Node Redis Delete All Keys (Detailed Guide w/ Code Examples)

Use Case(s)

In Node.js applications using Redis as a cache or session store, you may need to delete all keys in scenarios such as:

• Clearing the cache to refresh data.
• Deleting all sessions for system maintenance or security reasons.

Code Examples

1. Using flushdb command:

const redis = require('redis');
const client = redis.createClient();

client.flushdb((err, succeeded) => {
    console.log(succeeded); // will be true if success
});

flushdb is a Redis command that deletes all keys from the current database. This method is handy when you want to clear your entire cache.

2. Using keys and del commands:

const redis = require('redis');
const client = redis.createClient();

client.keys('*', (err, keys) => {
  if (err) return console.log(err);

  for(let i = 0; i < keys.length; i++) {
    client.del(keys[i], function(err, reply) {
        console.log(reply);
    });
  }
});

In this example, we first call the keys command with the wildcard '*' to fetch all keys in the database. After that, we loop over the keys and delete each one using the del command.

Best Practices

• Be cautious when using these commands, especially on production databases, as they will permanently delete all your keys.
• Avoid blocking Redis for a long time when deleting a large number of keys. Consider using the UNLINK command, which is a non-blocking alternative to DEL.

Common Mistakes

• Not handling errors from flushdb, del, or keys commands.
• Using these commands on the wrong database or the production environment by mistake.

FAQs

Q: Can I delete keys matching a specific pattern? A: Yes, in the second code example, replace '' in the keys method with your pattern. For example, 'session:' will match all keys that start with 'session:'.