Pedro Assunção » tips

Landing is every man for himself

Pedro Assuncao — Thu, 26 Aug 2010 00:24:37 +0000

I hurt a knee the last time I was out jumping, on a downwind landing. And it was all because of a combination of stupidity and lack of knowledge.

The first because I did something I shouldn’t: I trusted a fellow skydiver’s direction instead of the wind sleeve. Turns out his direction was perfect for his canopy’s rate of descent, which allowed him to make his final turn upwind.

The second cause for the crash was the lack of experience to deal with a downwind landing. Apparently one of the safest ways to do it is to land like a tandem: on your butt

Lessons learned and hopefully my knee will heal fast so I can jump again soon and put all this behind me.

Blue skies

Feedsquares: A refreshing view for Google Reader

Pedro Assuncao — Wed, 14 Jul 2010 08:03:33 +0000

I don’t know about you, but i have still to find the perfect RSS reader. I don’t dislike Google Reader, but i always feel that things can be better (yeah, it’s both a curse and a blessing) and, recently, i found a little thing – called Feedsquares – that puts a nice twist on its interface, making really non-distracting the act of reading each piece of news.

Feedsquares looks nice

It is comprised of a bunch of squares (one per feed you have) and, when clicked, it will show yet more squares; this time the stories in that feed. Clicking those will open the story full page. Check it out, you might like it

Google introduces GMail image drag and drop

Pedro Assuncao — Wed, 12 May 2010 12:41:27 +0000

At least if you are using Chrome

If you drag any picture from your desktop to the message body it will get automagically included in the email. Pretty neat, uh?

Latex in Google Docs

Pedro Assuncao — Fri, 07 May 2010 08:45:06 +0000

Pretty cool stuff, now you can edit Latex from google docs. Check it out here. Too bad i decided a long time ago to use HTML+CSS for my resume, otherwise i would definitely give this a try over offline Latex editors

Spring : inject proxy instead of proxied object

Pedro Assuncao — Tue, 20 Apr 2010 15:13:39 +0000

Today i found a neat trick.

Typically when you inject an AnnotationSessionFactoryBean into one of your classes you end up with a SessionFactory on the other side. This is because Spring is doing its magic inside, proxying stuff so you end up with an easy way to instantiate hibernate sessions. The problem is that i wanted to be able to access the actual AnnotationSessionFactoryBean, so i could run the createDatabaseSchema method on it (retrieve the connection properties would be another use case).

So how do you inject the proxy, instead of the proxied object? You prefix the bean ref with the “&” sign, like so:

If you want to do it inside, for instance, anything that extends AbstractTransactionalJUnit4SpringContextTests, you can do it like this:

sessionFactoryBean = (AnnotationSessionFactoryBean) super.applicationContext.getBean("&sessionFactory");

Hope it helps somebody

Sproutcore on OSX snow leopard

Pedro Assuncao — Tue, 13 Apr 2010 09:13:08 +0000

It recently came to my attention the existence of this heavily-client-based web framework to develop desktop-like applications called Sproutcore and is backed up by Apple (there is another cool alternative called Capuccino). Basically it relies on Javascript to create nice desktop-like applications, but on the web.

Ever since i heard about node.js i have been curious to try out one of these things. My ideas on it will come later but, for now, here are the required steps to make Sproutcore work well on OSX snow leopard. And i say work well because if you rely on the vanilla Ruby 1.8.7 that comes with snow leopard you will have a very crappy experience with Sproutcore; It will take approximately 35 seconds to reload any webpage every time you make a code change. And that will make you not want to use it at all.

Fortunately a lot of people have been kind enough to explain me, on twitter, how to make it faster.

But let’s start from the beginning:

1. Install Sproutcore using GEM, like so:

sudo gem install sproutcore

Note: I don’t remember if gem comes installed with snow leopard. If not, you can always google it

2. Follow the rest of the steps to setup your first application

By now you should have realized that (if you are using OSX snow leopard) the damn thing is freaking slow. So…

3. …download and compile the Ruby 1.9 source code for OSX

tar xzvf ruby-1.9.1-p376.tar.gz
cd ruby-1.9.1-p376
./configure --enable-shared --enable-pthread CFLAGS=-D_XOPEN_SOURCE=1
make
sudo make install

Note: The actual version could be different, as stuff evolves over time

4. Update the symbolic link on your system to point to the new ruby installation

sudo rm /usr/bin/ruby
sudo ln -s /usr/local/bin/ruby /usr/bin/ruby

5. Make sure the correct Ruby version is in use

ruby --version

Should return something like this:

ruby 1.9.1p376 (2009-12-07 revision 26041) [i386-darwin10.3.0]

6. Install thin. This server is faster than the one that comes with Sproutcore

sudo gem install thin

7. All done. Give it a try again

If you try to refresh the page of a Sproutcore example now you will notice the speed difference, like night to day. Have fun coding client-side desktop web applications

I’m planning to also take a look at Capuccino, another similar framework, but created in Objective-J – a derivative of Objective-C for javascript. Looks interesting and it might get me into iPhone development at last

Altruistic USB plug

Pedro Assuncao — Thu, 25 Mar 2010 13:44:59 +0000

I have to say i love the concept: A USB plug that becomes a USB slot itself, when connected. Check it out, here.

InfiniteUSB

How to beat a nail into a hard wall

Pedro Assuncao — Mon, 15 Mar 2010 08:09:52 +0000

This is probably the first useful mass email that my mother sent me in a long, long time

In any case, it shows how to put a nail into a really hard wall without ending up bending the nail. I know i had this problem before in more than one occasion.

Other (probably intelligent) wordpress plugins to install

Pedro Assuncao — Thu, 11 Mar 2010 11:24:36 +0000

Following up on my post about RAM (or lack of it), i decided to install a proper wordpress plugin to cache most of the stuff in static HTML files. It’s called WP-SuperCache and i’m hoping it’s really super

But now i cannot but wonder if i shouldn’t – somehow – find a way to have nginx serving these static files instead of passing the request to apache. I’m already caching static JS, CSS, and image files with nginx, so that would probably make sense.

In other news, installed a plugin that serves a different WordPress theme for mobile phones. It’s called wordpress-mobile-edition, in case you are interested.

Lack of RAM will kill your blog host virtual machine

Pedro Assuncao — Wed, 10 Mar 2010 08:39:39 +0000

I know what you are thinking: “Well, duh Pedro, how come you didn’t know that?”.

I’ll explain: Recently i started having some service shortages on my blog. From times to times the CPU usage would just go rooftop and then nginx and apache both stopped serving requests. I am using Linode as my host, where i have a nice virtual machine (or node, as they call it) with some reasonable values in terms of CPU and bandwidth monthly usage. The weakest link was the RAM; it only had 386Mb.

A while back i developed Jumperr.com and i figured “hey, i already have the node, so i’ll just host it there”. Some time after deploying jumperr, i started noticing these shortages coming up maybe once a month, or every two weeks (i notice the pattern now, not then ). At some point i even considered switching hosts (to slicehost, for example), but i never thought that memory could be the problem (after all they are not that accessed anyways). Looking at the system logs i just could not figure out what made the machine stop working just like that.

About one month ago, i decided to develop a stupid website that allows you to bomb countries using a Google maps interface. And then, surprise, the shortages became more and more frequent (sometimes 4 per day!). In one of these fails i decided to try to login to the node using Linode’s ajax ssh interface on their dashboard. And that’s when i saw it: a bunch of “out of memory” errors right on the boot list. Since when you connect normally via SSH you don’t see the prompt on the remote end, i never saw these before.

So there you go, lesson learned. If it spikes, chances are you are out of memory

By the way, if you are a proper Linux/Unix admin, was there a log that might contain those errors that i missed?