blog/data/2013-02-12-qr-invoice.txt

   1 Title: "Electronic" paper invoices - using vCard in a QR code
   2 Tags: english, standard
   3 Date: 2013-02-12 10:30
   4
   5 <p>Here in Norway, electronic invoices are spreading, and the
   6 <a href="http://www.anskaffelser.no/e-handel/faktura">solution promoted
   7 by the Norwegian government</a> require that invoices are sent through
   8 one of the approved facilitators, and it is not possible to send
   9 electronic invoices without an agreement with one of these
  10 facilitators.  This seem like a needless limitation to be able to
  11 transfer invoice information between buyers and sellers.  My preferred
  12 solution would be to just transfer the invoice information directly
  13 between seller and buyer, for example using SMTP, or some HTTP based
  14 protocol like REST or SOAP.  But this might also be overkill, as the
  15 "electronic" information can be transferred using paper invoices too,
  16 using a simple bar code.  My bar code encoding of choice would be QR
  17 codes, as this encoding can be read by any smart phone out there.  The
  18 content of the code could be anything, but I would go with
  19 <a href="http://en.wikipedia.org/wiki/VCard">the vCard format</a>, as
  20 it too is supported by a lot of computer equipment these days.</p>
  21
  22 <p>The vCard format support extentions, and the invoice specific
  23 information can be included using such extentions.  For example an
  24 invoice from SLX Debian Labs (picked because we
  25 <a href="http://www.linuxiskolen.no/slxdebianlabs/donations.html">ask
  26 for donations to the Debian Edu project</a> and thus have bank account
  27 information publicly available) for NOK 1000.00 could have these extra
  28 fields:</p>
  29
  30 <p><pre>
  31 X-INVOICE-NUMBER:1
  32 X-INVOICE-AMOUNT:NOK1000.00
  33 X-INVOICE-KID:123412341234
  34 X-INVOICE-MSG:Donation to Debian Edu
  35 X-BANK-ACCOUNT-NUMBER:16040884339
  36 X-BANK-IBAN-NUMBER:NO8516040884339
  37 X-BANK-SWIFT-NUMBER:DNBANOKKXXX
  38 </pre></p>
  39
  40 <p>The X-BANK-ACCOUNT-NUMBER field was proposed in a stackoverflow
  41 answer regarding
  42 <a href="http://stackoverflow.com/questions/10045664/storing-bank-account-in-vcard-file">how
  43 to put bank account information into a vCard</a>.  For payments in
  44 Norway, either X-INVOICE-KID (payment ID) or X-INVOICE-MSG could be
  45 used to pass on information to the seller when paying the invoice.</p>
  46
  47 <p>The complete vCard could look like this:</p>
  48
  49 <p><pre>
  50 BEGIN:VCARD
  51 VERSION:2.1
  52 ORG:SLX Debian Labs Foundation
  53 ADR;WORK:;;Gunnar Schjelderups vei 29D;OSLO;;0485;Norway
  54 URL;WORK:http://www.linuxiskolen.no/slxdebianlabs/
  55 EMAIL;PREF;INTERNET:sdl-styret@rt.nuug.no
  56 REV:20130212T095000Z
  57 X-INVOICE-NUMBER:1
  58 X-INVOICE-AMOUNT:NOK1000.00
  59 X-INVOICE-MSG:Donation to Debian Edu
  60 X-BANK-ACCOUNT-NUMBER:16040884339
  61 X-BANK-IBAN-NUMBER:NO8516040884339
  62 X-BANK-SWIFT-NUMBER:DNBANOKKXXX
  63 END:VCARD
  64 </pre></p>
  65
  66 <p>The resulting QR code created using
  67 <a href="http://fukuchi.org/works/qrencode/">qrencode</a> would look
  68 like this, and should be readable (and thus checkable) by any smart
  69 phone, or for example the <a href="http://zbar.sourceforge.net/">zbar
  70 bar code reader</a> and feed right into the approval and accounting
  71 system.</p>
  72
  73 <p><img src="http://people.skolelinux.org/pere/blog/images/2013-02-12-qr-invoice.png"></p>
  74
  75 <p>The extension fields will most likely not show up in any normal
  76 vCard reader, so those parts would have to go directly into a system
  77 handling invoices.  I am a bit unsure how vCards without name parts
  78 are handled, but a simple test indicate that this work just fine.</p>
  79
  80 <p><strong>Update 2013-02-12 11:30</strong>: Added KID to the proposal
  81 based on feedback from Sturle Sunde.</p>