---+ Shortening URIs with Virtuoso

Long URLs are hard for humans to type or remember, and don't work very well with short message services like [[http://twitter.com/OpenLink][Twitter]] or [[http://identi.ca/kidehen][identi.ca]].

*CURIs* are compressed URIs which redirect to the original long URL.  They are easier to share, type, and use in general.  

The Virtuoso URI Shortener offers a way to do this in your own domain and data space, without reliance on external services such as [[http://bit.ly/][bit.ly]], [[http://is.gd/][is.gd]], or [[http://tinyurl.com/][tinyurl.com]].

%TOC%

---++How does it work?

All full-length URIs are stored in a Virtuoso database table which keeps a unique ID number for each URI. This ID is converted to base32 encoding, which only uses uppercase letters and numbers from 2 to 7, for use in the CURI. 

<i><b>Note</b>: numbers 1 and 0 are not used in this encoding, eliminating the common visual confusion between uppercase o and number 0, and between uppercase i, lowercase L, and number 1.</i>

---+++ Configuration Options

The prefix for loading images, CSS, etc., can be set through the Virtuoso INI file option, <code><nowiki>CURIUISkinPrefix</nowiki></code>.

---++Package Installation and Accessibility

   1. Download the [[https://virtuoso.openlinksw.com/download/][Virtuoso URI Shortener VAD]] package.
   2. Install the package through the Virtuoso Conductor from the <code><nowiki>System Admin -> Packages</nowiki></code> tab or using the isql command line program as shown below:
<verbatim>
SQL> DB.DBA.VAD_INSTALL('tmp/c_uri_dav.vad',0);
VARCHAR  VARCHAR
_______________________________________________________________________________

00000    No errors detected
00000    Installation of "OpenLink Virtuoso URI Shortener" is complete.
00000    Now making a final checkpoint.
00000    Final checkpoint is made.
00000    SUCCESS


6 Rows. -- 1766 msec.
</verbatim>
   3. Go to Endpoint  - http://&lt;cname&gt;/c
      * Note: you could also use the page:<code><nowiki>http://&lt;cname&gt;[:&lt;port&gt;]/c/create.vsp?uri=xx</nowiki></code>
   4. Paste in long URL.

---++Example

   * Load your service, e.g., <code><nowiki>http://&lt;cname&gt;/c</nowiki></code> in your browser.
%BR%%BR%<img src="%ATTACHURLPATH%/c1.png" />%BR%%BR%
   * Enter a URI, e.g., 
<verbatim>
http://lod.openlinksw.com/sparql?default-graph-uri=&amp;should-sponge=&amp;query=SELECT+%3Fx%0D%0AWHERE%0D%0A++{%0D%0A++++%3Fx++foaf%3Aname++%22Alice%22++.%0D%0A++++FILTER%0D%0A++++++%28%0D%0A++++++++bif%3Aexists%0D%0A++++++++++%28+%28%0D%0A+++++++++++++SELECT+*%0D%0A+++++++++++++WHERE%0D%0A+++++++++++++++{%0D%0A+++++++++++++++++%3Fx++foaf%3Aknows++%3Fy++++++.%0D%0A+++++++++++++++++%3Fy++foaf%3Aname+++%22John%22%0D%0A+++++++++++++++}%0D%0A++++++++++%29+%29%0D%0A++++++%29%0D%0A++}&amp;format=text%2Fhtml&amp;debug=on&amp;timeout=
</verbatim>
%BR%%BR%<img src="%ATTACHURLPATH%/c2.png" />%BR%%BR%
   * Click <b>Make CURI</b>.
   * A new CURI will be created and displayed, e.g.,
<verbatim>
http://&lt;cname&gt;/c/7EFF
</verbatim>
%BR%%BR%<img src="%ATTACHURLPATH%/c3.png" />%BR%%BR%