In that case, you might also try ISBN search via Z39.50, and ask for an OPAC record to be returned. The call number comes back in a very predictable place, so it might be less trouble than screen scraping, and easier to adapt to different target libraries.

-Tod

> On Nov 29, 2021, at 10:50 AM, M Belvadi <[log in to unmask]> wrote:
> 
> Thank you all. I perhaps should have clarified that I am NOT trying to get
> a dump of a library's entire holdings. I just want to look for LC Call
> numbers for a few specific ISBNs, if they own that book with an LC call
> number.
> So I don't need the entire MARC record, and a dump would be incredibly
> inefficient and almost always out of date, as often the books I'm looking
> for are fairly new.
> 
> I am already using OCLC's Classify service, and I always check that first
> before trying any other site, but I find that that only has about 19 out of
> 20 that I look for, and when I look for the rest manually on various opacs,
> including UC's, I can often find about 50% of the missing ones. So I'm just
> trying to do that programmatically with BeautifulSoup.  I am also using
> Harvard's API as second choice to the ones that OCLC misses, but that
> almost never has the ones that OCLC didn't have, so I need more places to
> look and those are the only public APIs I've been able to find that have
> any chance of providing LC Calll Numbers (eg openlibrary and google apis
> have other metadata but not call numbers).
> 
> FYI, it seems to me that the new UC Library Search, when limited to the
> catalog which is what I want, is Alma underneath.
> 
> And further FYI, the reason I'm doing this is I'm attempting to write a
> python program that can take a COUNTER R5 book report and add to it LC call
> numbers to make it easier for librarians looking especially at the B1 (use)
> and B2 (turnaways) data to be able to quickly group the usage by "subject"
> since no kind of subject classification is included in the COUNTER standard.
> 
> When I have it completed, I will share it freely on Github, so I want to
> make sure I'm doing nothing furtive, but only touching servers whose owners
> wouldn't be upset to find themselves included in my code.
> 
> Melissa Belvadi
> [log in to unmask]
> 
> 
> On Mon, Nov 29, 2021 at 9:23 AM Eric Lease Morgan <[log in to unmask]> wrote:
> 
>> On Nov 28, 2021, at 6:01 AM, Peter Velikonja <[log in to unmask]> wrote:
>> 
>>> As Kyle mentioned, a screenscraping method is inefficient and will
>>> get you incomplete results.  As a vendor to public libraries, I routinely
>>> request (and receive) MARC dumps.  Some libraries are better than
>>> others at pulling these from their ILS, but records based on MARC come
>>> from the Library of Congress and are therefore public information -- to
>>> which you are entitled if you reside in the US.  A number of libraries
>>> make dumps available through various Open Data initiatives -- spotty but
>>> can be useful.  Screenscraping can be good for spot-checking, but if
>>> you want a complete catalog, working with an ILS administrator is, in
>>> my view, a better path.
>> 
>> 
>> I concur. See if you can get an MARC dump. If you are seeking the
>> bibliographic information, then this probably the most complete, accurate,
>> and efficient. --Eric Morgan
>>