Amazon Machine Tags

Description

Simple inclusion of Amazon items through machine tags.

1. Identifies any tag in the machine or triple tag form book:isbn=1234567890 or amazon:asin=1234567890. Works with native tags from WordPress 2.3 and later, Bunny’s Technorati Tags, and Jerome’s Keywords.
2. Gets the item information and a thumbnail image from the Amazon Web Services API.
3. Displays the item(s) in the sidebar or in a blog article with a link to the visitor’s best match (if the ip2country plugin is installed) or a default Amazon shop of your choice.
4. If you are an Amazon Associate for that locale, your Associate ID is included automatically.

You can edit the server-side, semantic and valid XHTML output via XSLT, change the CSS, or translate the admin interface through PO-files.

Screenshots

Installation

1. Upload the whole amazon-machine-tags folder into the wp-content/plugins/ directory.
2. Activate the plugin through the ‘Plugins’ menu in WordPress. Make sure that you don’t run it on localhost as XML files on the server need to be reached from the outside.
3. Get your own Amazon Web Services Access Key Identifyers.
4. Create a wp-content/cache/ directory with permissions set to 755, or 777 if you create the directory as root user.
5. Put <?php AMTAP::get_items(); ?> in your sidebar and start using machine tags.
6. Edit amtap-blog.css if you like.
7. If you want to use tags in a blog article, write [amtap book:isbn=1234567890] or [amtap amazon:asin=1234567890].

FAQ

Does it work in the sidebar on Pages, too?

Posts have tags, pages don’t, so it doesn’t work on those by default. But there’s a plugin called tags4page that enables tags for pages. Works like a charm.

Is there a limit of how many items can be requested?

Yes, Amazon has a limit of 10 items per request. Since they are separate requests, you can use a maximum of 10 items in the content plus a maximum of 10 in the sidebar.

Would it be possible to cache the images?

Technically it wouldn’t be a problem, but the Amazon Product Advertising API license explicitly forbids caching of images (see 5.1.10). Sorry.

I need to a larger thumbnail (medium), but can’t seem to find a place to edit the size of the image being requested.

The image size can be edited in the XSLT. The original result is a XML file that is transformed by Amazon using your local copy of amtap-html-sidebar.xsl and amtap-html-content.xsl, respectively. Replacing every occurance of .//aws:TinyImage with .//aws:MediumImage in lines 73-83 should do the trick.

You can view the original XML when you activate the “debug” option in the admin interface so that the request string is printed as a comment in the sidebar’s source code. XSLT is a very powerful tool, and there’s a lot more in the XML, for example customer reviews.

Getting an error about “private IP address space”?

The error message means you are running the blog on something like localhost. Amazon Web Services needs to get an XML file from your server, obviously that is impossible when it’s not located on a server that can be accessed with a public IP address from the outside.

Are all options really required?

No. The only required fields are the Amazon Web Services Access Key ID and your Secret Access Key. You can leave the others, they are set to defaults then.

Reviews

Contributors & Developers

Changelog

• 3.0.2: Bugfix in SHA256 calculation.
• 3.0.1: Fixed a bug in setting the timestamp that caused the key validation to fail. The included SHA256 encryption now has a GNU Lesser GPL.
• 3.0: Added signed requests for the new Amazon authorization requirement. Updated the API version to 2009-07-01 (please note: if you use your own XSL files, you must update the version in the XML namespace URL). Updated links.
• 2.0: Added fields for editing the sidebar headline, link target, and displaying rating stars. Added an error message if the plugin is run from a private IP address space. Changed priorities for price selection, they are now: LowestNewPrice, ListPrice, first offer, LowestUsedPrice. Added support for the display of an artist name. Added rating stars. Fixed EAN numbers with a dash. Fixed cutting of titles after a period. Changed CSS and XSL files.
• 1.1.3: Changed amtap-admin.css and amtap-admin.inc.php to make the admin interface look prettier with WordPress 2.5.
• 1.1.2: Fixed a bug in amtap.php when there are no other tags but default tags.
• 1.1.1: Fixed the sort order of inline items, a bug for returning an error message when the cache file is not writable, and added Amazon’s limit of 10 items per request.
• 1.1.0: Fixed the display of inline tags on the home page. Improved regular expression for filtering inline tags.
• 1.0.6: Fixed a bug introduced through the new function when there were no items to be displayed in the sidebar.
• 1.0.5: Added an option for default items on every page. Changed amtap-html-sidebar.xsl to sort items in the order of the request.
• 1.0.4: Bugfix for replacement of dollar characters in content. Also content items are now cached separately.
• 1.0.3: Fixed the display of inline tags on category pages.
• 1.0.2: Changed the plugin path from amtap to amazon-machine-tags for consistency with the file structure in the zipped file.
• 1.0.1: Bugfix for native WordPress tags.