# RSS

## RSS Component

The rss: component is used for polling RSS feeds. Apache Camel will default poll the feed every 60th seconds.

Note: The component currently only supports polling (consuming) feeds.

## URI format

    rss:rssUri

Where `rssUri` is the URI to the RSS feed to poll.

You can append query options to the URI in the following format, `?option=value&option=value&...`

## Options

Property | Default | Description
--- | --- | ---
`splitEntries` | `true` | If `true`, Apache Camel splits a feed into its individual entries and returns each entry, poll by poll. For example, if a feed contains seven entries, Apache Camel returns the first entry on the first poll, the second entry on the second poll, and so on. When no more entries are left in the feed, Apache Camel contacts the remote RSS URI to obtain a new feed. If `false`, Apache Camel obtains a fresh feed on every poll and returns all of the feed's entries.
`filter` | `true` | Use in combination with the `splitEntries` option in order to filter returned entries. By default, Apache Camel applies the `UpdateDateFilter` filter, which returns only new entries from the feed, ensuring that the consumer endpoint never receives an entry more than once. The filter orders the entries chronologically, with the newest returned last.
`throttleEntries` | `true` | Apache Camel 2.5: Sets whether all entries identified in a single feed poll should be delivered immediately. If true, only one entry is processed per consumer.delay. Only applicable when splitEntries is set to true.
`lastUpdate` | `null` | Use in combination with the `filter` option to block entries earlier than a specific date/time (uses the `entry.updated` timestamp). The format is: `yyyy-MM-ddTHH:MM:ss`. Example: `2007-12-24T17:45:59`.
`feedHeader` | `true` | Specifies whether to add the ROME `SyndFeed` object as a header.
`sortEntries` | `false` | If `splitEntries` is `true`, this specifies whether to sort the entries by updated date.
`consumer.delay` | `60000` | Delay in milliseconds between each poll.
`consumer.initialDelay` | `1000` | Milliseconds before polling starts.
`consumer.userFixedDelay` | `false` | Set to `true` to use fixed delay between pools, otherwise fixed rate is used. See ScheduledExecutorService in JDK for details.

## Exchange data types

Apache Camel initializes the In body on the Exchange with a ROME `SyndFeed`. Depending on the value of the `splitEntries` flag, Apache Camel returns either a `SyndFeed` with one `SyndEntry` or a `java.util.List` of `SyndEntrys`.

Option | Value | Behavior
--- | --- | ---
`splitEntries` | `true` | A single entry from the current feed is set in the exchange.
`splitEntries` | `false` | The entire list of entries from the current feed is set in the exchange.

## Message Headers

Header | Description
--- | ---
`org.apache.camel.component.rss.feed` | Apache Camel 1.x: The entire `SyncFeed` object.
`CamelRssFeed` | Apache Camel 2.0: The entire `SyncFeed` object.

## RSS Dataformat

The RSS component ships with an RSS dataformat that can be used to convert between String (as XML) and ROME RSS model objects.

- marshal = from ROME `SyndFeed` to XML `String`

- unmarshal = from XML `String` to ROME `SyndFeed`

A route using this would look something like this:

    from("rss:file:src/test/data/rss20.xml?splitEntries=false&consumer.delay=1000").marshal().rss().to("mock:marshal");

The purpose of this feature is to make it possible to use Apache Camel's lovely built-in expressions for manipulating RSS messages. As shown below, an XPath expression can be used to filter the RSS message:

    // only entries with Apache Camel in the title will get through the filter
    from("rss:file:src/test/data/rss20.xml?splitEntries=true&consumer.delay=100")
        .marshal().rss().filter().xpath("//item/title[contains(.,'Camel')]").to("mock:result");

## Filtering entries

You can filter out entries quite easily using XPath, as shown in the data format section above. You can also exploit Apache Camel's Bean Integration to implement your own conditions. For instance, a filter equivalent to the XPath example above would be:

    // only entries with Camel in the title will get through the filter
    from("rss:file:src/test/data/rss20.xml?splitEntries=true&consumer.delay=100").
        filter().method("myFilterBean", "titleContainsCamel").to("mock:result");

The custom bean for this would be:

    public static class FilterBean {
        public boolean titleContainsCamel(@Body SyndFeed feed) {
            SyndEntry firstEntry = (SyndEntry) feed.getEntries().get(0);
            return firstEntry.getTitle().contains("Camel");
        }
    }

## See also

- Atom