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author Chris Cannam
date Mon, 05 Feb 2018 12:34:32 +0000
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# Consuming Atom Feeds

`Zend\Feed\Reader\Feed\Atom` is used in much the same way as
`Zend\Feed\Reader\Feed\Rss`. It provides the same access to feed-level
properties and iteration over entries in the feed. The main difference is in the
structure of the Atom protocol itself. Atom is a successor to RSS; it is a
more generalized protocol and it is designed to deal more easily with feeds that
provide their full content inside the feed, splitting RSS' `description` tag
into two elements, `summary` and `content`, for that purpose.

## Basic Use of an Atom Feed

Read an Atom feed and print the `title` and `summary` of each entry:

```php
$feed = Zend\Feed\Reader\Reader::import('http://atom.example.com/feed/');
echo 'The feed contains ' . $feed->count() . ' entries.' . "\n\n";
foreach ($feed as $entry) {
    echo 'Title: ' . $entry->getTitle() . "\n";
    echo 'Description: ' . $entry->getDescription() . "\n";
    echo 'URL: ' . $entry->getLink() . "\n\n";
}
```

> ## Importing requires an HTTP client
>
> To import a feed, you will need to have an [HTTP client](zend.feed.http-clients)
> available. 
>
> If you are not using zend-http, you will need to inject `Reader` with the HTTP
> client. See the [section on providing a client to Reader](http-clients.md#providing-a-client-to-reader).

In an Atom feed, you can expect to find the following feed properties:

- `title`: The feed's title, same as RSS' channel title.
- `id`: Every feed and entry in Atom has a unique identifier.
- `link`: Feeds can have multiple links, which are distinguished by a `type`
  attribute. The equivalent to RSS's channel link would be `type="text/html"`.
  If the link is to an alternate version of the same content that's in the feed,
  it would have a `rel="alternate"` attribute.
- `subtitle`: The feed's description, equivalent to RSS' channel description.
- `author`: The feed's author, with `name` and `email` sub-tags.

Atom entries commonly have the following properties:

- `id`: The entry's unique identifier.
- `title`: The entry's title, same as RSS item titles.
- `link`: A link to another format or an alternate view of this entry.
   The link property of an atom entry typically has an `href` attribute.
- `summary`: A summary of this entry's content.
- `content`: The full content of the entry; can be skipped if the feed just
   contains summaries.
- `author`: with `name` and `email` sub-tags like feeds have.
- `published`: the date the entry was published, in RFC 3339 format.
- `updated`: the date the entry was last updated, in RFC 3339 format.

Where relevant, `Zend\Feed` supports a number of common RSS extensions including
Dublin Core; Content, Slash, Syndication, and Syndication/Thread; and several
others in common use on blogs.

For more information on Atom and plenty of resources, see
[http://www.atomenabled.org/](http://www.atomenabled.org/).