That makes some sense.  It would be good to know what those APIs are, since presumably everyone will (eventually) be moving towards a 13-digit basis.  

For our purposes, we already establish via pre-processing which ISBN we want to use for enhanced content matching (and move it to the front of the array), so getCleanISBN skipping over to the first 10-digit value was a surprise.  


On Tue, Sep 24, 2013 at 10:26 PM, Demian Katz <> wrote:
Several of the APIs VuFind uses only work correctly with 10-digit ISBNs (perhaps this has changed by now, but it at least used to be the case), and it's always possible to convert a 10-digit ISBN to a 13-digit ISBN if necessary, while the reverse is not always possible. Thus, if a 10-digit ISBN is available, and assuming all other things are equal, it's preferable to a 13-digit ISBN since it offers the widest range of compatibility.

- Demian

From: Joe Atzberger []
Sent: Tuesday, September 24, 2013 5:23 PM
To: vufind-tech Tech
Subject: [VuFind-Tech] getCleanISBN logic

What is the rationale behind getCleanISBN()'s preference for 10-digit ISBNs?