Petter Reinholdtsen

Entries from September 2018.

Valutakrambod - A python and bitcoin love story
29th September 2018

It would come as no surprise to anyone that I am interested in bitcoins and virtual currencies. I've been keeping an eye on virtual currencies for many years, and it is part of the reason a few months ago, I started writing a python library for collecting currency exchange rates and trade on virtual currency exchanges. I decided to name the end result valutakrambod, which perhaps can be translated to small currency shop.

The library uses the tornado python library to handle HTTP and websocket connections, and provide a asynchronous system for connecting to and tracking several services. The code is available from github.

There are two example clients of the library. One is very simple and list every updated buy/sell price received from the various services. This code is started by running bin/btc-rates and call the client code in valutakrambod/ The simple client look like this:

import functools
import tornado.ioloop
import valutakrambod
class SimpleClient(object):
    def __init__(self): = []
        self.streams = []
    def newdata(self, service, pair, changed):
        print("%-15s %s-%s: %8.3f %8.3f" % (
    async def refresh(self, service):
        await service.fetchRates(service.wantedpairs)
    def run(self):
        self.ioloop = tornado.ioloop.IOLoop.current() = valutakrambod.service.knownServices()
        for e in
            service = e()
            stream = service.websocket()
            if stream:
                # Fetch information from non-streaming services immediately
                                       functools.partial(self.refresh, service))
                # as well as regularly
        for stream in self.streams:
        except KeyboardInterrupt:
            print("Interrupted by keyboard, closing all connections.")
        for stream in self.streams:

The library client loops over all known "public" services, initialises it, subscribes to any updates from the service, checks and activates websocket streaming if the service provide it, and if no streaming is supported, fetches information from the service and sets up a periodic update every 60 seconds. The output from this client can look like this:

Bl3p            BTC-EUR: 5687.110 5653.690
Bl3p            BTC-EUR: 5687.110 5653.690
Bl3p            BTC-EUR: 5687.110 5653.690
Hitbtc          BTC-USD: 6594.560 6593.690
Hitbtc          BTC-USD: 6594.560 6593.690
Bl3p            BTC-EUR: 5687.110 5653.690
Hitbtc          BTC-USD: 6594.570 6593.690
Bitstamp        EUR-USD:    1.159    1.154
Hitbtc          BTC-USD: 6594.570 6593.690
Hitbtc          BTC-USD: 6594.580 6593.690
Hitbtc          BTC-USD: 6594.580 6593.690
Hitbtc          BTC-USD: 6594.580 6593.690
Bl3p            BTC-EUR: 5687.110 5653.690
Paymium         BTC-EUR: 5680.000 5620.240

The exchange order book is tracked in addition to the best buy/sell price, for those that need to know the details.

The other example client is focusing on providing a curses view with updated buy/sell prices as soon as they are received from the services. This code is located in bin/btc-rates-curses and activated by using the '-c' argument. Without the argument the "curses" output is printed without using curses, which is useful for debugging. The curses view look like this:

           Name Pair   Bid         Ask         Spr    Ftcd    Age
 BitcoinsNorway BTCEUR   5591.8400   5711.0800   2.1%   16    nan     60
       Bitfinex BTCEUR   5671.0000   5671.2000   0.0%   16     22     59
        Bitmynt BTCEUR   5580.8000   5807.5200   3.9%   16     41     60
         Bitpay BTCEUR   5663.2700         nan   nan%   15    nan     60
       Bitstamp BTCEUR   5664.8400   5676.5300   0.2%    0      1      1
           Bl3p BTCEUR   5653.6900   5684.9400   0.5%    0    nan     19
       Coinbase BTCEUR   5600.8200   5714.9000   2.0%   15    nan    nan
         Kraken BTCEUR   5670.1000   5670.2000   0.0%   14     17     60
        Paymium BTCEUR   5620.0600   5680.0000   1.1%    1   7515    nan
 BitcoinsNorway BTCNOK  52898.9700  54034.6100   2.1%   16    nan     60
        Bitmynt BTCNOK  52960.3200  54031.1900   2.0%   16     41     60
         Bitpay BTCNOK  53477.7833         nan   nan%   16    nan     60
       Coinbase BTCNOK  52990.3500  54063.0600   2.0%   15    nan    nan
        MiraiEx BTCNOK  52856.5300  54100.6000   2.3%   16    nan    nan
 BitcoinsNorway BTCUSD   6495.5300   6631.5400   2.1%   16    nan     60
       Bitfinex BTCUSD   6590.6000   6590.7000   0.0%   16     23     57
         Bitpay BTCUSD   6564.1300         nan   nan%   15    nan     60
       Bitstamp BTCUSD   6561.1400   6565.6200   0.1%    0      2      1
       Coinbase BTCUSD   6504.0600   6635.9700   2.0%   14    nan    117
         Gemini BTCUSD   6567.1300   6573.0700   0.1%   16     89    nan
         Hitbtc+BTCUSD   6592.6200   6594.2100   0.0%    0      0      0
         Kraken BTCUSD   6565.2000   6570.9000   0.1%   15     17     58
  Exchangerates EURNOK      9.4665      9.4665   0.0%   16 107789    nan
     Norgesbank EURNOK      9.4665      9.4665   0.0%   16 107789    nan
       Bitstamp EURUSD      1.1537      1.1593   0.5%    4      5      1
  Exchangerates EURUSD      1.1576      1.1576   0.0%   16 107789    nan
 BitcoinsNorway LTCEUR      1.0000     49.0000  98.0%   16    nan    nan
 BitcoinsNorway LTCNOK    492.4800    503.7500   2.2%   16    nan     60
 BitcoinsNorway LTCUSD      1.0221     49.0000  97.9%   15    nan    nan
     Norgesbank USDNOK      8.1777      8.1777   0.0%   16 107789    nan

The code for this client is too complex for a simple blog post, so you will have to check out the git repository to figure out how it work. What I can tell is how the three last numbers on each line should be interpreted. The first is how many seconds ago information was received from the service. The second is how long ago, according to the service, the provided information was updated. The last is an estimate on how often the buy/sell values change.

If you find this library useful, or would like to improve it, I would love to hear from you. Note that for some of the services I've implemented a trading API. It might be the topic of a future blog post.

As usual, if you use Bitcoin and want to show your support of my activities, please send Bitcoin donations to my address 15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

Tags: bitcoin, english.
VLC in Debian now can do bittorrent streaming
24th September 2018

Back in February, I got curious to see if VLC now supported Bittorrent streaming. It did not, despite the fact that the idea and code to handle such streaming had been floating around for years. I did however find a standalone plugin for VLC to do it, and half a year later I decided to wrap up the plugin and get it into Debian. I uploaded it to NEW a few days ago, and am very happy to report that it entered Debian a few hours ago, and should be available in Debian/Unstable tomorrow, and Debian/Testing in a few days.

With the vlc-plugin-bittorrent package installed you should be able to stream videos using a simple call to


It can handle magnet links too. Now if only native vlc had bittorrent support. Then a lot more would be helping each other to share public domain and creative commons movies. The plugin need some stability work with seeking and picking the right file in a torrent with many files, but is already usable. Please note that the plugin is not removing downloaded files when vlc is stopped, so it can fill up your disk if you are not careful. Have fun. :)

I would love to get help maintaining this package. Get in touch if you are interested.

As usual, if you use Bitcoin and want to show your support of my activities, please send Bitcoin donations to my address 15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

Tags: english, verkidetfri, video.
Using the Kodi API to play Youtube videos
2nd September 2018

I continue to explore my Kodi installation, and today I wanted to tell it to play a youtube URL I received in a chat, without having to insert search terms using the on-screen keyboard. After searching the web for API access to the Youtube plugin and testing a bit, I managed to find a recipe that worked. If you got a kodi instance with its API available from http://kodihost/jsonrpc, you can try the following to have check out a nice cover band.

curl --silent --header 'Content-Type: application/json' \
  --data-binary '{ "id": 1, "jsonrpc": "2.0", "method": "Player.Open",
  "params": {"item": { "file":
  "plugin://" } } }' \

I've extended kodi-stream program to take a video source as its first argument. It can now handle direct video links, youtube links and 'desktop' to stream my desktop to Kodi. It is almost like a Chromecast. :)

As usual, if you use Bitcoin and want to show your support of my activities, please send Bitcoin donations to my address 15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

Tags: debian, english, kodi, video.

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