frontend: display an error when access to localStorage is blocked

frontend/src/app/contribute.cljs

@@ -4,7 +4,10 @@
    ["html-entities" :as html-entities]
    [app.helpers :refer
     [current-path
-     remove-trailing-slash]]
+     remove-trailing-slash
+     local-storage-enabled
+     local-storage-get
+     local-storage-error]]
    [app.three-column-layout.core :refer
     [three-column-layout
      instructions-item
@@ -75,11 +78,15 @@
                    (set-atoms data)))))))
 
 (defn fetch-logs-upload []
-  (let [data {:build_id_title "Upload"
-              :logs [{:name (.getItem js/localStorage "name")
-                      :content (.getItem js/localStorage "content")}]}]
-
-    (set-atoms data)))
+  (if (local-storage-enabled)
+    (let [data {:build_id_title "Upload"
+                :logs [{:name (.getItem js/localStorage "name")
+                        :content (.getItem js/localStorage "content")}]}]
+      (set-atoms data))
+    (do
+      (reset! status "error")
+      (reset! error-title (:title (local-storage-error)))
+      (reset! error-description (:description (local-storage-error))))))
 
 (defn init-data []
   (if (= (remove-trailing-slash (current-path))  "/contribute/upload")
@@ -169,7 +176,7 @@
     [:input {:type "text"
              :class "form-control"
              :placeholder "Optional - Your FAS username"
-             :value (or @fas (.getItem js/localStorage "fas"))
+             :value (or @fas (local-storage-get "fas"))
              :on-change #(on-change-fas %)}]]
 
    [:label {:class "form-label"} "Interesting snippets:"]

frontend/src/app/contribute_events.cljs

@@ -5,7 +5,8 @@
    [app.helpers :refer
     [current-path
      remove-trailing-slash
-     previous-siblings]]
+     previous-siblings
+     local-storage-enabled]]
    [app.editor.core :refer [active-file]]
    [app.contribute-logic :refer
     [file-id
@@ -57,7 +58,7 @@
               :container_file @container}]
 
     ;; Remember the username, so we can prefill it the next time
-    (when @fas
+    (when (and @fas (local-storage-enabled))
       (.setItem js/localStorage "fas" @fas))
 
     (reset! status "submitting")

frontend/src/app/helpers.cljs

@@ -16,3 +16,18 @@
     (if-not sibling
       []
       (conj (previous-siblings sibling) sibling))))
+
+(defn local-storage-enabled []
+  (try
+    (.getItem js/localStorage "isenabled") true
+    (catch js/DOMException _ false)))
+
+(defn local-storage-get [name]
+  (when (local-storage-enabled)
+    (.getItem js/localStorage name)))
+
+(defn local-storage-error []
+  {:title "Local storage is blocked by the browser"
+   :description
+   (str "Log Detective needs to upload the file to a localStorage in order "
+        "to work properly. Please check your browser privacy settings.")})

frontend/src/app/homepage.cljs

@@ -5,8 +5,11 @@
             [cljs.core.match :refer-macros [match]]
             [app.homepage-validation :refer [validate]]
             [lambdaisland.fetch :as fetch]
+            [app.components.jumbotron :refer [render-error]]
             [app.helpers :refer
              [current-path
+              local-storage-enabled
+              local-storage-error
               remove-trailing-slash]]))
 
 (defn current-hash []
@@ -17,6 +20,7 @@
 (def backend-stats (r/atom nil))
 (def current-hash-atom (r/atom (or (current-hash) "#copr")))
 (def report-target (r/atom 1000))
+(def error (r/atom nil))
 
 (defn fetch-stats-backend []
   (let [url (remove-trailing-slash (str "/stats" (current-path)))]
@@ -44,11 +48,14 @@
 
 (defn on-submit-upload [event]
   (.preventDefault event)
-  (.setItem js/localStorage "name" (get @input-values :name))
-  (.setItem js/localStorage "content" (get @input-values :file))
-  (validate current-hash-atom input-values input-errors)
-  (when (empty? @input-errors)
-    (set! (.-href (.-location js/window)) "/contribute/upload")))
+  (if-not (local-storage-enabled)
+    (reset! error (local-storage-error))
+    (do
+      (.setItem js/localStorage "name" (get @input-values :name))
+      (.setItem js/localStorage "content" (get @input-values :file))
+      (validate current-hash-atom input-values input-errors)
+      (when (empty? @input-errors)
+        (set! (.-href (.-location js/window)) "/contribute/upload")))))
 
 (defn on-tab-click [href]
   (reset! current-hash-atom href)
@@ -230,7 +237,9 @@
     :else        (render-copr-card)))
 
 (defn homepage []
-  [:div {:class "card text-center"}
-   (render-stats)
-   (render-navigation)
-   (render-cards)])
+  (if @error
+    (render-error (:title @error) (:description @error))
+    [:div {:class "card text-center"}
+     (render-stats)
+     (render-navigation)
+     (render-cards)]))