https://github.com/frando/multihyperdb
Manage many hyperdbs.
https://github.com/frando/multihyperdb
hyperdb
Last synced: about 1 month ago
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Manage many hyperdbs.
- Host: GitHub
- URL: https://github.com/frando/multihyperdb
- Owner: Frando
- License: mit
- Created: 2018-03-27T12:59:30.000Z (about 7 years ago)
- Default Branch: master
- Last Pushed: 2018-03-27T14:26:11.000Z (about 7 years ago)
- Last Synced: 2025-03-28T03:41:27.174Z (about 2 months ago)
- Topics: hyperdb
- Language: JavaScript
- Size: 28.3 KB
- Stars: 9
- Watchers: 2
- Forks: 3
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# MultiHyperDB
Manage many [hyperdbs](https://github.com/mafintosh/hyperdb)s
## Installation
`npm install multihyperdb`
## Usage
```js
var multi = require('multihyperdb')
var opts = {
path: './db',
dbOpts: {valueEncoding: 'json'}
}
var Multi = multi(opts)
multi.createDB({}, {name: 'First database'}, function(err, db) {
db.put('hello', 'world', function (err, node) { } )
})
```
## API
#### `var multi = multihyperdb(opts)`
Create a new MultiHyperDB. Stores info about multiple hyperdbs in a master hyperdb.
Options include:
```js
{
path: './db' // Path to store the databases in
masterPath, dbPath // Set basepath for master databases and child databases manually
dbOpts // default hyperdb opts for child databases
storage // callback to return a random-access-storage (see below)
}
```
#### `multi.createDB(opts, meta, cb)`
Create a new hyperdb. `opts` are regular hyperdb opts (they override the global `dbOpts`). `meta` may have any JSON to be stored in the master hyperdb for this child db. `cb` will be called with `(err, db)` after the database is ready.
#### `multi.addDB(key, opts, meta, cb)`
Add a hyperdb with key `key`. Other options as in `createDB`.
#### `multi.dropDB(key, opts, cb)`
Drop database `key` from being managed in this MultiHyperDB. Pass `{delete: true}` as opts to physically delete the database from disc.
#### `multi.each(callback)`
Execute a callback for each database. `callback`s parameters are `(db, key, meta)`.
#### `multi.createReadStream(prefix)`
Get a combined read stream on all child databases. The `on('data'` callback receives an object with properties `node` (the node as returned from a regular hyperdb read stream, with `key` and `value` properties) and `dbKey` (the key of the database).
#### `multi.getDB(key)`
Get a database by key.
#### `multi.getDBbyProperty(prop, value, [single])`
Get a database by meta property. If `single` is true, only the first matching database is returned.
### Custom storage
By default, both master and child dbs are created with random-access-file storage in the path(s) configured via opts. Alternatively, pass a function as `opts.storage`.
```js
opts.storage = function(master, key, destroy, cb) {
}
```
If `destroy` is false, return a random-access-storage for either master (if `master` is `true`) or the child database with key `key`. If destroy is `true`, destroy (delete) the child database with key `key` and call the callback `cb`.
### Syncing and sharing
... is as simple as
```js
var multi = require('multihyperdb')
var hyperdiscovery = require('hyperdiscovery')
var Multi = multi({path: './db1'})
// Create some databases or add existing keys.
// Two-way sync them all!
Multi.each(function(db) {
hyperdiscovery(db, {live: true})
})
```
Try it out with example-cli.js:
```
$ node example-cli.js db1 create myfirstdb
db created with key: d7f69b22386fdc7751fb26e6a458a45c1a5d369525ac0e428eaf0331f59ff0e1
$ node example-cli.js db1 write myfirstdb hello world
Wrote node: Node(key=hello, value='world', seq=0, feed=0))
$ node example-cli.js db1 share
# In another terminal or on another computer
$ node example-cli.js db2 add remotedb d7f69b22386fdc7751fb26e6a458a45c1a5d369525ac0e428eaf0331f59ff0e1
$ node example-cli.js db2 share
# wait, then abort
$ node example-cli.js db2 read
Node(key=hello, value='world', seq=0, feed=0))
# This was synced from db1.myfirstdb !
```