NAME
WebService::GData::Feed - Abstract class wrapping json atom feed for google data API v2.
SYNOPSIS
use WebService::GData::Feed;
my $feed = new WebService::GData::Feed($jsonfeed);
$feed->title;
$feed->author;
my @entries = $feed->entry();#send back WebService::GData::Feed::Entry or a service related Entry object
DESCRIPTION
inherits from WebService::GData
This package wraps the result from a query using the json format of the Google Data API v2 (no other format is supported!). It gives you access to some of the data via wrapper methods and works as a factory to get access to the entries for each service. If you use a YouTube service, calling the entry() method will send you back YouTube::Feed::Entry's. If you use a Calendar service, calling the entry() method will send you back a Calendar::Feed::Entry. By default, it returns a WebService::GData::Feed::Entry which gives you only a read access to the data. Unless you implement a service, you should not instantiate this class directly.
CONSTRUCTOR
new
Create a WebService::GData::Feed instance.
Accept a json feed entry that has been perlified (from_json($json_string)) and an optional auth object. The auth object is passed along each entry classes but the Feed class itself does not use it.
Parameters
Returns
SET/GET METHODS
All the following methods work as both setter and getters.
title
set/get the title of the feed.
Parameters
Returns
Example:
use WebService::GData::Feed;
my $feed = new WebService::GData::Feed();
$feed->title("my Title");
$feed->title();#my Title
GET METHODS
All the following methods work as getters and do not accept parameters.
updated
use WebService::GData::Feed;
my $feed = new WebService::GData::Feed($jsonfeed);
$feed->updated();#"2010-09-20T13:49:20.028Z"
category
categories:ArrayRef
- an array ref containing WebService::GData::Feed::Category.
Get the categories of the feed in a array reference containing hash references with scheme/term keys. 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.
Parameters
Returns
Example:
use WebService::GData::Feed;
my $feed = new WebService::GData::Feed($jsonfeed);
my $categories = $feed->categories();
foreach my $category (@$categories) {
#$category->scheme,$category->term,$category->label
}
#json feed category is as below:
"category": [
{
"scheme": "http://schemas.google.com/g/2005#kind",
"term": "http://gdata.youtube.com/schemas/2007#video"
}
]
etag
Get the etag of the feed. The etag is a unique identifier key to track updates to the document.
Parameters
Returns
Example:
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.
author
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/"
}
}
],
PAGINATION RELATED METHODS
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.
total_items
Get the total result of the feed.
Parameters
Returns
Example:
use WebService::GData::Feed;
my $feed = new WebService::GData::Feed($jsonfeed);
$feed->total_items();#1000000
total_results
Get the total result of the feed. Alias for total_items
Parameters
Returns
Example:
use WebService::GData::Feed;
my $feed = new WebService::GData::Feed($jsonfeed);
$feed->total_results();#1000000
start_index
Get the start number of the feed.
Parameters
Returns
Example:
use WebService::GData::Feed;
my $feed = new WebService::GData::Feed($jsonfeed);
$feed->start_index();#1
items_per_page
Get the the number of items sent per result.
Parameters
Returns
Example:
use WebService::GData::Feed;
my $feed = new WebService::GData::Feed($jsonfeed);
$feed->items_per_page();#25
links
links:ArrayRef
- an array ref containing WebService::GData::Feed::Link instances. =back-
Example:
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 the links of the feed in a array reference.
Parameters
Returns
get_link
Get a specific link entry by looking in the rel attribute of the link tag.
Parameters
Returns
Example:
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');
previous_link
Get a the previous link if set or undef. Shortcut for $feed->get_link('previous');
next_link
Get a the next link if set or undef. Shortcut for $feed->get_link('next');
entry
This method return an array reference of Feed::* objects.
It works as a factory by instantiating the proper Feed::* class.
ie,if you read a Video feed from a youtube service, it will instantiate the WebService::GData::Youtube::Feed::Video class and feed it the result.
JSON FEED EXAMPLE
Below is a raw json feed example from querying youtube videos. Only the relevant parts are listed.
The actual feed does contain more information but a possible switch to JSONC, freed of meta information, being possible, this package only offers wrapper methods to what is relevant in the JSONC context.
{
"feed": {
"gd$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
}
}
BUGS AND LIMITATIONS
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)!
AUTHOR
shiriru <shirirulestheworld[arobas]gmail.com>
LICENSE AND COPYRIGHT
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
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