Merge pull request #874 from sharetribe/improve-clientside-coord-obfu…

…scation

Seeded random used on obfuscatedCoordinatesImpl

CHANGELOG.md

@@ -12,6 +12,10 @@ way to update this template, but currently, we follow a pattern:
 
 ---
 
+## Upcoming version
+* [change] Use seeded random for client side coordinate obfuscation
+  [#874](https://github.com/sharetribe/flex-template-web/pull/874)
+
 ## v1.2.2
 * [change] Change static map to dynamic map when clicked.
   [#871](https://github.com/sharetribe/flex-template-web/pull/871)

package.json

@@ -47,6 +47,7 @@
     "redux": "^4.0.0",
     "redux-thunk": "^2.2.0",
     "sanitize.css": "^5.0.0",
+    "seedrandom": "^2.4.3",
     "sharetribe-scripts": "1.1.2",
     "sharetribe-sdk": "https://github.com/sharetribe/sharetribe-sdk-js.git#b7ffe0fe0a5bdb0a1471e2ff36cdd25b997fb39b",
     "smoothscroll-polyfill": "^0.4.0",

src/util/maps.js

@@ -1,19 +1,36 @@
 import memoize from 'lodash/memoize';
+import seedrandom from 'seedrandom';
 import { types as sdkTypes } from './sdkLoader';
 import config from '../config';
 
 const { LatLng } = sdkTypes;
 
-const obfuscatedCoordinatesImpl = latlng => {
+/**
+ * This obfuscatedCoordinatesImpl function is a temporary solution for the coordinate obfuscation.
+ * In the future, improved version needs to have protectedData working and
+ * available in accepted transaction.
+ */
+const obfuscatedCoordinatesImpl = (latlng, cacheKey) => {
   const { lat, lng } = latlng;
   const offset = config.coordinates.coordinateOffset;
 
   // https://gis.stackexchange.com/questions/25877/generating-random-locations-nearby
   const r = offset / 111300;
   const y0 = lat;
   const x0 = lng;
-  const u = Math.random();
-  const v = Math.random();
+
+  // Two seeded random numbers to be used to calculate new location
+  // We need seeded so that the static map URL doesn't change between requests
+  // (i.e. URL is cacheable)
+  const u = cacheKey ? seedrandom(cacheKey)() : Math.random();
+  const v = cacheKey
+    ? seedrandom(
+        cacheKey
+          .split('')
+          .reverse()
+          .join('')
+      )()
+    : Math.random();
   const w = r * Math.sqrt(u);
   const t = 2 * Math.PI * v;
   const x = w * Math.cos(t);

yarn.lock

@@ -7406,6 +7406,10 @@ scriptjs@^2.5.8:
   version "2.5.8"
   resolved "https://registry.yarnpkg.com/scriptjs/-/scriptjs-2.5.8.tgz#d0c43955c2e6bad33b6e4edf7b53b8965aa7ca5f"
 
+seedrandom@^2.4.3:
+  version "2.4.3"
+  resolved "https://registry.yarnpkg.com/seedrandom/-/seedrandom-2.4.3.tgz#2438504dad33917314bff18ac4d794f16d6aaecc"
+
 select-hose@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/select-hose/-/select-hose-2.0.0.tgz#625d8658f865af43ec962bfc376a37359a4994ca"