Firefox擴展：存儲插件數據

Question

我正在構建一個允許用戶拖放東西的Firefox擴展。現在，如果用戶關閉應用程序或重新加載頁面，我想恢復他所做的最後一項活動。

Example : User moves a box from point X to Y. 
There can be many more boxes as well. 

現在，經過重新加載頁面或應用程序啓動時，如果用戶將插件，我要盒子的是Y.所以爲了此目的位置，我應該使用Firefox的偏好的事情或有任何其他更好的辦法做到這一點。

Answer 1

有人建議我通過Nickolay波諾馬廖夫，使用以下可以是一個很好的選擇：

• 註解服務
• 的SQLite數據庫

現在我打算使用數據庫用法。

Answer 2

我寫了一個Firefox擴展，用於從我的一位朋友開發的站點訪問書籤。在書籤服務關閉的情況下，我將書籤數據作爲JSON本地存儲在用戶的擴展配置文件目錄中的文本文件中。

我保存的書籤JSON功能是：

/** 
* Stores bookmarks JSON to local persistence asynchronously. 
* 
* @param bookmarksJson The JSON to store 
* @param fnSuccess The function to call upon success 
* @param fnError The function to call upon error 
*/ 
RyeboxChrome.saveBookmarkJson = function(bookmarksJson, fnSuccess, fnError) { 
    var cu = Components.utils; 
    cu.import("resource://gre/modules/NetUtil.jsm"); 
    cu.import("resource://gre/modules/FileUtils.jsm"); 

    var bookmarksJsonFile = RyeboxChrome.getOrCreateStorageDirectory(); 
    bookmarksJsonFile.append("bookmarks.txt"); 

    // You can also optionally pass a flags parameter here. It defaults to 
    // FileUtils.MODE_WRONLY | FileUtils.MODE_CREATE | FileUtils.MODE_TRUNCATE; 
    var ostream = FileUtils.openSafeFileOutputStream(bookmarksJsonFile); 

    var converter = Components.classes["@mozilla.org/intl/scriptableunicodeconverter"].createInstance(Components.interfaces.nsIScriptableUnicodeConverter); 
    converter.charset = "UTF-8"; 
    var istream = converter.convertToInputStream(bookmarksJson); 

    NetUtil.asyncCopy(istream, ostream, function(status) { 
     if (!Components.isSuccessCode(status) && typeof(fnError) === 'function') { 
      fnError(); 
     } else if (typeof(fnSuccess) === 'function') { 
      fnSuccess(); 
     } 
     return; 
    }); 
}; 

讀取數據的功能是：

/** 
* Reads bookmarks JSON from local persistence asynchronously. 
* 
* @param fnSuccess Function to call when successful. The bookmarks JSON will 
* be passed to this function. 
* 
* @param fnError Function to call upon failure. 
*/ 
RyeboxChrome.getBookmarksJson = function(fnSuccess, fnError) { 

    Components.utils.import("resource://gre/modules/NetUtil.jsm"); 

    var bookmarksJsonFile = RyeboxChrome.getOrCreateStorageDirectory(); 
    bookmarksJsonFile.append("bookmarks.txt"); 

    NetUtil.asyncFetch(bookmarksJsonFile, function(inputStream, status) { 
     if (!Components.isSuccessCode(status) && typeof(fnError) === 'function') { 
      fnError(); 
     } else if (typeof(fnSuccess) === 'function'){ 
      var data = NetUtil.readInputStreamToString(inputStream, inputStream.available()); 
      fnSuccess(data); 
     } 
    }); 
}; 

最後，我getOrCreateStorageDirectory功能是：

/** 
* Storage of data is done in a Ryebox directory within the user's profile 
* directory. 
*/ 
RyeboxChrome.getOrCreateStorageDirectory = function() { 

    var ci = Components.interfaces; 

    let directoryService = Components.classes["@mozilla.org/file/directory_service;1"].getService(ci.nsIProperties); 

    // Reference to the user's profile directory 
    let localDir = directoryService.get("ProfD", ci.nsIFile); 

    localDir.append("Ryebox"); 

    if (!localDir.exists() || !localDir.isDirectory()) { 
     localDir.create(ci.nsIFile.DIRECTORY_TYPE, 0774); 
    } 

    return localDir; 
};