RssParser.java

/*
 * Taken from the 'Learning Android' project,
 * released as Public Domain software at
 * http://github.com/digitalspaghetti/learning-android
 * and modified heavily for Transdroid
 */
package org.ifies.android.sax;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.transdroid.util.HttpHelper;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import java.io.IOException;
import java.util.Date;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

public class RssParser extends DefaultHandler {
	public RssParser(String url) {
		this.urlString = url;
		this.text = new StringBuilder();
	}

	/**
	 * Returns the feed as a RssFeed, which is a ListArray
	 * @return RssFeed rssFeed
	 */
	public Channel getChannel() {
		return (this.channel);
	}

	public void parse() throws ParserConfigurationException, SAXException, IOException {

		HttpClient httpclient = initialise();
		HttpResponse result = httpclient.execute(new HttpGet(urlString));
		//FileInputStream urlInputStream = new FileInputStream("/sdcard/rsstest2.txt");
		SAXParserFactory spf = SAXParserFactory.newInstance();
		if (spf != null) {
			SAXParser sp = spf.newSAXParser();
			sp.parse(result.getEntity().getContent(), this);
		}

	}

	/**
	 * Instantiates an HTTP client that can be used for all requests.
	 */
	protected HttpClient initialise() {
		return HttpHelper.buildDefaultSearchHttpClient(false);
	}

	/**
	 * By default creates a standard Item (with title, description and links), which may to overriden to add more data.
	 * @return A possibly decorated Item instance
	 */
	protected Item createNewItem() {
		return new Item();
	}

	public void startElement(String uri, String localName, String qName, Attributes attributes) {

		/** First lets check for the channel */
		if (localName.equalsIgnoreCase("channel")) {
			this.channel = new Channel();
		}

		/** Now lets check for an item */
		if (localName.equalsIgnoreCase("item") && (this.channel != null)) {
			this.item = createNewItem();
			this.channel.addItem(this.item);
		}

		/** Now lets check for an image */
		if (localName.equalsIgnoreCase("image") && (this.channel != null)) {
			this.imgStatus = true;
		}

		/** Checking for a enclosure */
		if (localName.equalsIgnoreCase("enclosure")) {
			/** Lets check we are in an item */
			if (this.item != null && attributes != null && attributes.getLength() > 0) {
				if (attributes.getValue("url") != null) {
					this.item.setEnclosureUrl(parseLink(attributes.getValue("url")));
				}
				if (attributes.getValue("type") != null) {
					this.item.setEnclosureType(attributes.getValue("type"));
				}
				if (attributes.getValue("length") != null) {
					this.item.setEnclosureLength(Long.parseLong(attributes.getValue("length")));
				}
			}
		}

	}

	/**
	 * This is where we actually parse for the elements contents
	 */
	public void endElement(String uri, String localName, String qName) {
		/** Check we have an RSS Feed */
		if (this.channel == null) {
			return;
		}

		/** Check are at the end of an item */
		if (localName.equalsIgnoreCase("item")) {
			this.item = null;
		}

		/** Check we are at the end of an image */
		if (localName.equalsIgnoreCase("image")) {
			this.imgStatus = false;
		}

		/** Now we need to parse which title we are in */
		if (localName.equalsIgnoreCase("title")) {
			/** We are an item, so we set the item title */
			if (this.item != null) {
				this.item.setTitle(this.text.toString().trim());
				/** We are in an image */
			} else {
				this.channel.setTitle(this.text.toString().trim());
			}
		}

		/** Now we are checking for a link */
		if (localName.equalsIgnoreCase("link")) {
			/** Check we are in an item **/
			if (this.item != null) {
				this.item.setLink(parseLink(this.text.toString()));
				/** Check we are in an image */
			} else if (this.imgStatus) {
				this.channel.setImage(parseLink(this.text.toString()));
				/** Check we are in a channel */
			} else {
				this.channel.setLink(parseLink(this.text.toString()));
			}
		}

		/** Checking for a description */
		if (localName.equalsIgnoreCase("description")) {
			/** Lets check we are in an item */
			if (this.item != null) {
				this.item.setDescription(this.text.toString().trim());
				/** Lets check we are in the channel */
			} else {
				this.channel.setDescription(this.text.toString().trim());
			}
		}

		/** Checking for a pubdate */
		if (localName.equalsIgnoreCase("pubDate")) {
			/** Lets check we are in an item */
			if (this.item != null) {
				try {
					this.item.setPubdate(new Date(Date.parse(this.text.toString().trim())));
				} catch (Exception e) {
					// Date is malformed (not parsable by Date.parse)
				}
				/** Lets check we are in the channel */
			} else {
				try {
					this.channel.setPubDate(new Date(Date.parse(this.text.toString().trim())));
				} catch (Exception e) {
					// Date is malformed (not parsable by Date.parse)
				}
			}
		}

		/** Check for the category */
		if (localName.equalsIgnoreCase("category") && (this.item != null)) {
			this.channel.addCategory(this.text.toString().trim());
		}

		addAdditionalData(localName, this.item, this.text.toString());

		this.text.setLength(0);
	}

	/**
	 * May be overridden to add additional data from tags that are not standard in RSS. Not used by this default RSS style parser.
	 * @param localName The tag name
	 * @param item The Item we are currently parsing
	 * @param text The new text content
	 */
	protected void addAdditionalData(String localName, Item item, String text) {
	}

	public void characters(char[] ch, int start, int length) {
		this.text.append(ch, start, length);
	}

	private String parseLink(String string) {
		return string.trim();
	}

	private String urlString;
	private Channel channel;
	private StringBuilder text;
	private Item item;
	private boolean imgStatus;

}