This blog is about Java (advanced Java topics like Reflection, Byte Code transformation, Code Generation), Maven, Web technologies, Raspberry Pi and IT in general.

Dienstag, 14. Mai 2013

Tutorial: how to setup a torrent-box (torrent-tracker + seeding client) on a Raspberry Pi


Most people use Dropbox and other cloud services to share their files. But if you want to be in control of your files - without any restrictions - than you need to setup your own share server. The simplest way to do so is to setup a FTP or HTTP server. I didn't want to use a FTP because the person you want to share your files with has first to setup the connection - too much work. Another problem with both options is that they don't handle a connection lost very well. So I decided to use a torrent network.
  • it can handles a connection lost very well
  • the peers will upload too (important if you share you files with many people)
  • easy to use: just send a magnet link or a torrent file

Setup a Torrent Tracker - opentracker

 At first we setup our own torrent tracker using opentracker.

sudo apt-get install cvs
cvs -d -z9 co libowfat
cd libowfat
cd ..
cvs co opentracker
cd opentracker
chmod a+x opentracker

That's it. Just start the torrent tracker


Setup a Torrent Client - rtorrent

The tracker connects the peers with each other but it doesn't seed (upload) anything. So we need a torrent client which will seed our shared files. Get the program

sudo apt-get install rtorrent

Configure rtorrent

mv rtorrent.rc ~/.rtorrent.rc
nano ~/.rtorrent.rc

The most important configuration settings

# sure use udp
use_udp_trackers = yes
# encryption is always a good idea
encryption = require
# change it so it doesn't conflict with our torrent tracker which uses the port 6969
port_range = 6890-6960
# where the files are saved
directory = ~/downloads/torrents/
# load automatically all torrent files from the directory and start downloading or seeding
schedule = watch_directory,5,5,load_start=/var/www/torrents/*.torrent
# if the torrent files are removed stop downloading or seeding
schedule = untied_directory,5,5,stop_untied=

Now you could start rtorrent and start downloading torrents.

Create a Torrent File - mktorrent

Now we need to create a torrent for the files we want to share.

sudo apt-get install mktorrent
mktorrent -p -a http://${YOUR_IP_OR_DOMAIN}:6969/announce -a udp://${YOUR_IP_OR_DOMAIN}:6969/announce FILE_OR_DIRECTORY -o OUTPUT_FILE.torrent

That's it. Put the torrent file in you torrent watch directory and start rtorrent. Rtorrent will read the file and start seeding. Don't forget the source file must be in the right directory (see the rtorrent setting directory=).

Setup your router and start sharing

You probably need to setup a port forwarding to your Raspberry Pi for the necessary ports.
Then you can start sharing your files in your own private torrent network :)

Further reading

How to automatically start opentracker and rtorrent
How to generate a magnetic link form a torrent file (convert torrent file to magnetic link)

Tutorial: How to automatically start opentracker and rtorrent on a Raspberry Pi


In my last post I explained how to setup a torrent-box on a Raspberry Pi. But there is still one important thing to do: automatically start opentracker and rtorrent so you needn't to do it yourself after each reboot. It's not that easy because rtorrent can't be started as deamon and you probably want to be able to get the background rtorrent process so you can change the setting (e.g. limit the upload speed). To solve this problem I used tmux.

Setup the autostart

The first thing is to put the opentracker executable into the /usr/bin
Then install tmux

sudo apt-get install tmux

Now we have to write our init.d script which will be called at the startup

sudo nano /etc/init.d/torrent

With this content

# !/bin/sh
# /etc/init.d/torrent


case "$1" in
    echo "Starting torrent"
    start-stop-daemon --start --background --chuid=pi --exec $BIN/opentracker
    start-stop-daemon --start --background --chuid=pi --exec $BIN/tmux -- new-session -d -n rtorrent -s rtorrent rtorrent
    echo "Stopping torrent"
    killall opentracker
    killall rtorrent
    echo "Usage: /etc/init.d/torrent {start|stop}:"
    exit 1

exit 0

Make the file executable and embed it into the starting process

sudo chmod 755 /etc/init.d/
sudo update-rc.d defaults

Basically that's it.


To get your running rtorrent process write

tmux attach

To put it back into the background press ctrl+b and then press d (for deattch).

tmux cheat cheet.

Tutorial: How to generate a magnet link form a torrent file (convert torrent file to magnetic link)


It's easier to send just a link instead of a file if you want to share a torrent file.

Create the magic link

To create the magic link I used the bencode library (python). To easily install it we need first easy_install. The first thing to to is to install easy_install

sudo chmod 755 setuptools-0.6c11-py2.7.egg
sudo ./setuptools-0.6c11-py2.7.egg

Now it's very simple to install bencode


That's your preconditions. Now we can write our python script which will generate the magnic link.


Put following content into it


import sys
import urllib
import bencode
import hashlib
import base64

if len(sys.argv) == 0:
print("Usage: file")

torrent = open(sys.argv[1], 'r').read()
metadata = bencode.bdecode(torrent)

hashcontents = bencode.bencode(metadata['info'])
digest = hashlib.sha1(hashcontents).digest()
b32hash = base64.b32encode(digest)

params = {'xt': 'urn:btih:%s' % b32hash,
'dn': metadata['info']['name']}

announcestr = ''
for announce in metadata['announce-list']:
announcestr += '&' + urllib.urlencode({'tr':announce[0]})

paramstr = urllib.urlencode(params) + announcestr
magneturi = 'magnet:?%s' % paramstr


Make the file executable

sudo nano 755

And the just call it with a torrent file

./ file.torrent

Samstag, 11. Mai 2013

Tutorial: How to install a Tiny Tiny RSS (tt-rss) server on a Raspberry Pi (nginx, php, mysql)


I love the Google Reader (RSS reader) very much and I used it heavily. But sadly Google decided to shutdown this great service. So it was time to look for an alternative and I found Tiny Tiny RSS (tt-rss). It's an open source RSS reader written in PHP. It's quite nice but there is one big issue: the website (JavaScript) is slow. It's impossible to use it on a smartphone. But there are Android apps for tt-rss which are quite nice.

Install & configure nginx, php & mysql-server

  • get all the packages
sudo apt-get update
sudo apt-get install nginx php5-fpm php5-cli php5-curl php5-gd php5-mcrypt php5-mysql php5-cgi mysql-server
  •  create the web directory
sudo mkdir /var/www
sudo chown www-data:www-data /var/www/
  •  configure nginx
    • open the config file
sudo nano /etc/nginx/sites-enabled/default 
    • modify it so it looks like this
server {
  listen   80;
  root /var/www;
  index index.html index.htm index.php;

  server_name localhost;

  location / {
    try_files $uri $uri/ /index.html;

  location ~ \.php$ {
    fastcgi_pass unix:/var/run/php5-fpm.sock;
    fastcgi_index index.php;
    include fastcgi_params;
  •  configure php-fpm
    • open the php.ini
sudo nano /etc/php5/fpm/php.ini
      • set: cgi.fix_pathinfo = 0;
    • open the www.conf
sudo nano /etc/php5/fpm/pool.d/www.conf
      •  set: listen = /var/run/php5-fpm.sock
  • restart nginx and php-fpm
sudo service php5-fpm restart
sudo service nginx restart
  • create the mysql database for tt-rss
mysql -u root -p
    • insert the password and execute those two commands
create database ttrss;


Install Tiny Tiny RSS (tt-rss)

It's quite simple. Just grab the .tar.gz file, unpack it move it to the web directory and set the permissions. It's done like this. But you probably want to check if there is a newer version.

tar zxfv 1.7.8.tar.gz
mv Tiny-Tiny-RSS-1.7.8/ ttrss
sudo mv ttrss /var/www
cd /var/www/ttrss
chmod -R 777 cache/images && chmod -R 777 cache/export && chmod -R 777 cache/js && chmod -R 777 feed-icons && chmod -R 777 lock

Perform the tt-rss installation


Setup the crontab

  • Open the crontab
crontab -e
    • Insert following line
*/15 * * * * cd /var/www/ttrss && /usr/bin/php update.php --feeds --quiet > /dev/null

With this setup the Raspberry Pi will load every 15 minutes the RSS feeds and update them so you can read them.

Enjoy your Tiny Tiny RSS (tt-rss) installation

That's it. Now you can open your installation, configure it and read your feeds. Have fun! :)