Web Info & Tutorials

Ext JS 2.1 has been released. In this point release the featured changes are:

• Full REST support
• Added Ext.StatusBar Component and Samples
• Added Ext.Slider Component and Samples
• Added Example to demonstrate Remote Loading of Component Configs
• Added Grid Filtering Sample
• Added Layout Browser Sample
• Added Spotlight Sample

Even more importantly, the license has changed to a simple GPLv3 version compared to the Ext version, which some complained about. Kudos to Jack and the team for listening to the community and making this change.

Jon Brisbin is a Java programmer doing iPhone development, and decided to scratch his own itch for a better iPhone remote debugger, creating iPhoneDebug:

The iPhone Debug Consle is meant to give greater visibility and interactivity on your iPhone/iPod Touch while doing development. I grew frustrated having to go through the “include console.log statement then reload” method of debugging. I wanted something similar to Firebug’s fantastic console and debugger.

I grew frustrated with trying to debug my iPhone/iPod Touch apps because I had no interactivity with the page. I couldn’t interrogate variable values or CSS values unless I put in a console.log statement and reloaded the page. This is far from ideal.

In trying to find something that would fit my needs, I came across Joe Hewitt’s iPhone/Firebug integration, but I wanted something more robust and that worked without firebug and requiring “console.log” in the desktop browser.

I’m a Java programmer, so naturally I thought of using COMET and Jetty to pass messages between a desktop browser and the iPhone. A couple days later, I had a workable solution. It lets you log things in your mobile JavaScript to a desktop console, but the biggest plus for my situation is that I can send JavaScript to the iPhone to be executed there, with the results logged back to my desktop console. Just like in Firebug, I can call methods, retrieve CSS values, and all manner of debugging activities I’ve grown used to doing while building apps with Firebug. There is also rudimentary UP and DOWN arrow command retrieval on the prompt.

Here it is in action, getting commands from the console:

Jacob Seidelin went on a ( crazy :) ) mission to create a pure JavaScript video player that didn't use Flash:

My first thought was to read binary video files using a technique like the Andy Na posted about here, figuring that there must be some really simple to parse video formats around, but I soon changed directions and decided to make up a whole new video format. Enter.. JSONVid. Using a player like mplayer, it is easy to export all frames in a movie clip to individual jpeg files, and using whichever language you prefer it is also fairly trivial to collect these files, base64 encode the bunch of them and throw them all together in a nice JSON file (I used this PHP script).

The format uses good ole data: URLs, which are finally supported in IE with version 8:

Then he created the player:

First strategy was to create an Image object for each frame and render it on a canvas element using drawImage(). That worked fine and performance was nice (although Opera used a lot of CPU), but I figured I'd try just using a regular image tag and just change the src property to another data:uri each frame. The change was barely noticeably in Firefox and Safari and it ran a bit better in Opera, so I lost the canvas and stuck with plain old images.

Now, it seems that Firefox will eat up all the memory in the world if you keep throwing new data:uris at the same image tag, which led to another change, so for each frame a new Image object was created and saved for later and as the video played, the previous frame Image was replaced by the new Image object. That seemed to work, but introduced an annoying delay as all these Image objects were created before playing, so I ended up moving the Image creation to actual render cycle where it simply checks if the frame Image has already been created, and if not, creates it.

You can now get going with HTML such as:

There are a couple of tests to play with. It was also pointed out that maybe an animated gif/png would be a choice (without controls), and of course, Flash is still the best choice here, until we get video support in most browsers.

I have just posted an article on the new attack on the RDBMS on my personal blog. The post talks about the new thinking around data in the cloud, and on the Web. It first starts out by remembering that this isn't the first time the RDBMS has been attacked, and remembers the OODBMS attack, which didn't do too well. Then it gets into the cloud-y Web:

SQL is an enterprise victory that managed to make its way into the consumer Web and application space. A lot of people knew SQL, and it seemed obvious to have a LAMP stack or a Java / .NET stack backed by a RDBMS.

Is this really the right choice for Web applications? Why was Rails so successful? It was due to the productivity gain. How much of that is due to ActiveRecord vs. the other Action* pieces that make up Rails? I would argue a large percentage. Working with the database was actually a big pain in the tuches. ActiveRecord together with migrations helped a lot. It gave us a nice middle man between a full ORM and the SQL that we know and …. know.

What if the database piece didn’t need to be that painful? The source of the pain can be the paradigm shift between the various worlds, but also a huge part of it is scalability. When you have to scale your website, it can be fairly easy to make your application stateless, and then the bottleneck becomes the poor database. This is when you break out the master / slave relationships, think about partitioning of the application, and caching layers (Tangosol Coherence, memcached). Now you have to really think about an architecture ;)

Google had to do this thinking a long time ago, as they obviously have to scale their applications to a huge degree. Scaling the fairly read-only search operation is one thing, but as soon as you get to read-write operations you have a lot more of a head-ache. Scaling a MMORG astounds me. To be that real-time, and having the world constantly changing. Wow. At least there are the separations of locations (world X can be this cluster of machines).

Now we get to Bigtable, the engine that Google built to scale in the cloud. Amazon has their new SimpleDB, and there are others.

What these guys are all doing, is revisiting the database story. Maybe it is time to think about if a RDBMS is the no-brainer choice.

When Google App Engine launched, I thought there would be a lot of people saying “oh man, I just want MySQL instead of this new thing”. I barely heard that, and instead heard more thoughts along the lines of “It is great to be able to use the scalable database that Google uses internally.” In fact, when you start using it and see that it is schema-less, you get a bit of a relief. You can build your model, and even use an Expando to be highly dynamic on the data in the backend. You go along your way, iterating on your code and model and you don’t have to spend time working on up and down migration methods. Doesn’t that remind you a little of the OODBMS dreams? But this time it is fast and scalable!

Resting on the Couch

With the interest in Bigtable via App Engine pushing thought, we also have CouchDB pushing from the other end. The end that says, what would a RESTful approach to a database be?

Apache CouchDB is a distributed, fault-tolerant and schema-free document-oriented database accessible via a RESTful HTTP/JSON API.

JSON built in. JavaScript right there. A database built for the Web?

It is great to see new ideas and thought about the storage of data. The RDBMS isn’t going anywhere of course. There are still a ton of tools out there for it and legacy code, and we all know that:

Data stays where it lies.

It is much easier to implement a new application talking to the old datastore, than migrate the datastore itself. It is like taking out the foundation. Also, SQL is getting new life in places too.

SQLite

I recently saw an application that used GWT on the client, and JavaScript on the server, which reminded me of my comic above. I wonder if we may end up with another flip, having SQL being used in the client, and other systems like CouchDB, Bigtable, etc being used in the enterprise / on the server.

It is happening on the client. SQLite seems to be everywhere. Your operating system, phone, browser, applications, everywhere. I bet I have around 20 SQLite engines on my system right now, and growing. Why is this happening? Well, instead of coming up with your own data format, parser, and search engine, why not just use SQLite and be done. It is very faster, perfect for single user mode, so everyone is a winner.

So, SQL has a looooong future ahead of it, but it will be interesting to see how the RDBMS weathers the latest storm.

Geoff Hendrey, of NextDB.net, emailed me discussing a similar issue and how he thinks that:

The database access issue is the "elephant in the room" as far as Ajax apps are concerned. It's a very hot topic, evolving rapidly, and related to cloud computing and DAAS (SimpleDB, LongJump, S3, Blist, NextDB.net, BigTable, etc).

Geoff is going to be at Web 2.0 Expo talking on the subject.

What are your thoughts on Ajax and the data tier?

ASIDE: I will be giving a joint talk with Ryan Stewart of Adobe there too, so come say hi, and ping me on Twitter with any thoughts.

Sometimes you poverty weekday to be a Friday, so we hit ProtoRPG, a persona activity mettlesome cursive by Pierre Chassaing in JavaScript using Prototype and Script.aculo.us.

Walk around, add to your inventory, and see same you are activity your prototypal RPG some moons ago, on a Friday.