src/camo.js

   1 import crypto from 'crypto';
   2 import * as urlparse from 'url';
   3
   4 const LOGGER = require('@calzoneman/jsli')('camo');
   5
   6 function isWhitelisted(camoConfig, url) {
   7     const whitelistedDomains = camoConfig.getWhitelistedDomainsRegexp();
   8     const parsed = urlparse.parse(url);
   9     return whitelistedDomains.test('.' + parsed.hostname);
  10 }
  11
  12 export function camoify(camoConfig, url) {
  13     if (typeof url !== 'string') {
  14         throw new TypeError(`camoify expected a string, not [${url}]`);
  15     }
  16
  17     if (isWhitelisted(camoConfig, url)) {
  18         return url.replace(/^http:/, 'https:');
  19     }
  20
  21     const hmac = crypto.createHmac('sha1', camoConfig.getKey());
  22     hmac.update(url);
  23     const digest = hmac.digest('hex');
  24     // https://github.com/atmos/camo#url-formats
  25     if (camoConfig.getEncoding() === 'hex') {
  26         const hexUrl = Buffer.from(url, 'utf8').toString('hex');
  27         return `${camoConfig.getServer()}/${digest}/${hexUrl}`;
  28     } else {
  29         const encoded = encodeURIComponent(url);
  30         return `${camoConfig.getServer()}/${digest}?url=${encoded}`;
  31     }
  32 }
  33
  34 export function transformImgTags(camoConfig, tagName, attribs) {
  35     if (typeof attribs.src === 'string') {
  36         try {
  37             const oldSrc = attribs.src;
  38             attribs.src = camoify(camoConfig, attribs.src);
  39             LOGGER.debug('Camoified "%s" to "%s"', oldSrc, attribs.src);
  40         } catch (error) {
  41             LOGGER.error(`Failed to generate camo URL for "${attribs.src}": ${error}`);
  42         }
  43     }
  44
  45     return { tagName, attribs };
  46 }