Re: SV: Integrating Google Book Search content into OPACs

GoogleBook API is designed to allow an asynchronous workflow:

   1. Client web browser send a request to Library server.
   2. Library server send back biblio records to client
   3. Client web browser display the HTML document containing biblio
      records.
   4. Client send to GoogleBook via JavaScript a list of retrieved bilio
      records isbn
   5. GoogleBook send back a list of image URLs for each available ISBN
      in GoogleBook.
   6. A JavaScript callback function receive URLs sent by GoogleBook and
      insert images into already displayed HTML document.

That's why there is a delay to display book cover images: at step 3
biblio records are already displayed but images are only available at
step 6.

All AJAX applications may encounter this delay. Spinning wait icons have
been created for this purpose:

    http://www.andrewdavidson.com/articles/spinning-wait-icons/

GoogleBook design has drawbacks:

    * delay
    * client IP-ISBN tracking as said by someone (Google-Big brother
      syndrome?)

But also advantages:

    * a light html document containing search result can be displayed
      quickly
    * with client IP address, GoogleBook knows where client comes from
      and so can send geographical relevant information like 'see this
      book in a local bookstore' links.

--
Frédéric