1 files changed, 58 insertions, 0 deletions
diff --git a/app/assets/javascripts/lib/utils/csrf.js b/app/assets/javascripts/lib/utils/csrf.js
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+++ b/app/assets/javascripts/lib/utils/csrf.js
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+/*
+This module provides easy access to the CSRF token and caches
+it for re-use. It also exposes some values commonly used in relation
+to the CSRF token (header key and headers object).
+
+If you need to refresh the csrfToken for some reason, just call `init` and
+then use the accessors as you would normally.
+
+If you need to compose a headers object, use the spread operator:
+
+```
+  headers: {
+    ...csrf.headers,
+    someOtherHeader: '12345',
+  }
+```
+
+see also http://guides.rubyonrails.org/security.html#cross-site-request-forgery-csrf
+and https://github.com/rails/jquery-rails/blob/v4.3.1/vendor/assets/javascripts/jquery_ujs.js#L59-L62
+ */
+
+const csrf = {
+  init() {
+    const tokenEl = document.querySelector('meta[name=csrf-token]');
+
+    if (tokenEl !== null) {
+      this.csrfToken = tokenEl.getAttribute('content');
+    } else {
+      this.csrfToken = null;
+    }
+  },
+
+  get token() {
+    return this.csrfToken;
+  },
+
+  get headerKey() {
+    return 'X-CSRF-Token';
+  },
+
+  get headers() {
+    if (this.csrfToken !== null) {
+      return {
+        [this.headerKey]: this.token,
+      };
+    }
+    return {};
+  },
+};
+
+csrf.init();
+
+// use our cached token for any $.rails-generated AJAX requests
+if ($.rails) {
+  $.rails.csrfToken = () => csrf.token;
+}
+
+export default csrf;