/*
* Copyright 2004 Sun Microsystems, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package com.sun.syndication.fetcher.impl;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.zip.GZIPInputStream;
import org.apache.commons.httpclient.Credentials;
import org.apache.commons.httpclient.Header;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.params.HttpClientParams;
import com.sun.syndication.feed.synd.SyndFeed;
import com.sun.syndication.fetcher.FetcherEvent;
import com.sun.syndication.fetcher.FetcherException;
import com.sun.syndication.io.FeedException;
import com.sun.syndication.io.SyndFeedInput;
import com.sun.syndication.io.XmlReader;
/**
* @author Nick Lothian
*/
public class HttpClientFeedFetcher extends AbstractFeedFetcher {
private FeedFetcherCache feedInfoCache;
private CredentialSupplier credentialSupplier;
private volatile HttpClientMethodCallbackIntf httpClientMethodCallback;
private volatile HttpClientParams httpClientParams;
public HttpClientFeedFetcher() {
super();
setHttpClientParams(new HttpClientParams());
}
/**
* @param cache
*/
public HttpClientFeedFetcher(FeedFetcherCache cache) {
this();
setFeedInfoCache(cache);
}
public HttpClientFeedFetcher(FeedFetcherCache cache, CredentialSupplier credentialSupplier) {
this(cache);
setCredentialSupplier(credentialSupplier);
}
/**
* @return Returns the httpClientParams.
*/
public synchronized HttpClientParams getHttpClientParams() {
return this.httpClientParams;
}
/**
* @param httpClientParams The httpClientParams to set.
*/
public synchronized void setHttpClientParams(HttpClientParams httpClientParams) {
this.httpClientParams = httpClientParams;
}
/**
* @param timeout Sets the connect timeout for the HttpClient but using the URLConnection method name.
* Uses the HttpClientParams method setConnectionManagerTimeout instead of setConnectTimeout
*
*/
public synchronized void setConnectTimeout(int timeout) {
httpClientParams.setConnectionManagerTimeout(timeout);
}
/**
* @return The currently used connect timeout for the HttpClient but using the URLConnection method name.
* Uses the HttpClientParams method getConnectionManagerTimeout instead of getConnectTimeout
*
*/
public int getConnectTimeout() {
return (int) this.getHttpClientParams().getConnectionManagerTimeout();
}
/**
* @return The currently used read timeout for the URLConnection, 0 is unlimited, i.e. no timeout
*/
public synchronized void setReadTimeout(int timeout) {
httpClientParams.setSoTimeout(timeout);
}
/**
* @param timeout Sets the read timeout for the URLConnection to a specified timeout, in milliseconds.
*/
public int getReadTimeout() {
return (int) this.getHttpClientParams().getSoTimeout();
}
public HttpClientMethodCallbackIntf getHttpClientMethodCallback() {
return httpClientMethodCallback;
}
public synchronized void setHttpClientMethodCallback(HttpClientMethodCallbackIntf httpClientMethodCallback) {
this.httpClientMethodCallback = httpClientMethodCallback;
}
/**
* @return the feedInfoCache.
*/
public synchronized FeedFetcherCache getFeedInfoCache() {
return feedInfoCache;
}
/**
* @param feedInfoCache the feedInfoCache to set
*/
public synchronized void setFeedInfoCache(FeedFetcherCache feedInfoCache) {
this.feedInfoCache = feedInfoCache;
}
/**
* @return Returns the credentialSupplier.
*/
public synchronized CredentialSupplier getCredentialSupplier() {
return credentialSupplier;
}
/**
* @param credentialSupplier The credentialSupplier to set.
*/
public synchronized void setCredentialSupplier(CredentialSupplier credentialSupplier) {
this.credentialSupplier = credentialSupplier;
}
/**
* @see com.sun.syndication.fetcher.FeedFetcher#retrieveFeed(java.net.URL)
*/
public SyndFeed retrieveFeed(URL feedUrl) throws IllegalArgumentException, IOException, FeedException, FetcherException {
if (feedUrl == null) {
throw new IllegalArgumentException("null is not a valid URL");
}
// TODO Fix this
//System.setProperty("org.apache.commons.logging.Log", "org.apache.commons.logging.impl.SimpleLog");
HttpClient client = new HttpClient(httpClientParams);
if (getCredentialSupplier() != null) {
client.getState().setAuthenticationPreemptive(true);
// TODO what should realm be here?
Credentials credentials = getCredentialSupplier().getCredentials(null, feedUrl.getHost());
if (credentials != null) {
client.getState().setCredentials(null, feedUrl.getHost(), credentials);
}
}
System.setProperty("httpclient.useragent", getUserAgent());
String urlStr = feedUrl.toString();
HttpMethod method = new GetMethod(urlStr);
method.addRequestHeader("Accept-Encoding", "gzip");
method.addRequestHeader("User-Agent", getUserAgent());
method.setFollowRedirects(true);
if (httpClientMethodCallback != null) {
synchronized (httpClientMethodCallback) {
httpClientMethodCallback.afterHttpClientMethodCreate(method);
}
}
FeedFetcherCache cache = getFeedInfoCache();
if (cache != null) {
// retrieve feed
try {
if (isUsingDeltaEncoding()) {
method.setRequestHeader("A-IM", "feed");
}
// get the feed info from the cache
// Note that syndFeedInfo will be null if it is not in the cache
SyndFeedInfo syndFeedInfo = cache.getFeedInfo(feedUrl);
if (syndFeedInfo != null) {
method.setRequestHeader("If-None-Match", syndFeedInfo.getETag());
if (syndFeedInfo.getLastModified() instanceof String) {
method.setRequestHeader("If-Modified-Since", (String)syndFeedInfo.getLastModified());
}
}
int statusCode = client.executeMethod(method);
fireEvent(FetcherEvent.EVENT_TYPE_FEED_POLLED, urlStr);
handleErrorCodes(statusCode);
SyndFeed feed = getFeed(syndFeedInfo, urlStr, method, statusCode);
syndFeedInfo = buildSyndFeedInfo(feedUrl, urlStr, method, feed, statusCode);
cache.setFeedInfo(new URL(urlStr), syndFeedInfo);
// the feed may have been modified to pick up cached values
// (eg - for delta encoding)
feed = syndFeedInfo.getSyndFeed();
return feed;
} finally {
method.releaseConnection();
method.recycle();
}
} else {
// cache is not in use
try {
int statusCode = client.executeMethod(method);
fireEvent(FetcherEvent.EVENT_TYPE_FEED_POLLED, urlStr);
handleErrorCodes(statusCode);
return getFeed(null, urlStr, method, statusCode);
} finally {
method.releaseConnection();
method.recycle();
}
}
}
/**
* @param feedUrl
* @param urlStr
* @param method
* @param feed
* @return
* @throws MalformedURLException
*/
private SyndFeedInfo buildSyndFeedInfo(URL feedUrl, String urlStr, HttpMethod method, SyndFeed feed, int statusCode) throws MalformedURLException {
SyndFeedInfo syndFeedInfo;
syndFeedInfo = new SyndFeedInfo();
// this may be different to feedURL because of 3XX redirects
syndFeedInfo.setUrl(new URL(urlStr));
syndFeedInfo.setId(feedUrl.toString());
Header imHeader = method.getResponseHeader("IM");
if (imHeader != null && imHeader.getValue().indexOf("feed") >= 0 && isUsingDeltaEncoding()) {
FeedFetcherCache cache = getFeedInfoCache();
if (cache != null && statusCode == 226) {
// client is setup to use http delta encoding and the server supports it and has returned a delta encoded response
// This response only includes new items
SyndFeedInfo cachedInfo = cache.getFeedInfo(feedUrl);
if (cachedInfo != null) {
SyndFeed cachedFeed = cachedInfo.getSyndFeed();
// set the new feed to be the orginal feed plus the new items
feed = combineFeeds(cachedFeed, feed);
}
}
}
Header lastModifiedHeader = method.getResponseHeader("Last-Modified");
if (lastModifiedHeader != null) {
syndFeedInfo.setLastModified(lastModifiedHeader.getValue());
}
Header eTagHeader = method.getResponseHeader("ETag");
if (eTagHeader != null) {
syndFeedInfo.setETag(eTagHeader.getValue());
}
syndFeedInfo.setSyndFeed(feed);
return syndFeedInfo;
}
/**
* @param client
* @param urlStr
* @param method
* @return
* @throws IOException
* @throws HttpException
* @throws FetcherException
* @throws FeedException
*/
private static SyndFeed retrieveFeed(String urlStr, HttpMethod method) throws IOException, HttpException, FetcherException, FeedException {
InputStream stream = null;
if ((method.getResponseHeader("Content-Encoding") != null) && ("gzip".equalsIgnoreCase(method.getResponseHeader("Content-Encoding").getValue()))) {
stream = new GZIPInputStream(method.getResponseBodyAsStream());
} else {
stream = method.getResponseBodyAsStream();
}
try {
XmlReader reader = null;
if (method.getResponseHeader("Content-Type") != null) {
reader = new XmlReader(stream, method.getResponseHeader("Content-Type").getValue(), true);
} else {
reader = new XmlReader(stream, true);
}
return new SyndFeedInput().build(reader);
} finally {
if (stream != null) {
stream.close();
}
}
}
private SyndFeed getFeed(SyndFeedInfo syndFeedInfo, String urlStr, HttpMethod method, int statusCode) throws IOException, HttpException, FetcherException, FeedException {
if (statusCode == HttpURLConnection.HTTP_NOT_MODIFIED && syndFeedInfo != null) {
fireEvent(FetcherEvent.EVENT_TYPE_FEED_UNCHANGED, urlStr);
return syndFeedInfo.getSyndFeed();
}
SyndFeed feed = retrieveFeed(urlStr, method);
fireEvent(FetcherEvent.EVENT_TYPE_FEED_RETRIEVED, urlStr, feed);
return feed;
}
public interface CredentialSupplier {
public Credentials getCredentials(String realm, String host);
}
public interface HttpClientMethodCallbackIntf {
/**
* Allows access to the underlying HttpClient HttpMethod object.
* Note that in most cases, method.setRequestHeader(String, String)
* is what you want to do (rather than method.addRequestHeader(String, String))
*
* @param method
*/
public void afterHttpClientMethodCreate(HttpMethod method);
}
}