public static void main(String args[]) throws Exception {
HttpProtocol protocol = new HttpProtocol();
Config conf = new Config();
String url = args[0];
ConfUtils.loadConf(args[1], conf);
protocol.configure(conf);
if (!protocol.skipRobots) {
BaseRobotRules rules = protocol.getRobotRules(url);
System.out.println("is allowed : " + rules.isAllowed(url));
}
Metadata md = new Metadata();
ProtocolResponse response = protocol.getProtocolOutput(url, md);
System.out.println(url);
System.out.println(response.getMetadata());
System.out.println(response.getStatusCode());
System.out.println(response.getContent().length);
}
@Override
public void execute(Tuple input) {
String urlString = input.getStringByField("url");
if (StringUtils.isBlank(urlString)) {
LOG.info("[Fetcher #{}] Missing value for field url in tuple {}", taskIndex, input);
// ignore silently
_collector.ack(input);
return;
}
Metadata metadata = null;
if (input.contains("metadata")) metadata = (Metadata) input.getValueByField("metadata");
if (metadata == null) metadata = Metadata.empty;
URL url;
try {
url = new URL(urlString);
} catch (MalformedURLException e) {
LOG.error("{} is a malformed URL", urlString);
// Report to status stream and ack
if (metadata == Metadata.empty) {
metadata = new Metadata();
}
metadata.setValue("error.cause", "malformed URL");
_collector.emit(
com.digitalpebble.storm.crawler.Constants.StatusStreamName,
input,
new Values(urlString, metadata, Status.ERROR));
_collector.ack(input);
return;
}
// check when we are allowed to process it
String key = getPolitenessKey(url);
Long timeAllowed = throttler.getIfPresent(key);
if (timeAllowed != null) {
long now = System.currentTimeMillis();
long timeToWait = timeAllowed - now;
if (timeToWait > 0) {
try {
Thread.sleep(timeToWait);
} catch (InterruptedException e) {
LOG.error("[Fetcher #{}] caught InterruptedException caught while waiting");
}
}
}
long delay = this.crawlDelay;
try {
Protocol protocol = protocolFactory.getProtocol(url);
BaseRobotRules rules = protocol.getRobotRules(urlString);
// autodiscovery of sitemaps
// the sitemaps will be sent down the topology
// as many times as there is a URL for a given host
// the status updater will certainly cache things
// but we could also have a simple cache mechanism here
// as well.
if (sitemapsAutoDiscovery) {
for (String sitemapURL : rules.getSitemaps()) {
handleOutlink(input, url, sitemapURL, metadata);
}
}
if (!rules.isAllowed(urlString)) {
LOG.info("Denied by robots.txt: {}", urlString);
metadata.setValue("error.cause", "robots.txt");
// Report to status stream and ack
_collector.emit(
com.digitalpebble.storm.crawler.Constants.StatusStreamName,
input,
new Values(urlString, metadata, Status.ERROR));
_collector.ack(input);
return;
}
// get the delay from robots
// value is negative when not set
long robotsDelay = rules.getCrawlDelay();
if (robotsDelay > 0) {
// cap the value to a maximum
// as some sites specify ridiculous values
if (robotsDelay > maxCrawlDelay) {
LOG.debug("Delay from robots capped at {} for {}", robotsDelay, url);
delay = maxCrawlDelay;
} else {
delay = robotsDelay;
}
}
long start = System.currentTimeMillis();
ProtocolResponse response = protocol.getProtocolOutput(urlString, metadata);
long timeFetching = System.currentTimeMillis() - start;
averagedMetrics.scope("fetch_time").update(timeFetching);
averagedMetrics.scope("bytes_fetched").update(response.getContent().length);
eventCounter.scope("fetched").incrBy(1);
perSecMetrics.scope("bytes_fetched_perSec").update(response.getContent().length);
perSecMetrics.scope("fetched_perSec").update(1);
LOG.info(
"[Fetcher #{}] Fetched {} with status {} in {}",
taskIndex,
urlString,
response.getStatusCode(),
timeFetching);
response
.getMetadata()
.setValue("fetch.statusCode", Integer.toString(response.getStatusCode()));
response.getMetadata().putAll(metadata);
// determine the status based on the status code
Status status = Status.fromHTTPCode(response.getStatusCode());
// if the status is OK emit on default stream
if (status.equals(Status.FETCHED)) {
_collector.emit(
Utils.DEFAULT_STREAM_ID,
input,
new Values(urlString, response.getContent(), response.getMetadata()));
} else if (status.equals(Status.REDIRECTION)) {
// Mark URL as redirected
_collector.emit(
com.digitalpebble.storm.crawler.Constants.StatusStreamName,
input,
new Values(urlString, response.getMetadata(), status));
// find the URL it redirects to
String redirection = response.getMetadata().getFirstValue(HttpHeaders.LOCATION);
if (allowRedirs && redirection != null && StringUtils.isNotBlank(redirection)) {
handleOutlink(input, url, redirection, response.getMetadata());
}
} else {
// Error
_collector.emit(
com.digitalpebble.storm.crawler.Constants.StatusStreamName,
input,
new Values(urlString, response.getMetadata(), status));
}
} catch (Exception exece) {
String message = exece.getMessage();
if (message == null) message = "";
// common exceptions for which we log only a short message
if (exece.getCause() instanceof java.util.concurrent.TimeoutException)
LOG.error("Socket timeout fetching {}", urlString);
else if (message.contains(" timed out")) LOG.error("Socket timeout fetching {}", urlString);
else if (exece.getCause() instanceof java.net.UnknownHostException)
LOG.error("Unknown host {}", urlString);
else if (message.contains(" timed out")) LOG.error("Socket timeout fetching {}", urlString);
// log the full stacktrace
else LOG.error("Exception while fetching {}", urlString, exece);
eventCounter.scope("exception").incrBy(1);
// could be an empty, immutable Metadata
if (metadata.size() == 0) {
metadata = new Metadata();
}
// add the reason of the failure in the metadata
metadata.setValue("fetch.exception", message);
_collector.emit(
com.digitalpebble.storm.crawler.Constants.StatusStreamName,
input,
new Values(urlString, metadata, Status.FETCH_ERROR));
}
// update the throttler
throttler.put(key, System.currentTimeMillis() + delay);
_collector.ack(input);
}
