100 lines
3.1 KiB
Markdown
100 lines
3.1 KiB
Markdown
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# Consuming RSS Feeds
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## Reading a feed
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To read an RSS feed, pass its URL to `Zend\Feed\Reader\Reader::import()`:
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```php
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$channel = Zend\Feed\Reader\Reader::import('http://rss.example.com/channelName');
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```
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> ## Importing requires an HTTP client
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>
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> To import a feed, 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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If any errors occur fetching the feed, a
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`Zend\Feed\Reader\Exception\RuntimeException` will be thrown.
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## Get properties
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Once you have a feed object, you can access any of the standard RSS channel
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properties via the various instance getter methods:
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```php
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echo $channel->getTitle();
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echo $channel->getAuthor();
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// etc.
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```
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If channel properties have attributes, the getter method will return a key/value
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pair, where the key is the attribute name, and the value is the attribute value.
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```php
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$author = $channel->getAuthor();
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echo $author['name'];
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```
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Most commonly, you'll want to loop through the feed and do something with its
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entries. `Zend\Feed\Reader\Feed\Rss` internally converts all entries to a
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`Zend\Feed\Reader\Entry\Rss` instance. Entry properties, similarly to channel
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properties, can be accessed via getter methods, such as `getTitle`,
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`getDescription`, etc.
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An example of printing all titles of articles in a channel is:
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```php
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foreach ($channel as $item) {
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echo $item->getTitle() . "\n";
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}
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```
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If you are not familiar with RSS, here are the standard elements you can expect
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to be available in an RSS channel and in individual RSS items (entries).
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Required channel elements:
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- `title`: The name of the channel.
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- `link`: The URL of the web site corresponding to the channel.
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- `description`: A sentence (or more) describing the channel.
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Common optional channel elements:
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- `pubDate`: The publication date of this set of content, in RFC 822 date
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format.
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- `language`: The language the channel is written in.
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- `category`: One or more (specified by multiple tags) categories the channel
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belongs to.
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RSS `<item>` elements do not have any strictly required elements. However,
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either `title` or `description` must be present.
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Common item elements:
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- `title`: The title of the item.
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- `link`: The URL of the item.
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- `description`: A synopsis of the item.
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- `author`: The author's email address.
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- `category`: One more categories that the item belongs to.
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- `comments`: URL of comments relating to this item.
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- `pubDate`: The date the item was published, in RFC 822 date format.
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In your code you can always test to see if an element is non-empty by calling
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the getter:
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```php
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if ($item->getPropname()) {
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// ... proceed.
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}
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```
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Where relevant, `Zend\Feed` supports a number of common RSS extensions including
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Dublin Core, Atom (inside RSS); the Content, Slash, Syndication,
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Syndication/Thread extensions; as well as several others.
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Please see the official [RSS 2.0 specification](http://cyber.law.harvard.edu/rss/rss.html)
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for further information.
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