Refactor, image support, improve error handling

.eslintrc

@@ -1,4 +1,8 @@
 {
+  "env": {
+    "node": true,
+    "mocha": true
+  },
   "parser": "babel-eslint",
   "extends": "airbnb/base"
 }

Dockerfile

@@ -1,6 +1,8 @@
 FROM node:slim
 
-ENV RENDERER_ACCESS_KEY=changeme CONCURRENCY=1
+MAINTAINER Mihkel Sokk <[email protected]>
+
+ENV RENDERER_ACCESS_KEY=changeme CONCURRENCY=1 WINDOW_WIDTH=1024 WINDOW_HEIGHT=768
 
 # Add subpixel hinting
 COPY .fonts.conf /root/.fonts.conf
@@ -16,4 +18,5 @@ RUN npm install --production && \
     apt-get clean
 
 EXPOSE 3000
-CMD xvfb-run --server-args="-screen 0 800x600x24" npm start
+
+CMD xvfb-run --server-args="-screen 0 $WINDOW_WIDTHx$WINDOW_HEIGHTx24" npm start

README.md

@@ -2,7 +2,7 @@
 [![Docker Hub](https://img.shields.io/badge/docker-ready-blue.svg)](https://registry.hub.docker.com/u/msokk/electron-render-service/)
 [![](https://badge.imagelayers.io/msokk/electron-render-service:latest.svg)](https://imagelayers.io/?images=msokk/electron-render-service:latest 'Get your own badge on imagelayers.io')
 
-Simple PDF render service, accepts webpage URL and returns it as a PDF.
+Simple PDF/PNG/JPEG render service, accepts webpage URL and returns the resource.
 
 
 ## Docker usage
@@ -28,7 +28,7 @@ git clone https://github.com/msokk/electron-render-service.git
 npm install
 
 # Run in virtual framebuffer
-RENDERER_ACCESS_KEY=secret xvfb-run --server-args="-screen 0 800x600x24" npm start
+RENDERER_ACCESS_KEY=secret xvfb-run --server-args="-screen 0 1024x768x24" npm start
 
 wget -o out.pdf http://localhost:3000/pdf?url=https://github.com/msokk/electron-render-service&access_key=secret
 ```
@@ -47,6 +47,20 @@ wget -o out.pdf http://localhost:3000/pdf?url=https://github.com/msokk/electron-
   * `printBackground` - Whether to print CSS backgrounds. (default: `true`)
   * `landscape` -  `true` for landscape, `false` for portrait. (default: `false`)
 
+#### `GET /png|jpeg` - Render PNG/JPEG
+
+*Query params:*
+
+  * `access_key` - Authentication key.
+  * `url` - Full URL to fetch.
+  * `quality` - JPEG quality. (default: `80`)
+  * `browserWidth` - Browser window width (default: `rect.width || env.WINDOW_WIDTH`, max: `3000`)
+  * `browserHeight` - Browser window height (default: `rect.height || env.WINDOW_HEIGHT`, max: `3000`)
+  * Clipping rectangle (optional, but all 4 integers need to be set)
+    * `x`
+    * `y`
+    * `width`
+    * `height`
 
 #### `GET /stats` - Display render pool stats
 
@@ -62,5 +76,8 @@ wget -o out.pdf http://localhost:3000/pdf?url=https://github.com/msokk/electron-
 
 ##### *Optional*
 * `CONCURRENCY` - Number of browser windows to run in parallel (default: `1`)
+* `TIMEOUT` - Number of seconds before request timeouts (default: `30`)
+* `WINDOW_WIDTH` - Default window width (default: `1024`)
+* `WINDOW_HEIGHT` - Default window height (default: `768`)
 * `INTERFACE` - Network interface for Express to listen on (default: `0.0.0.0`)
 * `PORT` - (default: `3000`)

lib/auth.js

@@ -21,8 +21,13 @@ if (Object.keys(validKeys).length === 0) throw new Error('No access key defined!
 function authMiddleware(req, res, next) {
   const sentKey = req.query.access_key;
   const key = Object.keys(validKeys).filter(k => validKeys[k] === sentKey);
-  if (!sentKey || key.length === 0) return res.sendStatus(403);
+  if (!sentKey || key.length === 0) {
+    return res.status(403).send({
+      error: { code: 'UNAUTHORIZED', message: 'Invalid or missing access key.' }
+    });
+  }
 
+  /* eslint-disable no-param-reassign */
   req.keyLabel = key[0];
   next();
 }

lib/renderer.js

@@ -0,0 +1,158 @@
+'use strict';
+
+var _slicedToArray = function () { function sliceIterator(arr, i) { var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"]) _i["return"](); } finally { if (_d) throw _e; } } return _arr; } return function (arr, i) { if (Array.isArray(arr)) { return arr; } else if (Symbol.iterator in Object(arr)) { return sliceIterator(arr, i); } else { throw new TypeError("Invalid attempt to destructure non-iterable instance"); } }; }();
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.renderWorker = renderWorker;
+exports.createWindow = createWindow;
+
+var _package = require('../package.json');
+
+var _package2 = _interopRequireDefault(_package);
+
+var _electron = require('electron');
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+const TIMEOUT = process.env.TIMEOUT || 30;
+const WINDOW_WIDTH = process.env.WINDOW_WIDTH || 1024;
+const WINDOW_HEIGHT = process.env.WINDOW_HEIGHT || 768;
+const LIMIT = 3000; // Constrain screenshots to 3000x3000px
+
+const DEFAULT_HEADERS = 'Cache-Control: no-cache, no-store, must-revalidate';
+
+/**
+ * Render PDF
+ */
+function renderPDF(_ref, done) {
+  let options = _ref.options;
+
+  this.webContents.printToPDF(options, done);
+}
+
+/**
+ * Render image
+ */
+function renderImage(_ref2, done) {
+  let type = _ref2.type;
+  let options = _ref2.options;
+
+  const handleCapture = image => {
+    done(null, type === 'png' ? image.toPng() : image.toJpeg(parseInt(options.quality, 10) || 80));
+  };
+
+  // Sanitize rect
+  const validKeys = ['x', 'y', 'width', 'height'];
+  const rect = {};
+  Object.keys(options).map(k => [k, options[k]]).filter(_ref3 => {
+    var _ref4 = _slicedToArray(_ref3, 2);
+
+    let k = _ref4[0];
+    let v = _ref4[1];
+    return validKeys.includes(k) && !isNaN(parseInt(v, 10));
+  }).forEach(_ref5 => {
+    var _ref6 = _slicedToArray(_ref5, 2);
+
+    let k = _ref6[0];
+    let v = _ref6[1];
+    return rect[k] = parseInt(v, 10);
+  });
+
+  // Use explicit browser size or rect size, capped by LIMIT, default to ENV variable
+  const browserSize = {
+    width: Math.min(parseInt(options.browserWidth, 10) || rect.width, LIMIT) || WINDOW_WIDTH,
+    height: Math.min(parseInt(options.browserHeight, 10) || rect.height, LIMIT) || WINDOW_HEIGHT
+  };
+
+  if (Object.keys(rect).length === 4) {
+    // Avoid stretching by adding rect coordinates to size
+    this.setSize(browserSize.width + rect.x, browserSize.height + rect.y);
+    this.capturePage(rect, handleCapture);
+  } else {
+    this.setSize(browserSize.width, browserSize.height);
+    this.capturePage(handleCapture);
+  }
+}
+
+/**
+ * Handle loading failure errors
+ */
+function handleLoadingError(done, e, code, desc) {
+  switch (code) {
+    case -105:
+      done({ statusCode: 500, code: 'NAME_NOT_RESOLVED',
+        message: `The host name could not be resolved.` });
+      break;
+    case -300:
+      done({ statusCode: 500, code: 'INVALID_URL', message: 'The URL is invalid.' });
+      break;
+    case -501:
+      done({ statusCode: 500, code: 'INSECURE_RESPONSE',
+        message: 'The server\'s response was insecure (e.g. there was a cert error).' });
+      break;
+    case -3:
+      done({ statusCode: 500, code: 'ABORTED', message: 'User aborted loading.' });
+      break;
+    default:
+      done({ statusCode: 500, code: 'GENERIC_ERROR', message: `${ code } - ${ desc }` });
+  }
+}
+
+/**
+ * Render job with error handling
+ */
+function renderWorker(window, task, done) {
+  const webContents = window.webContents;
+
+  // Prevent loading of malicious chrome:// URLS
+
+  if (task.url.startsWith('chrome://')) {
+    return done({ statusCode: 500, code: 'INVALID_URL', message: 'The URL is invalid.' });
+  }
+
+  // Loading failures
+  webContents.once('did-fail-load', function () {
+    for (var _len = arguments.length, args = Array(_len), _key = 0; _key < _len; _key++) {
+      args[_key] = arguments[_key];
+    }
+
+    return handleLoadingError(done, ...args);
+  });
+
+  // Renderer process has crashed
+  webContents.once('crashed', () => {
+    done({ statusCode: 500, code: 'RENDERER_CRASH', message: `Render process crashed.` });
+  });
+
+  webContents.once('did-finish-load', () => {
+    (task.type === 'pdf' ? renderPDF : renderImage).call(window, task, done);
+  });
+
+  webContents.once('timeout', () => {
+    done({ statusCode: 524, code: 'RENDERER_TIMEOUT', message: `Renderer timed out.` });
+  });
+
+  // Timeout render job
+  webContents.timeoutTimer = setTimeout(() => webContents.emit('timeout'), TIMEOUT * 1000);
+
+  webContents.loadURL(task.url, { extraHeaders: DEFAULT_HEADERS });
+}
+
+/**
+ * Create BrowserWindow
+ */
+function createWindow() {
+  const window = new _electron.BrowserWindow({
+    width: WINDOW_WIDTH, height: WINDOW_HEIGHT,
+    frame: false, show: false
+  });
+
+  // Set user agent
+  const webContents = window.webContents;
+
+  webContents.setUserAgent(`${ webContents.getUserAgent() } ${ _package2.default.name }/${ _package2.default.version }`);
+
+  return window;
+}

lib/server.js

@@ -8,53 +8,89 @@ var _morgan = require('morgan');
 
 var _morgan2 = _interopRequireDefault(_morgan);
 
+var _responseTime = require('response-time');
+
+var _responseTime2 = _interopRequireDefault(_responseTime);
+
 var _electron = require('electron');
 
-var _render_pool = require('./render_pool');
+var _window_pool = require('./window_pool');
 
-var _render_pool2 = _interopRequireDefault(_render_pool);
+var _window_pool2 = _interopRequireDefault(_window_pool);
 
 var _auth = require('./auth');
 
 var _auth2 = _interopRequireDefault(_auth);
 
+var _util = require('./util');
+
 function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
 
 const INTERFACE = process.env.INTERFACE || '0.0.0.0';
 const PORT = process.env.PORT || 3000;
 const app = (0, _express2.default)();
 
-function printPDFUsage() {
-  let url = arguments.length <= 0 || arguments[0] === undefined ? '' : arguments[0];
-
-  return `Usage: GET ${ url }/pdf?url=http://google.com&access_key=<token>`;
-}
+app.use((0, _responseTime2.default)());
 
 // Log with token
 _morgan2.default.token('key-label', req => req.keyLabel);
 app.use((0, _morgan2.default)(`[:date[iso]] :key-label@:remote-addr - :method :status
-:url :res[content-length] ":user-agent" :response-time ms`.replace('\n', '')));
+ :url :res[content-length] ":user-agent" :response-time ms`.replace('\n', '')));
+
+app.disable('x-powered-by');
+app.enable('trust proxy');
 
 /**
  * GET /pdf - Render PDF
  *
- * Query: https://github.com/atom/electron/blob/master/docs/api/web-contents.md#webcontentsprinttopdfoptions-callback
+ * Query params: https://github.com/atom/electron/blob/master/docs/api/web-contents.md#webcontentsprinttopdfoptions-callback
  */
 app.get('/pdf', _auth2.default, (req, res) => {
   var _req$query = req.query;
   var _req$query$url = _req$query.url;
-  const url = _req$query$url === undefined ? 'data:text/plain;charset=utf-8,' + printPDFUsage() : _req$query$url;
+  const url = _req$query$url === undefined ? 'data:text/plain;charset=utf-8,' + (0, _util.printUsage)('pdf') : _req$query$url;
   var _req$query$marginsTyp = _req$query.marginsType;
   const marginsType = _req$query$marginsTyp === undefined ? 0 : _req$query$marginsTyp;
   var _req$query$pageSize = _req$query.pageSize;
   const pageSize = _req$query$pageSize === undefined ? 'A4' : _req$query$pageSize;
   var _req$query$printBackg = _req$query.printBackground;
-  const printBackground = _req$query$printBackg === undefined ? true : _req$query$printBackg;
+  const printBackground = _req$query$printBackg === undefined ? 'true' : _req$query$printBackg;
   var _req$query$landscape = _req$query.landscape;
-  const landscape = _req$query$landscape === undefined ? false : _req$query$landscape;
+  const landscape = _req$query$landscape === undefined ? 'false' : _req$query$landscape;
+
+  req.app.pool.enqueue({ url, type: 'pdf',
+    options: {
+      pageSize,
+      marginsType: parseInt(marginsType, 10),
+      landscape: landscape === 'true',
+      printBackground: printBackground === 'true'
+    }
+  }, (err, buffer) => {
+    if ((0, _util.handleErrors)(err, req, res)) return;
+
+    (0, _util.setContentDisposition)(res, 'pdf');
+    res.type('pdf').send(buffer);
+  });
+});
 
-  _render_pool2.default.enqueue({ url, res, type: 'pdf',
-    options: { marginsType, pageSize, landscape, printBackground } });
+/**
+ * GET /png|jpeg - Render png or jpeg
+ *
+ * Query params:
+ * x = 0, y = 0, width, height
+ * quality = 80 - JPEG quality
+ */
+app.get(/^\/(png|jpeg)/, _auth2.default, (req, res) => {
+  const type = req.params[0];
+  var _req$query$url2 = req.query.url;
+  const url = _req$query$url2 === undefined ? 'data:text/plain;charset=utf-8,' + (0, _util.printUsage)(type) : _req$query$url2;
+
+  req.app.pool.enqueue({ url, type, options: req.query }, (err, buffer) => {
+    if ((0, _util.handleErrors)(err, req, res)) return;
+
+    (0, _util.setContentDisposition)(res, type);
+    res.type(type).send(buffer);
+  });
 });
 
 /**
@@ -63,29 +99,25 @@ app.get('/pdf', _auth2.default, (req, res) => {
 app.get('/stats', _auth2.default, (req, res) => {
   if (req.keyLabel !== 'global') return res.sendStatus(403);
 
-  res.send(_render_pool2.default.stats());
+  res.send(req.app.pool.stats());
 });
 
 /**
  * GET / - Print usage
  */
-app.get('/', (req, res) => res.status(404).send(printPDFUsage()));
+app.get('/', (req, res) => {
+  res.send((0, _util.printUsage)());
+});
 
 // Electron finished booting
 _electron.app.on('ready', () => {
-  _render_pool2.default.init();
-
-  const listener = app.listen(PORT, INTERFACE, () => {
-    var _listener$address = listener.address();
-
-    const port = _listener$address.port;
-    const address = _listener$address.address;
-
-    const url = `http://${ address }:${ port }`;
-    process.stdout.write(`Renderer listening on ${ url }\n\n`);
-    process.stdout.write(printPDFUsage(url) + '\n');
-  });
+  app.pool = new _window_pool2.default();
+  const listener = app.listen(PORT, INTERFACE, () => (0, _util.printBootMessage)(listener));
 });
 
 // Stop Electron on SIG*
-process.on('exit', code => _electron.app.exit(code));
+process.on('exit', code => _electron.app.exit(code));
+
+process.on('uncaughtException', err => {
+  throw err;
+});