, max-age=604800',
+    });
+    res.end(buf);
+  });
+  telemetry.count('chartCount');
+}
+
+app.get('/chart', (req, res) => {
+  if (req.query.cht) {
+    // This is a Google Image Charts-compatible request.
+    handleGChart(req, res);
+    return;
+  }
+
+  const outputFormat = (req.query.f || req.query.format || 'png').toLowerCase();
+  const opts = {
+    chart: req.query.c || req.query.chart,
+    height: req.query.h || req.query.height,
+    width: req.query.w || req.query.width,
+    backgroundColor: req.query.backgroundColor || req.query.bkg,
+    devicePixelRatio: req.query.devicePixelRatio,
+    version: req.query.v || req.query.version,
+    encoding: req.query.encoding || 'url',
+    format: outputFormat,
+  };
+
+  if (outputFormat === 'pdf') {
+    renderChartToPdf(req, res, opts);
+  } else if (outputFormat === 'svg') {
+    renderChartToSvg(req, res, opts);
+  } else if (!outputFormat || outputFormat === 'png') {
+    renderChartToPng(req, res, opts);
+  } else {
+    logger.error(`Request for unsupported format ${outputFormat}`);
+    res.status(500).end(`Unsupported format ${outputFormat}`);
+  }
+
+  telemetry.count('chartCount');
+});
+
+app.post('/chart', (req, res) => {
+  const outputFormat = (req.body.f || req.body.format || 'png').toLowerCase();
+  const opts = {
+    chart: req.body.c || req.body.chart,
+    height: req.body.h || req.body.height,
+    width: req.body.w || req.body.width,
+    backgroundColor: req.body.backgroundColor || req.body.bkg,
+    devicePixelRatio: req.body.devicePixelRatio,
+    version: req.body.v || req.body.version,
+    encoding: req.body.encoding || 'url',
+    format: outputFormat,
+  };
+
+  if (outputFormat === 'pdf') {
+    renderChartToPdf(req, res, opts);
+  } else if (outputFormat === 'svg') {
+    renderChartToSvg(req, res, opts);
+  } else {
+    renderChartToPng(req, res, opts);
+  }
+
+  telemetry.count('chartCount');
+});
+
+app.get('/qr', (req, res) => {
+  const qrText = req.query.text;
+  if (!qrText) {
+    failPng(res, 'You are missing variable `text`');
+    return;
+  }
+
+  let format = 'png';
+  if (req.query.format === 'svg') {
+    format = 'svg';
+  }
+
+  const { mode } = req.query;
+
+  const margin = typeof req.query.margin === 'undefined' ? 4 : parseInt(req.query.margin, 10);
+  const ecLevel = req.query.ecLevel || undefined;
+  const size = Math.min(3000, parseInt(req.query.size, 10)) || DEFAULT_QR_SIZE;
+  const darkColor = req.query.dark || '000';
+  const lightColor = req.query.light || 'fff';
+
+  const qrOpts = {
+    margin,
+    width: size,
+    errorCorrectionLevel: ecLevel,
+    color: {
+      dark: darkColor,
+      light: lightColor,
+    },
+  };
+
+  renderQr(format, mode, qrText, qrOpts)
+    .then((buf) => {
+      res.writeHead(200, {
+        'Content-Type': format === 'png' ? 'image/png' : 'image/svg+xml',
+        'Content-Length': buf.length,
+
+        // 1 week cache
+        'Cache-Control': isDev ? 'no-cache' : 'public, max-age=604800',
+      });
+      res.end(buf);
+    })
+    .catch((err) => {
+      failPng(res, err);
+    });
+
+  telemetry.count('qrCount');
+});
+
+app.get('/gchart', handleGChart);
+
+app.get('/healthcheck', (req, res) => {
+  // A lightweight healthcheck endpoint.
+  res.send({ success: true, version: packageJson.version });
+});
+
+app.get('/healthcheck/chart', (req, res) => {
+  // A heavier healthcheck endpoint that redirects to a unique chart.
+  const labels = [...Array(5)].map(() => Math.random());
+  const data = [...Array(5)].map(() => Math.random());
+  const template = `
+{
+  type: 'bar',
+  data: {
+    labels: [${labels.join(',')}],
+    datasets: [{
+      data: [${data.join(',')}]
+    }]
+  }
+}
+`;
+  res.redirect(`/chart?c=${template}`);
+});
+
+const port = process.env.PORT || 3400;
+const server = app.listen(port);
+
+const timeout = parseInt(process.env.REQUEST_TIMEOUT_MS, 10) || 5000;
+server.setTimeout(timeout);
+logger.info(`Setting request timeout: ${timeout} ms`);
+
+logger.info(`NODE_ENV: ${process.env.NODE_ENV}`);
+logger.info(`Listening on port ${port}`);
+
+if (!isDev) {
+  const gracefulShutdown = function gracefulShutdown() {
+    logger.info('Received kill signal, shutting down gracefully.');
+    server.close(() => {
+      logger.info('Closed out remaining connections.');
+      process.exit();
+    });
+
+    setTimeout(() => {
+      logger.error('Could not close connections in time, forcefully shutting down');
+      process.exit();
+    }, 10 * 1000);
+  };
+
+  // listen for TERM signal .e.g. kill
+  process.on('SIGTERM', gracefulShutdown);
+
+  // listen for INT signal e.g. Ctrl-C
+  process.on('SIGINT', gracefulShutdown);
+
+  process.on('SIGABRT', () => {
+    logger.info('Caught SIGABRT');
+  });
+}
+
+module.exports = app;

lefthook.yml

@@ -0,0 +1,6 @@
+pre-commit:
+  parallel: true
+  commands:
+    js:
+      glob: "*.js"
+      run: prettier --single-quote --trailing-comma all --print-width 100 --write {staged_files} && git add {staged_files}

lib/charts.js

@@ -0,0 +1,438 @@
+const canvas = require('canvas');
+const deepmerge = require('deepmerge');
+const pattern = require('patternomaly');
+const { CanvasRenderService } = require('chartjs-node-canvas');
+
+const { fixNodeVmObject } = require('./util');
+const { logger } = require('../logging');
+const { uniqueSvg } = require('./svg');
+
+// Polyfills
+require('canvas-5-polyfill');
+global.CanvasGradient = canvas.CanvasGradient;
+
+// Constants
+const ROUND_CHART_TYPES = new Set([
+  'pie',
+  'doughnut',
+  'polarArea',
+  'outlabeledPie',
+  'outlabeledDoughnut',
+]);
+
+const BOXPLOT_CHART_TYPES = new Set(['boxplot', 'horizontalBoxplot', 'violin', 'horizontalViolin']);
+
+const MAX_HEIGHT = process.env.CHART_MAX_HEIGHT || 3000;
+const MAX_WIDTH = process.env.CHART_MAX_WIDTH || 3000;
+
+const rendererCache = {};
+
+async function getChartJsForVersion(version) {
+  if (version && version.startsWith('4')) {
+    return (await import('chart.js-v4/auto')).Chart;
+  }
+  if (version && version.startsWith('3')) {
+    return require('chart.js-v3');
+  }
+  return require('chart.js');
+}
+
+async function getRenderer(width, height, version, format) {
+  if (width > MAX_WIDTH) {
+    throw `Requested width exceeds maximum of ${MAX_WIDTH}`;
+  }
+  if (height > MAX_HEIGHT) {
+    throw `Requested width exceeds maximum of ${MAX_WIDTH}`;
+  }
+
+  const key = `${width}__${height}__${version}__${format}`;
+  if (!rendererCache[key]) {
+    const Chart = await getChartJsForVersion(version);
+    rendererCache[key] = new CanvasRenderService(width, height, undefined, format, () => Chart);
+  }
+  return rendererCache[key];
+}
+
+function addColorsPlugin(chart) {
+  if (chart.options && chart.options.plugins && chart.options.plugins.colorschemes) {
+    return;
+  }
+
+  chart.options = deepmerge.all([
+    {},
+    chart.options,
+    {
+      plugins: {
+        colorschemes: {
+          scheme: 'tableau.Tableau10',
+        },
+      },
+    },
+  ]);
+}
+
+function getGradientFunctions(width, height) {
+  const getGradientFill = (colorOptions, linearGradient = [0, 0, width, 0]) => {
+    return function colorFunction() {
+      const ctx = canvas.createCanvas(20, 20).getContext('2d');
+      const gradientFill = ctx.createLinearGradient(...linearGradient);
+      colorOptions.forEach((options, idx) => {
+        gradientFill.addColorStop(options.offset, options.color);
+      });
+      return gradientFill;
+    };
+  };
+
+  const getGradientFillHelper = (direction, colors, dimensions = {}) => {
+    const colorOptions = colors.map((color, idx) => {
+      return {
+        color,
+        offset: idx / (colors.length - 1 || 1),
+      };
+    });
+
+    let linearGradient = [0, 0, dimensions.width || width, 0];
+    if (direction === 'vertical') {
+      linearGradient = [0, 0, 0, dimensions.height || height];
+    } else if (direction === 'both') {
+      linearGradient = [0, 0, dimensions.width || width, dimensions.height || height];
+    }
+    return getGradientFill(colorOptions, linearGradient);
+  };
+
+  return {
+    getGradientFill,
+    getGradientFillHelper,
+  };
+}
+
+function patternDraw(shapeType, backgroundColor, patternColor, requestedSize) {
+  return function doPatternDraw() {
+    const size = Math.min(200, requestedSize) || 20;
+    // patternomaly requires a document global...
+    global.document = {
+      createElement: () => {
+        return canvas.createCanvas(size, size);
+      },
+    };
+    return pattern.draw(shapeType, backgroundColor, patternColor, size);
+  };
+}
+
+async function renderChartJs(
+  width,
+  height,
+  backgroundColor,
+  devicePixelRatio,
+  version,
+  format,
+  untrustedChart,
+) {
+  let chart;
+  if (typeof untrustedChart === 'string') {
+    // The chart could contain Javascript - run it in a VM.
+    try {
+      const { getGradientFill, getGradientFillHelper } = getGradientFunctions(width, height);
+      const chartFunction = new Function(
+        'getGradientFill',
+        'getGradientFillHelper',
+        'pattern',
+        'Chart',
+        `return ${untrustedChart}`,
+      );
+      chart = chartFunction(
+        getGradientFill,
+        getGradientFillHelper,
+        { draw: patternDraw },
+        getChartJsForVersion(version),
+      );
+    } catch (err) {
+      logger.error('Input Error', err, untrustedChart);
+      return Promise.reject(new Error(`Invalid input\n${err}`));
+    }
+  } else {
+    // The chart is just a simple JSON object.
+    chart = untrustedChart;
+  }
+
+  // Patch some bugs and issues.
+  fixNodeVmObject(chart);
+
+  chart.options = chart.options || {};
+
+  if (chart.type === 'donut') {
+    // Fix spelling...
+    chart.type = 'doughnut';
+  }
+
+  // TODO(ian): Move special chart type out of this file.
+  if (chart.type === 'sparkline') {
+    if (chart.data.datasets.length < 1) {
+      return Promise.reject(new Error('"sparkline" requres 1 dataset'));
+    }
+    chart.type = 'line';
+    const dataseries = chart.data.datasets[0].data;
+    if (!chart.data.labels) {
+      chart.data.labels = Array(dataseries.length);
+    }
+    chart.options.legend = chart.options.legend || { display: false };
+    if (!chart.options.elements) {
+      chart.options.elements = {};
+    }
+    chart.options.elements.line = chart.options.elements.line || {
+      borderColor: '#000',
+      borderWidth: 1,
+    };
+    chart.options.elements.point = chart.options.elements.point || {
+      radius: 0,
+    };
+    if (!chart.options.scales) {
+      chart.options.scales = {};
+    }
+
+    let min = Number.POSITIVE_INFINITY;
+    let max = Number.NEGATIVE_INFINITY;
+    for (let i = 0; i < dataseries.length; i += 1) {
+      const dp = dataseries[i];
+      min = Math.min(min, dp);
+      max = Math.max(max, dp);
+    }
+
+    chart.options.scales.xAxes = chart.options.scales.xAxes || [{ display: false }];
+    chart.options.scales.yAxes = chart.options.scales.yAxes || [
+      {
+        display: false,
+        ticks: {
+          // Offset the min and max slightly so that pixels aren't shaved off
+          // under certain circumstances.
+          min: min - min * 0.05,
+          max: max + max * 0.05,
+        },
+      },
+    ];
+  }
+
+  if (chart.type === 'progressBar') {
+    chart.type = 'horizontalBar';
+
+    if (chart.data.datasets.length < 1 || chart.data.datasets.length > 2) {
+      throw new Error('progressBar chart requires 1 or 2 datasets');
+    }
+
+    let usePercentage = false;
+    const dataLen = chart.data.datasets[0].data.length;
+    if (chart.data.datasets.length === 1) {
+      // Implicit denominator, always out of 100.
+      usePercentage = true;
+      chart.data.datasets.push({ data: Array(dataLen).fill(100) });
+    }
+    if (chart.data.datasets[0].data.length !== chart.data.datasets[1].data.length) {
+      throw new Error('progressBar datasets must have the same size of data');
+    }
+
+    chart.data.labels = chart.labels || Array.from(Array(dataLen).keys());
+    chart.data.datasets[1].backgroundColor = chart.data.datasets[1].backgroundColor || '#fff';
+    // Set default border color to first Tableau color.
+    chart.data.datasets[1].borderColor = chart.data.datasets[1].borderColor || '#4e78a7';
+    chart.data.datasets[1].borderWidth = chart.data.datasets[1].borderWidth || 1;
+
+    const deepmerge = require('deepmerge');
+    chart.options = deepmerge(
+      {
+        legend: { display: false },
+        scales: {
+          xAxes: [
+            {
+              ticks: {
+                display: false,
+                beginAtZero: true,
+              },
+              gridLines: {
+                display: false,
+                drawTicks: false,
+              },
+            },
+          ],
+          yAxes: [
+            {
+              stacked: true,
+              ticks: {
+                display: false,
+              },
+              gridLines: {
+                display: false,
+                drawTicks: false,
+                mirror: true,
+              },
+            },
+          ],
+        },
+        plugins: {
+          datalabels: {
+            color: '#fff',
+            formatter: (val, ctx) => {
+              if (usePercentage) {
+                return `${val}%`;
+              }
+              return val;
+            },
+            display: ctx => ctx.datasetIndex === 0,
+          },
+        },
+      },
+      chart.options,
+    );
+  }
+
+  // Choose retina resolution by default. This will cause images to be 2x size
+  // in absolute terms.
+  chart.options.devicePixelRatio = devicePixelRatio || 2.0;
+
+  // Implement other default options
+  if (
+    chart.type === 'bar' ||
+    chart.type === 'horizontalBar' ||
+    chart.type === 'line' ||
+    chart.type === 'scatter' ||
+    chart.type === 'bubble'
+  ) {
+    if (!chart.options.scales) {
+      // TODO(ian): Merge default options with provided options
+      chart.options.scales = {
+        yAxes: [
+          {
+            ticks: {
+              beginAtZero: true,
+            },
+          },
+        ],
+      };
+    }
+    addColorsPlugin(chart);
+  } else if (chart.type === 'radar') {
+    addColorsPlugin(chart);
+  } else if (ROUND_CHART_TYPES.has(chart.type)) {
+    addColorsPlugin(chart);
+  } else if (chart.type === 'scatter') {
+    addColorsPlugin(chart);
+  } else if (chart.type === 'bubble') {
+    addColorsPlugin(chart);
+  }
+
+  if (chart.type === 'line') {
+    if (chart.data && chart.data.datasets && Array.isArray(chart.data.datasets)) {
+      chart.data.datasets.forEach(dataset => {
+        const data = dataset;
+        // Make line charts straight lines by default.
+        data.lineTension = data.lineTension || 0;
+      });
+    }
+  }
+
+  chart.options.plugins = chart.options.plugins || {};
+  let usingDataLabelsDefaults = false;
+  if (!chart.options.plugins.datalabels) {
+    usingDataLabelsDefaults = true;
+    chart.options.plugins.datalabels = {};
+    if (chart.type === 'pie' || chart.type === 'doughnut') {
+      chart.options.plugins.datalabels = {
+        display: true,
+      };
+    } else {
+      chart.options.plugins.datalabels = {
+        display: false,
+      };
+    }
+  }
+
+  if (ROUND_CHART_TYPES.has(chart.type) || chart.type === 'radialGauge') {
+    global.Chart = require('chart.js');
+    // These requires have side effects.
+    require('chartjs-plugin-piechart-outlabels');
+    if (chart.type === 'doughnut' || chart.type === 'outlabeledDoughnut') {
+      require('chartjs-plugin-doughnutlabel');
+    }
+    let userSpecifiedOutlabels = false;
+    chart.data.datasets.forEach(dataset => {
+      if (dataset.outlabels || chart.options.plugins.outlabels) {
+        userSpecifiedOutlabels = true;
+      } else {
+        // Disable outlabels by default.
+        dataset.outlabels = { display: false };
+      }
+    });
+
+    if (userSpecifiedOutlabels && usingDataLabelsDefaults) {
+      // If outlabels are enabled, disable datalabels by default.
+      chart.options.plugins.datalabels = {
+        display: false,
+      };
+    }
+  }
+  if (chart.options && chart.options.plugins && chart.options.plugins.colorschemes) {
+    global.Chart = require('chart.js');
+    require('chartjs-plugin-colorschemes');
+  }
+  logger.debug('Chart:', JSON.stringify(chart));
+
+  if (version.startsWith('3') || version.startsWith('4')) {
+    require('chartjs-adapter-moment');
+  }
+  if (!chart.plugins) {
+    if (version.startsWith('3') || version.startsWith('4')) {
+      chart.plugins = [];
+    } else {
+      const chartAnnotations = require('chartjs-plugin-annotation');
+      const chartBoxViolinPlot = require('chartjs-chart-box-and-violin-plot');
+      const chartDataLabels = require('chartjs-plugin-datalabels');
+      const chartRadialGauge = require('chartjs-chart-radial-gauge');
+      chart.plugins = [chartDataLabels, chartAnnotations];
+      if (chart.type === 'radialGauge') {
+        chart.plugins.push(chartRadialGauge);
+      }
+      if (BOXPLOT_CHART_TYPES.has(chart.type)) {
+        chart.plugins.push(chartBoxViolinPlot);
+      }
+    }
+  }
+
+  // Background color plugin
+  chart.plugins.push({
+    id: 'background',
+    beforeDraw: chartInstance => {
+      if (backgroundColor) {
+        // Chart.js v3 provides `chartInstance.chart` as `chartInstance`
+        const chart = chartInstance.chart ? chartInstance.chart : chartInstance;
+        const { ctx } = chart;
+        ctx.fillStyle = backgroundColor;
+        ctx.fillRect(0, 0, chart.width, chart.height);
+      }
+    },
+  });
+
+  // Pad below legend plugin
+  if (chart.options.plugins.padBelowLegend) {
+    chart.plugins.push({
+      id: 'padBelowLegend',
+      beforeInit: (chartInstance, val) => {
+        global.Chart.Legend.prototype.afterFit = function afterFit() {
+          this.height = this.height + (Number(val) || 0);
+        };
+      },
+    });
+  }
+
+  const canvasRenderService = await getRenderer(width, height, version, format);
+
+  if (format === 'svg') {
+    // SVG rendering doesn't work asychronously.
+    return Buffer.from(
+      uniqueSvg(canvasRenderService.renderToBufferSync(chart, 'image/svg+xml').toString()),
+    );
+  }
+  return canvasRenderService.renderToBuffer(chart);
+}
+
+module.exports = {
+  renderChartJs,
+};

lib/google_image_charts.js

@@ -0,0 +1,958 @@
+// Google Image Charts compatibility
+
+const DEFAULT_COLOR_WHEEL = ['#4D89F9', '#00B88A', 'red', 'purple', 'yellow', 'brown'];
+
+const AXIS_FORMAT_REGEX_CHXS = /^\d(N([^\*]+)?(\*([fpe]+)?(c[A-Z]{3})?(\d)?([zsxy]+)?\*)?(.*))?$/;
+
+function parseSize(chs) {
+  if (!chs) {
+    return {
+      width: 500,
+      height: 300,
+    };
+  }
+  const size = chs.split('x');
+  return {
+    width: Math.min(2048, parseInt(size[0], 10)),
+    height: Math.min(2048, parseInt(size[1], 10)),
+  };
+}
+
+function parseBackgroundColor(chf) {
+  if (!chf) {
+    return 'white';
+  }
+
+  const series = chf.split('|');
+
+  // For now we don't support any of the series coloring features - just look
+  // at the first part.
+  const parts = series[0].split(',');
+
+  if (parts[0] === 'a') {
+    // Transparency
+    backgroundColor = '#000000' + parts[2].slice(-2);
+  } else {
+    // Fill
+    backgroundColor = '#' + parts[2];
+  }
+  return backgroundColor;
+}
+
+/**
+ * Returns a list of series objects. Each series object is a list of values.
+ */
+function parseSeriesData(chd, chds) {
+  let seriesData;
+  const [encodingType, seriesStr] = chd.split(':');
+  switch (encodingType) {
+    case 't':
+      if (chds === 'a') {
+        // Basic text format with auto scaling
+        seriesData = seriesStr.split('|').map(valuesStr => {
+          return valuesStr.split(',').map(val => {
+            if (val === '_') {
+              return null;
+            }
+            return parseFloat(val);
+          });
+        });
+      } else {
+        // Basic text format with set range
+        const seriesValues = seriesStr.split('|');
+        const seriesRanges = [];
+        if (chds) {
+          if (Array.isArray(chds)) {
+            // We don't want to support Google weird scaling here per series...
+            chds = chds[0];
+          }
+          const ranges = chds.split(',');
+          for (let i = 0; i < ranges.length; i += 2) {
+            const min = parseFloat(ranges[i]);
+            const max = parseFloat(ranges[i + 1]);
+            seriesRanges.push({ min, max });
+          }
+
+          if (seriesRanges.length < seriesValues.length) {
+            // Fill out the remainder of ranges for all series, using the last
+            // value.
+            for (let i = 0; i <= seriesValues.length - seriesRanges.length; i++) {
+              seriesRanges.push(seriesRanges[seriesRanges.length - 1]);
+            }
+          }
+        } else {
+          // Apply default minimums of 0 and maximums of 100.
+          seriesValues.forEach(() => {
+            seriesRanges.push({ min: 0, max: 100 });
+          });
+        }
+        seriesData = seriesValues.map((valuesStr, idx) => {
+          return valuesStr.split(',').map(val => {
+            if (val === '_') {
+              return null;
+            }
+            const floatVal = parseFloat(val);
+            if (floatVal < seriesRanges[idx].min) {
+              return null;
+            }
+            if (floatVal > seriesRanges[idx].max) {
+              return seriesRanges[idx].max;
+            }
+            return floatVal;
+          });
+        });
+      }
+      break;
+    case 's':
+      // Simple encoding format
+      const SIMPLE_LOOKUP = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
+      seriesData = seriesStr.split(',').map(encoded => {
+        const vals = [];
+        for (let i = 0; i < encoded.length; i++) {
+          const char = encoded.charAt(i);
+          if (char === '_') {
+            vals.push(null);
+          } else {
+            vals.push(SIMPLE_LOOKUP.indexOf(char));
+          }
+        }
+        return vals;
+      });
+      break;
+    case 'e':
+      const EXTENDED_LOOKUP = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-.';
+      seriesData = seriesStr.split(',').map(encoded => {
+        const vals = [];
+        for (let i = 0; i < encoded.length; i += 2) {
+          const word = encoded.slice(i, i + 2);
+          if (word === '__') {
+            vals.push(null);
+          } else {
+            const idx1 = EXTENDED_LOOKUP.indexOf(word[0]);
+            const idx2 = EXTENDED_LOOKUP.indexOf(word[1]);
+
+            const val = idx1 * EXTENDED_LOOKUP.length + idx2;
+            vals.push(val);
+          }
+        }
+        return vals;
+      });
+      break;
+    case 'a':
+      // Image Chart "awesome" format
+      seriesData = seriesStr.split('|').map(valuesStr => {
+        return valuesStr.split(',').map(parseFloat);
+      });
+      break;
+  }
+  return seriesData;
+}
+
+function setChartType(cht, chartObj) {
+  let chartType;
+  switch (cht) {
+    case 'bhs':
+      // Horizontal with stacked bars
+      chartObj.type = 'horizontalBar';
+      chartObj.options.scales = {
+        xAxes: [
+          {
+            display: false,
+            stacked: true,
+            gridLines: { display: false },
+          },
+        ],
+        yAxes: [
+          {
+            display: false,
+            stacked: true,
+            gridLines: { display: false },
+            ticks: {
+              beginAtZero: true,
+            },
+          },
+        ],
+      };
+      break;
+    case 'bvs':
+      // Vertical with stacked bars
+      chartObj.type = 'bar';
+      chartObj.options.scales = {
+        xAxes: [
+          {
+            display: false,
+            stacked: true,
+            gridLines: { display: false },
+          },
+        ],
+        yAxes: [
+          {
+            display: false,
+            stacked: true,
+            gridLines: { display: false },
+            ticks: {
+              beginAtZero: true,
+            },
+          },
+        ],
+      };
+      break;
+    case 'bvo':
+      // Vertical stacked in front of each other
+      chartObj.type = 'bar';
+      chartObj.options.scales = {
+        xAxes: [
+          {
+            stacked: true,
+            gridLines: { display: false },
+          },
+        ],
+        yAxes: [
+          {
+            stacked: false,
+            gridLines: { display: false },
+            ticks: {
+              beginAtZero: true,
+            },
+          },
+        ],
+      };
+      break;
+    case 'bhg':
+      // Horizontal with grouped bars
+      chartObj.type = 'horizontalBar';
+      chartObj.options.scales = {
+        xAxes: [
+          {
+            display: false,
+            gridLines: { display: false },
+          },
+        ],
+        yAxes: [
+          {
+            display: false,
+            gridLines: { display: false },
+            ticks: {
+              beginAtZero: true,
+            },
+          },
+        ],
+      };
+      break;
+    case 'bvg':
+      // Vertical with grouped bars
+      chartObj.type = 'bar';
+      chartObj.options.scales = {
+        xAxes: [
+          {
+            display: false,
+            gridLines: { display: false },
+          },
+        ],
+        yAxes: [
+          {
+            display: false,
+            gridLines: { display: false },
+            ticks: {
+              beginAtZero: true,
+            },
+          },
+        ],
+      };
+      break;
+    case 'lc':
+      // TODO(ian): Support 'nda': no default axes to suppress axes
+      // https://chart.googleapis.com/chart?cht=lc:nda&chs=200x125&chd=t:40,60,60,45,47,75,70,72
+      chartObj.type = 'line';
+      chartObj.options.scales = {
+        xAxes: [
+          {
+            display: false,
+            gridLines: {
+              drawOnChartArea: false,
+              drawTicks: false,
+            },
+          },
+        ],
+        yAxes: [
+          {
+            display: false,
+            gridLines: {
+              drawOnChartArea: false,
+              drawTicks: false,
+            },
+            ticks: {
+              beginAtZero: true,
+            },
+          },
+        ],
+      };
+      break;
+    case 'ls':
+      // Sparkline
+      chartObj.type = 'line';
+      chartObj.options.scales = {
+        xAxes: [
+          {
+            display: false,
+            gridLines: { display: false },
+          },
+        ],
+        yAxes: [
+          {
+            display: false,
+            gridLines: { display: false },
+            ticks: {
+              beginAtZero: true,
+            },
+          },
+        ],
+      };
+      break;
+    case 'p':
+    case 'p3':
+    case 'pc':
+      chartObj.type = 'pie';
+      chartObj.options.plugins = {
+        datalabels: {
+          display: false,
+        },
+      };
+      break;
+    case 'lxy':
+      // TODO(ian): x-y coordinates/scatter chart
+      // https://developers.google.com/chart/image/docs/gallery/scatter_charts
+      break;
+  }
+}
+
+function setData(seriesData, chartObj) {
+  const lengths = seriesData.map(series => series.length);
+  const longestSeriesLength = Math.max(...lengths);
+
+  // TODO(ian): For horizontal stacked bar charts, indexes are shown top down
+  // instead of bottom up.
+  chartObj.data.labels = Array(longestSeriesLength)
+    .fill(0)
+    .map((_, idx) => idx);
+
+  // Round chart types (e.g. pie) have different color handling.
+  const isRound = chartObj.type === 'pie';
+
+  chartObj.data.datasets = seriesData.map((series, idx) => {
+    return {
+      data: series,
+      fill: false,
+      backgroundColor: isRound ? undefined : DEFAULT_COLOR_WHEEL[idx % DEFAULT_COLOR_WHEEL.length],
+      borderColor: isRound ? undefined : DEFAULT_COLOR_WHEEL[idx % DEFAULT_COLOR_WHEEL.length],
+      borderWidth: 2,
+      pointRadius: 0,
+    };
+  });
+
+  if (chartObj.type === 'pie') {
+    chartObj.data.datasets = chartObj.data.datasets.reverse();
+  }
+}
+
+function setTitle(chtt, chts, chartObj) {
+  if (!chtt) {
+    return;
+  }
+
+  let fontColor, fontSize;
+  if (chts) {
+    const splits = chts.split(',');
+    fontColor = `#${splits[0]}`;
+    fontSize = parseInt(splits[1], 10);
+  }
+  chartObj.options.title = {
+    display: true,
+    text: chtt.replace('|', '\n', 'g'),
+    fontSize,
+    fontColor,
+  };
+}
+
+function setDataLabels(chl, chartObj) {
+  if (!chl) {
+    return;
+  }
+
+  const labels = chl.split('|');
+
+  // TODO(ian): line charts are supposed to have an effect similar to axis
+  // value formatters, rather than data labels.
+  chartObj.options.plugins = chartObj.options.plugins || {};
+  chartObj.options.plugins.datalabels = {
+    display: true,
+    color: '#000',
+    font: {
+      size: 14,
+    },
+    formatter: (val, ctx) => {
+      let labelIdx = 0;
+      for (let datasetIndex = 0; datasetIndex < ctx.datasetIndex; datasetIndex++) {
+        // Skip over the labels for all the previous datasets.
+        labelIdx += chartObj.data.datasets[datasetIndex].data.length;
+      }
+
+      // Skip over the labels for data in the current dataset.
+      labelIdx += ctx.dataIndex;
+
+      if (!labels[labelIdx]) {
+        return '';
+      }
+      return labels[labelIdx].replace('\\n', '\n');
+    },
+  };
+}
+
+function setLegend(chdl, chdlp, chdls, chartObj) {
+  if (!chdl) {
+    chartObj.options.legend = {
+      display: false,
+    };
+    return;
+  }
+  chartObj.options.legend = {
+    display: true,
+  };
+  const labels = chdl.split('|');
+  labels.forEach((label, idx) => {
+    // Note that this overrides 'chl' labels right now
+    chartObj.data.datasets[idx].label = label;
+  });
+
+  switch (chdlp || 'r') {
+    case 'b':
+      chartObj.options.legend.position = 'bottom';
+      break;
+    case 't':
+      chartObj.options.legend.position = 'top';
+      break;
+    case 'r':
+      chartObj.options.legend.position = 'right';
+      chartObj.options.legend.align = 'start';
+      break;
+    case 'l':
+      chartObj.options.legend.position = 'left';
+      chartObj.options.legend.align = 'start';
+      break;
+    default:
+    // chdlp is not fully supported
+  }
+
+  // Make legend labels smaller.
+  chartObj.options.legend.labels = {
+    boxWidth: 10,
+  };
+
+  if (chdls) {
+    const [fontColor, fontSize] = chdls.split(',');
+    chartObj.options.legend.fontSize = parseInt(fontSize, 10);
+    chartObj.options.legend.fontColor = `#${fontColor}`;
+  }
+}
+
+function setMargins(chma, chartObj) {
+  const margins = {
+    left: 0,
+    right: 0,
+    top: 10,
+    bottom: 0,
+  };
+
+  if (chma) {
+    const inputs = chma.split(',').map(x => parseInt(x, 10));
+    margins.left = inputs[0];
+    margins.right = inputs[1];
+    margins.top = inputs[2];
+    margins.bottom = inputs[3];
+  }
+
+  chartObj.options.layout = chartObj.options.layout || {};
+  chartObj.options.layout.padding = margins;
+}
+
+function setColors(chco, chartObj) {
+  if (!chco) {
+    return null;
+  }
+
+  let seriesColors = chco.split(',').map(colors => {
+    if (colors.indexOf('|') > -1) {
+      return colors.split('|').map(color => `#${color}`);
+    }
+    return colors;
+  });
+
+  chartObj.data.datasets.forEach((dataset, idx) => {
+    if (Array.isArray(seriesColors[idx])) {
+      // Colors behave differently for Chart.js pie chart and bar charts.
+      dataset.backgroundColor = dataset.borderColor = seriesColors[idx];
+    } else {
+      dataset.backgroundColor = dataset.borderColor = '#' + seriesColors[idx];
+    }
+  });
+}
+
+function setAxes(chxt, chxr, chartObj) {
+  if (!chxt) {
+    return;
+  }
+
+  const enabledAxes = chxt.split(',');
+
+  if (chxr) {
+    // Custom axes range
+    const axesSettings = chxr.split('|');
+    axesSettings.forEach(axisSetting => {
+      const opts = axisSetting.split(',').map(parseFloat);
+
+      const axisName = enabledAxes[opts[0] /* axisIndex */];
+      const minVal = opts[1];
+      const maxVal = opts[2];
+      const stepVal = opts.length > 3 ? opts[3] : undefined;
+
+      let axis;
+      if (axisName === 'x') {
+        // Manually scale X-axis so  data values extend the full range:
+        // chart.js doesn't respect min/max in categorical axes.
+        axis = chartObj.options.scales.xAxes[0];
+        axis.type = 'linear';
+        chartObj.data.datasets.forEach(dataset => {
+          const step = (maxVal - minVal) / dataset.data.length;
+          let currentStep = minVal;
+          dataset.data = dataset.data.map(dp => {
+            const ret = {
+              x: currentStep,
+              y: dp,
+            };
+            currentStep += step;
+            return ret;
+          });
+        });
+      } else if (axisName === 'y') {
+        axis = chartObj.options.scales.yAxes[0];
+      }
+      axis.ticks = axis.ticks || {};
+      axis.ticks.min = minVal;
+      axis.ticks.max = maxVal;
+      axis.ticks.stepSize = stepVal;
+      axis.ticks.maxTicksLimit = Number.MAX_VALUE;
+    });
+  }
+}
+
+function setAxesLabels(chxt, chxl, chxs, chartObj) {
+  if (!chxt) {
+    return;
+  }
+
+  // e.g. {
+  //  0: 'x',
+  //  1: 'y',
+  // }
+  const axisByIndex = {};
+
+  // e.g. {
+  //   'x': ['Jan', 'Feb', 'March'],
+  //   'y': ['0', '1', '2'],
+  // }
+  const axisLabelsLookup = {
+    x: [],
+    y: [],
+  };
+
+  // e.g. {
+  //   'x': Array<Function>,
+  //   'y': Array<Function>,
+  // }
+  const axisValFormatters = {
+    x: [],
+    y: [],
+  };
+
+  // Parse chxt
+  const validAxesLabels = new Set();
+  const axes = chxt.split(',');
+  axes.forEach((axis, idx) => {
+    axisByIndex[idx] = axis;
+    validAxesLabels.add(`${idx}:`);
+  });
+
+  if (axes.indexOf('x') > -1) {
+    chartObj.options.scales.xAxes[0].display = true;
+
+    if (chartObj.type === 'horizontalBar') {
+      // Horizontal bar charts have x axis ticks.
+      chartObj.options.scales.xAxes[0].gridLines = chartObj.options.scales.xAxes[0].gridLines || {};
+      chartObj.options.scales.xAxes[0].gridLines.display =
+        chartObj.options.scales.xAxes[0].gridLines.display ?? true;
+      chartObj.options.scales.xAxes[0].gridLines.drawOnChartArea =
+        chartObj.options.scales.xAxes[0].gridLines.drawOnChartArea ?? false;
+      chartObj.options.scales.xAxes[0].gridLines.drawTicks =
+        chartObj.options.scales.xAxes[0].gridLines.drawTicks ?? true;
+    }
+
+    chartObj.options.scales.xAxes[0].ticks = chartObj.options.scales.xAxes[0].ticks || {};
+    chartObj.options.scales.xAxes[0].ticks.autoSkip =
+      chartObj.options.scales.xAxes[0].ticks.autoSkip ?? false;
+  }
+  if (axes.indexOf('y') > -1) {
+    chartObj.options.scales.yAxes[0].display = true;
+
+    // Google Image Charts show yAxes ticks.
+    chartObj.options.scales.yAxes[0].gridLines = chartObj.options.scales.yAxes[0].gridLines || {};
+    chartObj.options.scales.yAxes[0].gridLines.display =
+      chartObj.options.scales.yAxes[0].gridLines.display ?? true;
+    chartObj.options.scales.yAxes[0].gridLines.drawOnChartArea =
+      chartObj.options.scales.yAxes[0].gridLines.drawOnChartArea ?? false;
+    chartObj.options.scales.yAxes[0].gridLines.offsetGridLines =
+      chartObj.options.scales.yAxes[0].gridLines.offsetGridLines ?? false;
+    chartObj.options.scales.yAxes[0].gridLines.drawTicks =
+      chartObj.options.scales.yAxes[0].gridLines.drawTicks ?? true;
+  }
+
+  if (chxs) {
+    // TODO(ian): If chxs doesn't have N in front of it, then skip forward to
+    // color and labels.
+    // https://developers.google.com/chart/image/docs/gallery/bar_charts#axis-label-styles-chxs
+    // chxs=0,000000,0,0,_
+    const axisRules = chxs.split('|');
+    axisRules.forEach(rule => {
+      const parts = rule.split(',');
+
+      // Parse the first character of the first part as axis index.
+      const axisIdx = parseInt(parts[0][0], 10);
+      const axisName = axisByIndex[axisIdx];
+      const axis =
+        axisName === 'x' ? chartObj.options.scales.xAxes[0] : chartObj.options.scales.yAxes[0];
+
+      const hexColor = parts[1];
+      const fontSize = parts[2];
+      const alignment = parts[3];
+      const axisTickVisibility = parts[4];
+      const tickColor = parts[5];
+      const axisColor = parts[6];
+      const skipLabels = parts[7];
+
+      axis.gridLines = axis.gridLines || {};
+      switch (axisTickVisibility) {
+        case 'l':
+          // Axis line only
+          axis.display = true;
+          axis.gridLines.drawTicks = false;
+          break;
+        case 't':
+          // Tick marks only
+          axis.display = true;
+          axis.gridLines.drawTicks = true;
+          break;
+        case '_':
+          // Neither axis nor tick marks
+          axis.display = false;
+          break;
+        case 'lt':
+        default:
+          // Ticks and axis line
+          axis.display = true;
+          axis.gridLines.drawTicks = true;
+          break;
+      }
+
+      const matchResults = AXIS_FORMAT_REGEX_CHXS.exec(parts[0]);
+      if (matchResults && matchResults[1]) {
+        // Apply prefix and suffix.
+        let tickPrefix = matchResults[2] || '';
+        let tickSuffix = matchResults[8] || '';
+
+        // Apply cryptic formatting rules.
+        const valueType = matchResults[4];
+        const currency = matchResults[5];
+        const numDecimalPlaces = matchResults[6] ? parseInt(matchResults[6], 10) : 2;
+        const otherOptions = matchResults[7];
+
+        if (valueType && valueType.indexOf('p') > -1) {
+          // Display a percentage: add % sign and multiply by 100.
+          tickSuffix += '%';
+          axisValFormatters[axisName].push(val => {
+            return val * 100.0;
+          });
+        } else if (valueType && valueType.indexOf('e') > -1) {
+          // Exponential: scientific notation
+          axisValFormatters[axisName].push(val => {
+            return val.toExponential();
+          });
+        } else if (currency) {
+          const CURRENCY_SYMBOLS = {
+            AUD: '$',
+            CAD: '$',
+            CHF: 'CHF',
+            CNY: '元',
+            EUR: '€',
+            GBP: '£',
+            HKD: '$',
+            INR: '₹',
+            JPY: '¥',
+            KRW: '₩',
+            MXN: '$',
+            NOK: 'kr',
+            NZD: '$',
+            RUB: '₽',
+            SEK: 'kr',
+            TRY: '₺',
+            USD: '$',
+            ZAR: 'R',
+          };
+          const symbol = CURRENCY_SYMBOLS[currency.slice(1)] || '$';
+          tickPrefix += symbol;
+        }
+
+        if (otherOptions && otherOptions.indexOf('s')) {
+          // Add thousands separator and apply number of decimal places
+          axisValFormatters[axisName].push(val => {
+            return val.toLocaleString('en', {
+              minimumFractionDigits: numDecimalPlaces,
+            });
+          });
+        } else {
+          // Apply number of decimal places
+          axisValFormatters[axisName].push(val => {
+            return val.toFixed(numDecimalPlaces);
+          });
+        }
+
+        axisValFormatters[axisName].push(val => {
+          return tickPrefix + val + tickSuffix;
+        });
+
+        // TODO(ian): Support trailing zeroes option 'z'
+
+        // Apply formatters!
+        axis.ticks = axis.ticks || {};
+
+        let nextLabelIdx = 0;
+        axis.ticks.callback = (val, tickIdx, vals) => {
+          let retVal = val;
+          axisValFormatters[axisName].forEach(formatFn => {
+            retVal = formatFn(retVal);
+          });
+          return retVal;
+        };
+      }
+    });
+  }
+
+  if (chxl) {
+    const splits = chxl.split('|');
+    let currentAxisIdx, currentAxisName;
+    splits.forEach(label => {
+      if (validAxesLabels.has(label)) {
+        currentAxisIdx = parseInt(label.replace(':', ''), 10);
+        currentAxisName = axisByIndex[currentAxisIdx];
+        // Placeholder lists already created, below line unnecessary.
+        // axisLabelsLookup[currentAxisName] = axisLabelsLookup[currentAxisName] || [];
+      } else {
+        axisLabelsLookup[currentAxisName].push(label);
+      }
+    });
+
+    // These axis ticks override the above automatic formatting axis ticks.
+    setAxisTicks('x', axisLabelsLookup, chartObj);
+    setAxisTicks('y', axisLabelsLookup, chartObj);
+  }
+}
+
+function setAxisTicks(axisName, axisLabelsLookup, chartObj) {
+  let axisLabels = axisLabelsLookup[axisName];
+  if (axisLabels && axisLabels.length > 0) {
+    if (axisName === 'y') {
+      axisLabels = axisLabels.reverse();
+    }
+    const axis =
+      axisName === 'x' ? chartObj.options.scales.xAxes[0] : chartObj.options.scales.yAxes[0];
+    axis.ticks = axis.ticks || {};
+
+    let nextLabelIdx = 0;
+    axis.ticks.callback = (val, tickIdx, vals) => {
+      // This needs to be rebuilt every time in callback, because this is the
+      // only place we have access to accurate 'vals' (which varies based on
+      // axis scale etc).
+
+      // TODO(ian): Need an odd number of ticks for an odd number of axis
+      // labels. Otherwise they won't quite be spaced evenly.
+      const numTicks = vals.length;
+      const numLabels = axisLabels.length;
+
+      const idxToLabel = {};
+      const stepSize = numTicks / (numLabels - 1);
+      for (let i = 0; i < numLabels - 1; i++) {
+        const label = axisLabels[i];
+        idxToLabel[Math.floor(stepSize * i)] = label;
+      }
+      idxToLabel[numTicks - 1] = axisLabels[numLabels - 1];
+
+      return idxToLabel[tickIdx] || '';
+    };
+    axis.ticks.minRotation = 0;
+    axis.ticks.maxRotation = 0;
+    axis.ticks.padding = 2;
+  }
+}
+
+function setMarkers(chm, chartObj) {
+  if (!chm) {
+    return;
+  }
+
+  const enabledSeriesIndexes = new Set();
+  let hideMarkers = false;
+  chm.split('|').forEach((markerRule, idx) => {
+    const parts = markerRule.split(',');
+    const markerType = parts[0];
+    const markerColor = parts[1];
+
+    if (markerType === 'B' || markerType === 'b') {
+      chartObj.data.datasets[idx].fill = true;
+      chartObj.data.datasets[idx].backgroundColor = '#' + markerColor;
+    }
+
+    // TODO(ian): All of the marker options. See
+    // https://developers.google.com/chart/image/docs/chart_params#gcharts_data_point_labels
+    const seriesIndex = parts[2];
+    const size = parts[4];
+    if (parseInt(size, 10) === 0) {
+      hideMarkers = true;
+    }
+
+    enabledSeriesIndexes.add(parseInt(seriesIndex, 10));
+
+    // chm=N,000000,0,,10|N,000000,1,,10|N,000000,2,,10
+  });
+
+  chartObj.options.plugins = {
+    datalabels: {
+      display: !hideMarkers,
+      anchor: 'end',
+      align: 'end',
+      offset: 0,
+      font: {
+        size: 10,
+        weight: 'bold',
+      },
+      formatter: (value, context) => {
+        if (enabledSeriesIndexes.has(context.datasetIndex)) {
+          return value;
+        }
+        return null;
+      },
+    },
+  };
+}
+
+function setGridLines(chg, chartObj) {
+  if (!chg) {
+    return;
+  }
+
+  const parts = chg.split(',');
+
+  if (Number(parts[0]) > 0) {
+    chartObj.options.scales.xAxes[0].gridLines.display = true;
+    chartObj.options.scales.xAxes[0].gridLines.drawOnChartArea = true;
+  }
+  if (Number(parts[1]) > 0) {
+    chartObj.options.scales.yAxes[0].gridLines.display = true;
+    chartObj.options.scales.yAxes[0].gridLines.drawOnChartArea = true;
+  }
+
+  if (parts.length >= 2) {
+    const numGridLinesX = 100 / parseInt(parts[0], 10);
+    const numGridLinesY = 100 / parseInt(parts[1], 10);
+
+    chartObj.options.scales.xAxes[0].ticks = {
+      maxTicksLimit: numGridLinesX,
+    };
+    chartObj.options.scales.yAxes[0].ticks = {
+      maxTicksLimit: numGridLinesY,
+    };
+  }
+
+  // TODO(ian): dash sizes etc
+  // https://developers.google.com/chart/image/docs/gallery/line_charts
+
+  // TODO(ian): Full implementation https://developers.google.com/chart/image/docs/chart_params#gcharts_grid_lines
+}
+
+function setLineChartOptions(chl, chartObj) {
+  // Set options specific to line chart.
+  if (!chl) {
+    return;
+  }
+
+  const series = chl.split('|');
+  series.forEach((serie, idx) => {
+    const parts = serie.split(',');
+    const thickness = parseInt(parts[0], 10);
+    // TODO(ian): Support for dashed line
+    // dashLength = parts[1]
+    // spaceLength = parts[2]
+
+    if (!isNaN(thickness)) {
+      chartObj.data.datasets[idx].borderWidth = thickness;
+    }
+  });
+}
+
+function toChartJs(query) {
+  //renderChart(width, height, backgroundColor, devicePixelRatio, untrustedChart) {
+  const { width, height } = parseSize(query.chs);
+
+  const backgroundColor = parseBackgroundColor(query.chf);
+
+  // Parse data
+  const seriesData = parseSeriesData(query.chd, query.chds);
+
+  // Start building the chart
+  const chartObj = {
+    data: {},
+    options: {},
+  };
+
+  setChartType(query.cht, chartObj);
+  setData(seriesData, chartObj);
+  setTitle(query.chtt, query.chts, chartObj);
+  setGridLines(query.chg, chartObj);
+  setLegend(query.chdl, query.chdlp, query.chdls, chartObj);
+  setMargins(query.chma, chartObj);
+
+  setDataLabels(query.chl, chartObj);
+  setColors(query.chco, chartObj);
+  setAxes(query.chxt, query.chxr, chartObj);
+  setAxesLabels(query.chxt, query.chxl, query.chxs, chartObj);
+
+  setMarkers(query.chm, chartObj);
+  setGridLines(query.chg, chartObj);
+
+  setLineChartOptions(query.chls, chartObj);
+
+  // TODO(ian): Bar Width and Spacing chbh
+  // Zero Line chp
+
+  // console.log(JSON.stringify(chartObj, null, 2));
+
+  return {
+    width,
+    height,
+    backgroundColor,
+    chart: chartObj,
+  };
+}
+
+module.exports = {
+  toChartJs,
+  parseSeriesData,
+  parseSize,
+};

lib/graphviz.js

@@ -0,0 +1,31 @@
+const Viz = require('viz.js');
+const { Module, render } = require('viz.js/full.render.js');
+
+async function renderGraphviz(graphStr, opts) {
+  const { format, engine, width, height } = opts || {};
+  const viz = new Viz({ Module, render });
+  const result = await viz.renderString(graphStr, {
+    // Built-in format options don't work great. Hardcode to svg and convert it
+    // to other supported formats later.
+    format: 'svg',
+    engine,
+  });
+  if (format === 'png') {
+    // Defer require of sharp as it is not supported by docker container.
+    const sharp = require('sharp');
+    const img = sharp(Buffer.from(result));
+    if (width && height) {
+      img.resize({
+        width,
+        height,
+        fit: 'contain',
+      });
+    }
+    return img.png().toBuffer();
+  }
+  return result;
+}
+
+module.exports = {
+  renderGraphviz,
+};

lib/pdf.js

@@ -0,0 +1,63 @@
+const PDFDocument = require('pdfkit');
+
+// Minimum margin between image and any edge of PDF.
+const IMAGE_MARGIN = 35;
+
+function getPdfBufferFromPng(image, pdfKitImageOptions) {
+  const ret = new Promise((resolve, reject) => {
+    try {
+      const doc = new PDFDocument();
+
+      const buffers = [];
+      doc.on('data', buffers.push.bind(buffers));
+      doc.on('end', () => {
+        const pdfData = Buffer.concat(buffers);
+        resolve(pdfData);
+      });
+
+      doc.image(
+        image,
+        IMAGE_MARGIN,
+        100,
+        Object.assign(
+          {
+            fit: [doc.page.width - IMAGE_MARGIN * 2, doc.page.height - IMAGE_MARGIN * 2],
+            align: 'center',
+          },
+          pdfKitImageOptions || {},
+        ),
+      );
+      doc.end();
+    } catch (err) {
+      reject(`PDF generation error: ${err.message}`);
+    }
+  });
+  return ret;
+}
+
+function getPdfBufferWithText(text) {
+  const ret = new Promise((resolve, reject) => {
+    try {
+      const doc = new PDFDocument();
+
+      const buffers = [];
+      doc.on('data', buffers.push.bind(buffers));
+      doc.on('end', () => {
+        const pdfData = Buffer.concat(buffers);
+        resolve(pdfData);
+      });
+
+      doc.fontSize(24);
+      doc.text(text, 100, 100);
+      doc.end();
+    } catch (err) {
+      reject(`PDF generation error: ${err.message}`);
+    }
+  });
+  return ret;
+}
+
+module.exports = {
+  getPdfBufferFromPng,
+  getPdfBufferWithText,
+};

lib/qr.js

@@ -0,0 +1,53 @@
+const qrcode = require('qrcode');
+const toSJIS = require('qrcode/helper/to-sjis');
+
+const { logger } = require('../logging');
+
+// Default size of QR image in pixels.
+const DEFAULT_QR_SIZE = 150;
+
+function renderQr(format, mode, qrData, qrOpts) {
+  logger.debug('QR code', format, mode, qrOpts);
+
+  let finalQrData = qrData;
+  const finalQrOpts = qrOpts;
+  if (mode === 'sjis') {
+    finalQrData = [
+      {
+        data: qrData,
+        mode: 'kanji',
+      },
+    ];
+    finalQrOpts.toSJISFunc = toSJIS;
+  }
+  finalQrOpts.type = format === 'png' ? 'png' : 'svg';
+
+  return new Promise((resolve, reject) => {
+    if (format === 'svg') {
+      qrcode
+        .toString(finalQrData, finalQrOpts)
+        .then(qrStr => {
+          resolve(Buffer.from(qrStr, 'utf8'));
+        })
+        .catch(err => {
+          logger.error('QR render error (SVG)', err);
+          reject(new Error(`Could not generate QR\n${err}`));
+        });
+    } else {
+      qrcode
+        .toDataURL(finalQrData, finalQrOpts)
+        .then(dataUrl => {
+          resolve(Buffer.from(dataUrl.split(',')[1], 'base64'));
+        })
+        .catch(err => {
+          logger.error('QR render error (PNG)', err);
+          reject(new Error(`Could not generate QR\n${err}`));
+        });
+    }
+  });
+}
+
+module.exports = {
+  renderQr,
+  DEFAULT_QR_SIZE,
+};

lib/svg.js

@@ -0,0 +1,20 @@
+function generateRandomId(length) {
+  const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
+  let result = '';
+  for (let i = 0; i < length; i++) {
+    result += characters.charAt(Math.floor(Math.random() * characters.length));
+  }
+  return result;
+}
+
+// From https://blog.jim-nielsen.com/2022/multiple-inline-svgs/
+function uniqueSvg(svg) {
+  const id = generateRandomId(10);
+  return svg
+    .replace(/id="clip/g, `id="${id}__clip`)
+    .replace(/clip-path="url\(#clip/g, `clip-path="url(#${id}__clip`);
+}
+
+module.exports = {
+  uniqueSvg,
+};

lib/util.js

@@ -0,0 +1,22 @@
+function fixNodeVmObject(obj) {
+  // Fix for https://github.com/patriksimek/vm2/issues/198
+  if (!obj) return;
+
+  const objKeys = Object.keys(obj);
+  for (let i = 0; i < objKeys.length; i++) {
+    const key = objKeys[i];
+    const val = obj[key];
+    if (Array.isArray(val)) {
+      obj[key] = Array.from(val);
+      obj[key].forEach(arrObj => {
+        fixNodeVmObject(arrObj);
+      });
+    } else if (typeof val === 'object' && val !== null) {
+      fixNodeVmObject(val);
+    }
+  }
+}
+
+module.exports = {
+  fixNodeVmObject,
+};

logging.js

@@ -0,0 +1,10 @@
+const bunyan = require('bunyan');
+
+const logger = bunyan.createLogger({
+  name: 'quickchart',
+  streams: [{ stream: process.stdout, level: process.env.LOG_LEVEL }],
+});
+
+module.exports = {
+  logger,
+};

package.json

@@ -0,0 +1,71 @@
+{
+  "name": "quickchart",
+  "version": "1.8.1",
+  "main": "index.js",
+  "license": "AGPL-3.0",
+  "homepage": "https://quickchart.io/",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/typpo/quickchart.git"
+  },
+  "scripts": {
+    "start": "node --max-http-header-size=65536 index.js",
+    "format": "prettier --write \"**/*.js\"",
+    "test": "PORT=3401 NODE_ENV=test mocha --exit --recursive test/ci/",
+    "test:watch": "PORT=2998 NODE_ENV=test chokidar '**/*.js' --initial --ignore node_modules -c 'mocha --exit --recursive test/'"
+  },
+  "overrides": {
+    "canvas": "2.9.3"
+  },
+  "resolutions": {
+    "canvas": "2.9.3"
+  },
+  "dependencies": {
+    "bunyan": "^1.8.12",
+    "canvas": "2.9.3",
+    "canvas-5-polyfill": "^0.1.5",
+    "chart.js": "^2.9.4",
+    "chart.js-v3": "npm:chart.js@3.9.1",
+    "chart.js-v4": "npm:chart.js@4.0.1",
+    "chartjs-adapter-moment": "https://github.com/typpo/chartjs-adapter-moment.git#e9bc92ab6e0e500c91c4a9871db7b14d15b5c2e7",
+    "chartjs-chart-box-and-violin-plot": "^2.4.0",
+    "chartjs-chart-radial-gauge": "^1.0.3",
+    "chartjs-node-canvas": "^3.0.6",
+    "chartjs-plugin-annotation": "^0.5.7",
+    "chartjs-plugin-colorschemes": "https://github.com/typpo/chartjs-plugin-colorschemes.git#979ef8e599265f65c85d5dae90b543d5589c734a",
+    "chartjs-plugin-datalabels": "^0.5.0",
+    "chartjs-plugin-doughnutlabel": "^2.0.3",
+    "chartjs-plugin-piechart-outlabels": "^0.1.4",
+    "deepmerge": "^4.2.2",
+    "express": "^4.19.2",
+    "express-rate-limit": "^5.0.0",
+    "get-image-colors": "^4.0.1",
+    "javascript-stringify": "^2.0.0",
+    "node-fetch": "^2.6.7",
+    "patternomaly": "^1.3.2",
+    "pdfkit": "^0.10.0",
+    "qrcode": "^1.3.3",
+    "qs": "^6.7.0",
+    "sharp": "^0.32.6",
+    "text2png": "^2.1.0",
+    "viz.js": "^2.1.2"
+  },
+  "devDependencies": {
+    "@arkweid/lefthook": "^0.6.3",
+    "artillery": "^1.7.9",
+    "chokidar-cli": "^2.0.0",
+    "eslint": "^5.15.1",
+    "eslint-config-airbnb-base": "^13.1.0",
+    "eslint-plugin-import": "^2.16.0",
+    "image-size": "^0.8.3",
+    "jimp": "^0.13.0",
+    "mocha": "^6.2.3",
+    "pixelmatch": "^5.1.0",
+    "prettier": "^1.18.2",
+    "qrcode-reader": "^1.0.4",
+    "supertest": "^4.0.2"
+  },
+  "peerDependencies": {
+    "chart.js": ">= 2.0.0"
+  }
+}

telemetry.js

@@ -0,0 +1,87 @@
+const fs = require('fs');
+
+const fetch = require('node-fetch');
+
+const { logger } = require('./logging');
+
+const TELEMETRY_PATH = 'telemetry.log';
+
+const PROCESS_ID = Math.floor(Math.random() * 1e10).toString(16);
+
+let receivedCount = 0;
+let telemetry = {};
+
+function count(label) {
+  receive(PROCESS_ID, label, 1);
+}
+
+function receive(pid, label, count) {
+  if (!pid || !label || !count) {
+    return;
+  }
+  if (!telemetry[pid]) {
+    telemetry[pid] = {};
+  }
+  if (!telemetry[pid][label]) {
+    telemetry[pid][label] = 0;
+  }
+  telemetry[pid][label] += count;
+  receivedCount++;
+}
+
+function write() {
+  if (!receivedCount) {
+    return;
+  }
+
+  logger.info(`Writing ${receivedCount} telemetry records...`);
+  telemetry.timestamp = new Date().getTime();
+  if (process.env.WRITE_TELEMETRY_TO_CONSOLE) {
+    logger.info('Telemetry', JSON.stringify(telemetry));
+  } else {
+    fs.appendFileSync(TELEMETRY_PATH, JSON.stringify(telemetry) + '\n');
+  }
+  telemetry = {};
+  receivedCount = 0;
+}
+
+function send() {
+  if (!telemetry[PROCESS_ID]) {
+    return;
+  }
+  const data = {
+    pid: PROCESS_ID,
+    chartCount: telemetry[PROCESS_ID].chartCount,
+    qrCount: telemetry[PROCESS_ID].qrCount,
+  };
+  try {
+    fetch('https://quickchart.io/telemetry', {
+      method: 'POST',
+      body: JSON.stringify(data),
+      headers: {
+        'content-type': 'application/json',
+      },
+    });
+  } catch (err) {}
+
+  telemetry = {};
+}
+
+if (process.env.ENABLE_TELEMETRY_WRITE) {
+  logger.info('Telemetry writing is enabled');
+  setInterval(() => {
+    write();
+  }, 1000 * 60 * 60 * 1);
+}
+if (!process.env.DISABLE_TELEMETRY) {
+  logger.info('Telemetry is enabled');
+  setInterval(() => {
+    send();
+  }, 1000 * 60 * 60 * 12);
+}
+
+module.exports = {
+  count,
+  receive,
+  write,
+};