orbitdb
/
orbit-db
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
orbit-db/API.md

27 KiB
Raw Permalink Blame History

OrbitDB API Documentation

Read the GETTING STARTED guide for a more in-depth tutorial and to understand how OrbitDB works.

Table of Contents

Creating an OrbitDB instance

createInstance(ipfs, [options])

const orbitdb = await OrbitDB.createInstance(ipfs)

Creates and returns an instance of OrbitDB. Use the optional options argument for further configuration. It is an object with any of these properties:

  • directory (string): path to be used for the database files. By default it uses './orbitdb'.

  • peerId (string): By default it uses the base58 string of the ipfs peer id.

  • keystore (Keystore Instance) : By default creates an instance of Keystore. A custom keystore instance can be used, see this for an example.

  • cache (Cache Instance) : By default creates an instance of Cache. A custom cache instance can also be used.

  • identity (Identity Instance): By default it creates an instance of Identity

  • offline (boolean): Start the OrbitDB instance in offline mode. Databases are not be replicated when the instance is started in offline mode. If the OrbitDB instance was started offline mode and you want to start replicating databases, the OrbitDB instance needs to be re-created. Default: false.

After creating an OrbitDB instance, you can access the different data stores. Creating a database instance, eg. with orbitdb.keyvalue(...), returns a Promise that resolves to a database instance. See the Store section for details of common methods and properties.

For further details, see usage for kvstore, eventlog, feed, docstore and counter.

const db = await orbitdb.keyvalue('profile')

Public Instance Methods

Before starting, you should know that OrbitDB has different types of databases. Each one satisfies a different purpose. The databases that you can create are:

  • log: an immutable (write only) log database. Useful for transactions lists.
  • feed: a mutable log database. Useful for blog comments.
  • keyvalue: Useful for loading data from keywords or an id.
  • docs: a JSON documents database. Useful for user data or other structured data.
  • counter: Useful for ordered data (like an ordered list or a playlist.)

orbitdb.create(name, type, [options])

Creates and opens an OrbitDB database.

Returns a Promise that resolves to a database instance. name (string) should be the database name, not an OrbitDB address (i.e. user.posts). type is a supported database type (i.e. eventlog or an added custom type). options is an object with any of the following properties:

  • accessController (object): An object, as shown in the example below, containing the key write whose value is an array of hex encoded public keys which are used to set write access to the database. ["*"] can be passed in to give write access to everyone. See the GETTING STARTED guide for more info. (Default: uses the OrbitDB identity id orbitdb.identity.id, which would give write access only to yourself)

  • overwrite (boolean): Overwrite an existing database (Default: false)

  • replicate (boolean): Replicate the database with peers, requires IPFS PubSub. (Default: true)

  • meta (object): An optional object in database manifest. Immutably stores any JSON-serializable value. Readable via db.options.meta. Default: undefined.

const db = await orbitdb.create('user.posts', 'eventlog', {
    accessController: {
      write: [
        // Give access to ourselves
        orbitdb.identity.id,
        // Give access to the second peer
        '042c07044e7ea51a489c02854db5e09f0191690dc59db0afd95328c9db614a2976e088cab7c86d7e48183191258fc59dc699653508ce25bf0369d67f33d5d77839'
      ]
    },
    overwrite: true,
    replicate: false,
    meta: { hello: 'meta hello' }
})
// db created & opened

orbitdb.determineAddress(name, type, [options])

Returns the orbit-db address for given parameters

Returns a Promise that resolves to an orbit-db address. The parameters correspond exactly with the parameters of orbit-db.create. This is useful for determining a database address ahead of time, or deriving another peer's address from their public key and the database name and type. No database is actually created.

const dbAddress = await orbitdb.determineAddress('user.posts', 'eventlog', {
  accessController: {
    write: [
    // This could be someone else's public key
    '042c07044e7ea51a489c02854db5e09f0191690dc59db0afd95328c9db614a2976e088cab7c86d7e48183191258fc59dc699653508ce25bf0369d67f33d5d77839'
  ]}
})

orbitdb.open(address, [options])

Opens an OrbitDB database.

Returns a Promise that resolves to a database instance. address (string) should be a valid OrbitDB address. If a database name is provided instead, it will check options.create to determine if it should create the database. options is an object with any of the following properties:

  • localOnly (boolean): If set to true, will throw an error if the database can't be found locally. (Default: false)
  • create (boolean): Whether or not to create the database if a valid OrbitDB address is not provided. (Default: false)
  • type (string): A supported database type (i.e. eventlog or an added custom type). Required if create is set to true. Otherwise it's used to validate the manifest.
  • overwrite (boolean): Overwrite an existing database (Default: false)
  • replicate (boolean): Replicate the database with peers, requires IPFS PubSub. (Default: true)
const db = await orbitdb.open('/orbitdb/Qmd8TmZrWASypEp4Er9tgWP4kCNQnW4ncSnvjvyHQ3EVSU/first-database')

Convenience methods are available when opening/creating any of the default OrbitDB database types: feed, docs, log, keyvalue, counter

You can use: orbitdb.feed(address, options)

Instead of: orbitdb.open(address, { type: 'feed', ...options })

orbitdb.disconnect()

Close databases, connections, pubsub and reset orbitdb state.

Returns a Promise that resolves once complete.

await orbitdb.disconnect()

orbitdb.stop()

Alias for orbitdb.disconnect()

await orbitdb.stop()

orbitdb.keyvalue(name|address)

Creates and opens a keyvalue database

Returns a Promise that resolves to a KeyValueStore instance.

const db = await orbitdb.keyvalue('application.settings')
// Or:
const db = await orbitdb.keyvalue(anotherkvdb.address)

Module: orbit-db-kvstore

See the Store section for details of common methods and properties.

put(key, value)

Returns a Promise that resolves to a String that is the multihash of the entry.

await db.put('hello', { name: 'World' })

set(key, value)

Alias for .put()

await db.set('hello', { name: 'Friend' })

get(key)

Returns an Object with the contents of the entry.

const value = db.get('hello')
// { name: 'Friend' }

del(key)

Deletes the Object associated with key. Returns a Promise that resolves to a String that is the multihash of the deleted entry.

const hash = await db.del('hello')
// QmbYHhnXEdmdfUDzZKeEg7HyG2f8veaF2wBrYFcSHJ3mvd

all

Returns an Object with the contents of all entries in the index.

const value = db.all
// { hello: { name: 'Friend' } }

orbitdb.kvstore(name|address)

Alias for orbitdb.keyvalue()

orbitdb.log(name|address)

Creates and opens an eventlog database

Returns a Promise that resolves to a EventStore instance.

const db = await orbitdb.eventlog('site.visitors')
// Or:
const db = await orbitdb.eventlog(anotherlogdb.address)

Module: orbit-db-eventstore

See the Store section for details of common methods and properties.

add(event)

Returns a Promise that resolves to the multihash of the entry as a String.

const hash = await db.add({ name: 'User1' })

get(hash)

Returns an Object with the contents of the entry.

const event = db.get(hash)
  .map((e) => e.payload.value)
// { name: 'User1' }

iterator([options])

Returns an Array of Objects based on the options.

By default the Array is sorted in chronological order, such that the element at index 0 is the first element and the element at the last element is the last element in the Feed.

options : It is an object which supports the following properties

gt - (string) Greater than, takes an item's hash.

gte - (string) Greater than or equal to, takes an item's hash.

lt - (string) Less than, takes an item's hash.

lte - (string) Less than or equal to, takes an item's hash value.

limit - (integer) Limiting the entries of result, defaults to 1, and -1 means all items (no limit).

reverse - (boolean) If set to true will result in reversing the result.

If hash not found when passing gt, gte, lt, or lte, the iterator will return all items (respecting limit and reverse).

const all = db.iterator({ limit: -1 })
  .collect()
  .map((e) => e.payload.value)
// [{ name: 'User1' }]

orbitdb.eventlog(name|address)

Alias for orbitdb.log()

orbitdb.feed(name|address)

Creates and opens a feed database

Returns a Promise that resolves to a FeedStore instance.

const db = await orbitdb.feed('orbit-db.issues')
// Or:
const db = await orbitdb.feed(anotherfeeddb.address)

Module: orbit-db-feedstore

See the Store section for details of common methods and properties.

add(data)

Returns a Promise that resolves to the multihash of the entry as a String.

const hash = await db.add({ name: 'User1' })

get(hash)

Returns an Object with the contents of the entry.

const event = db.get(hash)
  .map((e) => e.payload.value)
// { name: 'User1' }

remove(hash)

Returns a Promise that resolves to the multihash of the entry as a String.

const hash = await db.remove(hash)

iterator([options])

Returns an Array of Objects based on the options.

options : It is an object which supports the following properties

gt - (string) Greater than, takes an item's hash.

gte - (string) Greater than or equal to, takes an item's hash.

lt - (string) Less than, takes an item's hash.

lte - (string) Less than or equal to, takes an item's hash.

limit - (integer) Limiting the entries of result, defaults to 1, and -1 means all items (no limit).

reverse - (boolean) If set to true will result in reversing the result.

If hash not found when passing gt, gte, lt, or lte, the iterator will return all items (respecting limit and reverse).

const all = db.iterator({ limit: -1 })
  .collect()
  .map((e) => e.payload.value)
// [{ name: 'User1' }]

orbitdb.docs(name|address, options)

Creates and opens a docstore database

Returns a Promise that resolves to a DocumentStore instance.

const db = await orbitdb.docs('orbit.users.shamb0t.profile')
// Or:
const db = await orbitdb.docs(anotherdocdb.address)

By default, documents are indexed by field _id. You can also specify the field to index by:

const db = await orbitdb.docs('orbit.users.shamb0t.profile', { indexBy: 'name' })

Module: orbit-db-docstore

See the Store section for details of common methods and properties.

put(doc)

Returns a Promise that resolves to the multihash of the entry as a String.

const hash = await db.put({ _id: 'QmAwesomeIpfsHash', name: 'shamb0t', followers: 500 })

get(key)

Returns an Array of all Objects that match the given key in their _id field or the field specified by indexBy. If no document with that key exists, this returns an empty array.

const profile = db.get('shamb0t')
// [{ _id: 'shamb0t', name: 'shamb0t', followers: 500 }]
// to get all the records
const profile = db.get('');
// returns all the records
// [{ _id: 'shamb0t', name: 'shamb0t', followers: 500 }]

query(mapper)

Returns an Array of Objects based on the mapper.

const all = db.query((doc) => doc.followers >= 500)
// [{ _id: 'shamb0t', name: 'shamb0t', followers: 500 }]

del(key)

Returns a Promise that resolves to the multihash of the entry as a String.

const hash = await db.del('shamb0t')

orbitdb.docstore(name|address, options)

Alias for orbitdb.docs()

orbitdb.counter(name|address)

Creates and opens a counter database

Returns a Promise that resolves to a CounterStore instance.

const counter = await orbitdb.counter('song_123.play_count')
// Or:
const counter = await orbitdb.counter(anothercounterdb.address)

Module: orbit-db-counterstore.

See the Store section for details of common methods and properties.

value

Returns a Number.

counter.value // 0

inc([value])

Returns a Promise that resolves to the multihash of the entry as a String.

await counter.inc()
counter.value // 1
await counter.inc(7)
counter.value // 8
await counter.inc(-2)
counter.value // 8

Static Properties

OrbitDB.databaseTypes

Returns supported database types (i.e. store types) as an Array of Strings

OrbitDB.databaseTypes
// [ 'counter', 'eventlog', 'feed', 'docstore', 'keyvalue']

Static Methods

OrbitDB.createInstance(ipfs)

Returns a Promise that resolved to an instance of OrbitDB.

const orbitdb = await OrbitDB.createInstance(ipfs)

OrbitDB.isValidType(type)

Returns true if the provided String is a supported database type

OrbitDB.isValidType('docstore')
// true

OrbitDB.addDatabaseType(type, store)

Adds a custom database type & store to OrbitDB

const CustomStore = require('./CustomStore')
OrbitDB.addDatabaseType(CustomStore.type, CustomStore)

OrbitDB.getDatabaseTypes()

Returns an Object mapping database types to Store Classes

OrbitDB.getDatabaseTypes()
// { counter: [Function: CounterStore],
//  eventlog: [Function: EventStore],
//  feed: [Function: FeedStore],
//  docstore: [Function: DocumentStore],
//  keyvalue: [Function: KeyValueStore] }

OrbitDB.isValidAddress(address)

Returns true if the provided String is a valid OrbitDB address

OrbitDB.isValidAddress('/orbitdb/Qmdgwt7w4uBsw8LXduzCd18zfGXeTmBsiR8edQ1hSfzcJC/first-database')
// true

OrbitDB.parseAddress(address)

Returns an instance of OrbitDBAddress if the provided String is a valid orbitdb address

OrbitDB.parseAddress('/orbitdb/Qmdgwt7w4uBsw8LXduzCd18zfGXeTmBsiR8edQ1hSfzcJC/first-database')
// OrbitDBAddress {
//  root: 'Qmdgwt7w4uBsw8LXduzCd18zfGXeTmBsiR8edQ1hSfzcJC',
//  path: 'first-database' }

Store API

Every database (store) has the following methods available in addition to their specific methods.

store.load([amount], { fetchEntryTimeout })

Load the locally persisted database state to memory. Use the optional amount argument to limit the number of entries loaded into memory, starting from the head(s) (Default: -1 will load all entries). fetchEntryTimeout defines the timeout for fetching an entry.

Returns a Promise that resolves once complete

With events:

db.events.on('ready', () => {
  /* database is now ready to be queried */
})
db.load()

Async:

await db.load()
/* database is now ready to be queried */

store.close()

Close the database. Returns a Promise that resolves once complete

Async:

await db.close()

store.drop()

Remove the database locally. This does not delete any data from peers.

Returns a Promise that resolves once complete

await db.drop()

store.identity

Returns an instance of Identity. The identity is used to sign the database entries. See the GUIDE for more information on how OrbitDB uses identity.

const identity = db.identity
console.log(identity.toJSON())
{ id: 'QmZyYjpG6SMJJx2rbye8HXNMufGRtpn9yFkdd27uuq6xrR',
  publicKey: '0446829cbd926ad8e858acdf1988b8d586214a1ca9fa8c7932af1d59f7334d41aa2ec2342ea402e4f3c0195308a4815bea326750de0a63470e711c534932b3131c',
  signatures:
   { id: '3045022058bbb2aa415623085124b32b254b8668d95370261ade8718765a8086644fc8ae022100c736b45c6b2ef60c921848027f51020a70ee50afa20bc9853877e994e6121c15',
     publicKey: '3046022100d138ccc0fbd48bd41e74e40ddf05c1fa6ff903a83b2577ef7d6387a33992ea4b022100ca39e8d8aef43ac0c6ec05c1b95b41fce07630b5dc61587a32d90dc8e4cf9766'
   },
  type: 'orbitdb'
}

The public key can be retrieved with:

console.log(db.identity.publicKey)
// 0446829cbd926ad8e858acdf1988b8d586214a1ca9fa8c7932af1d59f7334d41aa2ec2342ea402e4f3c0195308a4815bea326750de0a63470e711c534932b3131c

The key can also be accessed from the OrbitDB instance: orbitdb.identity.publicKey.

store.type

Returns the type of the database as a String.

Store Events

Each database in orbit-db contains an events (EventEmitter) object that emits events that describe what's happening in the database. Events can be listened to with:

db.events.on(name, callback)

replicated

db.events.on('replicated', (address) => ... )

Emitted when the database has synced with another peer. This is usually a good place to re-query the database for updated results, eg. if a value of a key was changed or if there are new events in an event log.

replicate

db.events.on('replicate', (address) => ... )

Emitted before replicating a part of the database with a peer.

replicate.progress

db.events.on('replicate.progress', (address, hash, entry, progress, have) => ... )

Emitted while replicating a database. address is id of the database that emitted the event. hash is the multihash of the entry that was just loaded. entry is the database operation entry. progress is the current progress. have is a map of database pieces we have.

load

db.events.on('load', (dbname) => ... )

Emitted before loading the database.

load.progress

db.events.on('load.progress', (address, hash, entry, progress, total) => ... )

Emitted while loading the local database, once for each entry. dbname is the name of the database that emitted the event. hash is the multihash of the entry that was just loaded. entry is the database operation entry. progress is a sequential number starting from 0 upon calling load().

ready

db.events.on('ready', (dbname, heads) => ... )

Emitted after fully loading the local database.

write

db.events.on('write', (address, entry, heads) => ... )

Emitted after an entry was added locally to the database. hash is the IPFS hash of the latest state of the database. entry is the added database op.

peer

db.events.on('peer', (peer) => ... )

Emitted when a new peer connects via ipfs pubsub. peer is a string containing the id of the new peer

closed

Emitted once the database has finished closing.

db.events.on('closed', (dbname) => ... )

peer.exchanged

db.events.on('peer.exchanged', (peer, address, heads) => ... )

Emitted after heads have been exchanged with a peer for a specific database. This will be emitted after every exchange, even if no heads are received from the peer, or if all received heads are already present. (This is in contrast with the replicated event, which will only fire when new heads have been received.) Note that heads here contains heads received as part of the exchange, not heads sent.

Oplog API

Oplog or IPFS-Log is the underlying data structure used by the OrbitDB Stores to store, replicate and add operations to any of their stores.

oplog.values

An Array of operations sorted by how they happened in ascending order. If an operation A is before B, A is before B in the Array.

Each oplog entry contains these fields:

 {
    hash: 'zdpuAuARU9C1MXvHGozGxvpv3rvSzghQg7JmoLQLWbedJzcd7',
    id: '/orbitdb/zdpuArEpCPwqpgQVMYrFSDQKhHLq5L6Es8HQkhWfhrad5oYdK/example',
    payload: { op: 'PUT', key: 'abc', value: 'def' },
    next: [ 'zdpuAzWC4phgt6eQeRPz58p33G1w1J5ciVnCwuoFa7szsDVP2' ],
    refs: [ 'zdpuAxFR9miMinzetRdZKvy9mBaiZLJByA6DV715Wcmgi7dwx' ],
    v: 2,
    clock: LamportClock {
      id: '04f75c96cb240d8b254df96fcc7d9d7a1260fd838cb0d085f009d2f0c78b74f7984c168da6afa1f0ee9400f5022952e70955c10798beb0c168966faf746c7202ad',
      time: 3
    },
    key: '04f75c96cb240d8b254df96fcc7d9d7a1260fd838cb0d085f009d2f0c78b74f7984c168da6afa1f0ee9400f5022952e70955c10798beb0c168966faf746c7202ad',
    identity: {
      id: '0336124289bdb2384ef7f3f5991d25bb1e02bf2a98edb02f94b0bc9f292c41156b',
      publicKey: '04f75c96cb240d8b254df96fcc7d9d7a1260fd838cb0d085f009d2f0c78b74f7984c168da6afa1f0ee9400f5022952e70955c10798beb0c168966faf746c7202ad',
      signatures: [Object],
      type: 'orbitdb'
    },
    sig: '3045022100e618887439bcaa8cffe0196d5655c710cc117af7de4390a313d137dd02a993a402205fb0b657600216944a0e7f68d2bb07854e8f47cc01a74d7cc632870ad7055758'
  }

Let's got through each of them in turn:

hash

Hash of the entry on IPFS. "zd...".

id

Address of the oplog. (A.k.a. the OrbitDB Address)

payload

Payload of the operation. Provided by the Store to _addOperation.

next

Array of hashes of the oplog entries that happened before this one.

refs

TBD

v

TBD

clock

Lamport clock instance of the entry. A Lamport clock contains a time, an integer, that for all operations depending on each other increases.

If Operation A depends on Operation B, B's time < A's time.

See the Wikipedia description of Lamport Clocks for more details

key

Public key of the Identity that added this entry.

identity

Identity that added this entry.

sig

Signature of the entry. If the entry is in the oplog, the signature is valid.