277 lines
9.9 KiB
Markdown
277 lines
9.9 KiB
Markdown
|
<h1 align="center">
|
||
|
|
<img width="250" src="https://rawgit.com/lukechilds/keyv/master/media/logo.svg" alt="keyv">
|
||
|
|
<br>
|
||
|
|
<br>
|
||
|
|
</h1>
|
||
|
|
|
||
|
|
> Simple key-value storage with support for multiple backends
|
||
|
|
|
||
|
|
[](https://travis-ci.org/lukechilds/keyv)
|
||
|
|
[](https://coveralls.io/github/lukechilds/keyv?branch=master)
|
||
|
|
[](https://www.npmjs.com/package/keyv)
|
||
|
|
[](https://www.npmjs.com/package/keyv)
|
||
|
|
|
||
|
|
Keyv provides a consistent interface for key-value storage across multiple backends via storage adapters. It supports TTL based expiry, making it suitable as a cache or a persistent key-value store.
|
||
|
|
|
||
|
|
## Features
|
||
|
|
|
||
|
|
There are a few existing modules similar to Keyv, however Keyv is different because it:
|
||
|
|
|
||
|
|
- Isn't bloated
|
||
|
|
- Has a simple Promise based API
|
||
|
|
- Suitable as a TTL based cache or persistent key-value store
|
||
|
|
- [Easily embeddable](#add-cache-support-to-your-module) inside another module
|
||
|
|
- Works with any storage that implements the [`Map`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map) API
|
||
|
|
- Handles all JSON types plus `Buffer`
|
||
|
|
- Supports namespaces
|
||
|
|
- Wide range of [**efficient, well tested**](#official-storage-adapters) storage adapters
|
||
|
|
- Connection errors are passed through (db failures won't kill your app)
|
||
|
|
- Supports the current active LTS version of Node.js or higher
|
||
|
|
|
||
|
|
## Usage
|
||
|
|
|
||
|
|
Install Keyv.
|
||
|
|
|
||
|
|
```
|
||
|
|
npm install --save keyv
|
||
|
|
```
|
||
|
|
|
||
|
|
By default everything is stored in memory, you can optionally also install a storage adapter.
|
||
|
|
|
||
|
|
```
|
||
|
|
npm install --save @keyv/redis
|
||
|
|
npm install --save @keyv/mongo
|
||
|
|
npm install --save @keyv/sqlite
|
||
|
|
npm install --save @keyv/postgres
|
||
|
|
npm install --save @keyv/mysql
|
||
|
|
```
|
||
|
|
|
||
|
|
Create a new Keyv instance, passing your connection string if applicable. Keyv will automatically load the correct storage adapter.
|
||
|
|
|
||
|
|
```js
|
||
|
|
const Keyv = require('keyv');
|
||
|
|
|
||
|
|
// One of the following
|
||
|
|
const keyv = new Keyv();
|
||
|
|
const keyv = new Keyv('redis://user:pass@localhost:6379');
|
||
|
|
const keyv = new Keyv('mongodb://user:pass@localhost:27017/dbname');
|
||
|
|
const keyv = new Keyv('sqlite://path/to/database.sqlite');
|
||
|
|
const keyv = new Keyv('postgresql://user:pass@localhost:5432/dbname');
|
||
|
|
const keyv = new Keyv('mysql://user:pass@localhost:3306/dbname');
|
||
|
|
|
||
|
|
// Handle DB connection errors
|
||
|
|
keyv.on('error', err => console.log('Connection Error', err));
|
||
|
|
|
||
|
|
await keyv.set('foo', 'expires in 1 second', 1000); // true
|
||
|
|
await keyv.set('foo', 'never expires'); // true
|
||
|
|
await keyv.get('foo'); // 'never expires'
|
||
|
|
await keyv.delete('foo'); // true
|
||
|
|
await keyv.clear(); // undefined
|
||
|
|
```
|
||
|
|
|
||
|
|
### Namespaces
|
||
|
|
|
||
|
|
You can namespace your Keyv instance to avoid key collisions and allow you to clear only a certain namespace while using the same database.
|
||
|
|
|
||
|
|
```js
|
||
|
|
const users = new Keyv('redis://user:pass@localhost:6379', { namespace: 'users' });
|
||
|
|
const cache = new Keyv('redis://user:pass@localhost:6379', { namespace: 'cache' });
|
||
|
|
|
||
|
|
await users.set('foo', 'users'); // true
|
||
|
|
await cache.set('foo', 'cache'); // true
|
||
|
|
await users.get('foo'); // 'users'
|
||
|
|
await cache.get('foo'); // 'cache'
|
||
|
|
await users.clear(); // undefined
|
||
|
|
await users.get('foo'); // undefined
|
||
|
|
await cache.get('foo'); // 'cache'
|
||
|
|
```
|
||
|
|
|
||
|
|
### Custom Serializers
|
||
|
|
|
||
|
|
Keyv uses [`json-buffer`](https://github.com/dominictarr/json-buffer) for data serialization to ensure consistency across different backends.
|
||
|
|
|
||
|
|
You can optionally provide your own serialization functions to support extra data types or to serialize to something other than JSON.
|
||
|
|
|
||
|
|
```js
|
||
|
|
const keyv = new Keyv({ serialize: JSON.stringify, deserialize: JSON.parse });
|
||
|
|
```
|
||
|
|
|
||
|
|
**Warning:** Using custom serializers means you lose any guarantee of data consistency. You should do extensive testing with your serialisation functions and chosen storage engine.
|
||
|
|
|
||
|
|
## Official Storage Adapters
|
||
|
|
|
||
|
|
The official storage adapters are covered by [over 150 integration tests](https://travis-ci.org/lukechilds/keyv/jobs/260418145) to guarantee consistent behaviour. They are lightweight, efficient wrappers over the DB clients making use of indexes and native TTLs where available.
|
||
|
|
|
||
|
|
Database | Adapter | Native TTL | Status
|
||
|
|
---|---|---|---
|
||
|
|
Redis | [@keyv/redis](https://github.com/lukechilds/keyv-redis) | Yes | [](https://travis-ci.org/lukechilds/keyv-redis) [](https://coveralls.io/github/lukechilds/keyv-redis?branch=master)
|
||
|
|
MongoDB | [@keyv/mongo](https://github.com/lukechilds/keyv-mongo) | Yes | [](https://travis-ci.org/lukechilds/keyv-mongo) [](https://coveralls.io/github/lukechilds/keyv-mongo?branch=master)
|
||
|
|
SQLite | [@keyv/sqlite](https://github.com/lukechilds/keyv-sqlite) | No | [](https://travis-ci.org/lukechilds/keyv-sqlite) [](https://coveralls.io/github/lukechilds/keyv-sqlite?branch=master)
|
||
|
|
PostgreSQL | [@keyv/postgres](https://github.com/lukechilds/keyv-postgres) | No | [](https://travis-ci.org/lukechildskeyv-postgreskeyv) [](https://coveralls.io/github/lukechilds/keyv-postgres?branch=master)
|
||
|
|
MySQL | [@keyv/mysql](https://github.com/lukechilds/keyv-mysql) | No | [](https://travis-ci.org/lukechilds/keyv-mysql) [](https://coveralls.io/github/lukechilds/keyv-mysql?branch=master)
|
||
|
|
|
||
|
|
## Third-party Storage Adapters
|
||
|
|
|
||
|
|
You can also use third-party storage adapters or build your own. Keyv will wrap these storage adapters in TTL functionality and handle complex types internally.
|
||
|
|
|
||
|
|
```js
|
||
|
|
const Keyv = require('keyv');
|
||
|
|
const myAdapter = require('./my-storage-adapter');
|
||
|
|
|
||
|
|
const keyv = new Keyv({ store: myAdapter });
|
||
|
|
```
|
||
|
|
|
||
|
|
Any store that follows the [`Map`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map) api will work.
|
||
|
|
|
||
|
|
```js
|
||
|
|
new Keyv({ store: new Map() });
|
||
|
|
```
|
||
|
|
|
||
|
|
For example, [`quick-lru`](https://github.com/sindresorhus/quick-lru) is a completely unrelated module that implements the Map API.
|
||
|
|
|
||
|
|
```js
|
||
|
|
const Keyv = require('keyv');
|
||
|
|
const QuickLRU = require('quick-lru');
|
||
|
|
|
||
|
|
const lru = new QuickLRU({ maxSize: 1000 });
|
||
|
|
const keyv = new Keyv({ store: lru });
|
||
|
|
```
|
||
|
|
|
||
|
|
The following are third-party storage adapters compatible with Keyv:
|
||
|
|
|
||
|
|
- [quick-lru](https://github.com/sindresorhus/quick-lru) - Simple "Least Recently Used" (LRU) cache
|
||
|
|
- [keyv-file](https://github.com/zaaack/keyv-file) - File system storage adapter for Keyv
|
||
|
|
- [keyv-dynamodb](https://www.npmjs.com/package/keyv-dynamodb) - DynamoDB storage adapter for Keyv
|
||
|
|
|
||
|
|
## Add Cache Support to your Module
|
||
|
|
|
||
|
|
Keyv is designed to be easily embedded into other modules to add cache support. The recommended pattern is to expose a `cache` option in your modules options which is passed through to Keyv. Caching will work in memory by default and users have the option to also install a Keyv storage adapter and pass in a connection string, or any other storage that implements the `Map` API.
|
||
|
|
|
||
|
|
You should also set a namespace for your module so you can safely call `.clear()` without clearing unrelated app data.
|
||
|
|
|
||
|
|
Inside your module:
|
||
|
|
|
||
|
|
```js
|
||
|
|
class AwesomeModule {
|
||
|
|
constructor(opts) {
|
||
|
|
this.cache = new Keyv({
|
||
|
|
uri: typeof opts.cache === 'string' && opts.cache,
|
||
|
|
store: typeof opts.cache !== 'string' && opts.cache,
|
||
|
|
namespace: 'awesome-module'
|
||
|
|
});
|
||
|
|
}
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
Now it can be consumed like this:
|
||
|
|
|
||
|
|
```js
|
||
|
|
const AwesomeModule = require('awesome-module');
|
||
|
|
|
||
|
|
// Caches stuff in memory by default
|
||
|
|
const awesomeModule = new AwesomeModule();
|
||
|
|
|
||
|
|
// After npm install --save keyv-redis
|
||
|
|
const awesomeModule = new AwesomeModule({ cache: 'redis://localhost' });
|
||
|
|
|
||
|
|
// Some third-party module that implements the Map API
|
||
|
|
const awesomeModule = new AwesomeModule({ cache: some3rdPartyStore });
|
||
|
|
```
|
||
|
|
|
||
|
|
## API
|
||
|
|
|
||
|
|
### new Keyv([uri], [options])
|
||
|
|
|
||
|
|
Returns a new Keyv instance.
|
||
|
|
|
||
|
|
The Keyv instance is also an `EventEmitter` that will emit an `'error'` event if the storage adapter connection fails.
|
||
|
|
|
||
|
|
### uri
|
||
|
|
|
||
|
|
Type: `String`<br>
|
||
|
|
Default: `undefined`
|
||
|
|
|
||
|
|
The connection string URI.
|
||
|
|
|
||
|
|
Merged into the options object as options.uri.
|
||
|
|
|
||
|
|
### options
|
||
|
|
|
||
|
|
Type: `Object`
|
||
|
|
|
||
|
|
The options object is also passed through to the storage adapter. Check your storage adapter docs for any extra options.
|
||
|
|
|
||
|
|
#### options.namespace
|
||
|
|
|
||
|
|
Type: `String`<br>
|
||
|
|
Default: `'keyv'`
|
||
|
|
|
||
|
|
Namespace for the current instance.
|
||
|
|
|
||
|
|
#### options.ttl
|
||
|
|
|
||
|
|
Type: `Number`<br>
|
||
|
|
Default: `undefined`
|
||
|
|
|
||
|
|
Default TTL. Can be overridden by specififying a TTL on `.set()`.
|
||
|
|
|
||
|
|
#### options.serialize
|
||
|
|
|
||
|
|
Type: `Function`<br>
|
||
|
|
Default: `JSONB.stringify`
|
||
|
|
|
||
|
|
A custom serialization function.
|
||
|
|
|
||
|
|
#### options.deserialize
|
||
|
|
|
||
|
|
Type: `Function`<br>
|
||
|
|
Default: `JSONB.parse`
|
||
|
|
|
||
|
|
A custom deserialization function.
|
||
|
|
|
||
|
|
#### options.store
|
||
|
|
|
||
|
|
Type: `Storage adapter instance`<br>
|
||
|
|
Default: `new Map()`
|
||
|
|
|
||
|
|
The storage adapter instance to be used by Keyv.
|
||
|
|
|
||
|
|
#### options.adapter
|
||
|
|
|
||
|
|
Type: `String`<br>
|
||
|
|
Default: `undefined`
|
||
|
|
|
||
|
|
Specify an adapter to use. e.g `'redis'` or `'mongodb'`.
|
||
|
|
|
||
|
|
### Instance
|
||
|
|
|
||
|
|
Keys must always be strings. Values can be of any type.
|
||
|
|
|
||
|
|
#### .set(key, value, [ttl])
|
||
|
|
|
||
|
|
Set a value.
|
||
|
|
|
||
|
|
By default keys are persistent. You can set an expiry TTL in milliseconds.
|
||
|
|
|
||
|
|
Returns `true`.
|
||
|
|
|
||
|
|
#### .get(key)
|
||
|
|
|
||
|
|
Returns the value.
|
||
|
|
|
||
|
|
#### .delete(key)
|
||
|
|
|
||
|
|
Deletes an entry.
|
||
|
|
|
||
|
|
Returns `true` if the key existed, `false` if not.
|
||
|
|
|
||
|
|
#### .clear()
|
||
|
|
|
||
|
|
Delete all entries in the current namespace.
|
||
|
|
|
||
|
|
Returns `undefined`.
|
||
|
|
|
||
|
|
## License
|
||
|
|
|
||
|
|
MIT © Luke Childs
|