Merge pull request #86 from sebastian1118/master

new feature: PatternProcessor

webmagic-extension/src/main/java/us/codecraft/webmagic/example/PatternProcessorDemo.java

+package us.codecraft.webmagic.example;
+
+import org.apache.log4j.Logger;
+import us.codecraft.webmagic.Page;
+import us.codecraft.webmagic.ResultItems;
+import us.codecraft.webmagic.Spider;
+import us.codecraft.webmagic.Task;
+import us.codecraft.webmagic.handler.PatternHandler;
+import us.codecraft.webmagic.pipeline.PatternPipeline;
+import us.codecraft.webmagic.processor.PatternPageProcessor;
+
+/**
+ * Created with IntelliJ IDEA.
+ * User: Sebastian MA
+ * Date: April 04, 2014
+ * Time: 21:23
+ */
+public class PatternProcessorDemo {
+
+	private static Logger log = Logger.getLogger(PatternProcessorDemo.class);
+
+	public static void main(String... args) {
+
+		PatternPageProcessor processor
+				= new PatternPageProcessor("http://item.jd.com/981821.html",
+				PatternPageProcessor.TARGET_PATTERN_ALL
+		);
+
+		PatternPipeline pipeline = new PatternPipeline();
+
+		// define a handler which handles only "http://item.jd.com/.*"
+		PatternHandler handler = new PatternHandler("http://item.jd.com/.*") {
+
+			@Override
+			public void onExtract(Page page) {
+
+				log.info("Extracting from " + page.getUrl());
+				page.putField("test", "hello world:)");
+			}
+
+			@Override
+			public void onHandle(ResultItems result, Task task) {
+
+				log.info("Handling " + result.getRequest().getUrl());
+				log.info("Retrieved test=" + result.get("test"));
+			}
+		};
+
+		handler.register(processor, pipeline);
+
+		Spider.create(processor).thread(5).addPipeline(pipeline).runAsync();
+	}
+}

webmagic-extension/src/main/java/us/codecraft/webmagic/handler/PatternHandler.java

+package us.codecraft.webmagic.handler;
+
+import us.codecraft.webmagic.Page;
+import us.codecraft.webmagic.ResultItems;
+import us.codecraft.webmagic.Task;
+import us.codecraft.webmagic.pipeline.PatternPipeline;
+import us.codecraft.webmagic.processor.PatternPageProcessor;
+
+import java.util.UUID;
+
+/**
+ * Created with IntelliJ IDEA.
+ * User: Sebastian MA
+ * Date: April 03, 2014
+ * Time: 10:00
+ * <p></p>
+ * A PatternHandler is in charge of both page extraction and data processing by implementing
+ * its two abstract methods.
+ */
+public abstract class PatternHandler {
+
+	/**
+	 * identity of the handler.
+	 */
+	protected String id;
+
+	/**
+	 * match pattern. only matched page should be handled.
+	 */
+	protected String pattern;
+
+	/**
+	 * @param pattern
+	 * 		url pattern to handle
+	 */
+	protected PatternHandler(String pattern) {
+
+		this.pattern = pattern;
+		this.id = UUID.randomUUID().toString();
+	}
+
+	/**
+	 * determine if the page should be handled.
+	 */
+	public boolean match(String url) {
+
+		return url.matches(pattern);
+	}
+
+	/**
+	 * registers to both the page processor and the pipeline so the handler could take charge of
+	 * both end of procedure.
+	 *
+	 * @param processor
+	 * 		the processor to handle
+	 * @param pipeline
+	 * 		the pipeline to handle
+	 */
+	public void register(PatternPageProcessor processor, PatternPipeline pipeline) {
+
+		processor.addHandler(this);
+		pipeline.addHandler(this);
+	}
+
+	public void unregister(PatternPageProcessor processor, PatternPipeline pipeline) {
+
+		processor.removeHandler(this);
+		pipeline.removeHandler(this);
+	}
+
+	public boolean process(Page page) {
+
+		if(match(page.getUrl().toString())) {
+			page.putField(id, true);
+			onExtract(page);
+			return true;
+		} else {
+			return false;
+		}
+	}
+
+	public boolean process(ResultItems resultItems, Task task) {
+
+		if(resultItems.isSkip()) {
+			return false;
+		}
+
+		if(match(resultItems.getRequest().getUrl()) && resultItems.get(id) != null) {
+			onHandle(resultItems, task);
+			return true;
+		} else {
+			return false;
+		}
+	}
+
+	/**
+	 * implements this method to extract from page.
+	 *
+	 * @param page
+	 * 		the page to extract
+	 */
+	public abstract void onExtract(Page page);
+
+	/**
+	 * implements this method to handle the extraction result.
+	 *
+	 * @param result
+	 * 		extraction result
+	 * @param task
+	 */
+	public abstract void onHandle(ResultItems result, Task task);
+
+}

webmagic-extension/src/main/java/us/codecraft/webmagic/pipeline/PatternPipeline.java

+package us.codecraft.webmagic.pipeline;
+
+import us.codecraft.webmagic.ResultItems;
+import us.codecraft.webmagic.Task;
+import us.codecraft.webmagic.handler.PatternHandler;
+
+import java.util.ArrayList;
+
+/**
+ * Created with IntelliJ IDEA.
+ * User: Sebastian MA
+ * Date: April 04, 2014
+ * Time: 20:44
+ */
+public class PatternPipeline implements Pipeline {
+
+	protected ArrayList<PatternHandler> handlers = new ArrayList<PatternHandler>();
+
+	/**
+	 * A handler works only if it is added to BOTH the page processor and the pipeline.
+	 * Uses PatternHandler's register instead.
+	 *
+	 * @param handler the pattern handler
+	 *
+	 * @see PatternHandler#register
+	 */
+	public void addHandler(PatternHandler handler) {
+
+		handlers.add(handler);
+	}
+
+	public void removeHandler(PatternHandler handler) {
+
+		handlers.remove(handler);
+	}
+
+	@Override
+	public void process(ResultItems resultItems, Task task) {
+
+		for(PatternHandler handler : handlers) {
+			handler.process(resultItems, task);
+		}
+	}
+}

webmagic-extension/src/main/java/us/codecraft/webmagic/processor/PatternPageProcessor.java

+package us.codecraft.webmagic.processor;
+
+import us.codecraft.webmagic.Page;
+import us.codecraft.webmagic.Site;
+import us.codecraft.webmagic.handler.PatternHandler;
+import us.codecraft.webmagic.utils.UrlUtils;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Created with IntelliJ IDEA.
+ * User: Sebastian MA
+ * Date: April 04, 2014
+ * Time: 15:36
+ * <p></p>
+ * A PatternPageProcessor uses PatternHandler to setup extraction rules for specific url pattern.
+ *
+ * @see us.codecraft.webmagic.handler.PatternHandler
+ */
+public class PatternPageProcessor implements PageProcessor {
+
+	public static final String TARGET_PATTERN_ALL = "http://*";
+
+	protected Site site;
+
+	protected String targetPattern;
+
+	protected ArrayList<PatternHandler> handlers = new ArrayList<PatternHandler>();
+
+	public PatternPageProcessor(String startUrl, String targetPattern) {
+
+		this.targetPattern = targetPattern;
+
+		this.site = Site.me().addStartUrl(startUrl).setDomain(UrlUtils.getDomain(startUrl));
+		this.targetPattern = "(" + targetPattern.replace(".", "\\.").replace("*",
+				"[^\"'#]*") + ")";
+
+		site.setUserAgent("Chrome/5.0.354.0");
+	}
+
+	@Override
+	public void process(Page page) {
+
+
+		List<String> requests = page.getHtml().links().regex(targetPattern).all();
+		page.addTargetRequests(requests);
+		for(PatternHandler handler : handlers) {
+			if(handler.match(page.getUrl().toString())) {
+				handler.process(page);
+			}
+		}
+	}
+
+	/**
+	 * A handler works only if it is added to BOTH the page processor and the pipeline.
+	 * Uses PatternHandler's register instead.
+	 *
+	 * @param handler the pattern handler
+	 *
+	 * @see PatternHandler#register
+	 */
+	public void addHandler(PatternHandler handler) {
+
+		handlers.add(handler);
+	}
+
+	public void removeHandler(PatternHandler handler) {
+
+		handlers.remove(handler);
+	}
+
+	@Override
+	public Site getSite() {
+
+		return site;
+	}
+}