Use redis to manage the user login session

Login and cookie cache

For cookie used for login, there are two common ways to store login information in cookie: a signature (signed) cookie and a token (token) cookie.

Signing cookie typically stores the user name, possibly ID, the time of the last successful login, and any other information the site finds useful. In addition to the user's information, signature cookie contains a signature that the server can use to verify that the sent information is unchanged (such as changing the login username in cookie to another customer).

Token cookie stores a string of random bytes as a token in cookie, and the server can look up the owner of the token in the database based on the token. The following table shows the advantages and disadvantages of signature cookie and token cookie.

Here is an example written in java

import java.util.ArrayList;
import java.util.Set;
import redis.clients.jedis.Jedis;
public class Login {
 public String checkToken(Jedis conn,String token){
  return conn.hget("login:", token);
 }
 public void updateToken(Jedis conn,String token,String user,String item){
  long time=System.currentTimeMillis()/1000;
  conn.hset("login:", token, user);// Maintains the mapping between token and user 
  conn.zadd("recent:", time, token);// Save the token last 1 The time of the second occurrence 
  if(item!=null){
   conn.zadd("viewd:"+token, time, item);// Based on this token, set the name of the item that the user accesses at this timestamp 
   conn.zremrangeByRank("viewd:"+token, 0, -26);// Remove existing user records and keep only those that the user has browsed 25 A commodity. 
   conn.zincrby("viewd:", -1, item);
  }
 }
 public class CleanSessionsThread extends Thread{
  private Jedis conn;
  private int limit;
  private boolean quit;
  public CleanSessionsThread(int limit) {
   // TODO Auto-generated constructor stub
   this.conn=new Jedis("localhost");
   conn.select(15);
   this.limit=limit;
  }
  public void quit(){
   quit=true;
  }
  @Override
  public void run() {
   // TODO Auto-generated method stub
   while(!quit){
    long size=conn.zcard("recent:");// Determine the number of people online according to the login time 
    if(size<=limit){
     try {
      Thread.sleep(1000);
     } catch (InterruptedException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }
    }else{
     long endIndex=Math.min(size-limit,100);
     Set<String> tokensSet=conn.zrange("recent:", 0, endIndex-1);
     String[] tokens=tokensSet.toArray(new String[tokensSet.size()]);
     ArrayList<String> sessionKeys=new ArrayList<>();
     for(String token:tokens){
      sessionKeys.add("viewd:"+token);
     }
     conn.del(sessionKeys.toArray(new String[sessionKeys.size()]));
     conn.hdel("login:", tokens);
     conn.zrem("recent:", tokens);
    }
   }
  }
 }
}