ccollie / redis-level

Redis based abstract-level database for Node.js.

redis-level

• Redis based abstract-level database for Node.js.

Requirements:

• redis-2.8 or more recent.
• node-12.x

Uses a sorted-set to order the keys and a hash to store the values.

Fetches the ordered key value pairs during iterations with a single redis lua call.

Usage

const { RedisLevel } = require('redis-level')

// Create a database
const db = new RedisLevel('tokens', { valueEncoding: 'buffer' })

// Add an entry with key 'a' and value 1
await db.put('a', 1)

// Add multiple entries
await db.batch([{ type: 'put', key: 'b', value: 2 }])

// Get value of key 'a': 1
const value = await db.get('a')

// Iterate entries with keys that are greater than 'a'
for await (const [key, value] of db.iterator({ gt: 'a' })) {
  console.log(value) // 2
}

With callbacks:

db.put('example', { hello: 'world' }, (err) => {
  if (err) throw err

  db.get('example', (err, value) => {
    if (err) throw err
    console.log(value) // { hello: 'world' }
  })
})

API

The API of redis-level follows that of abstract-level with a few additional options and methods specific to Redis. The documentation below covers it all except for Encodings, Events and Errors which are exclusively documented in abstract-level.

An abstract-level and thus redis-level database is at its core a key-value database. A key-value pair is referred to as an entry here and typically returned as an array, comparable to Object.entries().

db = new RedisLevel(location[, options])

Returns a new RedisLevel instance. location is a String pointing at the root namespace of the data in redis.

• location+':h' is the hash where the values are stored.
• location+':z' is the set where the keys are sorted.

Aside from the basic abstract-level options, the optional options object may contain:

• connection represents the connection parameters, and can be one of the following :
  • an already configured redis client. RedisLevel will not open or close it.
  • a string representing a redis URL
  • options as specified by ioredis
• highWaterMark number of values to fetch in one redis call for iteration. Defaults to 256.
• clearOnOpen clears the database on open. Defaults to false.

The createIfMissing option of abstract-level is ignored, as this is the way that redis works.

Install

With npm do:

npm install redis-level

Credits

Based on redisDown, copyright HMalphettes.

Contributing

Level/redis-level is an OPEN Open Source Project. This means that:

Individuals making significant and valuable contributions are given commit-access to the project to contribute as they see fit. This project is more like an open wiki than a standard guarded open source project.

See the Contribution Guide for more details.

License

MIT