Posts Categorized: Goodies to go

A while ago I released IDBWrapper. If you don’t know it, it’s a wrapper for IndexedDB, a current specification (in draft status) for an in-browser object store. It’s implemented in Firefox and Chrome, and somehow (as a plugin of sorts) also in IE, but, honestly, I don’t care about that too much.

It is mainly meant to serve as an example implementation, so that you could have a look at the code and see how to work with IndexedDB. But I figured that people are also interested in actually using it, as it abstracts away many of the tedious internals of IndexedDB (like transactions) – and it is perfectly fine to use IDBWrapper for all non-overly-complex scenarios.

So here’s a tutorial about how to work with IDBWrapper and add a little background info about IndexedDB internals every now and then, instead of writing Yet-Another-Super-Technical-IDB-Blargh. Part one will cover some info about what IndexedDB is, getting IDBWrapper to run and how to read and write data to a store. Part two will be about querying the store.

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[Note: This is a cross-post. I also published this on the uxebu blog.]

As of version 1.6, dojo comes with the new Dojo Object Store API. This is an awesome thing, as it greatly simplifies the work with data stores in Dojo. Everybody who had to do with the traditional dojo.data API felt it was overly complex and hard to use – this has finally changed now. There are also wrappers from and to the old and new APIs, so that you can do stuff like using your traditional data-aware widgets with a new Object Store. And the goodness doesn’t end here; but more on this later. If you haven’t done so yet, you might want to read the excellent post on the new Dojo Object Stores by Kris Zyp where he explains all the awesomeness he created.

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A couple of days ago, Nicholas Zakas wrote an article about secure client side storage. I think the scenario he mentioned (working from a cyber cafe) is not unsafe by nature, and could be well handled by an application. Nonetheless, client side storage such as localStorage still is subject to DNS spoofing attacks (which is the main security issue, I think). To handle this, one needs to encrypt the keys and values in the store.

So here you go: dojox.storage.encrypted, a Blowfish encrypted storage. It sits on top of dojox.storage, and you get all the dojo storage manager goodness, mainly the automatic selection of the best storage provider available. It exposes the complete API that dojox.storage does. If an attacker gains access to the storage area, he can still nuke the storage, but the data found within will be useless.
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Last year, Brian Leroux‘s Lawnchair caught my interest – it is an easy and fast way to access local persistant local storage.

Uh, persistant local storage?

Ahm, yeah, in case you don’t know, that means a client-side storage, be it in a browser, or in an Air app. It’s not very popular, but that concept has been around for a long time. So why local? There are two major reasons for it: First, we need this for apps and tools that work offline – and apps and tools that work online but need an offline backup and sync later. Kris Zyp wrote a post about the JsonRestStore and OfflineRest back in 2008, he goes a little into detail there. Secondly, we need it for apps and tools that rely on persistence for other reasons, no matter if online or offline – like it happended to me. When I ran into Lawnchair, I had the idea to build a tool that was monitoring CSS selector usage on websites and apps (you know how you sometimes lose control about CSS selectors in webapps…). To achieve this, I needed to store data locally, and persistent.
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In the series “convenience wrappers for small tasks that increase code readability”, today contains() is starring. Having a contains() method could also serve another purpose: to maybe prevent people from using match() to find out if a string contains a given substring (what is still proposed in some JS tutorials out there…). So, I want the contains() method to also have a switch to work case-insensitive.

Besides indexOf(), there are some other ways to achieve this, so – let’s have a competition and find out who’s the fastest!
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Most cases where you find String.substr() in the wild are to check if a given string begins with a certain other string. Be it checking for a prefix or sorting out zipcodes that begin with certain numbers. And because code readability is a good thing (really, it is important), it would be nice to have a String.beginsWith() method. Or, because of dojo love, a dojo.string.beginsWith() method.

Consider the following code:

var nearbyZipcodes = dojo.filter(givenZipcodes,function(zipcode){
    return dojo.string.beginsWith(zipcode,'12');
});

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Though many people would disagree, I for one like to use fieldsets to structure complex forms. Even better do I like fieldsets that are collapsible.

As there is no such fieldset with dojo, I decided to write my own widget. While doing so, I learnt an interesting lesson…

First, I wrote it pretty simple, inheriting the widget from dijit._Widget and dijit._Templated. It had a toggle button next to its legend, which could be clicked. The toggle was a simple display none/block change.
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Or: Still ending the ga.js wait…

It has become quiet here the last weeks – due to an awesome trip to Italy. Returning home, I decided to put Google Analytics on this page.

As I always hate waiting for the ga.js to load while visiting websites, I wanted a mechanism to delay the load of it. Why this is a good idea has been discussed often enough elsewhere, so we take it as fact. Peter Higgins once wrote such a wrapper for dojo, and as of dojo 1.3, it’s officially included in dojox (see Alex Russel’s post). But this WordPress theme runs jQuery, and I didn’t want to have two frameworks in one website – so I searched for something that did the job for jQuery.
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