TagiPhoneDev

JSON vs XML – Part 1: Data Size

In this test to compare XML vs JSON files data size, I transformed a sample of our XML data files to JSON, and I’ve obtained the following results:

File Name XML Size (bytes) JSON Size (bytes) Difference (bytes) Difference (%)
groups 6.218 3.379 – 2.839 -45.6 %
matches 14.541 8.823 -5.718 -39,3 %
scorers 1.250 652 -598 -47,8 %
TOTAL/Average 22.009 12.854 -9.155 -41,6 %

Well, after this first experiment it seems that I can save about 41,5 % on my data size if I change from XML to JSON files.

But wait! And if I reduce my tag/field names’ length to only 2 characters long?

Here are the new results that I obtained after that change…

File Name XML Size (bytes) JSON Size (bytes) Difference (bytes) Difference (%)
groups 3.444 2.934 -510 -14,8 %
matches 8.189 7.154 -1.035 -12,6 %
scorers 756 556 -200 -26,5 %
TOTAL/Average 12.389 10.644 -1.745 -14,1 %

Well, that size difference becomes reduced from near 41,5% to about 14%! It seems that with JSON I can save at least almost 2 KB per App update.

If I have 1.000 updates/day it gives less 2 MB of bandwidth which is perfectly negligible.With 1.000.000 updates/day it gives 2 GB/day, which becomes about 60 GB/month. It’s true that can save me some bucks if I’m paying a non unlimited bandwidth hosting service. But maybe it isn’t sufficient to make me change my App, specially if it doesn’t will make my App to be implemented faster and run significantly better.

By the way, until I publish the next post “JSON vs XML – Part 2: Parsing and Display Speed“, I recommend that you read an interesting article from Nicholas C. Zakas, which I found among many other articles about XML vs JSON: “Is JSON better than XML?“.

It compares several aspects of those two technologies in a succinct way.

Note: This is the first post of the “JSON vs XML – Data Size, Parsing and Display Speed” set.

JSON vs XML – Data Size, Parsing and Display Speed

In my previous post “App Interface and Data Update with UIWebViews, XML, XSLT and HTML“, I’ve written a little bit about how I have used XML to dynamically update and display our App’s data.

Following that, now that I’m preparing a new similar App, I’ve read lots of stuff about JSON and about JSON vs XML on the web, which is making me to consider the change of XML by JSON.

Many people argues that JSON is better than XML but that’s not clear and it seems that it depends a lot in what we need to do! Well, I know that’s not something new, it’s what happens most of the times when we’ve to choose some technology against other(s).

But I want to choose the “best” for my case, since I have plans to port this new App at least to Android OS and maybe to Windows Phone 7. And if that choice can reduce my total work in those platforms, it’ll be an important choice.

In general what I’ve seen is that XML is largely supported in all common browsers and in those mobile platforms. JSON is relatively new, however it’s becoming supported almost everywhere but mostly without native parsers.

That’s the case with iOS and WebKit (Safari’s engine). So I decided to do some previous experiments…

Since this article is growing a little more than I preview, I’ll publish the results of my tests in the following posts:

App Interface and Data Update with UIWebViews, XML, XSLT and HTML

I haven’t wrote almost anything about the development of my first App launched on the App Store: SA2010SS. Now it’s time for a little about that…

I’m picking up that code to reuse it on the next App, which will be similar  but this time, based on the National Soccer League(s) with the addition of one or two interesting features, I hope.

This post is focused on the strategy that I used for our App’s main interface and data updates.

Starting by the data updates, our App gets the data from the server, downloading three XML files, each one with:

  • match results;
  • standings;
  • best scorers.

For the user interface I’ve used some standard iPhone controls (mainly for buttons) but the main screen is almost filled with an UIWebView.

What that means?

That means that the mainly part of our App UI is done using standard HTML web pages. I had some problems to implement this “workflow”, but after achieving that, it allowed us to easily tune our UI, using standard web technologies: HTML + CSS.

The main pages/views are obtained via XSLT:

XML -> XSLT (with CSS) applied -> HTML

So, when the App updates data, it receives three XML files, the correspondent XML data for the screen that the user is seeing, is transformed applying a corresponding XSLT file and then the new HTML page is generated and presented on the UIWebView.

I know this method is not so fast as if I had only used iPhone controls from the UIKit Framework for the views. But the pages scroll and transitions are fluid, except on the first time the App creates and presents each view, which take maybe 2 or 3 seconds do appear.

That’s not perfect, but it was a nice trade-off which allowed us to cut some time (that would be used to learn to use those controls) on our App development and design.

Nevertheless, in the future maybe it’ll be easily to port it to Android OS or any other platform which supports web views.

I’d like to hear your opinions and suggestions about this scheme or better alternatives. Leave me a comment…

How I “killed” a Bug on my published App without touching the code! ;-)

Hi!

This post consists on just a little curiosity which I decided to share with you but, hopping that it will maybe make you think a little different, the next time you find a bug on your App…

There has been almost 3 months since we launched South Africa 2010 Soccer Scores.

Today I was reviewing its code and doing some changes because our next planned app will be based on that. Then I was completely surprised when I discovered a little bug that nobody had reported neither we had never noticed!

The little bug is that on the “About” tab of our App:

SA2010SS-About(marked)

SA2010SS - About screen tab

the link that I marked with yellow on the above screen-shot is WRONG!

Why is it wrong? Because it should link to: “http://xphone.me/sa2010ss” instead of “http://xphone.me/wcs2010“.

That happened for a reason that I’ll also share with you…

The wrong link was because our original submitted App name was “World Cup Scores 2010” but due to the possibility of some FIFA legal copyright/trademarks infringement with the expression “World Cup”, we had to change it at the last hour, to the final name “South Africa 2010 Soccer Scores”.

In order to maintain the coherence we had also changed our original web page about that App, from the “http://xphone.me/wcs2010” URL to the new one “http://xphone.me/sa2010ss“.

Well it seems we updated all the image assets but we forgot that little link on the “About” tab!

Today when I discovered it, the first thought on my head was to correct the code and update the App on the App Store. That would be simple but why should I do that if probably almost nobody will update this App since the World Cup had already finished quite a long time. Simple conclusion: it is not worth the effort!

But because I don’t like to known that there are some living bugs on my code and I would like that if someone click on that link he/she can reach our web page and not a blank error page, I thought a little more on this issue and then I realized, the solution was even simpler… I had just created a simple “index.html” page on “http://xphone.me/wcs2010” that redirects the users the right page! And now the insect is killed! 🙂

Disclaimer: I have nothing against real bugs! 😉

Well, this post doesn’t teach you anything special but I think it can give you an useful message:

  • the obvious solution is not always the best choice!


By the way, if you want to know a little more about SA2010SS, read my old post: “My first iPhone App on the App Store! 🙂“.

New Project… New iPhone…

That’s it! New project…

I’m working against the clock trying to implement an iPhone App dedicated to the 2010 Football World Cup in South Africa.

I have a friend who promissed to help me with the graphics, let’s wait I can arrange the time (in my little spare time!) to make a functional prototype! If I can do it, then my friend will do the graphics, we’ll polish ant test the App and try to launch it in the App Store!

Unfortunately I only had this idea a few days ago (it didn’t existed on the App Store, now I can see some similar Apps), but I think that it will be nice to try hard to achieve it, so that I/we can at least gain some more experience on iPhone development.

I hope luck is on our side!

Now, the new iPhone…

Today, Apple announced the new iPhone 4 (powered by the new Apple A4 processor) and featuring quite a lot of new interesting features, like:

  • Multitasking
  • Retina Display, an incredible 960×640 resolution, glass display with a
  • 5 MegaPixel Camera with a LED Flash
  • FaceTime (video calls)
  • 720p HD Video Recording (up to 30fps)
  • Improved Battery Time and so on…

Apple, also announced the new iOS4 that will be available through a free software update. Unfortunately it will be compatible with all previous iPhone versions, except my 2G! :-/

You can see the new iOS4 features on the following page: “http://www.apple.com/iphone/softwareupdate/“.

With so much Apps on my iPhone, the Folders new feature would be very welcome!

I’m also curious and interesting in exploring 2 new features:

  • Gift Apps and
  • Apple’s iAds.

Well, now I have some code to type…

Ricardo

PS:  Here you have a nice video about the new iPhone 4 design: “http://www.apple.com/iphone/design/index.html#design-video“.

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