giftwrap.js

A simple tool for reading and writing Javascript objects to a user's filesystem using the FileSystem API and JSON.

Basic Use

GiftWrap is great for wrapping up your objects and handing them over to the local filesystem. Because the FileSystem API is asynchronous, reading and writing is asynchronous.

To start out with, create a new present:

new GW.Present({onReady: function(myPresent) {console.log("Ready to go!");}});

You can pass plenty of parameters to the constructor to specify exactly how you want the present to work. Remember, the GiftWrap library uses one file per json object.

new GW.Present({
  size: 1024*1024*3, // Request 3MB from filesystem
  fileName: "legLamp.json", // Use the file "legLamp.json"
  persistent: false, // Use temporary storage
  errorCallback: function(e) { console.log("Ruh-roh!"); }, // Specify an action if there's an error
  onReady: function(myPresent) { console.log("Let's get going!"); } // What to do once permission granted
});

Usually you'll want to start using your present in the onReady function. Here, we write an object to the file once the object has permission to use the filesystem.

myReady = function(myPresent) {
  var forWriting = {a: "appless", b: "bananas", c: "cucumbers"}
  myPresent.writeObject(forWriting, function() {
    console.log("Successfully saved object!");
  });
};

Alternatively, if you've already written an object to the filesystem, you could read it out like this:

myPresent.readObject(function() {
  var readObject = myPresent.getObject();
  console.log("Object read!");
  console.log(readObject);
});

And that's pretty much it. You're good to go!

FileSystem Lock

One last thing - gitwrap.js implements locking functionality that is not included in the FileSystem API. Specifically, giftwrap.js will prevent concurrent read/writes from occuring in the same file. This means you'll never have to worry about pesky race conditions or concurrent access problems while using giftwrap.js.

Collaborators

GiftWrap was part of the work Jonathan Balsano did for a project in UI Design.