blog/archive/2018/09/09.rss

   1 <?xml version="1.0" encoding="ISO-8859-1"?>
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   3         <channel>
   4                 <title>Petter Reinholdtsen - Entries from September 2018</title>
   5                 <description>Entries from September 2018</description>
   6                 <link>http://www.hungry.com/~pere/blog/</link>
   7
   8
   9         <item>
  10                 <title>Valutakrambod - A python and bitcoin love story</title>
  11                 <link>http://www.hungry.com/~pere/blog/Valutakrambod___A_python_and_bitcoin_love_story.html</link>
  12                 <guid isPermaLink="true">http://www.hungry.com/~pere/blog/Valutakrambod___A_python_and_bitcoin_love_story.html</guid>
  13                 <pubDate>Sat, 29 Sep 2018 22:20:00 +0200</pubDate>
  14                 <description>&lt;p&gt;It would come as no surprise to anyone that I am interested in
  15 bitcoins and virtual currencies.  I&#39;ve been keeping an eye on virtual
  16 currencies for many years, and it is part of the reason a few months
  17 ago, I started writing a python library for collecting currency
  18 exchange rates and trade on virtual currency exchanges.  I decided to
  19 name the end result valutakrambod, which perhaps can be translated to
  20 small currency shop.&lt;/p&gt;
  21
  22 &lt;p&gt;The library uses the tornado python library to handle HTTP and
  23 websocket connections, and provide a asynchronous system for
  24 connecting to and tracking several services.  The code is available
  25 from
  26 &lt;a href=&quot;http://github.com/petterreinholdtsen/valutakrambod&quot;&gt;github&lt;/a&gt;.&lt;/p&gt;
  27
  28 &lt;/p&gt;There are two example clients of the library.  One is very simple and
  29 list every updated buy/sell price received from the various services.
  30 This code is started by running bin/btc-rates and call the client code
  31 in valutakrambod/client.py.  The simple client look like this:&lt;/p&gt;
  32
  33 &lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
  34 import functools
  35 import tornado.ioloop
  36 import valutakrambod
  37 class SimpleClient(object):
  38     def __init__(self):
  39         self.services = []
  40         self.streams = []
  41         pass
  42     def newdata(self, service, pair, changed):
  43         print(&quot;%-15s %s-%s: %8.3f %8.3f&quot; % (
  44             service.servicename(),
  45             pair[0],
  46             pair[1],
  47             service.rates[pair][&#39;ask&#39;],
  48             service.rates[pair][&#39;bid&#39;])
  49         )
  50     async def refresh(self, service):
  51         await service.fetchRates(service.wantedpairs)
  52     def run(self):
  53         self.ioloop = tornado.ioloop.IOLoop.current()
  54         self.services = valutakrambod.service.knownServices()
  55         for e in self.services:
  56             service = e()
  57             service.subscribe(self.newdata)
  58             stream = service.websocket()
  59             if stream:
  60                 self.streams.append(stream)
  61             else:
  62                 # Fetch information from non-streaming services immediately
  63                 self.ioloop.call_later(len(self.services),
  64                                        functools.partial(self.refresh, service))
  65                 # as well as regularly
  66                 service.periodicUpdate(60)
  67         for stream in self.streams:
  68             stream.connect()
  69         try:
  70             self.ioloop.start()
  71         except KeyboardInterrupt:
  72             print(&quot;Interrupted by keyboard, closing all connections.&quot;)
  73             pass
  74         for stream in self.streams:
  75             stream.close()
  76 &lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;
  77
  78 &lt;p&gt;The library client loops over all known &quot;public&quot; services,
  79 initialises it, subscribes to any updates from the service, checks and
  80 activates websocket streaming if the service provide it, and if no
  81 streaming is supported, fetches information from the service and sets
  82 up a periodic update every 60 seconds.  The output from this client
  83 can look like this:&lt;/p&gt;
  84
  85 &lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
  86 Bl3p            BTC-EUR: 5687.110 5653.690
  87 Bl3p            BTC-EUR: 5687.110 5653.690
  88 Bl3p            BTC-EUR: 5687.110 5653.690
  89 Hitbtc          BTC-USD: 6594.560 6593.690
  90 Hitbtc          BTC-USD: 6594.560 6593.690
  91 Bl3p            BTC-EUR: 5687.110 5653.690
  92 Hitbtc          BTC-USD: 6594.570 6593.690
  93 Bitstamp        EUR-USD:    1.159    1.154
  94 Hitbtc          BTC-USD: 6594.570 6593.690
  95 Hitbtc          BTC-USD: 6594.580 6593.690
  96 Hitbtc          BTC-USD: 6594.580 6593.690
  97 Hitbtc          BTC-USD: 6594.580 6593.690
  98 Bl3p            BTC-EUR: 5687.110 5653.690
  99 Paymium         BTC-EUR: 5680.000 5620.240
 100 &lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;
 101
 102 &lt;p&gt;The exchange order book is tracked in addition to the best buy/sell
 103 price, for those that need to know the details.&lt;/p&gt;
 104
 105 &lt;p&gt;The other example client is focusing on providing a curses view
 106 with updated buy/sell prices as soon as they are received from the
 107 services.  This code is located in bin/btc-rates-curses and activated
 108 by using the &#39;-c&#39; argument.  Without the argument the &quot;curses&quot; output
 109 is printed without using curses, which is useful for debugging.  The
 110 curses view look like this:&lt;/p&gt;
 111
 112 &lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
 113            Name Pair   Bid         Ask         Spr    Ftcd    Age
 114  BitcoinsNorway BTCEUR   5591.8400   5711.0800   2.1%   16    nan     60
 115        Bitfinex BTCEUR   5671.0000   5671.2000   0.0%   16     22     59
 116         Bitmynt BTCEUR   5580.8000   5807.5200   3.9%   16     41     60
 117          Bitpay BTCEUR   5663.2700         nan   nan%   15    nan     60
 118        Bitstamp BTCEUR   5664.8400   5676.5300   0.2%    0      1      1
 119            Bl3p BTCEUR   5653.6900   5684.9400   0.5%    0    nan     19
 120        Coinbase BTCEUR   5600.8200   5714.9000   2.0%   15    nan    nan
 121          Kraken BTCEUR   5670.1000   5670.2000   0.0%   14     17     60
 122         Paymium BTCEUR   5620.0600   5680.0000   1.1%    1   7515    nan
 123  BitcoinsNorway BTCNOK  52898.9700  54034.6100   2.1%   16    nan     60
 124         Bitmynt BTCNOK  52960.3200  54031.1900   2.0%   16     41     60
 125          Bitpay BTCNOK  53477.7833         nan   nan%   16    nan     60
 126        Coinbase BTCNOK  52990.3500  54063.0600   2.0%   15    nan    nan
 127         MiraiEx BTCNOK  52856.5300  54100.6000   2.3%   16    nan    nan
 128  BitcoinsNorway BTCUSD   6495.5300   6631.5400   2.1%   16    nan     60
 129        Bitfinex BTCUSD   6590.6000   6590.7000   0.0%   16     23     57
 130          Bitpay BTCUSD   6564.1300         nan   nan%   15    nan     60
 131        Bitstamp BTCUSD   6561.1400   6565.6200   0.1%    0      2      1
 132        Coinbase BTCUSD   6504.0600   6635.9700   2.0%   14    nan    117
 133          Gemini BTCUSD   6567.1300   6573.0700   0.1%   16     89    nan
 134          Hitbtc+BTCUSD   6592.6200   6594.2100   0.0%    0      0      0
 135          Kraken BTCUSD   6565.2000   6570.9000   0.1%   15     17     58
 136   Exchangerates EURNOK      9.4665      9.4665   0.0%   16 107789    nan
 137      Norgesbank EURNOK      9.4665      9.4665   0.0%   16 107789    nan
 138        Bitstamp EURUSD      1.1537      1.1593   0.5%    4      5      1
 139   Exchangerates EURUSD      1.1576      1.1576   0.0%   16 107789    nan
 140  BitcoinsNorway LTCEUR      1.0000     49.0000  98.0%   16    nan    nan
 141  BitcoinsNorway LTCNOK    492.4800    503.7500   2.2%   16    nan     60
 142  BitcoinsNorway LTCUSD      1.0221     49.0000  97.9%   15    nan    nan
 143      Norgesbank USDNOK      8.1777      8.1777   0.0%   16 107789    nan
 144 &lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;
 145
 146 &lt;p&gt;The code for this client is too complex for a simple blog post, so
 147 you will have to check out the git repository to figure out how it
 148 work.  What I can tell is how the three last numbers on each line
 149 should be interpreted.  The first is how many seconds ago information
 150 was received from the service.  The second is how long ago, according
 151 to the service, the provided information was updated.  The last is an
 152 estimate on how often the buy/sell values change.&lt;/p&gt;
 153
 154 &lt;p&gt;If you find this library useful, or would like to improve it, I
 155 would love to hear from you.  Note that for some of the services I&#39;ve
 156 implemented a trading API.  It might be the topic of a future blog
 157 post.&lt;/p&gt;
 158
 159 &lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
 160 activities, please send Bitcoin donations to my address
 161 &lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
 162 </description>
 163         </item>
 164
 165         <item>
 166                 <title>VLC in Debian now can do bittorrent streaming</title>
 167                 <link>http://www.hungry.com/~pere/blog/VLC_in_Debian_now_can_do_bittorrent_streaming.html</link>
 168                 <guid isPermaLink="true">http://www.hungry.com/~pere/blog/VLC_in_Debian_now_can_do_bittorrent_streaming.html</guid>
 169                 <pubDate>Mon, 24 Sep 2018 21:20:00 +0200</pubDate>
 170                 <description>&lt;p&gt;Back in February, I got curious to see
 171 &lt;a href=&quot;https://people.skolelinux.org/pere/blog/Using_VLC_to_stream_bittorrent_sources.html&quot;&gt;if
 172 VLC now supported Bittorrent streaming&lt;/a&gt;.  It did not, despite the
 173 fact that the idea and code to handle such streaming had been floating
 174 around for years.  I did however find
 175 &lt;a href=&quot;https://github.com/johang/vlc-bittorrent&quot;&gt;a standalone plugin
 176 for VLC&lt;/a&gt; to do it, and half a year later I decided to wrap up the
 177 plugin and get it into Debian.  I uploaded it to NEW a few days ago,
 178 and am very happy to report that it
 179 &lt;a href=&quot;https://tracker.debian.org/pkg/vlc-plugin-bittorrent&quot;&gt;entered
 180 Debian&lt;/a&gt; a few hours ago, and should be available in Debian/Unstable
 181 tomorrow, and Debian/Testing in a few days.&lt;/p&gt;
 182
 183 &lt;p&gt;With the vlc-plugin-bittorrent package installed you should be able
 184 to stream videos using a simple call to&lt;/p&gt;
 185
 186 &lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
 187 vlc https://archive.org/download/TheGoat/TheGoat_archive.torrent
 188 &lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;
 189
 190 &lt;/p&gt;It can handle magnet links too.  Now if only native vlc had
 191 bittorrent support.  Then a lot more would be helping each other to
 192 share public domain and creative commons movies.  The plugin need some
 193 stability work with seeking and picking the right file in a torrent
 194 with many files, but is already usable.  Please note that the plugin
 195 is not removing downloaded files when vlc is stopped, so it can fill
 196 up your disk if you are not careful.  Have fun. :)&lt;/p&gt;
 197
 198 &lt;p&gt;I would love to get help maintaining this package.  Get in touch if
 199 you are interested.&lt;/p&gt;
 200
 201 &lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
 202 activities, please send Bitcoin donations to my address
 203 &lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
 204 </description>
 205         </item>
 206
 207         <item>
 208                 <title>Using the Kodi API to play Youtube videos</title>
 209                 <link>http://www.hungry.com/~pere/blog/Using_the_Kodi_API_to_play_Youtube_videos.html</link>
 210                 <guid isPermaLink="true">http://www.hungry.com/~pere/blog/Using_the_Kodi_API_to_play_Youtube_videos.html</guid>
 211                 <pubDate>Sun, 2 Sep 2018 23:40:00 +0200</pubDate>
 212                 <description>&lt;p&gt;I continue to explore my Kodi installation, and today I wanted to
 213 tell it to play a youtube URL I received in a chat, without having to
 214 insert search terms using the on-screen keyboard.  After searching the
 215 web for API access to the Youtube plugin and testing a bit, I managed
 216 to find a recipe that worked.  If you got a kodi instance with its API
 217 available from http://kodihost/jsonrpc, you can try the following to
 218 have check out a nice cover band.&lt;/p&gt;
 219
 220 &lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;curl --silent --header &#39;Content-Type: application/json&#39; \
 221   --data-binary &#39;{ &quot;id&quot;: 1, &quot;jsonrpc&quot;: &quot;2.0&quot;, &quot;method&quot;: &quot;Player.Open&quot;,
 222   &quot;params&quot;: {&quot;item&quot;: { &quot;file&quot;:
 223   &quot;plugin://plugin.video.youtube/play/?video_id=LuRGVM9O0qg&quot; } } }&#39; \
 224   http://projector.local/jsonrpc&lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;
 225
 226 &lt;p&gt;I&#39;ve extended kodi-stream program to take a video source as its
 227 first argument.  It can now handle direct video links, youtube links
 228 and &#39;desktop&#39; to stream my desktop to Kodi.  It is almost like a
 229 Chromecast. :)&lt;/p&gt;
 230
 231 &lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
 232 activities, please send Bitcoin donations to my address
 233 &lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
 234 </description>
 235         </item>
 236
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 238 </rss>