feat(backend): enable cors

.gitignore

@@ -15,6 +15,7 @@ node_modules
 /backend/dist/
 /backend/-
 /backend/.rebel_readline_history
+/frontend/.rebel_readline_history
 /frontend/.cpcache
 /frontend/npm-debug.log
 /frontend/target/

backend/src/uxbox/http/cors.clj

@@ -0,0 +1,78 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+;;
+;; Copyright (c) 2019 Andrey Antukh <niwi@niwi.nz>
+
+(ns uxbox.http.cors
+  "CORS Implementation for Async Ring"
+  (:require [cuerdas.core :as str]))
+
+(defn- allow-origin?
+  [value {:keys [origin]}]
+  (prn "allow-origin?" value origin)
+  (cond
+    (nil? value) value
+    (= origin "*") origin
+    (set? origin) (origin value)
+    (= origin value) origin))
+
+(defn- normalize-headers
+  [headers]
+  (->> (map (comp str/lower name) headers)
+       (str/join ",")))
+
+(defn- normalize-methods
+  [methods]
+  (->> (map (comp str/upper name) methods)
+       (str/join ",")))
+
+(defn- get-preflight-headers
+  [origin {:keys [allow-methods allow-headers max-age allow-credentials]
+           :or {allow-methods #{:get :post :put :delete}}
+           :as opts}]
+  (when-let [origin (allow-origin? origin opts)]
+    (cond-> {"access-control-allow-origin" origin
+             "access-control-allow-methods" (normalize-methods allow-methods)}
+      allow-credentials
+      (assoc "access-control-allow-credentials" "true")
+
+      max-age
+      (assoc "access-control-max-age" (str max-age))
+
+      allow-headers
+      (assoc "access-control-allow-headers" (normalize-headers allow-headers)))))
+
+(defn get-response-headers
+  [origin {:keys [allow-headers expose-headers allow-credentials] :as opts}]
+  (when-let [origin (allow-origin? origin opts)]
+    (cond-> {"access-control-allow-origin" origin}
+      allow-credentials
+      (assoc "access-control-allow-credentials" "true")
+
+      allow-headers
+      (assoc "access-control-allow-headers" (normalize-headers allow-headers))
+
+      expose-headers
+      (assoc "access-control-expose-headers" (normalize-headers expose-headers)))))
+
+(defn- cors-preflight?
+  [{:keys [request-method headers] :as req}]
+  (and (= request-method :options)
+       (contains? headers "origin")
+       (contains? headers "access-control-request-method")))
+
+(defn wrap-cors
+  "A chain handler that handles cors related headers."
+  [handler opts]
+  (fn [{:keys [headers] :as req} respond raise]
+    (let [origin (get headers "origin")]
+      (if (cors-preflight? req)
+        (let [headers (get-preflight-headers origin opts)]
+          (respond {:status 200 :headers headers :body ""}))
+        (let [headers (get-response-headers origin opts)
+              wrapped-respond (fn [response] (respond (update response :headers merge headers)))]
+          (handler req wrapped-respond raise))))))
+
+
+

backend/src/uxbox/http/middleware.clj

@@ -19,6 +19,7 @@
             [ring.middleware.session :refer [wrap-session]]
             [ring.middleware.session.cookie :refer [cookie-store]]
             [ring.middleware.multipart-params :refer [wrap-multipart-params]]
+            [uxbox.http.cors :refer [wrap-cors]]
             [uxbox.http.errors :as errors]
             [uxbox.http.response :as rsp]
             [uxbox.util.data :refer [normalize-attrs]]
@@ -107,10 +108,22 @@
 (def ^:private session-middleware
   (let [options {:store (cookie-store {:key "a 16-byte secret"})
                  :cookie-name "session"
-                 :cookie-attrs {:same-site :lax :http-only true}}]
+                 :cookie-attrs {:same-site :lax
+                                :http-only false}}]
     {:name ::session-middleware
      :wrap #(wrap-session % options)}))
 
+(def cors-conf
+  {:origin #{"http://127.0.0.1:3449"}
+   :max-age 3600
+   :allow-credentials true
+   :allow-methods #{:post :put :get :delete}
+   :allow-headers #{:x-requested-with :content-type :cookie}})
+
+(def ^:private cors-middleware
+  {:name ::cors-middleware
+   :wrap #(wrap-cors % cors-conf)})
+
 ;; (def ^:private cors-middleware
 ;;   {:name ::cors-middleware
 ;;    :wrap #(wrap-cors %
@@ -152,7 +165,8 @@
                 (respond (rsp/forbidden nil))))))})
 
 (def middleware
-  [session-middleware
+  [cors-middleware
+   session-middleware
    parameters/parameters-middleware
    muuntaja/format-negotiate-middleware
    ;; encoding response body