Federico Cargnelutti fedecarg

MySQL Split String Function

The following example function takes 3 parameters, performs an operation using an SQL function, and returns the result.

Function

CREATE FUNCTION SPLIT_STR(
  x VARCHAR(255),
  delim VARCHAR(12),

pos INT

Intercept class method calls

Here’s an example of how to use metaclass programming to intercept class method calls similar to the method_missing technique in Ruby:

class ClassMethodInterceptor(type):

    def __getattr__(cls, name):
        return lambda *args, **kwargs: \
                   cls.static_method_missing(name, *args, **kwargs)

Search

grep -Irl --include=\*.txt "keyword" .

or

find . -type f -print0 | xargs -0 grep "keyword"

Search and Replace

Amazon EC2

Monitoring

ssh -i ~/.ec2/my.pem root@ec2.compute-1.amazonaws.com "cat /var/log/secure | grep 'refused connect'"

When using SSH to run commands across multiple machines without exchanging your public key, you need to type in your password for each machine. A quick and simple way of setting this up is to create a public key:

ssh-keygen -t rsa

Installing Ruby with RVM

Install RVM

federico@~$ echo insecure >> ~/.curlrc
federico@~$ curl -L https://get.rvm.io | bash -s stable --ruby
federico@~$ source ~/.bash_profile

Create a Gem set (Ruby and RoR)

Get the absolute position of every link in an html document using JavaScript:

/**
 * The HTML <area> coords attribute needs the position of the left, top, right, bottom corner 
 * of the rectangle. Element.getBoundingClientRect returns a text rectangle object that encloses 
 * a group of text rectangles.
 */
function getElementAbsolutePosition(element) {
    var pos = {};

pos.left = 0;

Spike: Image-based BBC News website

Create list of sites to visit: arabic, hindi, russian, mundo, etc.
Define supported screen widths, for example: 176, 208, 240, 320, 352.
Define the maximum size of an image. The current average size of a mobile page is 250 KB.
Quality: 100% - File size: 822 KB: http://goo.gl/A4ldIF
Quality: 50% - File size: 272 KB:http://goo.gl/AAbrY9
Quality: 30% - File size: 193 KB: http://goo.gl/gOUkXK
Crawl sites in a distributed, scalable and efficient way (scheduling policy, async requests, politeness, message queues, path-ascending crawling).
Note: The app must run very well on Linux and should also be capable of test runs on OSX.

	#!/bin/bash
	# Author federico.cargnelutti@bbc.co.uk

	svn_url="$(svn info . \| grep 'URL:' \| cut -c6-)"
	echo "Repository ${svn_url}"

	svn log -v --xml . > templog.log

	touch svnlog.log

	def rgb_from_str(s):
	# s starts with a #.
	r, g, b = int(s[1:3],16), int(s[3:5], 16),int(s[5:7], 16)
	return r, g, b

	def find_nearest_colour(R,G, B, colorD):
	mindiff = None

	for d in colorD:
	r, g, b = rgb_from_str(colorD[d])

	function rgbToHex(r, g, b) {
	return "#" + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1);
	}