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121 lines
3.4 KiB
Markdown
121 lines
3.4 KiB
Markdown
# OrbitDB
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## Introduction
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Distributed, peer-to-peer Key-Value Store and Event Log on IPFS.
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- Stores all data in IPFS, including the database index
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- Replication happens on client side and data is eventually consistent
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- Uses a LWW-element-set [CRDT](https://en.wikipedia.org/wiki/Conflict-free_replicated_data_type) and (sort of) Vector Clocks for partial ordering
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- Designed to work offline first and to be easily embeddable to applications
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_Currently requires [orbit-server](https://github.com/haadcode/orbit-server) for pubsub communication. This will change in the future as soon as IPFS provides pubsub._
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_OrbitDB calls its namespaces channels. A channel is similar to "table", "keyspace", "topic", "feed" or "collection" in other db systems._
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## Examples
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Before running the examples, install dependencies with:
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```
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npm install
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```
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Key-Value store example:
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```
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node examples/keyvalue.js <channel> <username> <key> <value>
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node examples/keyvalueReader.js <channel> <username> <key>
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```
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Event log example (run several in separate shells):
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```
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node examples/reader.js <channel> <username> <data> <interval in ms>
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```
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## API
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_See usage example below_
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connect(host, port, username, password)
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channel(name, password)
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.add(data: String) // Insert an event to a channel, returns <ipfs-hash> of the event
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.iterator([options]) // Returns an iterator of events
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// options : {
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// gt: <ipfs-hash>, // Return events newer than <ipfs-hash>
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// gte: <ipfs-hash>, // Return events newer then <ipfs-hash> (inclusive)
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// lt: <ipfs-hash>, // Return events older than <ipfs-hash>
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// lte: <ipfs-hash>, // Return events older than <ipfs-hash> (inclusive)
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// limit: -1, // Number of events to return, -1 returns all, default 1
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// reverse: true // Return items oldest first, default latest first
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// }
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.put(key, data: String) // Insert (key,value) to a channel
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.get(key) // Retrieve value
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.del({ key: <key or hash> }) // Remove entry
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.delete() // Deletes the channel, all data will be "removed" (unassociated with the channel, actual data is not deleted from ipfs)
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## Usage
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```javascript
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const async = require('asyncawait/async');
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const OrbitClient = require('./OrbitClient');
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// orbit-server
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const host = 'localhost';
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const port = 3333;
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async(() => {
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// Connect
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const orbit = OrbitClient.connect(host, port, username, password);
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const channelName = 'hello-world';
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const db = orbit.channel(channelName);
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/* Event Log */
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const hash = db.add('hello'); // <ipfs-hash>
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// Remove event
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db.remove(hash);
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// Iterator options
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const options = { limit: -1 }; // fetch all messages
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// Get events
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const iter = db.iterator(options); // Symbol.iterator
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const next = iter.next(); // { value: <item>, done: false|true}
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// OR:
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// var all = iter.collect(); // returns all elements as an array
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// OR:
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// for(let i of iter)
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// console.log(i.hash, i.item);
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/* KV Store */
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db.put('key1', 'hello world');
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db.get('key1'); // returns "hello world"
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db.del('key1');
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/* Delete channel */
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const result = db.delete(); // true | false
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})();
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```
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### Development
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#### Run Tests
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```
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npm test
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```
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Keep tests running while development:
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```
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mocha -w
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```
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### TODO
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- Fix encryption
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- Caching
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