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package de.danoeh.antennapod.util.syndication;
import android.net.Uri;
import org.apache.commons.lang3.StringUtils;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import java.io.File;
import java.io.IOException;
import java.util.LinkedHashMap;
import java.util.Map;
/**
* Finds RSS/Atom URLs in a HTML document using the auto-discovery techniques described here:
* <p/>
* http://www.rssboard.org/rss-autodiscovery
* <p/>
* http://blog.whatwg.org/feed-autodiscovery
*/
public class FeedDiscoverer {
private static final String MIME_RSS = "application/rss+xml";
private static final String MIME_ATOM = "application/atom+xml";
/**
* Discovers links to RSS and Atom feeds in the given File which must be a HTML document.
*
* @return A map which contains the feed URLs as keys and titles as values (the feed URL is also used as a title if
* a title cannot be found).
*/
public Map<String, String> findLinks(File in, String baseUrl) throws IOException {
return findLinks(Jsoup.parse(in, null), baseUrl);
}
/**
* Discovers links to RSS and Atom feeds in the given File which must be a HTML document.
*
* @return A map which contains the feed URLs as keys and titles as values (the feed URL is also used as a title if
* a title cannot be found).
*/
public Map<String, String> findLinks(String in, String baseUrl) throws IOException {
return findLinks(Jsoup.parse(in), baseUrl);
}
private Map<String, String> findLinks(Document document, String baseUrl) {
Map<String, String> res = new LinkedHashMap<String, String>();
Elements links = document.head().getElementsByTag("link");
for (Element link : links) {
String rel = link.attr("rel");
String href = link.attr("href");
if (!StringUtils.isEmpty(href) &&
(rel.equals("alternate") || rel.equals("feed"))) {
String type = link.attr("type");
if (type.equals(MIME_RSS) || type.equals(MIME_ATOM)) {
String title = link.attr("title");
String processedUrl = processURL(baseUrl, href);
if (processedUrl != null) {
res.put(processedUrl,
(StringUtils.isEmpty(title)) ? href : title);
}
}
}
}
return res;
}
private String processURL(String baseUrl, String strUrl) {
Uri uri = Uri.parse(strUrl);
if (uri.isRelative()) {
Uri res = Uri.parse(baseUrl).buildUpon().path(strUrl).build();
return (res != null) ? res.toString() : null;
} else {
return strUrl;
}
}
}
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