[CONF] Apache Camel: RSS (page edited)

[confluence]

Page Edited : CAMEL : RSS RSS has been edited by Jonathan Anstey (Dec 09, 2008). (View changes) Content: RSS Component The rss: component is used for polling RSS feeds. Camel will default poll the feed every 60th seconds. Note: The component currently only supports polling (consuming) feeds. New in Camel 2.0 URI format rss:rssUri Where rssUri is the URI to the RSS feed to poll. Options Property Default Description splitEntries true If true Camel will poll the feed and for the subsequent polls return each entry poll by poll. If the feed contains 7 entries then Camel will return the first entry on the first poll, the 2nd entry on the next poll, until no more entries where as Camel will do a new update on the feed. If false then Camel will poll a fresh feed on every invocation. filter true Is only used by the split entries to filter the entries to return. Camel will default use the UpdateDateFilter that only return new entries from the feed. So the client consuming from the feed never receives the same entry more than once. The filter will return the entries ordered by the newest last. lastUpdate null Is only used by the filter, as the starting timestamp for selection never entries (uses the entry.updated timestamp). Syntax format is: yyyy-MM-ddTHH:MM:ss. Example: 2007-12-24T17:45:59. feedHeader true Sets whether to add the ROME SyndFeed object as a header. sortEntries false If splitEntries is true, this sets whether to sort those entries by updated date. consumer.delay 60000 Delay in millis between each poll consumer.initialDelay 1000 Millis before polling starts consumer.userFixedDelay false true to use fixed delay between pools, otherwise fixed rate is used. See ScheduledExecutorService in JDK for details. Exchange data types Camel will set the in body on the returned Exchange with a ROME SyndFeed. Depending on the splitEntries flag Camel will either return a SyndFeed with one SyndEntry or a List of SyndEntrys. Option Value Behavior splitEntries true Only a single entry from the currently being processed feed is set in the new exchange feed. splitEntries false The entires list of entries from the feed is set in the new exchange feed. Camel can also set the entire SyndFeed object on the in header (see feedHeader option above to disable): exchange.in.header("org.apache.camel.component.rss.feed", feed) 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=100").marshal().rss().to("mock:marshal"); The idea is to be able 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: // 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").marshal().rss(). filter().xpath("//item/title[contains(.,'Camel')]").to("mock:result"); Merging multiple incoming feeds To merge multiple incoming feeds into a single feed, you can utilize a custom AggregationCollection provided with camel-rss. An example usage would look something like this: from("rss:file:src/test/data/rss20.xml?sortEntries=true&consumer.delay=50").to("seda:temp"); from("rss:file:target/rss20.xml?sortEntries=true&consumer.delay=50").to("seda:temp"); from("seda:temp").aggregate(new AggregateRssFeedCollection()).batchTimeout(5000L).to("mock:result"); Here we use a Seda queue to gather up entries from two RSS feeds. The entries are then fed into a custom aggregator which combines these entries into a single ROME SyndFeed object. See Also Configuring Camel Component Endpoint Getting Started

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