WebService::GData::Feed - Base class wrapping json atom feed for google data API v2.
use WebService::GData::Feed; my $feed = new WebService::GData::Feed($jsonfeed); $feed->title; $feed->author; my @entries = $feed->entry();#send back WebService::GData::Feed::Entry or a service related Entry object
inherits from WebService::GData
This package wraps the result from a query using the json format of the Google Data API v2 (no other format is supported!). It gives you access to some of the data via wrapper methods and works as a factory to get access to the entries for each service. If you use a YouTube service, calling the entry() method will send you back YouTube::Feed::Entry's. If you use a Calendar service, calling the entry() method will send you back a Calendar::Feed::Entry. By default, it returns a WebService::GData::Feed::Entry which gives you only a read access to the data. Unless you implement a service, you should not instantiate this class directly.
Create a WebService::GData::Feed instance.
Accept a json feed entry that has been perlified (from_json($json_string)) and an optional request object (WebService::GData::Base). The request object is passed along each entry classes but the Feed class itself does not use it.
Parameters
json_feed:Object
request:Object
Returns
WebService::GData::Feed
All the following methods work as both setter and getters.
set/get the title of the feed.
none
title:Scalar
Example:
use WebService::GData::Feed; my $feed = new WebService::GData::Feed(); $feed->title("my Title"); $feed->title();#my Title
All the following methods work as getters and do not accept parameters.
Get the id of the feed.
id:Scalar
use WebService::GData::Feed; my $feed = new WebService::GData::Feed($jsonfeed); $feed->id();#"tag:youtube.com,2008:video"
Get the updated date of the feed.
updated:Scalar
use WebService::GData::Feed; my $feed = new WebService::GData::Feed($jsonfeed); $feed->updated();#"2010-09-20T13:49:20.028Z"
Get the categories of the feed. At the feed level, it is almost always one category that defines the kind of the feed (video feed, related feed,etc). The entry() uses this information to load the proper class, ie Video or Comment entries.
entry()
categories:Collection
use WebService::GData::Feed; my $feed = new WebService::GData::Feed($jsonfeed); my $categories = $feed->category(); foreach my $category (@$categories) { #$category->scheme,$category->term,$category->label } #search for a particular kind of category my $kind = $categories->scheme('kind')->[0]; #json feed category is as below: "category": [ { "scheme": "http://schemas.google.com/g/2005#kind", "term": "http://gdata.youtube.com/schemas/2007#video" } ]
Get the etag of the feed. The etag is a unique identifier key to track updates to the document.
etag:Scalar
use WebService::GData::Feed; my $feed = new WebService::GData::Feed($jsonfeed); $feed->etag();#W/\"CkICQX45cCp7ImA9Wx5XGUQ.\"
See also http://code.google.com/intl/en/apis/gdata/docs/2.0/reference.html#ResourceVersioning for further information about resource versioning.
Get the author of the feed.
author:Collection
use WebService::GData::Feed; my $feed = new WebService::GData::Feed($jsonfeed); my $authors= $feed->author(); foreach my $author (@$authors){ #$author->name,$author->uri } #raw json feed: "author": [ { "name": { "$t": "YouTube" }, "uri": { "$t": "http://www.youtube.com/" } } ],
The following methods sent back information that can be useful to paginate the result. You get access to the number of result, the number of item sent and the offset from which the result start.
Get the total result of the feed.
total_items:Int
use WebService::GData::Feed; my $feed = new WebService::GData::Feed($jsonfeed); $feed->total_items();#1000000
Get the total result of the feed. Alias for total_items
total_results:Int
use WebService::GData::Feed; my $feed = new WebService::GData::Feed($jsonfeed); $feed->total_results();#1000000
Get the start number of the feed.
start_index:Int
use WebService::GData::Feed; my $feed = new WebService::GData::Feed($jsonfeed); $feed->start_index();#1
Get the the number of items sent per result.
items_per_page:Int
use WebService::GData::Feed; my $feed = new WebService::GData::Feed($jsonfeed); $feed->items_per_page();#25
Get the links of the feed in a array reference.
links:Collection
use WebService::GData::Feed; my $feed = new WebService::GData::Feed($jsonfeed); my $links = $feed->links(); foreach my $link (@$links){ #link->rel,$link->type,$link->href } #raw json data: "link": [ { "rel": "alternate", "type": "text/html", "href": "http://www.youtube.com" }, { "rel": "http://schemas.google.com/g/2005#feed", "type": "application/atom+xml", "href": "http://gdata.youtube.com/feeds/api/videos" }, { "rel": "http://schemas.google.com/g/2005#batch", "type": "application/atom+xml", "href": "http://gdata.youtube.com/feeds/api/videos/batch" } ]
Get a specific link entry by looking in the rel attribute of the link tag.
link_type:Scalar
undef
url:Scalar
use WebService::GData::Feed; my $feed = new WebService::GData::Feed($jsonfeed); my $previous_url= $feed->get_link('previous'); my $batch_url = $feed->get_link('batch');
Get a the previous link if set or undef. Shortcut for $feed->get_link('previous');
Get a the next link if set or undef. Shortcut for $feed->get_link('next');
This method return an array reference of Feed::* objects.
It works as a factory by instantiating the proper Feed::* class.
For example,if you read a video feed from a youtube service, it will instantiate the WebService::GData::Youtube::Feed::Video class and feed it the result.
It will look first at the category scheme set in the feed or at the entry category scheme that contains the base schema name of the feed.
If it does not guess properly,you can always specify the name of the package to load as its first argument.
class_name::Scalar
entries:ArrayRef
use WebService::GData::Feed; my $feed = new WebService::GData::Feed($jsonfeed); my $entries = $feed->entry('WebService::GData::Feed::Entry');#force a particular class to be used my $entries = $feed->entry();#let entry figure it out by looking at the feed meta information. foreach my $entry (@$entries) { #$entry->title,$entry->id... all entry sub classes should inherit from WebService::GData::Feed::Entry }
Below is a raw json feed example from querying youtube videos. Only the relevant parts are listed.
The actual feed does contain more information but a possible switch to JSONC, freed of meta information, being possible, this package only offers wrapper methods to what is relevant in the JSONC context.
{ "feed": { "gd$etag": "W/\"CkICQX45cCp7ImA9Wx5XGUQ.\"", "id": { "$t": "tag:youtube.com,2008:videos" }, "updated": { "$t": "2010-09-20T13:49:20.028Z" }, "category": [ { "scheme": "http://schemas.google.com/g/2005#kind", "term": "http://gdata.youtube.com/schemas/2007#video" } ], "title": { "$t": "YouTube Videos" }, "link": [ { "rel": "alternate", "type": "text/html", "href": "http://www.youtube.com" }, { "rel": "http://schemas.google.com/g/2005#feed", "type": "application/atom+xml", "href": "http://gdata.youtube.com/feeds/api/videos" }, { "rel": "http://schemas.google.com/g/2005#batch", "type": "application/atom+xml", "href": "http://gdata.youtube.com/feeds/api/videos/batch" }, { "rel": "self", "type": "application/atom+xml", "href": "http://gdata.youtube.com/feeds/api/videos?alt=json&start-index=1&max-results=25" }, { "rel": "service", "type": "application/atomsvc+xml", "href": "http://gdata.youtube.com/feeds/api/videos?alt\u003datom-service" }, { "rel": "next", "type": "application/atom+xml", "href": "http://gdata.youtube.com/feeds/api/videos?alt=json&start-index=3&max-results=25" } ], "author": [ { "name": { "$t": "YouTube" }, "uri": { "$t": "http://www.youtube.com/" } } ], "openSearch$totalResults": { "$t": 1000000 }, "openSearch$startIndex": { "$t": 1 }, "openSearch$itemsPerPage": { "$t": 25 }, "entry": [....]#erased as there are implemented in each sub classes } }
If you do me the favor to _use_ this module and find a bug, please email me i will try to do my best to fix it (patches welcome)!
shiriru <shirirulestheworld[arobas]gmail.com>
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
4 POD Errors
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You forgot a '=back' before '=head3'
To install WebService::GData, copy and paste the appropriate command in to your terminal.
cpanm
cpanm WebService::GData
CPAN shell
perl -MCPAN -e shell install WebService::GData
For more information on module installation, please visit the detailed CPAN module installation guide.