RSS Component

Table of Contents

URI format
Options
Exchange data types
Message Headers
RSS Dataformat
Filtering entries
See Also

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:

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-rss</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>

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

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

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

The RSS component has no options.

The RSS component supports 28 endpoint options which are listed below:

{% raw %}

Name	Group	Default	Java Type	Description
feedUri	consumer		`String`	Required The URI to the feed to poll.
bridgeErrorHandler	consumer	`false`	`boolean`	Allows for bridging the consumer to the Camel routing Error Handler which mean any exceptions occurred while the consumer is trying to pickup incoming messages or the likes will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions that will be logged at WARN/ERROR level and ignored.
feedHeader	consumer	`true`	`boolean`	Sets whether to add the feed object as a header
filter	consumer	`true`	`boolean`	Sets whether to use filtering or not of the entries.
lastUpdate	consumer		`Date`	Sets the timestamp to be used for filtering entries from the atom feeds. This options is only in conjunction with the splitEntries.
password	consumer		`String`	Sets the password to be used for basic authentication when polling from a HTTP feed
sendEmptyMessageWhenIdle	consumer	`false`	`boolean`	If the polling consumer did not poll any files you can enable this option to send an empty message (no body) instead.
sortEntries	consumer	`false`	`boolean`	Sets whether to sort entries by published date. Only works when splitEntries = true.
splitEntries	consumer	`true`	`boolean`	Sets whether or not entries should be sent individually or whether the entire feed should be sent as a single message
throttleEntries	consumer	`true`	`boolean`	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 = true.
username	consumer		`String`	Sets the username to be used for basic authentication when polling from a HTTP feed
exceptionHandler	consumer (advanced)		`ExceptionHandler`	To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this options is not in use. By default the consumer will deal with exceptions that will be logged at WARN/ERROR level and ignored.
exchangePattern	consumer (advanced)		`ExchangePattern`	Sets the exchange pattern when the consumer creates an exchange.
pollStrategy	consumer (advanced)		`PollingConsumerPollStrategy`	A pluggable org.apache.camel.PollingConsumerPollingStrategy allowing you to provide your custom implementation to control error handling usually occurred during the poll operation before an Exchange have been created and being routed in Camel.
synchronous	advanced	`false`	`boolean`	Sets whether synchronous processing should be strictly used or Camel is allowed to use asynchronous processing (if supported).
backoffErrorThreshold	scheduler		`int`	The number of subsequent error polls (failed due some error) that should happen before the backoffMultipler should kick-in.
backoffIdleThreshold	scheduler		`int`	The number of subsequent idle polls that should happen before the backoffMultipler should kick-in.
backoffMultiplier	scheduler		`int`	To let the scheduled polling consumer backoff if there has been a number of subsequent idles/errors in a row. The multiplier is then the number of polls that will be skipped before the next actual attempt is happening again. When this option is in use then backoffIdleThreshold and/or backoffErrorThreshold must also be configured.
delay	scheduler	`500`	`long`	Milliseconds before the next poll. You can also specify time values using units such as 60s (60 seconds) 5m30s (5 minutes and 30 seconds) and 1h (1 hour).
greedy	scheduler	`false`	`boolean`	If greedy is enabled then the ScheduledPollConsumer will run immediately again if the previous run polled 1 or more messages.
initialDelay	scheduler	`1000`	`long`	Milliseconds before the first poll starts. You can also specify time values using units such as 60s (60 seconds) 5m30s (5 minutes and 30 seconds) and 1h (1 hour).
runLoggingLevel	scheduler	`TRACE`	`LoggingLevel`	The consumer logs a start/complete log line when it polls. This option allows you to configure the logging level for that.
scheduledExecutorService	scheduler		`ScheduledExecutorService`	Allows for configuring a custom/shared thread pool to use for the consumer. By default each consumer has its own single threaded thread pool.
scheduler	scheduler	`none`	`ScheduledPollConsumerScheduler`	To use a cron scheduler from either camel-spring or camel-quartz2 component
schedulerProperties	scheduler		`Map`	To configure additional properties when using a custom scheduler or any of the Quartz2 Spring based scheduler.
startScheduler	scheduler	`true`	`boolean`	Whether the scheduler should be auto started.
timeUnit	scheduler	`MILLISECONDS`	`TimeUnit`	Time unit for initialDelay and delay options.
useFixedDelay	scheduler	`true`	`boolean`	Controls if fixed delay or fixed rate is used. See ScheduledExecutorService in JDK for details.

{% endraw %}

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:

	Tip
	Query parameters 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: