orbit-db-mfsstore
Key-Value database for orbit-db backed by IPFS MFS.
A key-value database backed by the IPFS Mutable File System. Also allows indexing and searching by non-primary indexes. Unlike other orbit-db stores it does not load the entire dataset into memory. Each store uses a schema and when records are inserted we build btree indexes. They get built and stored locally.
Used in orbit-db.
Table of Contents
Install
npm install orbit-db ipfs orbit-db-mfsstore
Usage
First, create an instance of OrbitDB:
const MfsStore = require('orbit-db-mfsstore')
const IPFS = require('ipfs')
const OrbitDB = require('orbit-db')
const ipfs = new IPFS()
const orbitdb = await OrbitDB.createInstance(ipfs)
Add custom datastore type
OrbitDB.addDatabaseType("mfsstore", MfsStore)
Create a datastore with a schema. In this example we're saving baseball players. We'll add 4 different indexed fields. Indexes and can unique.
store = await orbitdb.open("baseballplayers", {
create: true,
type: "mfsstore",
schema: {
name: { unique: false },
currentTeam: { unique: false },
battingHand: { unique: false },
throwingHand: { unique: false }
}
})
Add a record and retreive it by the primary key
await store.put(101, {
name: "Andrew McCutchen",
currentTeam: "PIT",
battingHand: "R",
throwingHand: "R"
})
let player = await store.get(101)
Now we're going to add a few more players
await store.put(102, {
id: 102,
name: "Pedro Alvarez",
currentTeam: "BAL",
battingHand: "R",
throwingHand: "R"
})
await store.put(103, {
id: 103,
name: "Jordy Mercer",
currentTeam: "PIT",
battingHand: "L",
throwingHand: "R"
})
await store.put(104, {
id: 104,
name: "Doug Drabek",
currentTeam: "BAL",
battingHand: "L",
throwingHand: "R"
})
Now retreive the values by the secondary indexes.
let teamPIT = await store.getByIndex("currentTeam", "PIT", "desc", 0, 100)
let battingR = await store.getByIndex("battingHand", "R", "desc", 0, 100)
API
See orbit-db's API Documenations for full details.
An MFSStore has the following additional functions:
store.list(offset, limit)
- Returns a subset of the available records based on the offset and limit. Allows for paging.
let result = await store.list(0, 100)
store.getByIndex(indexName, value, sortDirection, offset, limit )
- Returns a subset of records stored in the index that match the passed in value. Offset and limit allow for paging.
let result = await store.getByIndex("currentTeam", "PIT", "desc", 0, 100 )
store.count()
- Returns the total number of records stored in the store. Does not load the actual records into memory.
let count = await store.count()
Contributing
If you think this could be better, please open an issue!
Please note that all interactions in @orbitdb fall under our Code of Conduct.
License
MIT ©️ 2016-2018 Protocol Labs Inc., 2018 Haja Networks Oy