Implement reCAPTCHA for abuse prevention (#311)

* Implement reCAPTCHA for abuse prevention

* Update the README

Dockerfile

@@ -10,4 +10,4 @@ RUN npm install --unsafe-perm
 
 EXPOSE 3000
 
-CMD ./bin/slackin --coc "$SLACK_COC" --channels "$SLACK_CHANNELS" --port $PORT $SLACK_SUBDOMAIN $SLACK_API_TOKEN
+CMD ./bin/slackin --coc "$SLACK_COC" --channels "$SLACK_CHANNELS" --port $PORT $SLACK_SUBDOMAIN $SLACK_API_TOKEN $GOOGLE_CAPTCHA_SECRET $GOOGLE_CAPTCHA_SITEKEY

Procfile

@@ -1 +1 @@
-web: bin/slackin --coc "$SLACK_COC" --channels "$SLACK_CHANNELS" --port $PORT $SLACK_SUBDOMAIN $SLACK_API_TOKEN
+web: bin/slackin --coc "$SLACK_COC" --channels "$SLACK_CHANNELS" --port $PORT $SLACK_SUBDOMAIN $SLACK_API_TOKEN $GOOGLE_CAPTCHA_SECRET $GOOGLE_CAPTCHA_SITEKEY

README.md

@@ -5,6 +5,7 @@
 - A landing page you can point users to fill in their emails and receive an invite (`https://slack.yourdomain.com`)
 - An `<iframe>` badge to embed on any website that shows connected users in *realtime* with socket.io.
 - A SVG badge that works well from static mediums (like GitHub README pages)
+- Abuse prevention via [Google reCAPTCHA](https://www.google.com/recaptcha/intro/)
 
 Check out the [Demo](https://slackin.now.sh/) or read more about the [motivations and history](http://rauchg.com/slackin) behind Slackin.
 
@@ -13,7 +14,11 @@ Check out the [Demo](https://slackin.now.sh/) or read more about the [motivation
 Set up [Now](https://zeit.co/now) on your device and run this command:
 
 ```bash
-$ now -e SLACK_API_TOKEN="<token>" -e SLACK_SUBDOMAIN="<team-name>" now-examples/slackin
+$ now -e SLACK_API_TOKEN="<token>" \
+      -e SLACK_SUBDOMAIN="<team-name>" \
+      -e GOOGLE_CAPTCHA_SECRET="<secret>" \
+      -e GOOGLE_CAPTCHA_SITEKEY="<sitekey>" \
+      now-examples/slackin
 ```
 
 Other platforms:
@@ -35,6 +40,9 @@ times 5. If you are not getting invite emails, this might be the reason.
 Workaround: sign up for a free org, and set up Slackin to point to it
 (all channels will be visible).
 
+Here is where to [generate a secret and
+sitekey](https://www.google.com/recaptcha/admin) for Google reCAPTCHA.
+
 ### Badges
 
 #### Realtime ([demo](https://cldup.com/IaiPnDEAA6.gif))

app.json

@@ -13,6 +13,14 @@
       "description": "A Slack API token (find it on https://api.slack.com/web)",
       "required": true
     },
+    "GOOGLE_CAPTCHA_SECRET": {
+      "description": "Google captcha secret key",
+      "required": true
+    },
+    "GOOGLE_CAPTCHA_SITEKEY": {
+      "description": "Google captcha site key",
+      "required": true
+    },
     "SLACK_COC": {
       "description": "A URL to a Code of Conduct people must agree on before joining.",
       "required": false

bin/slackin

@@ -17,24 +17,31 @@ args
   .option(['?', 'help'], 'Show the usage information')
 
 var flags = args.parse(process.argv, {
-  value: '<team-id> <api-token>',
+  value: '<team-id> <api-token> <google-captcha-secret> <google-captcha-sitekey>',
   help: false
 })
 
 var org = args.sub[0] || process.env.SLACK_SUBDOMAIN
 var token = args.sub[1] || process.env.SLACK_API_TOKEN
 var emails = process.env.EMAIL_SLACK_LIST || ''
 
+var gcaptcha_secret = args.sub[2] || process.env.GOOGLE_CAPTCHA_SECRET
+var gcaptcha_sitekey = args.sub[3] || process.env.GOOGLE_CAPTCHA_SITEKEY
+
+
+
 if (flags.help) {
   args.showHelp()
 }
 
-if (!org || !token) {
+if (!org || !token || !gcaptcha_sitekey || !gcaptcha_secret) {
   args.showHelp()
 } else {
   flags.org = org
   flags.token = token
   flags.emails = emails
+  flags.gcaptcha_secret = gcaptcha_secret
+  flags.gcaptcha_sitekey = gcaptcha_sitekey
 }
 
 var port = flags.port

lib/assets/client.js

@@ -19,7 +19,8 @@ body.addEventListener('submit', function (ev){
   button.disabled = true
   button.className = ''
   button.innerHTML = 'Please Wait'
-  invite(channel ? channel.value : null, coc && coc.checked ? 1 : 0, email.value, function (err, msg){
+  var gcaptcha_response = form.elements['g-recaptcha-response']
+  invite(channel ? channel.value : null, coc && coc.checked ? 1 : 0, email.value, gcaptcha_response.value, function (err, msg){
     if (err) {
       button.removeAttribute('disabled')
       button.className = 'error'
@@ -31,10 +32,11 @@ body.addEventListener('submit', function (ev){
   })
 })
 
-function invite (channel, coc, email, fn){
+function invite (channel, coc, email, gcaptcha_response_value, fn){
   request
   .post(data.path + 'invite')
   .send({
+    "g-recaptcha-response": gcaptcha_response_value,
     coc: coc,
     channel: channel,
     email: email

lib/index.js

@@ -9,6 +9,7 @@ import { Server as http } from 'http'
 import remail from 'email-regex'
 import dom from 'vd'
 import cors from 'cors'
+import request from 'superagent';
 
 // our code
 import Slack from './slack'
@@ -22,6 +23,8 @@ export default function slackin ({
   token,
   interval = 5000, // jshint ignore:line
   org,
+  gcaptcha_secret,
+  gcaptcha_sitekey,
   css,
   coc,
   cors: useCors = false,
@@ -33,6 +36,8 @@ export default function slackin ({
   // must haves
   if (!token) throw new Error('Must provide a `token`.')
   if (!org) throw new Error('Must provide an `org`.')
+  if (!gcaptcha_secret) throw new Error('Must provide a `gcaptcha_secret`.')
+  if (!gcaptcha_sitekey) throw new Error('Must provide an `gcaptcha_sitekey`.')
 
   if (channels) {
     // convert to an array
@@ -84,11 +89,12 @@ export default function slackin ({
         dom('title',
           'Join ', name, ' on Slack!'
         ),
+        dom("script src=https://www.google.com/recaptcha/api.js"),
         dom('meta name=viewport content="width=device-width,initial-scale=1.0,minimum-scale=1.0,user-scalable=no"'),
         dom('link rel="shortcut icon" href=https://slack.global.ssl.fastly.net/272a/img/icons/favicon-32.png'),
         css && dom('link rel=stylesheet', { href: css })
       ),
-      splash({ coc, path, css, name, org, logo, channels, active, total })
+      splash({ coc, path, css, name, org, logo, channels, active, total, gcaptcha_sitekey})
     )
     res.type('html')
     res.send(page.toHTML())
@@ -130,13 +136,20 @@ export default function slackin ({
     }
 
     let email = req.body.email
+    let captcha_response = req.body['g-recaptcha-response'];
 
     if (!email) {
       return res
       .status(400)
       .json({ msg: 'No email provided' })
     }
 
+    if(captcha_response == undefined || !captcha_response.length){
+      return res
+      .status(400)
+      .send({ msg: 'Invalid captcha' });
+    }
+
     if (!remail().test(email)) {
       return res
       .status(400)
@@ -156,23 +169,67 @@ export default function slackin ({
       .json({ msg: 'Agreement to CoC is mandatory' })
     }
 
-    invite({ token, org, email, channel: chanId }, err => {
-      if (err) {
-        if (err.message === `Sending you to Slack...`) {
-          return res
-          .status(303)
-          .json({ msg: err.message, redirectUrl: `https://${org}.slack.com` })
-        }
+    /////////////////////////////////////////////////////////////////////////
+
 
+    const captcha_data = {
+      secret: gcaptcha_secret,
+      response: captcha_response,
+      remoteip: req.connection.remoteAddress
+    }
+
+
+    const captcha_callback = (err, resp) => {
+
+      if (err) {
         return res
         .status(400)
-        .json({ msg: err.message })
+        .send({ msg: err });
+
+      }else{
+
+        if(resp.body.success){
+
+          let chanId = slack.channel ? slack.channel.id : null;
+
+          invite({ token, org, email, channel: chanId }, err => {
+            if (err) {
+              if (err.message === `Sending you to Slack...`) {
+                return res
+                .status(303)
+                .json({ msg: err.message, redirectUrl: `https://${org}.slack.com` })
+              }
+
+              return res
+              .status(400)
+              .json({ msg: err.message })
+            }
+
+            res
+            .status(200)
+            .json({ msg: 'WOOT. Check your email!' })
+          });
+
+        }else{
+
+          if (err) {
+            return res
+            .status(400)
+            .send({ msg: "Captcha check failed" });
+          }
+        }
+
       }
 
-      res
-      .status(200)
-      .json({ msg: 'WOOT. Check your email!' })
-    })
+    }
+
+
+    request.post('https://www.google.com/recaptcha/api/siteverify')
+    .type('form')
+    .send(captcha_data)
+    .end(captcha_callback);
+
+
   })
 
   // iframe

lib/splash.js

@@ -1,6 +1,6 @@
 import dom from 'vd'
 
-export default function splash ({ path, name, org, coc, logo, active, total, channels, large, iframe }){
+export default function splash ({ path, name, org, coc, logo, active, total, channels, large, iframe, gcaptcha_sitekey }){
   let div = dom('.splash',
     !iframe && dom('.logos',
       logo && dom('.logo.org'),
@@ -34,6 +34,8 @@ export default function splash ({ path, name, org, coc, logo, active, total, cha
       ),
       dom('input.form-item type=email name=email placeholder=you@yourdomain.com '
         + (!iframe ? 'autofocus' : '')),
+      dom('br'),
+      dom(`div class="g-recaptcha" data-sitekey="${gcaptcha_sitekey}"`),
       coc && dom('.coc',
         dom('label',
           dom('input type=checkbox name=coc value=1'),