Submitting a hidden form with javascript on Firefox

Chrome is either more lax, or there isn't standard covering this.

In firefox, make sure the form has a name attribute, does not have a submit button named submit, and lastly, the form must have a parent element. This last bit was a bit of a guess on my part, but this was the solution I needed.
The other two tips are from elsewhere on the web.

Chrome
var f = document.createElement("form");
//... ( add stuff to form )
f.submit();

Firefox is a bit more picky, it must have a parent, and a name:

var f = document.createElement("form");
f.name="myForm";
f.style.visibility="collapse";
document.body.appendChild( f );
//... ( add stuff to form )
f.submit();

How to make the GAE blobstore upload be a bit more pretty.

It was really odd to see the rather clunky blobstore 'API' amidst the rather clean APIs that make up the rest of the Java Google App Engine SDK.

While I can add an entity to the regular datastore with a few lines of code, getting a blob (1MB+) of data into the blob store is a pain.

1. ask GAE to serve up an upload URL string.

2. shove this URL into a form 'action' field.

3. attach a File Input element to the form - let the user interact with it.

4. submit the form

5. watch in horror as your 'web app' redirects after the upload completes.

So, no way to get callbacks or events to show a progress bar. My first thought was to emulate the form post with XmlHttpRequest, but send() only takes a string or a File object, not both.

One of the arguments to that "give me an upload URL" call is a callback URI. What it does is reflect your form back this URI (a servlet), but it replaces the file contents with a blob key.

However, that means a redirect, actually two, since once your servlet grabs the form data, one would probably want to go back to the main JSP or servlet page and get on with the rest of the app.

Then I remembered a dirty (?) little trick - IFrames.

The form can have a 'target' attribute set, which means that when done, it 'dumps' the results (in this case, the redirect) into the iframe, and not 'document'.

Make the iframe small and invisible, and no more 'full screen' redirects. One can then hook into the "onload" event of the iframe, and have this tell the 'parent' document that a particular file upload has completed with any javascript tricks one could want.

Even with this, there is no feedback to the user as to when things will get done, only exactly when they are done.

What this should have been is a way to get a XmlHttpRequest URL, which could then directly feed a file to the blobstore with a 'prebaked' URL containing just enough data to get the job done. it would then kick back a XML or JSON object with a blob key in it. I could then hook into the client side events, and track progress and show feedback to the user. Banging through one or two redirects is very 1998.

Amazon S3 does this better, including a groovy UI for managing content. Unfortunately, GAE does not have anything so slick.

At least fetching a blob from the blobstore is easy to do in java, and it appears to support the streaming case of fractional data fetches. Thats good because I have podcasts to serve up.

USB Keyboard on Vegan/G-Tablet

Yup, it works. Plug-n-play. Writing this using a USB keyboard I had laying around.

I switched to Vegan as TnT Lite was constantly hanging (some sort of notification issue?)

The Tablet Life - first few hours

I grabbed a Viewsonic G-Tablet today from Office Depot. Its a Tegra 2 Android Tablet with decent specs. I wanted to find out how viable it might be for day-to-day use, and to use as a development platform for my avionics software.

The first step was to put an unskinned Android on it. I randomly chose TnT Lite, as I couldn't quickly find a stable cyanogen 7 for it. This is pretty simple, a few reboots later, I had a 'fully functional' Android 2.2 environment. Market, Google Apps, and so on.

I can tell you right now that Docks or stands must be a hot seller for iPad owners and soon to be Xoom owners, as I wanted to prop this thing up practically every where I went. I think I'm gonna get some cardboard and an X-Acto knife to carve up a cheap stand.

The G-Tablet unfortunately has a low end notebook display on it. while it is 1200x600 resolution with decent enough colors/brightness, it falls down with anything other than a 'straight on' viewing angle. This shows itself mainly when watching video, as a shift in angle can increase contrast to the point where every compression artifact is magnified 100x, making the image look blocky. Reading black text on white background in Google Books or an RSS reader doesn't show this off as much. My HP TM2T also has this problem of really bad viewing angles, which was surprising, and its also a tablet, albeit a convertible.

The build quality seems decent enough, I don't see any gaps in the seams nor do I feel any flexing. It has a similar backing to what my EVO has, it doesn't have 'slippery bar of soap' feel like my old Palm Pre did. The tablet is about 1.5 pounds. Which is light compared to the TM2T at 4, but still 'too heavy'. I feel like a one hand grip may be too tenuous (or tiring) at times.

Touch response is top notch. Just like my EVO or any capacitive, I do end up with 'too light' of a touch at times, causing things not to register, but I have this same problem with every screen I've came across. Any time I do properly register a hit and receive feedback, the tablet is very prompt to respond. Note that this is all with a near 'stock' Android 2.2. running here. My very limited experience with the shipping viewsonic skin left me with feelings of revulsion. They do their customers a disservice by shipping such poorly performing and buggy software. The first time I booted resulted in every application (including Wi-fi or other settings) causing crashes. The performance in the viewsonic skin was right out of a memory starved Win95 machine from 1997. Switching to TnT cured every problem.

Once 'upgraded' to stock android 2.2 with all the google apps and what not, I could run though the old standbys to be treated to very smooth performance. Scrolling is smooth everywhere, (Gmail, Reader, Books, Web Browsers) Angry Birds works flawlessly, and video playback from the multiple sources I tried is stutter free. Google Maps 5.1 and its vector graphics are all here and running fine, though it the 3D buildings show up as solid, instead of 'ghostly'. Flash performance is decent, but not stellar. Video is ok, but many flash heavy sites are already at a disadvantage due to lack of mouse over.

I attempted to load marvel digital comics, (all flash), but the flash plugin died after it loaded the first page.

This comes to the next bit of quick impressions... The world isn't quite ready for tablets yet. Many sites just don't like them (prefer mouseovers and hovers), or have CPU crushing flash. In that regard, some of these sites even fall down on my PC. I'm not sure how iPadders cope. At least I can SEE the Flash controls and what not. The other side of this is the content providers themselves. I recently switched my AOPA magazine over to the 'digital' edition, which I attempted to read on the tablet. While this site is all HTML, its very quick and dirty. Its simply the pages of the paper magazine scanned and saved as images. I know this as the text refuses to scale well, and nothing is selectable. There are a few hyperlinks in the table of contents, but other than that its the same content as before.

The other big issue that I believe will keep coming up for me is the lack of content creation ability on these tablets. On my Win7 convertible, I have the pressure sensitive stylus and a full keyboard, which lets me create things quickly. Not only that, but I have compilers, IDEs and 3D editing packages and can install things like web or SQL servers. This is nearly impossible on 'pure' tablet form factors, even for something as open/flexible as android. Sure, there are a few finger painting apps, but a finger is not a good instrument for content creation. Typing long emails is also out of the question, although I do find the dictation decent enough and a bit of a time saver, as long as I speak one sentence at a time very clearly. I also can't see composing a webpage on these.

Where a tablet would seem to shine is a long plane trip, or a 'just got up in the morning and don't wanna get outta bet' sorta thing. Grab the tablet, its 'on' in 1 second, and start reading the mornings RSS feeds, or peeking at emails.

I'm spoiled, used to, and own other better displays, so for movie watching I'm more likely to fire up the desktop PC or the projector. Other than using this as a display in the plane, I'm not entirely convinced that any tablet (even the XOOM) really fits in in my life. I say this knowing that most people aren't me. In fact, most people would LOVE to 'ditch the PC' (or mac for that matter), and be able to get near instant access to content. Most people simply want to consume content such as video streams or read a book. It might be slightly more difficult for a heavy email user, but at least with the case of android, pairing a keyboard (or plugging one in if a USB host is available) is an option for those people.

I'll be trying out a few of these scenarios, perhaps even write my next Tablet Life blog post from the viewsonic.

Python blows, why do people use it?

At work, its no secret we use python and C++. The python is used to do stuff like guide the initialization of the game, and set up things, like graphics.

The python advocates claim the following:

• Its script! Just change it and you can see things right away, its great!
• Type safe coding is sooo 20th century.
• Compilers are lame.
• No large projects are written in C++ any more.

Heres what really happens:

I get the C++ code to compile, then I have to make another stop in python code to write the 'glue'.

If the C++ code crashes, I can attach a debugger, this might be because the python is all jacked up.

The python code may not 'compile', which is a runtime step... It might even not compile 'later', or it throws an error after 5 minutes of running the game/app. Then guess what, I'm screwed. There is no reloading of that script.

How would I debug python? There is no debugger for it. I'm back to putting in print statements.

It's like I've stepped back in time to 1983, and BASIC.

Then there is the whole "white space defines scope', which turns out to cause no end of trouble. It basically feeds back into the "Oh, you ain't done until the code is executed"

Also, being one of these languages where everything is an object and dynamically mutable, there is no IDE that can provide any help for me, like auto-complete. Working on a large python project is a nightmare.

I cringe every time I have to delve into the python code. Hopefully that will be less and less as time goes on.

Cyanogen on my EVO

After a bit of white knuckle 'clear all data' panic attacks, I got CM6 on my EVO. The process is actually quite easy, but there was a bit of 'read between the lines'.

Good riddance to HTC Sense.

Oh, and HTC, please stop developing Sense. It's terrible. I love your hardware, but if you keep shipping this crap, I'll have to look elsewhere.

So, I'm a web guy now?

Since my last post, I've been busy. I finished the video indexing website, and from that, I got another job building a 'kiosk' like application using tomcat/js/chrome, then my pet sitter had me update her website for payments. It's not quite paying all the bills (I do have a regular day job), but it's a nice chunk of extra money.

I've also helped out here and there with other sites, and dang, people really suck at HTML. I was poking around a website made for UGA, to see if I could help out my girlfriend, and was aghast at how poorly designed it was. It was made by a local web services company, to the tune of $5000. Thing is, it looked like it was a 'template' that they simply copied over. If thats what people are paying for, then maybe I should try to ramp up a bit more business and see what happens.

I also finally started android development, and the first thing I'm doing there is to do a port of sorts of my windows EFIS software, but update the UI to fit the android platform of course.

This is quite an interesting time to work on android. We've seen 2.3 pop out, and within a month, 3.0 announced and demoed. Its still unclear as to what the 'line in the sand' is between the two. Are phone devs supposed to target 2.3, or skip it for 3.0?

We'll find out tomorrow I suppose, there will be a Honeycomb launch at 1pm EST.