package com.commafeed.backend.feed;
import java.io.IOException;
import java.util.Date;
import javax.inject.Inject;
import javax.inject.Singleton;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.codec.binary.StringUtils;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.http.client.ClientProtocolException;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.select.Elements;
import com.commafeed.backend.HttpGetter;
import com.commafeed.backend.HttpGetter.HttpResult;
import com.commafeed.backend.HttpGetter.NotModifiedException;
import com.commafeed.backend.model.Feed;
import com.rometools.rome.io.FeedException;
@Slf4j
@RequiredArgsConstructor(onConstructor = @__({ @Inject }))
@Singleton
public class FeedFetcher {
private final FeedParser parser;
private final HttpGetter getter;
public FetchedFeed fetch(String feedUrl, boolean extractFeedUrlFromHtml, String lastModified, String eTag, Date lastPublishedDate,
String lastContentHash) throws FeedException, ClientProtocolException, IOException, NotModifiedException {
log.debug("Fetching feed {}", feedUrl);
FetchedFeed fetchedFeed = null;
int timeout = 20000;
HttpResult result = getter.getBinary(feedUrl, lastModified, eTag, timeout);
byte[] content = result.getContent();
try {
fetchedFeed = parser.parse(feedUrl, content);
} catch (FeedException e) {
if (extractFeedUrlFromHtml) {
String extractedUrl = extractFeedUrl(StringUtils.newStringUtf8(result.getContent()), feedUrl);
if (org.apache.commons.lang3.StringUtils.isNotBlank(extractedUrl)) {
feedUrl = extractedUrl;
result = getter.getBinary(extractedUrl, lastModified, eTag, timeout);
content = result.getContent();
fetchedFeed = parser.parse(feedUrl, content);
} else {
throw e;
}
} else {
throw e;
}
}
if (content == null) {
throw new IOException("Feed content is empty.");
}
String hash = DigestUtils.sha1Hex(content);
if (lastContentHash != null && hash != null && lastContentHash.equals(hash)) {
log.debug("content hash not modified: {}", feedUrl);
throw new NotModifiedException("content hash not modified");
}
if (lastPublishedDate != null && fetchedFeed.getFeed().getLastPublishedDate() != null
&& lastPublishedDate.getTime() == fetchedFeed.getFeed().getLastPublishedDate().getTime()) {
log.debug("publishedDate not modified: {}", feedUrl);
throw new NotModifiedException("publishedDate not modified");
}
Feed feed = fetchedFeed.getFeed();
feed.setLastModifiedHeader(result.getLastModifiedSince());
feed.setEtagHeader(FeedUtils.truncate(result.getETag(), 255));
feed.setLastContentHash(hash);
fetchedFeed.setFetchDuration(result.getDuration());
fetchedFeed.setUrlAfterRedirect(result.getUrlAfterRedirect());
return fetchedFeed;
}
private String extractFeedUrl(String html, String baseUri) {
String foundUrl = null;
Document doc = Jsoup.parse(html, baseUri);
String root = doc.children().get(0).tagName();
if ("html".equals(root)) {
Elements atom = doc.select("link[type=application/atom+xml]");
Elements rss = doc.select("link[type=application/rss+xml]");
if (!atom.isEmpty()) {
foundUrl = atom.get(0).attr("abs:href");
} else if (!rss.isEmpty()) {
foundUrl = rss.get(0).attr("abs:href");
}
}
return foundUrl;
}
}