# /research/projects/xisbn/technical.htm

originally: http://www.oclc.org/research/projects/xisbn/technical.htm

# xISBN—Technical details

Note: The experimental xISBN prototype transitioned to production service on 15 February 2007. The information here is provided for historical purposes only. Information about the new service is available at http://www.worldcat.org/affiliate/webservices/xisbn/app.jsp.

The xISBN service is a REST-based web service. Queries sent to the service must take the form of URLs. The user may choose from either an XML (default) or XHTML response. Because several cases are possible with any given ISBN, the information below summarizes how the service will respond to common situations:

## ISBN is valid:

- single ISBN linked to single work which has multiple ISBN's
  - All ISBN values are returned in a list:
    - ISBN passed into the service is always returned as the first ISBN
    - Following the initial ISBN, values are returned ranked by holdings in WorldCat (i.e. number of libraries signifying ownership of item against respective bibliographic records) - order is descending (most held to least held)

    For example, the URI http://labs.oclc.org/xisbn/0192816640 [The Expedition of Humphrey Clinker / George Tobias Smollett] returns XML:

        <?xml version="1.0" encoding="UTF-8" ?>
        - <idlist>
            <isbn>0192816640</isbn>
            <isbn>0820312037</isbn>
            <isbn>0820315370</isbn>
            <isbn>0393015920</isbn>
            <isbn>0393952274</isbn>
            <isbn>0393952835</isbn>
            <isbn>0140430210</isbn>
            <isbn>0192811320</isbn>
            <isbn>0192835947</isbn>
            <isbn>0460872885</isbn>
            <isbn>1853262706</isbn>
            <isbn>0874131219</isbn>
        </idlist>

    Alternately if an XTHML response is preferred, the same query with the value ".html" appended - e.g., http://labs.oclc.org/xisbn/0192816640.html returns:

        <!DOCTYPE html
            PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
            "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
        <html xmlns="http://www.w3.org/1999/xhtml">
        <head><title>ISBN List</title></head>
        <body>
        <a>0192816640</a><br/>
        <a>0820312037</a><br/>
        <a>0820315370</a><br/>
        <a>0393015920</a><br/>
        <a>0393952274</a><br/>
        <a>0393952835</a><br/>
        <a>0140430210</a><br/>
        <a>0192811320</a><br/>
        <a>0192835947</a><br/>
        <a>0460872885</a><br/>
        <a>1853262706</a><br/>
        <a>0874131219</a><br/>
        </body>
        </html>

- single ISBN linked to multiple works with multiple ISBNs:
  - All ISBN values for the dominant work (i.e. most records/most holdings) are returned in a list as above
    - Note: ISBN's linked to works other than dominant work are not returned.
      - Example: 0736691316 is associated with both:
        - Harry Potter and the prisoner of Azkaban [sound recording] / J.K. Rowling
        - The speed of dark [sound recording] / by Elizabeth Moon
- "one-off's" -- single ISBN linked to a single work which has only a single ISBN:
  - The ISBN value in the query is the only value returned
  - For example: http://labs.oclc.org/xisbn/8878120677 [Seminario FRBR : Functional requirements for bibliographic records = Requisiti funzionali per record bibliografici : Firenze, 27-28 gennaio 2000 ] returns:

        <?xml version="1.0" encoding="UTF-8" ?>
        - <idlist>
            <isbn>8878120677</isbn>
        </idlist>

- valid ISBN but unknown to xISBN service (i.e. the ISBN does not appear in WorldCat) - same response as "one-off" ISBN:
  - The ISBN value in the query is the only value returned
  - For example: http://labs.oclc.org/xisbn/9570140445 [National Digital Archives Program 2003 (National Science Council, R.O.C.)] returns:

        <?xml version="1.0" encoding="UTF-8" ?>
        - <idlist>
            <isbn>9570140445</isbn>
        </idlist>

- Note: the xISBN service automatically normalizes values - e.g., dashes are removed before the query is run so users may supply ISBN values with or without dashes.

## ISBN is invalid:

- If the ISBN does not appear to be a valid ISBN, then that it is tagged as an <unknownID> and returned.
- For example: http://labs.oclc.org/xisbn/10001000 returns:

      <?xml version="1.0" encoding="UTF-8" ?>
      - <idlist>
          <unknownID>10001000</unknownID>
      </idlist>

## Terms of availability

Note: The experimental xISBN prototype transitioned to production service on 15 February 2007. The information here is provided for historical purposes only. Information about the new service is available at http://www.worldcat.org/affiliate/webservices/xisbn/app.jsp.

As an experimental project of OCLC Research, the service is available without charge or guarantee. Access does not require registration or authentication. OCLC reserves the right to modify or discontinue the service without prior notice. The xISBN server is believed to be stable, have good uptime, and to have the capacity to handle a reasonably high volume of requests without a significant degradation of response time or service failures, but OCLC does not guarantee service levels for experimental systems.

## Further information

- Inquiries: contact Thom Hickey (hickey@oclc.org)