RSS Component

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

Maven users will need to add the following dependency to their pom.xml for this component:

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

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Camel-rss internally uses a patched version of ROME hosted on ServiceMix to solve some OSGi class loading issues.

URI format

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, Camel splits a feed into its individual entries and returns each entry, poll by poll. For example, if a feed contains seven entries, 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, Camel contacts the remote RSS URI to obtain a new feed. If false, 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, 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

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

Camel initializes the In body on the Exchange with a ROME SyndFeed. Depending on the value of the splitEntries flag, 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

CamelRssFeed

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:

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

Query parameters

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If the URL for the RSS feed uses query parameters, this component will understand them as well, for example if the feed uses alt=rss, then you can for example do
from("rss:http://someserver.com/feeds/posts/default?alt=rss&splitEntries=false&consumer.delay=1000").to("bean:rss");

Filtering entries

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

The custom bean for this would be:

See Also

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