@Override
public void execute(Tuple tuple) {
Metadata metadata = (Metadata) tuple.getValueByField("metadata");
byte[] content = tuple.getBinaryByField("content");
String url = tuple.getStringByField("url");
boolean isfeed = Boolean.valueOf(metadata.getFirstValue(isFeedKey));
// doesn't have the metadata expected
if (!isfeed) {
if (sniffWhenNoMDKey) {
// uses mime-type
// won't work when servers return text/xml
// TODO use Tika instead?
String ct = metadata.getFirstValue(HttpHeaders.CONTENT_TYPE);
if (ct.contains("rss+xml")) isfeed = true;
}
}
// still not a feed file
if (!isfeed) {
// just pass it on
this.collector.emit(tuple, tuple.getValues());
this.collector.ack(tuple);
return;
} else {
// can be used later on for custom scheduling
metadata.setValue(isFeedKey, "true");
}
List<Outlink> outlinks;
try {
outlinks = parseFeed(url, content, metadata);
} catch (Exception e) {
// exception while parsing the feed
String errorMessage = "Exception while parsing " + url + ": " + e;
LOG.error(errorMessage);
// send to status stream in case another component wants to update
// its status
metadata.setValue(Constants.STATUS_ERROR_SOURCE, "feed parsing");
metadata.setValue(Constants.STATUS_ERROR_MESSAGE, errorMessage);
collector.emit(Constants.StatusStreamName, tuple, new Values(url, metadata, Status.ERROR));
this.collector.ack(tuple);
return;
}
// apply the parse filters if any to the current document
try {
ParseResult parse = new ParseResult();
parse.setOutlinks(outlinks);
ParseData parseData = parse.get(url);
parseData.setMetadata(metadata);
parseFilters.filter(url, content, null, parse);
} catch (RuntimeException e) {
String errorMessage = "Exception while running parse filters on " + url + ": " + e;
LOG.error(errorMessage);
metadata.setValue(Constants.STATUS_ERROR_SOURCE, "content filtering");
metadata.setValue(Constants.STATUS_ERROR_MESSAGE, errorMessage);
collector.emit(StatusStreamName, tuple, new Values(url, metadata, Status.ERROR));
collector.ack(tuple);
return;
}
// send to status stream
for (Outlink ol : outlinks) {
Values v = new Values(ol.getTargetURL(), ol.getMetadata(), Status.DISCOVERED);
collector.emit(Constants.StatusStreamName, tuple, v);
}
// marking the main URL as successfully fetched
// regardless of whether we got a parse exception or not
collector.emit(Constants.StatusStreamName, tuple, new Values(url, metadata, Status.FETCHED));
this.collector.ack(tuple);
}
private List<Outlink> parseFeed(String url, byte[] content, Metadata parentMetadata)
throws MalformedURLException {
List<Outlink> links = new ArrayList<>();
SyndFeed feed = null;
try (ByteArrayInputStream is = new ByteArrayInputStream(content)) {
SyndFeedInput input = new SyndFeedInput();
feed = input.build(new InputSource(is));
} catch (Exception e) {
LOG.error("Exception parsing feed from DOM {}", url);
return links;
}
URL sURL = new URL(url);
List<SyndEntry> entries = feed.getEntries();
for (SyndEntry entry : entries) {
String targetURL = entry.getLink();
// build an absolute URL
try {
targetURL = URLUtil.resolveURL(sURL, targetURL).toExternalForm();
} catch (MalformedURLException e) {
LOG.debug("MalformedURLException on {}", targetURL);
continue;
}
targetURL = urlFilters.filter(sURL, parentMetadata, targetURL);
if (StringUtils.isBlank(targetURL)) continue;
Outlink newLink = new Outlink(targetURL);
Metadata targetMD = metadataTransfer.getMetaForOutlink(targetURL, url, parentMetadata);
newLink.setMetadata(targetMD);
String title = entry.getTitle();
if (StringUtils.isNotBlank(title)) {
targetMD.setValue("feed.title", title.trim());
}
Date publishedDate = entry.getPublishedDate();
if (publishedDate != null) {
// filter based on the published date
if (filterHoursSincePub != -1) {
Calendar rightNow = Calendar.getInstance();
rightNow.add(Calendar.HOUR, -filterHoursSincePub);
if (publishedDate.before(rightNow.getTime())) {
LOG.info(
"{} has a published date {} which is more than {} hours old",
targetURL,
publishedDate.toString(),
filterHoursSincePub);
continue;
}
}
targetMD.setValue("feed.publishedDate", publishedDate.toString());
}
SyndContent description = entry.getDescription();
if (description != null && StringUtils.isNotBlank(description.getValue())) {
targetMD.setValue("feed.description", description.getValue());
}
links.add(newLink);
}
return links;
}