implement html5 localStorage support for client-side cache

diff --git a/functions.js b/functions.js
index 2aa0dab4fded804dd5f6c06a110f1474e31fe9da..8b4945edcef63fe2df9c1c354c2612d18fdcfa5a 100644 (file)
--- a/functions.js
+++ b/functions.js
@@ -2184,3 +2184,10 @@ function backend_sanity_check_callback(transport) {
        } 
 }
 
+function has_local_storage() {
+       try {
+               return 'localStorage' in window && window['localStorage'] != null;
+       } catch (e) {
+               return false;
+       }
+}

diff --git a/tt-rss.js b/tt-rss.js
index 51c1d3c5f79e8ecc69fab3b6229b74823b43367a..6dd53c8b556ece49eb177a463172daf79287dd8e 100644 (file)
--- a/tt-rss.js
+++ b/tt-rss.js
@@ -421,6 +421,9 @@ function init_second_stage() {
 
                enable_offline_reading();
 
+               if (has_local_storage())
+                       localStorage.clear();
+
        } catch (e) {
                exception_error("init_second_stage", e);
        }

diff --git a/viewfeed.js b/viewfeed.js
index a6065ecb4b4c04bd427a8c7d3b5ff8a09d752e3c..e2b20779ea1730ae5839651756c21609d7c0fbf5 100644 (file)
--- a/viewfeed.js
+++ b/viewfeed.js
@@ -1696,13 +1696,19 @@ function cache_inject(id, article, param) {
                                        [id, article, param, ts]);                              
                        } else {
        
-                               var cache_obj = new Array();
+                               var cache_obj = {};
        
                                cache_obj["id"] = id;
                                cache_obj["data"] = article;
                                cache_obj["param"] = param;
-       
-                               article_cache.push(cache_obj);
+                               cache_obj["added"] = new Date();
+
+                               if (param) id = id + ":" + param;
+
+                               if (has_local_storage()) 
+                                       localStorage.setItem(id, JSON.stringify(cache_obj));
+                               else
+                                       article_cache.push(cache_obj);
                        }
        
                } else {
@@ -1728,9 +1734,22 @@ function cache_find(id) {
                return a;
 
        } else {
-               for (var i = 0; i < article_cache.length; i++) {
-                       if (article_cache[i]["id"] == id) {
-                               return article_cache[i]["data"];
+
+               if (has_local_storage()) {
+                       var cache_obj = localStorage.getItem(id);
+       
+                       if (cache_obj) {
+                               cache_obj = JSON.parse(cache_obj);
+
+                               if (cache_obj)
+                                       return cache_obj['data'];
+                       }
+
+               } else {
+                       for (var i = 0; i < article_cache.length; i++) {
+                               if (article_cache[i]["id"] == id) {
+                                       return article_cache[i]["data"];
+                               }
                        }
                }
        }
@@ -1753,9 +1772,22 @@ function cache_find_param(id, param) {
                return a;
 
        } else {
-               for (var i = 0; i < article_cache.length; i++) {
-                       if (article_cache[i]["id"] == id && article_cache[i]["param"] == param) {
-                               return article_cache[i]["data"];
+
+               if (has_local_storage()) {
+                       var cache_obj = localStorage.getItem(id + ":" + param);
+
+                       if (cache_obj) {
+                               cache_obj = JSON.parse(cache_obj);
+
+                               if (cache_obj)
+                                       return cache_obj['data'];
+                       }
+
+               } else {
+                       for (var i = 0; i < article_cache.length; i++) {
+                               if (article_cache[i]["id"] == id && article_cache[i]["param"] == param) {
+                                       return article_cache[i]["data"];
+                               }
                        }
                }
        }
@@ -1778,9 +1810,14 @@ function cache_check(id) {
                return a;
 
        } else {
-               for (var i = 0; i < article_cache.length; i++) {
-                       if (article_cache[i]["id"] == id) {
-                               return true;
+               if (has_local_storage) {
+                       if (localStorage.getItem(id))
+                                       return true;
+               } else {
+                       for (var i = 0; i < article_cache.length; i++) {
+                               if (article_cache[i]["id"] == id) {
+                                       return true;
+                               }
                        }
                }
        }
@@ -1803,9 +1840,15 @@ function cache_check_param(id, param) {
                return a;
 
        } else {
-               for (var i = 0; i < article_cache.length; i++) {
-                       if (article_cache[i]["id"] == id && article_cache[i]["param"] == param) {
-                               return true;
+
+               if (has_local_storage) {
+                       if (localStorage.getItem(id + ':' + param))
+                                       return true;
+               } else {
+                       for (var i = 0; i < article_cache.length; i++) {
+                               if (article_cache[i]["id"] == id && article_cache[i]["param"] == param) {
+                                       return true;
+                               }
                        }
                }
        }
@@ -1823,8 +1866,14 @@ function cache_expire() {
 
 
        } else {
-               while (article_cache.length > 25) {
-                       article_cache.shift();
+               if (has_local_storage()) {
+                       while (localStorage.length > 25) {
+                               localStorage.removeItem(localStorage.key(localStorage.length-1));
+                       }
+               } else {
+                       while (article_cache.length > 25) {
+                               article_cache.shift();
+                       }
                }
        }
 }
@@ -1841,15 +1890,25 @@ function cache_invalidate(id) {
                        return rs.rowsAffected != 0;
                } else {
 
-                       var i = 0
+                       if (has_local_storage()) {
+                               for (var i = 0; i < localStorage.length; i++) {
+                                       var key = localStorage.key(i);
 
-                       while (i < article_cache.length) {
-                               if (article_cache[i]["id"] == id) {
-                                       console.log("cache_invalidate: removed id " + id);
-                                       article_cache.splice(i, 1);
-                                       return true;
+                                       if (key == id || key.indexOf(id + ":") == 0)
+                                               localStorage.removeItem(key);
+
+                               }
+                       } else {
+                               var i = 0
+
+                               while (i < article_cache.length) {
+                                       if (article_cache[i]["id"] == id) {
+                                               console.log("cache_invalidate: removed id " + id);
+                                               article_cache.splice(i, 1);
+                                               return true;
+                                       }
+                                       i++;
                                }
-                               i++;
                        }
                }