add: redis scheduler with priority

webmagic-extension/src/main/java/us/codecraft/webmagic/scheduler/RedisPriorityScheduler.java

+package us.codecraft.webmagic.scheduler;
+
+import com.alibaba.fastjson.JSON;
+import com.sun.org.apache.regexp.internal.RE;
+import org.apache.commons.codec.digest.DigestUtils;
+import org.apache.commons.lang.StringUtils;
+import redis.clients.jedis.Jedis;
+import redis.clients.jedis.JedisPool;
+import us.codecraft.webmagic.Request;
+import us.codecraft.webmagic.Task;
+
+import java.util.Set;
+
+/**
+ * the redis scheduler with priority
+ * @author sai
+ * Created by sai on 16-5-27.
+ */
+public class RedisPriorityScheduler extends RedisScheduler
+{
+
+    private static final String ZSET_PREFIX = "zset_";
+
+    private static final String QUEUE_PREFIX = "queue_";
+
+    private static final String NO_PRIORITY_SUFFIX = "_zore";
+
+    private static final String PLUS_PRIORITY_SUFFIX    = "_plus";
+
+    private static final String MINUS_PRIORITY_SUFFIX   = "_minus";
+
+    public RedisPriorityScheduler(String host) {
+        super(host);
+    }
+
+    public RedisPriorityScheduler(JedisPool pool) {
+        super(pool);
+    }
+
+    @Override
+    protected void pushWhenNoDuplicate(Request request, Task task)
+    {
+        Jedis jedis = pool.getResource();
+        try
+        {
+            if(request.getPriority() > 0)
+                jedis.zadd(getZsetPlusPriorityKey(task), request.getPriority(), request.getUrl());
+            else if(request.getPriority() < 0)
+                jedis.zadd(getZsetMinusPriorityKey(task), request.getPriority(), request.getUrl());
+            else
+                jedis.lpush(getQueueNoPriorityKey(task), request.getUrl());
+
+            setExtrasInItem(jedis, request, task);
+        }
+        finally
+        {
+            pool.returnResource(jedis);
+        }
+    }
+
+    @Override
+    public synchronized Request poll(Task task)
+    {
+        Jedis jedis = pool.getResource();
+        try
+        {
+            String url = getRequest(jedis, task);
+            if(StringUtils.isBlank(url))
+                return null;
+            return getExtrasInItem(jedis, url, task);
+        }
+        finally
+        {
+            pool.returnResource(jedis);
+        }
+    }
+
+    private String getRequest(Jedis jedis, Task task)
+    {
+        String url;
+        Set<String> urls = jedis.zrevrange(getZsetPlusPriorityKey(task), 0, 0);
+        if(urls.isEmpty())
+        {
+            url = jedis.lpop(getQueueNoPriorityKey(task));
+            if(StringUtils.isBlank(url))
+            {
+                urls = jedis.zrevrange(getZsetMinusPriorityKey(task), 0, 0);
+                if(!urls.isEmpty())
+                {
+                    url = urls.toArray(new String[0])[0];
+                    jedis.zrem(getZsetMinusPriorityKey(task), url);
+                }
+            }
+        }
+        else
+        {
+            url = urls.toArray(new String[0])[0];
+            jedis.zrem(getZsetPlusPriorityKey(task), url);
+        }
+        return url;
+    }
+
+    @Override
+    public void resetDuplicateCheck(Task task)
+    {
+        Jedis jedis = pool.getResource();
+        try
+        {
+            jedis.del(getSetKey(task));
+        }
+        finally
+        {
+            pool.returnResource(jedis);
+        }
+    }
+
+    private String getZsetPlusPriorityKey(Task task)
+    {
+        return ZSET_PREFIX + task.getUUID() + PLUS_PRIORITY_SUFFIX;
+    }
+
+    private String getQueueNoPriorityKey(Task task)
+    {
+        return QUEUE_PREFIX + task.getUUID() + NO_PRIORITY_SUFFIX;
+    }
+
+    private String getZsetMinusPriorityKey(Task task)
+    {
+        return ZSET_PREFIX + task.getUUID() + MINUS_PRIORITY_SUFFIX;
+    }
+
+    private void setExtrasInItem(Jedis jedis,Request request, Task task)
+    {
+        if(request.getExtras() != null)
+        {
+            String field = DigestUtils.shaHex(request.getUrl());
+            String value = JSON.toJSONString(request);
+            jedis.hset(getItemKey(task), field, value);
+        }
+    }
+
+    private Request getExtrasInItem(Jedis jedis, String url, Task task)
+    {
+        String key      = getItemKey(task);
+        String field    = DigestUtils.shaHex(url);
+        byte[] bytes    = jedis.hget(key.getBytes(), field.getBytes());
+        if(bytes != null)
+            return JSON.parseObject(new String(bytes), Request.class);
+        return new Request(url);
+    }
+}

webmagic-extension/src/main/java/us/codecraft/webmagic/scheduler/RedisScheduler.java

@@ -17,7 +17,7 @@ import us.codecraft.webmagic.scheduler.component.DuplicateRemover;
  */
 public class RedisScheduler extends DuplicateRemovedScheduler implements MonitorableScheduler, DuplicateRemover {
 
-    private JedisPool pool;
+    protected JedisPool pool;
 
     private static final String QUEUE_PREFIX = "queue_";
 
@@ -104,6 +104,11 @@ public class RedisScheduler extends DuplicateRemovedScheduler implements Monitor
         return QUEUE_PREFIX + task.getUUID();
     }
 
+    protected String getItemKey(Task task)
+    {
+        return ITEM_PREFIX + task.getUUID();
+    }
+
     @Override
     public int getLeftRequestsCount(Task task) {
         Jedis jedis = pool.getResource();

webmagic-extension/src/test/java/us/codecraft/webmagic/scheduler/RedisPrioritySchedulerTest.java

+package us.codecraft.webmagic.scheduler;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Ignore;
+import org.junit.Test;
+import us.codecraft.webmagic.Request;
+import us.codecraft.webmagic.Site;
+import us.codecraft.webmagic.Task;
+
+/**
+ * @author sai
+ * Created by sai on 16-7-5.
+ */
+public class RedisPrioritySchedulerTest
+{
+
+    private RedisPriorityScheduler scheduler;
+
+    @Before
+    public void setUp()
+    {
+        scheduler = new RedisPriorityScheduler("localhost");
+    }
+
+    @Ignore("environment depended")
+    @Test
+    public void test()
+    {
+        Task task = new Task() {
+            @Override
+            public String getUUID() {
+                return "TestTask";
+            }
+
+            @Override
+            public Site getSite() {
+                return null;
+            }
+        };
+
+        scheduler.resetDuplicateCheck(task);
+
+        Request request = new Request("https://www.google.com");
+        Request request1= new Request("https://www.facebook.com/");
+        Request request2= new Request("https://twitter.com");
+
+        request.setPriority(1).putExtra("name", "google");
+        request1.setPriority(0).putExtra("name", "facebook");
+        request2.setPriority(-1).putExtra("name", "twitter");
+
+        scheduler.push(request, task);
+        scheduler.push(request1, task);
+        scheduler.push(request2, task);
+
+        Request GRequest    = scheduler.poll(task);
+        Request FBRequest   = scheduler.poll(task);
+        Request TRequest    = scheduler.poll(task);
+
+        Assert.assertEquals(GRequest.getUrl(), request.getUrl());
+        Assert.assertEquals(GRequest.getExtra("name"), request.getExtra("name"));
+
+        Assert.assertEquals(FBRequest.getUrl(), request1.getUrl());
+        Assert.assertEquals(FBRequest.getExtra("name"), request.getExtra("name"));
+
+        Assert.assertEquals(TRequest.getUrl(), request2.getUrl());
+        Assert.assertEquals(TRequest.getExtra("name"), request.getExtra("name"));
+    }
+
+}