49 lines
1.8 KiB
Markdown
49 lines
1.8 KiB
Markdown
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# Feed Discovery from Web Pages
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Web pages often contain `<link>` tags that refer to feeds with content relevant
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to the particular page. `Zend\Feed\Reader\Reader` enables you to retrieve all
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feeds referenced by a web page with one method call:
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```php
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$feedLinks = Zend\Feed\Reader\Reader::findFeedLinks('http://www.example.com/news.html');
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```
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> ## Finding feed links requires an HTTP client
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>
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> To find feed links, you will need to have an [HTTP client](zend.feed.http-clients)
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> available.
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>
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> If you are not using zend-http, you will need to inject `Reader` with the HTTP
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> client. See the [section on providing a client to Reader](http-clients.md#providing-a-client-to-reader).
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Here the `findFeedLinks()` method returns a `Zend\Feed\Reader\FeedSet` object,
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which is in turn a collection of other `Zend\Feed\Reader\FeedSet` objects, each
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referenced by `<link>` tags on the `news.html` web page.
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`Zend\Feed\Reader\Reader` will throw a
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`Zend\Feed\Reader\Exception\RuntimeException` upon failure, such as an HTTP
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404 response code or a malformed feed.
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You can examine all feed links located by iterating across the collection:
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```php
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$rssFeed = null;
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$feedLinks = Zend\Feed\Reader\Reader::findFeedLinks('http://www.example.com/news.html');
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foreach ($feedLinks as $link) {
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if (stripos($link['type'], 'application/rss+xml') !== false) {
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$rssFeed = $link['href'];
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break;
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}
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```
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Each `Zend\Feed\Reader\FeedSet` object will expose the `rel`, `href`, `type`,
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and `title` properties of detected links for all RSS, Atom, or RDF feeds. You
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can always select the first encountered link of each type by using a shortcut:
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the first encountered link of a given type is assigned to a property named after
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the feed type.
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```php
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$rssFeed = null;
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$feedLinks = Zend\Feed\Reader\Reader::findFeedLinks('http://www.example.com/news.html');
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$firstAtomFeed = $feedLinks->atom;
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```
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