BREAKING CHANGE: Support trust proxy and frameworks other than Express

.prettierignore

@@ -0,0 +1,2 @@
+package.json
+package-lock.json

README.md

@@ -1,23 +1,47 @@
 # cloudflare-middleware
 
-Restores request origin ip to `req.origin_ip`. Denies other requests.
+Allows requests which originate from Cloudflare. Restores request origin IP
+to `req.origin_ip`. Denies other requests.
 
 ## Usage
 
-```nodejs
-let app = express();
-app.use(require("cloudflare-middleware")());
+Using [Express trust proxy][trust proxy] (preferred):
+
+```js
+const { trustProxy } = require('cloudflare-middleware')
+
+const app = express()
+app.set('trust proxy', trustProxy)
+```
+
+Using Express middleware:
+
+```js
+const { middleware } = require('cloudflare-middleware')
+
+const app = express()
+app.use(middleware())
 ```
 
-This is a safer alternative to naively using `app.set("trust proxy");`, as this checks CloudFlare IP address ranges.
+Using with another framework:
+
+```js
+const http = require('http')
+const { isCloudflare } = require('cloudflare-middleware')
+
+http.createServer((req, res) => {
+  if (!isCloudflare(req.socket.remoteAddress)) {
+    response.end()
+  }
+
+  // Proceed with the response.
+  response.write('oh, you good')
+  response.end()
+})
+```
 
-This, however, has been deprecated in favor of the following:
+[trust proxy]: https://expressjs.com/en/guide/behind-proxies.html
 
-```nodejs
-const cloudflareIp = require('cloudflare-ip');
+## License
 
-app.set('trust proxy', ip => {
-  if(ip.startsWith('::ffff:'))
-    ip = ip.substr(7);
-  return ip == '127.0.0.1' || cloudflareIp(ip);
-});
+This project is licensed under the ISC license.

index.js

@@ -1,16 +1,32 @@
-const rangeCheck = require("range_check");
-const ranges = require("./ranges");
+const rangeCheck = require('range_check')
+const ranges = require('./ranges')
 
-module.exports = function(options){
-  return function(req, res, next) {
-    ip = req.ip;
-    if(ip.startsWith("::ffff:"))
-      ip = ip.substr(7);
-    if(rangeCheck.inRange(ip, ranges)){
-      req.origin_ip = req.headers['cf-connecting-ip'];
-      next();
-    }else{
-      res.end();
+function trimIp(ip) {
+  return ip.startsWith('::ffff:') ? ip.substr(7) : ip
+}
+
+function isCloudflare(ip) {
+  return rangeCheck.inRange(ip, ranges)
+}
+
+function trustProxy(ip) {
+  const trimmed = trimIp(ip)
+  return trimmed == '127.0.0.1' || isCloudflare(trimmed)
+}
+
+function middleware(options) {
+  return function (req, res, next) {
+    if (isCloudflare(trimIp(req.ip))) {
+      req.origin_ip = req.headers['cf-connecting-ip']
+      next()
+    } else {
+      res.end()
     }
-  };
-};
+  }
+}
+
+module.exports = {
+  isCloudflare,
+  middleware,
+  trustProxy,
+}

package.json

@@ -9,10 +9,20 @@
   "devDependencies": {
     "chai": "^4.2.0",
     "got": "^11.7.0",
-    "mocha": "^8.1.3"
+    "mocha": "^8.1.3",
+    "prettier": "^2.1.2"
   },
   "scripts": {
-    "test": "mocha ranges.integration.js"
+    "format": "prettier --check \"**/*.@(js|md|json)\"",
+    "format:fix": "prettier --write \"**/*.@(js|md|json)\"",
+    "mocha": "mocha ranges.integration.js",
+    "test": "npm run mocha && npm run format"
+  },
+  "prettier": {
+    "semi": false,
+    "singleQuote": true,
+    "bracketSpacing": true,
+    "arrowParens": "avoid"
   },
   "repository": {
     "type": "git",

ranges.integration.js

@@ -1,25 +1,25 @@
-const got = require("got");
-const { expect } = require("chai");
-const ranges = require("./ranges");
+const got = require('got')
+const { expect } = require('chai')
+const ranges = require('./ranges')
 
 async function collectAdvertisedRanges() {
-  let result = [];
+  let result = []
   for (const url of [
-    "https://www.cloudflare.com/ips-v4",
-    "https://www.cloudflare.com/ips-v6",
+    'https://www.cloudflare.com/ips-v4',
+    'https://www.cloudflare.com/ips-v6',
   ]) {
-    const { body } = await got(url);
-    const theseRanges = body.split("\n").filter(Boolean);
-    result = result.concat(theseRanges);
+    const { body } = await got(url)
+    const theseRanges = body.split('\n').filter(Boolean)
+    result = result.concat(theseRanges)
   }
-  return result;
+  return result
 }
 
-describe("Ranges", function () {
+describe('Ranges', function () {
   it("match Cloudflare's advertised ranges", async function () {
-    const advertisedRanges = await collectAdvertisedRanges();
+    const advertisedRanges = await collectAdvertisedRanges()
 
-    expect(ranges).to.have.members(advertisedRanges);
-    expect(advertisedRanges).to.have.members(ranges);
-  });
-});
+    expect(ranges).to.have.members(advertisedRanges)
+    expect(advertisedRanges).to.have.members(ranges)
+  })
+})

ranges.js

@@ -1,25 +1,25 @@
 module.exports = [
-// From https://www.cloudflare.com/ips-v4
-  "103.21.244.0/22",
-  "103.22.200.0/22",
-  "103.31.4.0/22",
-  "104.16.0.0/12",
-  "108.162.192.0/18",
-  "131.0.72.0/22",
-  "141.101.64.0/18",
-  "162.158.0.0/15",
-  "172.64.0.0/13",
-  "173.245.48.0/20",
-  "188.114.96.0/20",
-  "190.93.240.0/20",
-  "197.234.240.0/22",
-  "198.41.128.0/17",
-// From https://www.cloudflare.com/ips-v6
-  "2400:cb00::/32",
-  "2405:8100::/32",
-  "2405:b500::/32",
-  "2606:4700::/32",
-  "2803:f800::/32",
-  "2c0f:f248::/32",
-  "2a06:98c0::/29",
-];
+  // From https://www.cloudflare.com/ips-v4
+  '103.21.244.0/22',
+  '103.22.200.0/22',
+  '103.31.4.0/22',
+  '104.16.0.0/12',
+  '108.162.192.0/18',
+  '131.0.72.0/22',
+  '141.101.64.0/18',
+  '162.158.0.0/15',
+  '172.64.0.0/13',
+  '173.245.48.0/20',
+  '188.114.96.0/20',
+  '190.93.240.0/20',
+  '197.234.240.0/22',
+  '198.41.128.0/17',
+  // From https://www.cloudflare.com/ips-v6
+  '2400:cb00::/32',
+  '2405:8100::/32',
+  '2405:b500::/32',
+  '2606:4700::/32',
+  '2803:f800::/32',
+  '2c0f:f248::/32',
+  '2a06:98c0::/29',
+]

yarn.lock

@@ -851,6 +851,11 @@ picomatch@^2.0.4, picomatch@^2.2.1:
   resolved "https://registry.yarnpkg.com/picomatch/-/picomatch-2.2.2.tgz#21f333e9b6b8eaff02468f5146ea406d345f4dad"
   integrity sha512-q0M/9eZHzmr0AulXyPwNfZjtwZ/RBZlbN3K3CErVrk50T2ASYI7Bye0EvekFY3IP1Nt2DHu0re+V2ZHIpMkuWg==
 
+prettier@^2.1.2:
+  version "2.1.2"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-2.1.2.tgz#3050700dae2e4c8b67c4c3f666cdb8af405e1ce5"
+  integrity sha512-16c7K+x4qVlJg9rEbXl7HEGmQyZlG4R9AgP+oHKRMsMsuk8s+ATStlf1NpDqyBI1HpVyfjLOeMhH2LvuNvV5Vg==
+
 [email protected]:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/promise.allsettled/-/promise.allsettled-1.0.2.tgz#d66f78fbb600e83e863d893e98b3d4376a9c47c9"