Adam's Blog

I've written a web-app using the google maps API which for a given point works out how long it will take to get to any other point in a grid. The times are then plotted using an intensity colour map. Unfortunately due to the nature of the google maps API this is only an academic exercise as the plots take an hour or so to create.

Potential uses could be for would-be house buyers to see what things are in a given travel-time radius.

For example. Search grid over London and surrounding area.

Another example, Sheffield.

Quick start/refresher cheat-sheet on setup of fresh LAMP test server on Ubuntu 9.10. Intended for local development only, no security concerns addressed.

Installation

apt-get install apache2 libapache2-mod-php5 php5 mysql-server php5-mysql

Login as root user to create a dedicated user and database.

mysql --user root --password
mysql> USE mysql;
mysql> CREATE DATABASE testdb;
mysql> CREATE USER adam@localhost IDENTIFIED BY 'password1234';
mysql> GRANT ALL ON testdb.* TO adam@localhost;
mysql> FLUSH PRIVILEGES;

Login in new user and create a table in the database.

mysql --user adam --password
mysql> USE testdb;
mysql> CREATE table test (c CHAR(255));
mysql> INSERT INTO test (c) VALUES ("hello world");

Write some PHP to read the hello world value. Put it at /var/www/hw.php

<?php
$db_username="adam";
$db_password="password1234";
$db_host="localhost";
$db_name="testdb";

$link = mysql_connect($db_host, $db_username, $db_password);
mysql_select_db($db_name, $link);

$result = mysql_query("SELECT * FROM test", $link);
$row = mysql_fetch_assoc($result);
print_r($row);

mysql_close($link);
?>

Visit http://localhost/hw.php. and you should see the output.

Array ( [c] => hello world )

Summary of information from debugging broadband connection drop outs on bethere internet, UK.

• FEC error count not to be worried about.
• CRC error count should be low and will increment slowly.
• HEC error count should be low and will increment slowly. Large number indicates line noise.

Bonus fact. Be support admitted large numbers of DSL drop outs will cause the bebox router to crash (locks up, no response to pings on wireless or wired interfaces). In my case this is a SpeedTouch 585.

Support line staff extremely helpful and changed the upped the error tolerance level as temporary solution till BT sort out the line.

Line noise test. Use corded phone, not cordless into master socket without ADSL filter, using test socket if possible. Dial 17070, option 2. Listen to line. Should be quiet, no crackles, etc. If there is noise contact BT. Full details on noise line from BT.

Line faults can be test online but only if you have the luxury of another Internet connection you can use.

I thought this would be another build-your-own airline seat mission, but no, ubuntu karmic koala* 9.10 installed flawlessly on a Samsung NC10 netbook.

Bluetooth, webcam, sound, wifi, power management like screen brightness, sleep, the custom function keys for volume etc. all work out of the box. Even connecting to the internet using my mobile phone as bluetooth modem works with zero faffing around.

*Karmic is currently based on a 2.6.31 kernel if you want to check against your favourite distribution.

There were however some shocking omissions in the default ubuntu install.

apt-get install nmap john aircrack-ng amsn sharutils php5-cli imagemagick emacs

Want to use VPN to circumvent geo-IP detection on channel 4OD, BBC iPlayer etc whilst abroad?

Here's a quick checklist.

Make sure your UK home network isn't using a standard IP subnet (192.168.0.*, 192.168.1.* or 10.0.0.*). This is important as these addresses tend to allocated for hotel/airport wireless networks and home routers and you can't VPN between addresses on the same subnet. I'm using 10.5.1.*.

Make sure your linux machine has a static address. Edit /etc/network/interfaces if necessary.

auto eth0
iface eth0 inet static
address 10.5.1.51
netmask 255.255.255.0
gateway 10.5.1.254

Setup port mapping on your router for port 1723 to the static address of your linux machine.

Get a dyndns account or similar and set it up so can find your machine whilst abroad.

Install the VPN server.

apt-get install pptpd

Edit /etc/pptpd.conf, add the following options. localip is the address of your linux machine, and remoteip is the range of address to allocate to VPN clients.

localip 10.5.1.51
remoteip 10.5.1.27-37

Edit /etc/ppp/pptpd-options, set the DNS server to give to clients. This should be the address of your broadband router.

ms-dns 10.5.1.254

Edit /etc/ppp/chap-secrets, add usernames/passwords. * means allow all client IP address which is probably what you want if roaming abroad.

# client        server  secret         IP addresses
joebloggs       pptpd   password123    *

Restart daemon to apply changes

/etc/init.d/pptpd restart

Edit /etc/sysctl.conf, enable forwarding if necessary. You'll need to reboot to apply this change.

# Uncomment the next line to enable packet forwarding for IPv4
net.ipv4.ip_forward=1

Client setup, example with windows XP, other clients probably similar.

• Network connections - New connection
• Connect to the network at my workplace, Next.
• Virtual Private Nework Connection, Next.
• Company Name, enter something random, Next.
• Hostname, enter your dyndns hostname, Next.
• Finish.
• Select new connect, right click menu, connect.
• Properties, Security, Advanced Custom, Settings..., Select "Allow these protocols", un tick MS-CHAP and tick MS-CHAP v2. OK.
• Enter username password, then Press Connect.

Having trouble changing the default subnet on your BeBox (aka SpeedTouch 585 6.1.4.3)?

Can't figure out why the default DHCP pool of DHCP pool of 192.168.1.64 to 192.168.1.253 doesn't have an edit / delete option?

Just un-tick the "Use DHCP server" option, press Apply, and the edit option will become available. FFS!

Full instructions

• Home network - Interfaces - LocalNetwork - Configure
• Add a new IP for the bebox on custom subnet, e.g. 10.5.1.254
• Un-tick "Use DHCP Server", press Apply, edit button will now be available, make your changes, e.g. 10.5.1.80 - 10.5.1.120
• Tick "Use DHCP Server", press Apply

Thanks to http://www.youtube.com/watch?v=wgXx34WiSFo

Symptoms: Some files sourced from freeview DVB re-encoded using mencoder have silent soundtracks.

Analysis: The MPEG-TS stream often contains additional sountracks, for example "audio commentaries" for blind viewers. mencoder incorrectly selects these tracks, even if switch -alang en is given. It seems mencoder will give up trying to find the requested soundtrack and go with the first one it finds.

Solution: Use the -tsprobe <byte position> option to make mencoder search further into the file than it would by default. Also switch -tskeepbroken appears to help deal with broken files.

Example. Set byte offset to half the size of the file

file=1741_20091125102600.mpg
size=$(stat -c %s "$file")
size=$(( $size / 2 ));
mencoder -tskeepbroken -tsprobe $size -alang en <other options....> $file

If you get a weird error like this in your browser when trying to access mythweb it's because the username/password in /etc/apache2/sites-available/mythweb.conf have been defaulted. Just edit the file with your actual username/password and all will be well.

Fatal error: require() [function.require]: Failed opening required 'modules/_shared
/tmpl/tmpl/header.php' (include_path='.:/usr/share/php:/usr/share/pear') in /usr/share
/mythtv/mythweb/modules/_shared/tmpl/_errors/fatal.php on line 23

How to get your Haupauge Nova T500 DVB tuner card working with Ubuntu Karmic (9.10)

# Change configuration filename (none .conf extension files now deprecated)
mv /etc/modprobe.d/options /etc/modprobe.d/options.conf

Add the following lines to /etc/modprobe.d/options.conf if you haven't already.

options dvb-usb-dib0700 force_lna_activation=1 
options dvb_usb disable_rc_polling=1

Rebuild video for linux DVB. Maybe not strictly necessary.

# get deps
apt-get install linux-source linux-headers-$(uname -r) build-essential

# prepare linux source (ubuntu install is just an archive in /usr/src. WTF
cd /usr/src
bunzip2 linux-source-2.6.31.tar.bz2
tar xf linux-source-2.6.31.tar

# Change link from /lib
rm /lib/modules/2.6.31-14-386/build
ln -s /usr/src/linux-source-2.6.31 /lib/modules/2.6.31-14-386/build

# Merge in headers (avoids full kernel rebuild but provides configuration etc)
cp -rv /usr/src/linux-headers-2.6.31-14-386/* /usr/src/linux-source-2.6.31/

# get sources
mkdir /tmp/v4l-dvb-build
cd /tmp/v4l-dvb-build
hg clone http://linuxtv.org/hg/v4l-dvb
cd v4l-dvb
make install

Now COLD-RESTART, that means power off, remove power, power on. This is the only way to ensure new firmware is reset. A simple reboot will not work, trust me I've tried.

Not got anything interesting to say? Why not have your twitter account update from /usr/games/fortune

#!/usr/bin/php

<?php

/**
 * Broadcast a twitter
 * @param username Username, typically email address
 * @param password Password in plaintext
 * @param message Message to update, warning, might be truncated
 */
function updateTwitter($username, $password, $message) {
  $message=urlencode($message);

  $rv=0;
  // The twitter API address
  $url = 'http://twitter.com/statuses/update.xml';

  $curl_handle = curl_init();
  curl_setopt($curl_handle, CURLOPT_URL, "$url");
  curl_setopt($curl_handle, CURLOPT_CONNECTTIMEOUT, 2);
  curl_setopt($curl_handle, CURLOPT_RETURNTRANSFER, 1);
  curl_setopt($curl_handle, CURLOPT_POST, 1);
  curl_setopt($curl_handle, CURLOPT_POSTFIELDS, "status=$message");
  curl_setopt($curl_handle, CURLOPT_USERPWD, "$username:$password");
  $buffer = curl_exec($curl_handle);
  curl_close($curl_handle);

  if (empty($buffer)) {
    $rv=0;
  } else {
    $rv=1;
  }
  return $rv;
}

/**
 * Use fortune to get a fortune suitable for a twitter update
 * @return String, no new lines, 140 characters or less
 */
function getTwitterFortune() {
  $TWITTER_CHAR_LIMIT=140;
  $found = false;
  $rv="";
  while ($found == false) {
    $cmd="/usr/games/fortune";
    $fp=popen($cmd, "r");
    $fortune="";
    if ($fp) {
      while (feof($fp) == false) {
        $fortune.=fread($fp, 1024);
      }
      $fortune = twitterize($fortune);
      fclose($fp);
      if (strlen($fortune) <= $TWITTER_CHAR_LIMIT) {
        $rv = $fortune;
        break;
      }
    }
  }
  return $rv;
}

/**
 * Make text suitable for twitter update.
 * Single line, no tabs or other crazy characters etc.
 * $param input Input line
 * @return Twitterized text
 */
function twitterize($input) {
  $output="";
  for ($i = 0; $i < strlen($input); $i++) {
    $c = $input[$i];
    if (preg_match("/[A-Za-z0-9\.\-\:\ \'\"]/", $c)) {
      $output .= $c;
    } else {
      $output .= " ";
    }
  }
  return $output;
}


updateTwitter("mrhorse@horse.com", "ilikehorses", getTwitterFortune());

?>

I keep getting "Disc burn error 0xFFFFFFCA" on Mac OS 10.5 Leopard.

The cause was that I didn't have read access to all the files that I was trying to burn.

If you need to change this: Ctrl-Click on the file -> get info -> Sharing and permissions.

Noticed how google tries to auto-complete your search as you're typing...

Here are the most popular words by letter and number.

a	718,000,000	ask
b	163,000,000	bt
c	102,000,000	channel 4
d	483,000,000	dell
e	485,000,000	ebay
f	718,000,000	facebook
g	1240,000,000	games
h	364,000,000	hotmail
I	998,000,000	images
j	846,000,000	jobs
k	245,000,000	kiss
l	134,000,000	last minute
m	955,000,000	msn
n	3,190,000,000	news
o	1,130,000,000	office
p	413,000,000	paypal
q	227,000,000	quotes
r	192,000,000	radio 1
s	269,000,000	sky
t	218,000,000	twitter
u	232,000,000	ups
v	120,000,000	virgin
w	415,000,000	weather
x	258,000,000	xbox
y	2,160,000,000	yahoo
z	22,500,000	zara
0	5,030,000,000	2
1	386,000,000	118
2	7,050,000,000	24
3	1,060,000,000	300
4	559,000,000	4 music
5	1,320,000,000	5 music
6	349,000,000	6 music
7	8,3200,000	7 pounds
8	148,000,000	888
9	410,000,000	9 11

If you're struggling to enable any of the functions (system, exec, popen etc) by disabling safe mode, then you're going down the wrong path. You need to change the disabled_functions key in php.ini instead.

; This directive allows you to disable certain functions for security reasons.
; It receives a comma-delimited list of function names. This directive is
; *NOT* affected by whether Safe Mode is turned On or Off.
disable_functions = system,dl,passthru,chown,popen,proc_open

Underworld (2003)
Underworld: Evolution (2006)
Underworld: Rise of the Lycans (2009)

ffmpeg SVN build is required if you're using nuvexport or what to do some say H264 encoding.

# Sources / dependencies
svn checkout svn://svn.ffmpeg.org/ffmpeg/trunk ffmpeg

apt-get install libgsm1-dev libvorbis-dev libxvidcore4-dev  libfaac-dev libmp3lame-dev libx264-dev libfaad-dev libtheora-dev libsdl1.2-dev

# Configure/build

./configure --enable-gpl --enable-postproc  --enable-pthreads --enable-x11grab --enable-libdc1394 --enable-libfaac --enable-libfaad --enable-libgsm --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --enable-nonfree

make

# Install
checkinstall --fstrans=no --install=yes --pkgname=ffmpeg --pkgversion "3:0.svn`date +%Y%m%d`-12ubuntu3" --default


Nuvexport changes required in /usr/share/nuvexport/export/ffmpeg/MP4.pm
* remove -slice option
* remove -chroma option
* remove -title option