13 digit ISBNs / EAN support / converting to ASINs

In my tests I have not been able to get a 13 digit ISBN to work yet, but may be related to http://drupal.org/node/302721

The Amazon ASIN number is often identical to the same product's ISBN-10 number. However, they are different things. My understanding is that products with 13 digit ISBNs (EANs) also have a 10 character ASIN. For more about the relationship between ISBN-13 numbers and ASINs, read https://affiliate-program.amazon.com/gp/associates/help/t5/a16.

Attached is a patch that implements a lookup for 13 character EANs for the ASIN CCK field. The lookup will validate and convert EANs to ASINs on save (converted during the presave op in hook_field). This lookup uses the Amazon API and therefore has the advantage of being an 'official' conversion from EAN to ASIN. You may also test EAN lookups in the admin test interface. This patch also wraps up the one-line fixes at #302721: Amazon field rejects any product ID. Amazon API test feature works fine though. and #329463: Force fetch when testing ASINs via admin interface.

In most locales, when looking up EANs, you must also specify the search index (e.g. "Books"). This patch adds the ability to configure which search index is used for EAN lookups on the module settings page. Possibly this should be configurable per instance of the ASIN CCK field.

Note: this patch applies against DRUPAL-6--1 but there's no release for 6.x-1.x-dev. It won't apply to 6.x-1.0-beta3.

Your patch worked like a charm for me. (The first patch I've ever installed, btw.) Thanks much!

Thanks for your work on this, and for being willing to contribute.

I'm concerned about the extent and complexity of this patch and would like to discuss it further. I also hate to trigger the child requests to Amazon.com that are a significant performance hit.

Note that Amazon Store has the categories already managed for all locales... Perhaps that should move into Amazon.

Interested in the discussion, here or on IRC. I'm often on.

I hope the ASIN field would accept data format like "0-672-32884-4 " (just remove all dashes and spaces automatically ). A quick dirty hack to do the job also will be welcome.

I just managed to put in the changes into the beta-10 and it works again with 13-digit ISBNs. But according to lots of changes in beta-10 it wasn't as easy as supposed to.

I would strongly suggest to put this patch into the destribution as it improves the amazon-module a lot.

Best regards
Stefan

@svogel, do you have a patch to contribute?

Amazon's API is about ASINs, so this module is also focused around ASINs. Amazon started out as a book company, and they based their identifiers around ISBNs, which were 10 digit. Well, they're stuck there.

You can read about this issue at this link. It looks to me like it would be complicated and beyond the scope of this module to do 13-digit ISBNs.

@conniec, I don't know everything about 13-digit ISBNs, but did you read the Amazon link about 13-digit ISBNs carefully? Your code must not just convert into a 10-digit ISBN, it must convert to the correct Amazon ASIN. If you have confidence you can do that, then I'm interested.

The patch in #8 does try to do this, and the ideas there, if they work, might end up working.

I'm using amazon.module revision 1.27.2.23 and I'm getting "Invalid argument supplied for foreach() in /home... on line 348 when using the ten and thirteen digit ASINs. This happens for both test and for live pages. I'm using Drupal 6.14. Is there something I'm missing in the setup, or is this a bug?

@volantis, there's no revision of that number in amazon module.... Or amazon_store.

I imagine you're testing with amazon and you don't have your AWS credentials configured. Your issue is going to be #608624: Test should detect and report invalid credentials. Please make sure to get an Amazon AWS account, configure the credentials, and then use a valid ASIN to test with (a 13-digit is not valid)

@conniec: I'm glad you're interested in this. I'll consider doing it, or maybe @tirsales will come back in with a current patch. The problem is that it requires a separate lookup just to get the ASIN, so is definitely a different thing.

@rfay

Actually, I did fill in the AWS credentials when I created the AWS account. However, I went back again after your comment to see if I copied them correctly. The credentials that I saw upon registering were completely different from the credentials I just saw. Other site administrators new to the Amazon Module in the future will want to check the information on the Your Account:Security Credentials page at aws.amazon.com. After changing to the right credentials, everything works fine.

I took a look at this tonight and feel like it's a bit destabilizing just as we're getting to a 1.0 release. I kind of feel like we're hacking at it and may need to step back.

Any complete solution should handle 13-char ASINs in

• Filters
• Views (including filters)
• CCK fields

I don't think I'm open to a new table that would map 13-digit ISBNs to ASINs, but that would be one way to do this.

The patches in #3 and #8 are decent working patches (out of date, of course), but they don't improve the overall quality of the code - they're workarounds to make the 13-digit ISBN work. Neither of those patches handles the database lookup (which is always by ASIN).

I think perhaps we should be looking at an "amazon_ean_mapper" module that we could add on. It could even maintain its own database table that mapped 13->10. It could intercept hook_filter calls... And it would be used only by those who want 13-digit EANs, so wouldn't have any impact on the code for the larger audience.

What do you say to this? Anybody rise to the challenge?

@conniec, just attach it to a comment in this issue. Zip it up, or tar it up, and attach it.

I think probably the best approach might be a module that does hook_form_alter to alter the ASIN field's input and goes and gets the 10-digit when a 13-digit is entered. That would do it for the CCK route.

For filters, perhaps there's a way for an add-on module to hook_filter and capture before Amazon gets to it (or after).

With this patch you can now use the following formats in either an Amazon ASIN field or a filter, and hyphens are stripped.

• ISBN-13/EAN: for example, 978-1890437541 or 9781890437541
• Amazon.com links, for example, http://www.amazon.com/More-That-Never-About-Colorado/dp/1890437549/ref=n...

So there are now several more options for input formats.

Please test it out and let me know if I broke anything.

Committed to HEAD: This will be in the next dev release.
http://drupal.org/cvs?commit=312126

The admin 'test' interface did not handle 13-digit ISBNs. It's updated in this patch.

Committed: http://drupal.org/cvs?commit=321336

Ups, sorry. I haven't looked into this one a long time.

I have used the patch from @mleicester
http://drupal.org/files/issues/amazon_ean_support.txt

No I didn't have a working patch, I did this line by line.

Best regards
Stefan