Net::Amazon - Framework for accessing amazon.com via SOAP and XML/HTTP use Net::Amazon; my $ua = Net::Amazon->new(token => 'YOUR_AMZN_TOKEN'); # Get a request object my $response = $ua->search(asin => '0201360683'); if($response->is_success()) { print $response->as_string(), "\n"; } else { print "Error: ", $response->message(), "\n"; } Net::Amazon provides an object-oriented interface to amazon.com's SOAP and XML/HTTP interfaces. This way it's possible to create applications using Amazon's vast amount of data via a functional interface, without having to worry about the underlying communication mechanism. "Net::Amazon" works very much like "LWP": First you define a useragent like my $ua = Net::Amazon->new( token => 'YOUR_AMZN_TOKEN', max_pages => 3, ); which you pass your personal amazon developer's token (can be obtained from <http://amazon.com/soap>) and (optionally) the maximum number of result pages the agent is going to request from Amazon in case all results don't fit on a single page (typically holding 20 items). Note that each new page requires a minimum delay of 1 second to comply with Amazon's one-query-per-second policy. According to the different search methods on Amazon, there's a bunch of different request types in "Net::Amazon". The user agent's convenience method "search()" triggers different request objects, depending on which parameters you pass to it: The "asin" parameter has Net::Amazon search for an item with the specified ASIN. If the specified value is an arrayref instead of a single scalar, like in $ua->search(asin => ["0201360683", "0596005083"]) then a search for multiple ASINs is performed, returning a list of results. The "artist" parameter has the user agent search for items created by the specified artist. Can return many results. Returns a list of items by category ID (node). For example node "4025" is the CGI books category. You can add a keywords parameter to filter the results by that keyword. Returns an item offered by a third-party seller. The item is referenced by the so-called exchange ID. Search by keyword, mandatory parameters "keyword" and "mode". Can return many results. Search for all items in a specified wishlist. Can return many results. Music search by UPC (product barcode), mandatory parameter "upc". "mode" has to be set to "music". Returns at most one result. Search for all items similar to the one represented by the ASIN provided. Can return many results. Initiate a power search for all books matching the power query. Can return many results. See Net::Amazon::Request::Power for details. Initiate a search for all items made by a given manufacturrer. Can return many results. See Net::Amazon::Request::Manufacturer for details. Initiate a search for items in all categories. Start a search on items sold by a specific third-party seller, referenced by its ID (not seller name). Find items related to keywords within a text stream. The user agent's "search" method returns a response object, which can be checked for success or failure: if($resp->is_success()) { print $resp->as_string(); } else { print "Error: ", $resp->message(), "\n"; } In case the request for an item search succeeds, the response contains one or more Amazon 'properties', as it calls the products found. All matches can be retrieved from the Response object using it's "properties()" method. In case the request fails, the response contains one or more error messages. The response object's "message()" method will return it (or them) as a single string, while "messages()" (notice the plural) will return a reference to an array of message strings. Response objects always have the methods "is_success()", "is_error()", "message()", "total_results()", "as_string()" and "properties()" available. "total_results()" returns the total number of results the search yielded. "properties()" returns one or more "Net::Amazon::Property" objects of type "Net::Amazon::Property" (or one of its subclasses like "Net::Amazon::Property::Book", "Net::Amazon::Property::Music" or Net::Amazon::Property::DVD), each of which features accessors named after the attributes of the product found in Amazon's database: for ($resp->properties) { print $_->Asin(), " ", $_->OurPrice(), "\n"; } In scalar context, "properties()" just returns the first "Net::Amazon::Property" object found. Commonly available accessors to "Net::Amazon::Property" objects are "OurPrice()", "ImageUrlLarge()", "ImageUrlMedium()", "ImageUrlSmall()", "ReleaseDate()", "Catalog()", "Asin()", "url()", "Manufacturer()", "UsedPrice()", "ListPrice()", "ProductName()", "Availability()", "SalesRank()", "CollectiblePrice()", "CollectibleCount()", "NumberOfOfferings()", "UsedCount()", "ThirdPartyNewPrice()", "ThirdPartyNewCount()", "similar_asins()". For details, check Net::Amazon::Property. Also, the specialized classes "Net::Amazon::Property::Book" and "Net::Amazon::Property::Music" feature convenience methods like "authors()" (returning the list of authors of a book) or "album()" for CDs, returning the album title. Customer reviews: Every property features a "review_set()" method which returns a "Net::Amazon::Attribute::ReviewSet" object, which in turn offers a list of "Net::Amazon::Attribute::Review" objects. Check the respective man pages for details on what's available.

Requests behind the scenes
"Net::Amazon"'s "search()" method is just a convenient way to create different kinds of request objects behind the scenes and trigger them to send requests to Amazon. Depending on the parameters fed to the "search" method, "Net::Amazon" will determine the kind of search requested and create one of the following request objects: Search by ASIN, mandatory parameter "asin". Returns at most one result. Music search by Artist, mandatory parameter "artist". Can return many results. Returns category (node) listing. Mandatory parameters "browsenode" (must be numeric) and "mode". Can return many results. Keyword search, mandatory parameters "keyword" and "mode". Can return many results. Music search by UPC (product barcode), mandatory parameter "upc". "mode" has to be set to "music". Returns at most one result. 'Blended' search on a keyword, resulting in matches across the board. No 'mode' parameter is allowed. According to Amazon's developer's kit, this will result in up to three matches per category and can yield a total of 45 matches. Understands power search strings. See Net::Amazon::Request::Power for details. Mandatory parameter "power". Searches for all items made by a given manufacturer. Mandatory parameter "manufacturer". Finds items similar to a given one. Find item on someone's wish list. Searches for a third-party seller on Amazon by seller ID. This search is different than the previous ones, since it doesn't return Amazon items, but a single seller record. Don't use the "properties()" method on the response, use "result()" instead, which returns a Net::Amazon::Result::Seller object. Check the manpage for details. Searches for items offered by third-party sellers. Items are referenced by their so-called Exchange ID. Similar to Net::Amazon::Request::Seller, this request doesn't return a list of Amazon properties, so please use "result()" instead, which will return a single Net::Amazon::Result::Seller::Listing item. Check the manpage for details on what attributes are available there. Check the respective man pages for details on these request objects. Request objects are typically created like this (with a Keyword query as an example): my $req = Net::Amazon::Request::Keyword->new( keyword => 'perl', mode => 'books', ); and are handed over to the user agent like that: # Response is of type Net::Amazon::Response::ASIN my $resp = $ua->request($req); The convenient "search()" method just does these two steps in one.

METHODS
Create a new Net::Amazon useragent. $token is the value of the mandatory Amazon developer's token, which can be obtained from <http://amazon.com/soap>. Additional optional parameters: Sets how many result pages the module is supposed to fetch back from Amazon, which only sends back 10 results per page. Since each page requires a new query to Amazon, at most one query per second will be made in "strict" mode to comply with Amazon's terms of service. This will impact performance if you perform a search returning many pages of results. your Amazon affiliate ID, if you have one. It defaults to "webservices-20" which is currently (as of 06/2003) required by Amazon. Makes sure that "Net::Amazon" complies with Amazon's terms of service by limiting the number of outgoing requests to 1 per second. Defaults to 1, enabling rate limiting as defined via "rate_limit". Sets the rate limit to $reqs_per_sec requests per second if rate limiting has been enabled with "strict" (see above). Defaults to 1, limiting the number of outgoing requests to 1 per second. Sends a request to the Amazon web service. $request is of a "Net::Amazon::Request::*" type and $response will be of the corresponding "Net::Amazon::Response::*" type.

Accessing foreign Amazon Catalogs
As of this writing (07/2003), Amazon also offers its web service for the UK, Germany, and Japan. Just pass in locale => 'uk' locale => 'de' locale => 'jp' respectively to "Net::Amazon"'s constructor "new()" and instead of returning results sent by the US mothership, it will query the particular country's catalog and show prices in (gack!) local currencies.

EXAMPLE
Here's a full-fledged example doing a artist search: use Net::Amazon; use Net::Amazon::Request::Artist; use Data::Dumper; die "usage: $0 artist\n(use Zwan as an example)\n" unless defined $ARGV[0]; my $ua = Net::Amazon->new( token => 'YOUR_AMZN_TOKEN', ); my $req = Net::Amazon::Request::Artist->new( artist => $ARGV[0], ); # Response is of type Net::Amazon::Artist::Response my $resp = $ua->request($req); if($resp->is_success()) { print $resp->as_string, "\n"; } else { print $resp->message(), "\n"; } And here's one displaying someone's wishlist: use Net::Amazon; use Net::Amazon::Request::Wishlist; die "usage: $0 wishlist_id\n" . "(use 1XL5DWOUFMFVJ as an example)\n" unless $ARGV[0]; my $ua = Net::Amazon->new( token => 'YOUR_AMZN_TOKEN', ); my $req = Net::Amazon::Request::Wishlist->new( id => $ARGV[0] ); # Response is of type Net::Amazon::ASIN::Response my $resp = $ua->request($req); if($resp->is_success()) { print $resp->as_string, "\n"; } else { print $resp->message(), "\n"; } Responses returned by Amazon's web service can be cached locally. "Net::Amazon"'s "new" method accepts a reference to a "Cache" object. "Cache" (or one of its companions like "Cache::Memory", "Cache::File", etc.) can be downloaded from CPAN, please check their documentation for details. In fact, any other type of cache implementation will do as well, see the requirements below. Here's an example utilizing a file cache which causes "Net::Amazon" to cache responses for 30 minutes: use Cache::File; my $cache = Cache::File->new( cache_root => '/tmp/mycache', default_expires => '30 min', ); my $ua = Net::Amazon->new( token => 'YOUR_AMZN_TOKEN', cache => $cache, ); "Net::Amazon" uses positive caching only, errors won't be cached. Erroneous requests will be sent to Amazon every time. Positive cache entries are keyed by the full URL used internally by requests submitted to Amazon. Caching isn't limited to the "Cache" class. Any cache object which adheres to the following interface can be used: # Set a cache value $cache->set($key, $value); # Return a cached value, 'undef' if it doesn't exist $cache->get($key); "Net::Amazon" uses "LWP::UserAgent" under the hood to send web requests to Amazon's web site. If you're in an environment where all Web traffic goes through a proxy, there's two ways to configure that. First, "Net::Amazon" picks up proxy settings from environment variables: export http_proxy=http://proxy.my.place:8080 in the surrounding shell or setting $ENV{http_proxy} = "http://proxy.my.place:8080"; in your Perl script will route all requests through the specified proxy. Secondly, you can pass a user agent instance to Net::Amazon's constructor: use Net::Amazon; use LWP::UserAgent; my $ua = LWP::UserAgent->new(); my $na = Net::Amazon->new(ua => $ua, token => 'YOUR_AMZN_TOKEN'); # ... This way, you can configure $ua up front before Net::Amazon will use it. If something's going wrong and you want more verbosity, just bump up "Net::Amazon"'s logging level. "Net::Amazon" comes with "Log::Log4perl" statements embedded, which are disabled by default. However, if you initialize "Log::Log4perl", e.g. like use Net::Amazon; use Log::Log4perl qw(:easy); Log::Log4perl->easy_init($DEBUG); my Net::Amazon->new(); # ... you'll see what's going on behind the scenes, what URLs the module is requesting from Amazon and so forth. Log::Log4perl allows all kinds of fancy stuff, like writing to a file or enabling verbosity in certain parts only -- check http://log4perl.sourceforge.net for details. Results returned by Amazon can be incomplete or simply wrong at times, due to their "best effort" design of the service. This is why the test suite that comes with this module has been changed to perform its test cases against canned data. If you want to perform the tests against the live Amazon servers instead, just set the environment variable NET_AMAZON_LIVE_TESTS=1 Because nobody wrote it yet. If Net::Amazon doesn't yet support a method advertised on Amazon's web service, you could help us out. Net::Amazon has been designed to be expanded over time, usually it only takes a couple of lines to support a new method, the rest is done via inheritance within Net::Amazon. Here's the basic plot: Get Net::Amazon from CVS. Use # (Just hit enter when prompted for a password) cvs -d:pserver:anonymous@cvs.net-amazon.sourceforge.net:/cvsroot/net-amazon login cvs -z3 -d:pserver:anonymous@cvs.net-amazon.sourceforge.net:/cvsroot/net-amazon co Net-Amazon If this doesn't work, just use the latest distribution from net-amazon.sourceforge.net. Write a new Net::Amazon::Request::XYZ package, start with this template ###################################### package Net::Amazon::Request::XYZ; ###################################### use base qw(Net::Amazon::Request); ###################################### sub new { ###################################### my($class, %options) = @_; if(!exists $options{XYZ_option}) { die "Mandatory parameter 'XYZ_option' not defined"; } my $self = $class->SUPER::new(%options); bless $self, $class; # reconsecrate } and add documentation. Then, create a new Net::Amazon::Response::XYZ module: ############################## package Net::Amazon::Response; ############################## use base qw(Net::Amazon::Response); use Net::Amazon::Property; ############################## sub new { ############################## my($class, %options) = @_; my $self = $class->SUPER::new(%options); bless $self, $class; # reconsecrate } and also add documentation to it. Then, add the line use Net::Amazon::Request::XYZ; to Net/Amazon.pm. And that's it! Again, don't forget the add documentation part. Modules without documentation are of no use to anybody but yourself. Check out the different Net::Amazon::Request::* and Net::Amazon::Response modules in the distribution if you need to adapt your new module to fulfil any special needs, like a different Amazon URL or a different way to handle the as_string() method. Also, post and problems you might encounter to the mailing list, we're gonna help you out. If possible, provide a test case for your extension. When finished, send a patch to the mailing list at net-amazon-devel@lists.sourceforge.net and if it works, I'll accept it and will work it into the main distribution. Your name will show up in the contributor's list below (unless you tell me otherwise).

SAMPLE SCRIPTS
There's a number of useful scripts in the distribution's eg/ directory. Take "power" for example, written by Martin Streicher <martin.streicher@apress.com>: I lets you perform a power search using Amazon's query language. To search for all books written by Randal Schwartz about Perl, call this from the command line: power 'author: schwartz subject: perl' Note that you need to quote the query string to pass it as one argument to "power". If a power search returns more results than you want to process at a time, just limit the number of pages, telling "power" which page to start at ("-s") and which one to finish with ("-f"). Here's a search for all books on the subject "computer", limited to the first 10 pages: power -s 1 -f 10 'subject: computer' Check out the script "power" in eg/ for more options.

HOW TO SEND ME PATCHES
If you want me to include your modification or enhancement in the distribution of Net::Amazon, please do the following: Work off the latest CVS version. Here's the steps to get it: CVSROOT=:pserver:anonymous@cvs.net-amazon.sourceforge.net:/cvsroot/net-amazon export CVSROOT cvs login (just hit Enter) cvs co Net-Amazon This will create a new "Net-Amazon" directory with the latest development version of "Net::Amazon" on your local machine. Apply your changes to this development tree. Run a diff between the tree and your changes it in this way: cd Net-Amazon cvs diff -Nau >patch_to_mike.txt Email me "patch_to_mike.txt". If your patch works (and you've included test cases and documentation), I'll apply it on the spot. "Net::Amazon" depends on Log::Log4perl, which can be pulled from CPAN by simply saying perl -MCPAN -eshell 'install Log::Log4perl' Also, it needs LWP::UserAgent and XML::Simple 2.x, which can be obtained in a similar way. Once all dependencies have been resolved, "Net::Amazon" installs with the typical sequence perl Makefile.PL make make test make install Make sure you're connected to the Internet while running "make test" because it will actually contact amazon.com and run a couple of live tests. The module's distribution tarball and documentation are available at http://perlmeister.com/devel/#amzn and on CPAN. The following modules play well within the "Net::Amazon" framework: by David Emery <dave@skiddlydee.com> provides a complete API for creating Amazon shopping carts on a local site, managing them and finally submitting them to Amazon for checkout. It is available on CPAN. The "Net::Amazon" project's home page is hosted on http://net-amazon.sourceforge.net where you can find documentation, news and the latest development and stable releases for download. If you have questions about how to use "Net::Amazon", want to report a bug or just participate in its development, please send a message to the mailing list net-amazon-devel@lists.sourceforge.net Mike Schilli, <na@perlmeister.com> (Please contact me via the mailing list: net-amazon-devel@lists.sourceforge.net ) Contributors (thanks y'all!): Andy Grundman <andy@hybridized.org> Barnaby Claydon <bclaydon@perseus.com> Batara Kesuma <bkesuma@gaijinweb.com> Bill Fitzpatrick Brian <brianbrian@gmail.com> Brian Hirt <bhirt@mobygames.com> Dan Kreft <dan@kreft.net> Dan Sully <daniel@electricrain.com> Jackie Hamilton <kira@cgi101.com> Konstantin Gredeskoul <kig@get.topica.com> Lance Cleveland <lancec@proactivewm.com> Martha Greenberg <marthag@mit.edu> Martin Streicher <martin.streicher@apress.com> Mike Evron <evronm@dtcinc.net> Padraic Renaghan <padraic@renaghan.com> rayg <rayg@varchars.com> Robert Graff <rgraff@workingdemo.com> Robert Rothenberg <wlkngowl@i-2000.com> Steve Rushe <steve@deeden.co.uk> Tatsuhiko Miyagawa <miyagawa@livedoor.jp> Tony Bowden <tony@kasei.com> Copyright 2003, 2004 by Mike Schilli <na@perlmeister.com> This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.