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Simon Prickettleibale
Simon Prickett
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leibale
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Adds Bloom Filter example using RedisBloom. (#1835)
* Adds Bloom Filter example using RedisBloom. * Update bloom-filter.js Co-authored-by: Leibale Eidelman <[email protected]>
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‎examples/README.md

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This folder contains example scripts showing how to use Node Redis in different scenarios.
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| File Name | Description |
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|-----------------------------|----------------------------------------------------------------------------------------------------------------|
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| `blocking-list-pop.js` | Block until an element is pushed to a list |
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| `command-with-modifiers.js` | Define a script that allows to run a command with several modifiers |
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| `connect-as-acl-user.js` | Connect to Redis 6 using an ACL user |
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| `lua-multi-incr.js` | Define a custom lua script that allows you to perform INCRBY on multiple keys |
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| `managing-json.js` | Store, retrieve and manipulate JSON data atomically with [RedisJSON](https://redisjson.io/) |
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| `search-hashes.js` | Uses [RediSearch](https://redisearch.io) to index and search data in hashes |
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| `search-json.js` | Uses [RediSearch](https://redisearch.io/) and [RedisJSON](https://redisjson.io/) to index and search JSON data |
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| `set-scan.js` | An example script that shows how to use the SSCAN iterator functionality |
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| `stream-producer.js` | Adds entries to a [Redis Stream](https://redis.io/topics/streams-intro) using the `XADD` command |
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| `stream-consumer.js` | Reads entries from a [Redis Stream](https://redis.io/topics/streams-intro) using the blocking `XREAD` command |
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| `topk.js` | Use the [RedisBloom](https://redisbloom.io) TopK to track the most frequently seen items. |
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| File Name | Description |
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|-----------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------|
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| `blocking-list-pop.js` | Block until an element is pushed to a list |
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| `bloom-filter.js` | Space efficient set membership checks with a [Bloom Filter](https://en.wikipedia.org/wiki/Bloom_filter) using [RedisBloom](https://redisbloom.io) |
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| `command-with-modifiers.js` | Define a script that allows to run a command with several modifiers |
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| `connect-as-acl-user.js` | Connect to Redis 6 using an ACL user |
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| `lua-multi-incr.js` | Define a custom lua script that allows you to perform INCRBY on multiple keys |
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| `managing-json.js` | Store, retrieve and manipulate JSON data atomically with [RedisJSON](https://redisjson.io/) |
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| `search-hashes.js` | Uses [RediSearch](https://redisearch.io) to index and search data in hashes |
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| `search-json.js` | Uses [RediSearch](https://redisearch.io/) and [RedisJSON](https://redisjson.io/) to index and search JSON data |
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| `set-scan.js` | An example script that shows how to use the SSCAN iterator functionality |
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| `stream-producer.js` | Adds entries to a [Redis Stream](https://redis.io/topics/streams-intro) using the `XADD` command |
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| `stream-consumer.js` | Reads entries from a [Redis Stream](https://redis.io/topics/streams-intro) using the blocking `XREAD` command |
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| `topk.js` | Use the [RedisBloom](https://redisbloom.io) TopK to track the most frequently seen items. |
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## Contributing
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‎examples/bloom-filter.js

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// This example demonstrates the use of the Bloom Filter
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// in the RedisBloom module (https://redisbloom.io/)
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import { createClient } from 'redis';
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async function bloomFilter() {
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const client = createClient();
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await client.connect();
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// Delete any pre-existing Bloom Filter.
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await client.del('mybloom');
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// Reserve a Bloom Filter with configurable error rate and capacity.
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// https://oss.redis.com/redisbloom/Bloom_Commands/#bfreserve
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try {
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await client.bf.reserve('mybloom', 0.01, 1000);
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console.log('Reserved Bloom Filter.');
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} catch (e) {
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if (e.message.endsWith('item exists')) {
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console.log('Bloom Filter already reserved.');
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} else {
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console.log('Error, maybe RedisBloom is not installed?:');
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console.log(e);
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}
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}
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// Add items to Bloom Filter individually with BF.ADD command.
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await Promise.all([
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client.bf.add('mybloom', 'leibale'),
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client.bf.add('mybloom', 'simon'),
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client.bf.add('mybloom', 'guy'),
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client.bf.add('mybloom', 'suze'),
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client.bf.add('mybloom', 'brian'),
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client.bf.add('mybloom', 'steve'),
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client.bf.add('mybloom', 'kyle'),
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client.bf.add('mybloom', 'josefin'),
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client.bf.add('mybloom', 'alex'),
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client.bf.add('mybloom', 'nava'),
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]);
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// Add multiple items to Bloom Filter at once with BF.MADD command.
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await client.bf.mAdd('mybloom', [
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'kaitlyn',
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'rachel'
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]);
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console.log('Added members to Bloom Filter.');
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// Check whether a member exists with the BF.EXISTS command.
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const simonExists = await client.bf.exists('mybloom', 'simon');
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console.log(`simon ${simonExists ? 'may' : 'does not'} exist in the Bloom Filter.`);
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// Check whether multiple members exist with the BF.MEXISTS command:
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const [ lanceExists, leibaleExists ] = await client.bf.mExists('mybloom', [
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'lance',
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'leibale'
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]);
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console.log(`lance ${lanceExists ? 'may' : 'does not'} exist in the Bloom Filter.`);
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console.log(`leibale ${leibaleExists ? 'may' : 'does not'} exist in the Bloom Filter.`);
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// Get stats for the Bloom Filter with the BF.INFO command:
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const info = await client.bf.info('mybloom');
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// info looks like this:
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//
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// {
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// capacity: 1000,
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// size: 1531,
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// numberOfFilters: 1,
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// numberOfInsertedItems: 12,
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// expansionRate: 2
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// }
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console.log(info);
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await client.quit();
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}
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bloomFilter();

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