interface-datastore
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# interface-datastore
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> datastore interface
# About
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A Datastore is a key/value database that lets store/retrieve binary blobs using namespaced Keys.
It is used by IPFS to store/retrieve arbitrary metadata needed to run the node - DHT provider records, signed peer records, etc.
## Backed Implementations
- File System: [`datastore-fs`](https://github.com/ipfs/js-stores/tree/main/packages/datastore-fs)
- IndexedDB: [`datastore-idb`](https://github.com/ipfs/js-stores/blob/main/packages/datastore-idb)
- level: [`datastore-level`](https://github.com/ipfs/js-stores/tree/main/packages/datastore-level) (supports any levelup compatible backend)
- Memory: [`datastore-core/memory`](https://github.com/ipfs/js-stores/blob/main/packages/datastore-core/src/memory.ts)
- S3: [`datastore-s3`](https://github.com/ipfs/js-stores/tree/main/packages/datastore-s3)
## Wrapper Implementations
- Keytransform: [`datstore-core/src/keytransform`](https://github.com/ipfs/js-stores/blob/main/packages/datastore-core/src/keytransform.ts)
- Mount: [`datastore-core/src/mount`](https://github.com/ipfs/js-stores/blob/main/packages/datastore-core/src/mount.ts)
- Namespace: [`datastore-core/src/namespace`](https://github.com/ipfs/js-stores/blob/main/packages/datastore-core/src/namespace.ts)
- Sharding: [`datastore-core/src/sharding`](https://github.com/ipfs/js-stores/blob/main/packages/datastore-core/src/sharding.ts)
- Tiered: [`datstore-core/src/tiered`](https://github.com/ipfs/js-stores/blob/main/packages/datastore-core/src/tiered.ts)
If you want the same functionality as [go-ds-flatfs](https://github.com/ipfs/go-ds-flatfs), use sharding with fs.
## Example
```js
import FsStore from 'datastore-fs'
import { ShardingDataStore, shard } from 'datastore-core'
const fs = new FsStore('path/to/store')
// flatfs now works like go-flatfs
const flatfs = await ShardingStore.createOrOpen(fs, new shard.NextToLast(2))
```
### Test suite
Available via the [`interface-datastore-tests`](https://npmjs.com/package/interface-datastore-tests) module
```js
import { interfaceDatastoreTests } from 'interface-datastore-tests'
describe('mystore', () => {
interfaceDatastoreTests({
async setup () {
return instanceOfMyStore
},
async teardown () {
// cleanup resources
}
})
})
```
### Aborting requests
Most API methods accept an \[AbortSignal]\[] as part of an options object. Implementations may listen for an `abort` event emitted by this object, or test the `signal.aborted` property. When received implementations should tear down any long-lived requests or resources created.
### Concurrency
The streaming `(put|get|delete)Many` methods are intended to be used with modules such as [it-parallel-batch](https://www.npmjs.com/package/it-parallel-batch) to allow calling code to control levels of parallelisation. The batching method ensures results are returned in the correct order, but interface implementations should be thread safe.
```js
import batch from 'it-parallel-batch'
const source = [{
key: ..,
value: ..
}]
// put values into the datastore concurrently, max 10 at a time
for await (const { key, data } of batch(store.putMany(source), 10)) {
console.info(`Put ${key}`)
}
```
### Keys
To allow a better abstraction on how to address values, there is a `Key` class which is used as identifier. It's easy to create a key from a `Uint8Array` or a `string`.
```js
const a = new Key('a')
const b = new Key(new Uint8Array([0, 1, 2, 3]))
```
The key scheme is inspired by file systems and Google App Engine key model. Keys are meant to be unique across a system. They are typically hierarchical, incorporating more and more specific namespaces. Thus keys can be deemed 'children' or 'ancestors' of other keys:
- `new Key('/Comedy')`
- `new Key('/Comedy/MontyPython')`
Also, every namespace can be parameterized to embed relevant object information. For example, the Key `name` (most specific namespace) could include the object type:
- `new Key('/Comedy/MontyPython/Actor:JohnCleese')`
- `new Key('/Comedy/MontyPython/Sketch:CheeseShop')`
- `new Key('/Comedy/MontyPython/Sketch:CheeseShop/Character:Mousebender')`
# Install
```console
$ npm i interface-datastore
```
## Browser `<script>` tag
Loading this module through a script tag will make its exports available as `InterfaceDatastore` in the global namespace.
```html
<script src="https://unpkg.com/interface-datastore/dist/index.min.js"></script>
```
# API Docs
- <https://ipfs.github.io/js-stores/modules/interface_datastore.html>
# License
Licensed under either of
- Apache 2.0, ([LICENSE-APACHE](https://github.com/ipfs/js-stores/blob/main/packages/interface-datastore/LICENSE-APACHE) / <http://www.apache.org/licenses/LICENSE-2.0>)
- MIT ([LICENSE-MIT](https://github.com/ipfs/js-stores/blob/main/packages/interface-datastore/LICENSE-MIT) / <http://opensource.org/licenses/MIT>)
# Contribute
Contributions welcome! Please check out [the issues](https://github.com/ipfs/js-stores/issues).
Also see our [contributing document](https://github.com/ipfs/community/blob/master/CONTRIBUTING_JS.md) for more information on how we work, and about contributing in general.
Please be aware that all interactions related to this repo are subject to the IPFS [Code of Conduct](https://github.com/ipfs/community/blob/master/code-of-conduct.md).
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.
[](https://github.com/ipfs/community/blob/master/CONTRIBUTING.md)