How to return RSS with REST service?

Question

I'm using ROME for RSS feed generating and Jersey as REST service.

Here is my RSS feed generation.

public SyndFeed generate()
{
    SyndFeed feed = new SyndFeedImpl();
    feed.setFeedType( "rss_2.0" );
    feed.setTitle( "My Site" );
    feed.setLink("http://example.com");
    feed.setDescription("Test Site.");

    List<SyndEntry> entries = new ArrayList<SyndEntry>();
    SyndEntry entry = null;
    SyndContent description = null;

    entry = new SyndEntryImpl();
    entry.setTitle( "Entry1" );
    entry.setLink( "http://example.com/entry1" );
    entry.setPublishedDate( new Date() );

    description = new SyndContentImpl();
    description.setType("text/html");
    description.setValue( "This is the content of entry 1." );
    entry.setDescription( description );

    entries.add( entry );
    feed.setEntries(entries);

    return feed;
}

And method of getting the feed

@GET
@Path("/getFeed")
@Produces(MediaType.APPLICATION_XML)
public SyndFeed getFeed()
{
    RSSFeed rssFeed = new RSSFeed ();
    return rssFeed.generate();
}

I'm getting an error for incompatible type for body writer. How could make service to return XML with the feed?

Answer 1

Jersey does not know how to map an instance of SyndFeed to XML. This works.

@Path("stackoverflow")
public class RomeRessource {

    @GET
    @Path("/feed")
    @Produces("application/rss+xml")
    public Response getFeed() throws IOException, FeedException {
        final SyndFeed feed = generate();

        // Write the SyndFeed to a Writer.
        final SyndFeedOutput output = new SyndFeedOutput();
        final Writer writer = new StringWriter();
        output.output(feed, writer);

        // Return a JAX-RS Response with the Writer as the body.
        return Response.ok(writer.toString()).build();
    }

    private SyndFeed generate() {
        final SyndFeed feed = new SyndFeedImpl();
        feed.setFeedType("rss_2.0");
        feed.setTitle("My Site");
        feed.setLink("http://example.com");
        feed.setDescription("Test Site.");

        final List<SyndEntry> entries = new ArrayList<>();

        final SyndEntry entry = new SyndEntryImpl();
        entry.setTitle("Entry1");
        entry.setLink("http://example.com/entry1");
        entry.setPublishedDate(new Date());

        final SyndContent description = new SyndContentImpl();
        description.setType("text/html");
        description.setValue("This is the content of entry 1.");

        entry.setDescription(description);

        entries.add(entry);

        feed.setEntries(entries);

        return feed;
    }
}

GET the resource:

$ curl -v http://localhost:8080/StackOverflowWeb/webresources/stackoverflow/feed
*   Trying ::1...
* Connected to localhost (::1) port 8080 (#0)
> GET /StackOverflowWeb/webresources/stackoverflow/feed HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.42.1
> Accept: */*
>
< HTTP/1.1 200 OK
< Server: GlassFish Server Open Source Edition  4.1
< X-Powered-By: Servlet/3.1 JSP/2.3 (GlassFish Server Open Source Edition  4.1  Java/Oracle Corporation/1.8)
< Content-Type: application/rss+xml
< Date: Sun, 14 Jun 2015 13:15:54 GMT
< Content-Length: 565
<
<?xml version="1.0" encoding="UTF-8"?>
<rss xmlns:dc="http://purl.org/dc/elements/1.1/" version="2.0">
  <channel>
    <title>My Site</title>
    <link>http://example.com</link>
    <description>Test Site.</description>
    <item>
      <title>Entry1</title>
      <link>http://example.com/entry1</link>
      <description>This is the content of entry 1.</description>
      <pubDate>Sun, 14 Jun 2015 13:15:54 GMT</pubDate>
      <guid>http://example.com/entry1</guid>
      <dc:date>2015-06-14T13:15:54Z</dc:date>
    </item>
  </channel>
</rss>

* Connection #0 to host localhost left intact