John Leach's Blog

Chat Roulette: Eye Vagina
March 10th, 2010

Chat Roulette is a web site that hooks you up to a random person. It streams their webcam video and audio to you, and your’s to them. When you’re done, you click next and get another random person. That’s the whole thing. It’s fun, for a short period of time.

Anyway, whilst holding my webcam to different parts of my body (if you ever use my webcam, wash your hands) I discovered that my eye, on its side, with the right lighting, and right shadows, and bad focus, through a webcam… looks kinda, possibly, a bit like girl bits.

It’s probably fair to say that, for a large proportion of the random strangers on Chat Roulette, the “Next” button is usually clicked in the hope of seeing a girl flashing some part of her body.

Combine these two seemingly unconnected facts together, and you get some of the reactions you see in my Eye Vagina video! The music is “My Vagina” by NOFX. I edited out roughly 300 people jerking off. The vid has had more than half a million hits on you tube. I’m expecting my share of their fat advertising profits any day now.

I recorded it using recordmydesktop and edited it using Pitivi (which actually had some very annoying audo sync problems I had to jump through hoops to avoid, which was a shame).

Tags: chat roulette, chatroulette, eye, flash, prank, vagina
Posted in Personal | 1 Comment »
Advertising and ad blocking
March 7th, 2010

I’ve thought about advertising and ad-blockers a lot over the years, and the debate is getting some attention right now starting with a recent Ars Technica article, so I thought I’d put down some of my own thoughts on it.

Funding your content through advertising is hugely inefficient. Of the people who visit your site, usually only a tiny proportion click on (or notice) an advert, and only a tiny proportion of those then spends any money. So a tiny, tiny proportion of your visitors give any money to your advertisers. So money filters down this system in tiny margins. Then, at the bottom of the system, a tiny amount of the profits from the income covers the cost of advertising. Then this money moves back up the system to you, usually via your advertising agent who takes a nice cut (I’ve heard Google pass as little as one twelfth onto the publisher in some cases).

And this doesn’t consider the costs of the advertiser choosing and designing the ad or the tonnes of bandwidth and gatrillions of CPU cycles used to serve the actual adverts.

It also does not consider externalities, such as pollution. Advertising is mind pollution. Advertising is designed to affect the behaviour of people for the benefit of the advertiser. Why would anyone willingly expose themselves to something designed to steal their attention?

You might argue that advertising creates value – some viewers choose to buy when otherwise they wouldn’t have. But what of the huge proportion of people who just had their attention stolen? No value was created there.

Because not everyone is suckered in by it, advertising squanders billions of hours of attention every day to produce nothing.
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Tags: ad-blocking, adblock, adblocking, advertising, externalities, money, pollution
Posted in Tech | 17 Comments »
Xapian Fu: Full Text Indexing in Ruby
January 31st, 2010
Xapian is an Open Source Search Engine Library written in C++. It has Ruby bindings, but they’re generated with SWIG, so they basically just mirror the C++ bindings – not very Ruby-like (and pretty ugly).

Being a self-confessed full text indexing nerd and a Ruby-lover, I wrote Xapian Fu: a library to provide access to Xapian that is more in line with “The Ruby Way”.

I started writing Xapian Fu exactly a year ago today but left it for a couple of months, then restarted work on it on the train on the way back from the 2009 Scotland on Rails conference. Development was test driven, so it’s got an extensive test suite (using rspec). Documentation is in rdoc and is quite detailed. As of the latest version, it supports Ruby 1.9 too.

Xapian Fu basically gives you a Hash interface to Xapian – so you get a persistent Hash with full text indexing built in (and ACID transactions!).

Example

For example, create a database called example.db, put three documents into it and search them and print the results:
```
  require 'xapian-fu'
  include XapianFu
  db = XapianDb.new(:dir => 'example.db', :create => true,
                    :store => [:title, :year])
  db << { :title => 'Brokeback Mountain', :year => 2005 }
  db << { :title => 'Cold Mountain', :year => 2004 }
  db << { :title => 'Yes Man', :year => 2008 }
  db.flush
  db.search("mountain").each do |match|
    puts match.values[:title]
  end
```
There are of course a whole bunch more examples in the documentation.
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Tags: active record, database, full text indexing, indexing, ruby, search, stemming, stopping, the ruby way, xapian, xapian-fu
Posted in Ruby, Tech | 1 Comment »
Ruby’s case statement uses ===
August 30th, 2009
I’ve not found this stated clearly enough elsewhere so I’m doing so myself.

Ruby’s case statement calls the === method on the argument to each of the when statements

So, this example:
```
case my_number
  when 6883
    :prime
end
```
Will execute 6883 === my_number

This is all fine and dandy, because the === method on a Fixnum instance does what you’d expect in this scenario.

However, the === method on the Fixnum class does something different. It’s an alias of is_a?

That is cute, because it allows you to do this:
```
case my_number
  when Fixnum
    "Easy to memorize"
  when Bignum
    "Hard to memorize"
  end
```
But it won’t work as you might expect in this scenario:
```
my_type = Fixnum
case my_type
  when Fixnum
    "Fixed number"
end
```
This won’t work because Fixnum === Fixnum returns false because the Fixnum class is not an instance of Fixnum.

My workaround for this is to convert it to a string first. Not sure if that’s the best solution, but it works for me(tm).
```
my_type = Fixnum
case my_type.to_s
  when "Fixnum"
    "Fixed number"
end
```
Tags: case, coding, condiitonal, programming, ruby, switch, when
Posted in Ruby, Tech | 5 Comments »
Song In Code: Ramones, I wanna be sedated
August 21st, 2009

Just the first verse:

go = Proc.new { sleep 24.hours } self.wants :sedatation begin ; nil ; end case go ; where "no" ; nil ; end self.wants :sedatation self.get '/airport' self.put '/airport/plane' before self.insane? do 3.times { hurry! } end return if self.can_control? :fingers return if self.can_control? :brain 5.times { "no" }

I recorded me singing it, which is kinda stupid tbh.

I used mencoder to convert this to something Youtube found tasty. Like this:

mencoder -ss 15 -endpos 1:18 -vf pp=al:f,scale=480:360 -oac mp3lame -ovc lavc -lavcopts vcodec=libx264:mbd=1:vbitrate=2000 MOV01362.MPG -o MOV01362.x264

Also, pimp for another Geek/Ukelele project: Ukepedia, all 3 million Wikipedia articles one song at a time

Tags: code, Music, ramones, ruby, sing, song, songsincode, ukelele
Posted in Music, Tech | 5 Comments »
Boron Fights Grass
July 5th, 2009

Tags: armley, bite, boron, cats, claws, fight, grass, leeds, sun
Posted in Photoblog, Photography | 1 Comment »
Netfilter Conntrack Memory Usage
June 17th, 2009

On a busy Linux Netfilter-based firewall, you usually need to up the maximum number of allowed tracked connections (or new connections will be denied and you’ll see log messages from the kernel link this: nf_conntrack: table full, dropping packet.

More connections will use more RAM, but how much? We don’t want to overcommit, as the connection tracker uses unswappable memory and things will blow up. If we set aside 512MB for connection tracking, how many concurrent connections can we track?

There is some Netfilter documentation on wallfire.org, but it’s quite old. How can we be sure it’s still correct without completely understanding the Netfilter code? Does it account for real life constraints such as page size, or is it just derived from looking at the code? A running Linux kernel gives us all the info we need through it’s slabinfo proc file.
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Tags: conntrack, firewall, iptables, kernel, limit, linux, max, netfilter, performance, ram, slab
Posted in Tech | 1 Comment »
My Ukepedia Talk at Barcamp Leeds 2009
June 5th, 2009

Tim Dobson very kindly recorded and uploaded my talk on the Ukepedia at Barcamp Leeds last Saturday.

For those of your with short attention spans, I finally get started with the talk at about 2mins 30, and start singing the first article, Otitis Media, at about 7mins.

Tags: barcamp, bcleeds09, leeds, microsoft, otitis media, performance, sing, song, ukelele, ukepedia, wikipedia
Posted in Personal | No Comments »
Live this Saturday at the Packhorse in Leeds, The Gillroyd Parade
May 12th, 2009

My band, The Gillroyd Parade, are hosting an evening of acoustic music at the Packhorse Pub this Saturday (7pm to 11pm, 16th May). Supported by Ukelele Bitch Slap. Do come along, it’d be just dandy to see you. Full poster here.

Tags: folk, gospel, guitar, harmonica, sci-fi, theremin, ukelele
Posted in Music, Personal | No Comments »
April Fool: A man in Jalawla walked into a bar…
April 1st, 2009

Medialens spotted that the BBC attributed a bomb attack on Monday in Iraq to “al-Qaeda”, with apparently little evidence. They wrote to the BBC’s “man in Baghdad”, Hugh Sykes, and asked him “what is the evidence that al-Qaeda, rather than some other insurgent group, were behind the attacks”?.

Hugh’s answer genuinely made me think this was an early April Fool’s joke. In fact I’m still not sure Medialens aren’t making me look like an idiot:

No proof, but circumstantial evidence and reasonable presumption of AQI [al-Qaeda in Iraq] involvement – very much their modus operandum. Suicide attacks are their signature method, and this was a dramatic detonation suggesting a lot of explosive – again, very AQI.

And…who else would do this?

So, process of elimination, history of AQI attacks in Diyala etc.

And the logic of it Sunni Arab vs Iraqi Kurds. As a man in Jalawla told Reuters:

“Al-Qaida is targeting the Kurds because it believes that
we are involved in the political process and collaborating
with the Americans.”

This blows my mind. “very AQI” and “a man in Jalawla told Reuters”. “Who else would do this?”

As Medialens point out, the BBC claim they are “committed to evidence-based journalism”. Except they pick and choose when their committment applies, such as when they refused to report the use of banned weapons by US forces in their November 2004 assault on Falljuah.

Tags: al-qaeda, bbc, bomb, iraq, journalism, media, medialens, news, propaganda
Posted in Politics | No Comments »
My NWRUG Ferret Talk
March 24th, 2009

I did a short talk on Ferret, the Ruby “Information Retreival Library”, at the North West Ruby Users Group last Thursday. We had a bit of a theme too, with Will Jessop speaking about Sphinx and Asa Calow speaking about Solr.

I got to have a bit of a nosey around the Manchester BBC building too – though I was worried I’d open the wrong door and end up on TV. Didn’t fancy having to apologise to Jeremy Paxman.

Brightbox also sponsored some pizza, and gave away t-shirts and stickers like candy (there was no candy though).

My slides are available here, and contain a little example file system indexer. I made my slides with webby and S6 if you’re interested.

Tags: ferret, indexing, inverse index, rails, ruby, search, solr, sphinx, talk
Posted in Ruby on Rails, Tech | 2 Comments »
Women in Technology
March 16th, 2009

Dom kicked up a women in technology debate again recently. I’ve seen a few responses, from one chap who thinks women have achieved equality already to a woman who doesn’t think girl’s brains are generally good for “programming” – and someone else who thinks there isn’t a problem as long as you’re thick skinned enough to put up with a sexually hostile workplace.

The main gripe appears to be with “women only” conferences, such as the Women on the Web conference, organised by a group called Forward Ladies, or the Geek Girl dinners.

I think a fair summary of his, and some other commenters, opinion is that these “women-only” events don’t help the effort to get more women involved in technology. Comparing it to positive discrimination in many ways.

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Tags: conference, event, forward-ladies, geek-girl, geeks, geekup, leeds, social, Tech, women, women on the web
Posted in Personal, Tech | 13 Comments »