From a0fd9b1f8c333aa9987442bbce27e1cd04a03b01 Mon Sep 17 00:00:00 2001
From: gered <gered@blarg.ca>
Date: Sat, 27 Dec 2014 18:10:32 -0500
Subject: [PATCH] add support for automatically including anti-forgery tokens
 in POST reqs

---
 project.clj                                   |  3 ++-
 .../clj_browserchannel_messaging/server.clj   |  9 ++++----
 .../clj_browserchannel_messaging/client.cljs  | 22 ++++++++++++++++---
 3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/project.clj b/project.clj
index 2edf086..e10347e 100644
--- a/project.clj
+++ b/project.clj
@@ -7,7 +7,8 @@
   :dependencies [[org.clojure/clojure "1.6.0"]
                  [org.clojure/clojurescript "0.0-2371" :scope "provided"]
                  [org.clojure/core.async "0.1.346.0-17112a-alpha"]
-                 [net.thegeez/clj-browserchannel-server "0.1.0"]]
+                 [net.thegeez/clj-browserchannel-server "0.1.0"]
+                 [prismatic/dommy "1.0.0"]]
 
   :source-paths   ["target/generated/src/clj" "src/clj"]
   :resource-paths ["target/generated/src/cljs" "src/cljs"]
diff --git a/src/clj/clj_browserchannel_messaging/server.clj b/src/clj/clj_browserchannel_messaging/server.clj
index 6ae994d..0674186 100644
--- a/src/clj/clj_browserchannel_messaging/server.clj
+++ b/src/clj/clj_browserchannel_messaging/server.clj
@@ -1,9 +1,10 @@
 (ns clj-browserchannel-messaging.server
   (:refer-clojure :exclude [send])
-  (:require [clojure.edn :as edn]
-            [clojure.core.async :refer [chan pub sub <! put! go-loop]]
-            [net.thegeez.browserchannel :as browserchannel]
-            [clj-browserchannel-messaging.utils :refer [run-middleware get-handlers encode-message decode-message]]))
+  (:require
+    [clojure.edn :as edn]
+    [clojure.core.async :refer [chan pub sub <! put! go-loop]]
+    [net.thegeez.browserchannel :as browserchannel]
+    [clj-browserchannel-messaging.utils :refer [run-middleware get-handlers encode-message decode-message]]))
 
 (defonce ^:private handler-middleware (atom nil))
 
diff --git a/src/cljs/clj_browserchannel_messaging/client.cljs b/src/cljs/clj_browserchannel_messaging/client.cljs
index b5be427..215858f 100644
--- a/src/cljs/clj_browserchannel_messaging/client.cljs
+++ b/src/cljs/clj_browserchannel_messaging/client.cljs
@@ -1,10 +1,12 @@
 (ns clj-browserchannel-messaging.client
-  (:require-macros [cljs.core.async.macros :refer [go-loop]])
+  (:require-macros
+    [cljs.core.async.macros :refer [go-loop]])
   (:require
     [cljs.reader :as reader]
     [cljs.core.async :refer [pub sub chan <! put!]]
     goog.net.BrowserChannel
     [goog.events :as events]
+    [dommy.core :refer-macros [sel1]]
     [clj-browserchannel-messaging.utils :refer [run-middleware get-handlers encode-message decode-message]]))
 
 (defonce ^:private handler-middleware (atom nil))
@@ -105,6 +107,9 @@
      :on-receive (get-handlers middleware :on-receive)
      :on-send    (get-handlers middleware :on-send)}))
 
+(defn- get-anti-forgery-token []
+  (.-content (sel1 "meta[name='anti-forgery-token']")))
+
 (defn init!
   "Sets up browserchannel for use, creating a handler with the specified
    properties. this function should be called once on page load.
@@ -160,9 +165,18 @@
    receives 1 argument: the message that was received. note that this event is
    only raised for messages which can be decoded by decode-message. also note
    that this event is raised for all messages received, regardless of any
-   listeners created via message-handler."
+   listeners created via message-handler.
+
+   CSRF Anti-Forgery Tokens
+
+   If the page contains a <meta> tag with a name of 'anti-forgery-token',
+   the value of this meta tag will be automatically included under the
+   X-CSRF-Token HTTP header on all BrowserChannel POST requests to work with
+   any CSRF protection your web app uses (e.g. Ring's wrap-anti-forgery
+   middleware)."
   [& {:keys [base middleware]}]
-  (let [base (or base "/browserchannel")]
+  (let [base               (or base "/browserchannel")
+        anti-forgery-token (get-anti-forgery-token)]
     (register-middleware! middleware)
     (events/listen
       js/window "unload"
@@ -173,6 +187,8 @@
     ; this seems to help prevent premature session timeouts from occuring (vs the default of 3)
     (set! goog.net.BrowserChannel/BACK_CHANNEL_MAX_RETRIES 20)
     (.setHandler browser-channel (->handler))
+    (if anti-forgery-token
+      (.setExtraHeaders browser-channel (js-obj "X-CSRF-Token" anti-forgery-token)))
     (.connect browser-channel
               (str base "/test")
               (str base "/bind"))))