dwebs-core

> dwebs-core is a high-level module for building DWeb applications on the file system.

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DWeb is a decentralized tool for distributing data and
files, built for scientific and research data.
You can start using DWeb today in these client applications:

* DWeb Command Line: Use DWeb in the command line
* DWeb Desktop: A desktop application for DWeb
* DBrowser Browser: An experimental P2P browser with DWeb built in

#### DWeb Project Documentation & Resources

* DWeb Project Docs
* DWeb Protocol
* Gitter Chat or #dweb on IRC

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* High-level glue for common DWeb and dwebfs modules.
* Sane defaults and consistent management of storage & secret keys across applications, using dweb-storage.
* Easily connect to the DWeb network, using dweb-discovery-swarm
* Import files from the file system, using mirror-folder
* Serve dwebs over http with dwebfs-http
* Access APIs to lower level modules with a single require!

#### Browser Support

Many of our dependencies work in the browser, but dwebs-core is tailored for file system applications. See dweb-js if you want to build browser-friendly DWeb applications.

Example

To send files via DWeb:

1. Tell dwebs-core where the files are.
2. Import the files.
3. Share the files on the DWeb network! (And share the link)

``js
var DWeb = require('dwebs-core')

// 1. My files are in /joe/cat-pic-analysis
DWeb('/joe/cat-pic-analysis', function (err, dweb) {
if (err) throw err

// 2. Import the files
dweb.importFiles()

// 3. Share the files on the network!
dweb.joinNetwork()
// (And share the link)
console.log('My DWeb link is: dweb://', dweb.key.toString('hex'))
})
`

These files are now available to share over the dweb network via the key printed in the console.

To download the files, you can make another dwebs-core instance in a different folder. This time we also have three steps:

1. Tell dweb where I want to download the files.
2. Tell dweb what the link is.
3. Join the network and download!

`js
var DWeb = require('dwebs-core')

// 1. Tell DWeb where to download the files
DWeb('/download/cat-analysis', {
// 2. Tell DWeb what link I want
key: '' // (a 64 character hash from above)
}, function (err, dweb) {
if (err) throw err

// 3. Join the network & download (files are automatically downloaded)
dweb.joinNetwork()
})
`

That's it! By default, all files are automatically downloaded when you connect to the other users.

Dig into more use cases below and please let us know if you have questions! You can open a new issue or talk to nice humans in our chat room.

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* DWeb CLI: We use dwebs-core in the dweb CLI.
* DWeb Desktop: The DWeb Desktop application manages multiple dwebs-core instances via dweb-worker.
* See the examples folder for a minimal share + download usage.
* And more! Let us know if you have a neat dwebs-core application to add here.

Usage

All dwebs-core applications have a similar structure around three main elements:

1. Storage - where the files and metadata are stored.
2. Network - connecting to other users to upload or download data.
3. Adding Files - adding files from the file system to the dwebfs archive.

We'll go through what these are for and a few of the common usages of each element.

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Every dweb archive has storage, this is the required first argument for dwebs-core. By default, we use dweb-storage which stores the secret key in ~/.dweb/ and the rest of the data in dir/.dweb. Other common options are:

* Persistent storage: Stored files in /my-dir and metadata in my-dir/.dweb by passing /my-dir as the first argument.
* Temporary Storage: Use the temp: true option to keep metadata stored in memory.

`js
// Permanent Storage
DWeb('/my-dir', function (err, dweb) {
// Do DWeb Stuff
})

// Temporary Storage
DWeb('/my-dir', {temp: true}, function (err, dweb) {
// Do DWeb Stuff
})
`

Both of these will import files from /my-dir when doing dweb.importFiles() but only the first will make a .dweb folder and keep the metadata on disk.

The storage argument can also be passed through to dwebfs for more advanced storage use cases.

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DWeb is all about the network! You'll almost always want to join the network right after you create your DWeb:

`js
DWeb('/my-dir', function (err, dweb) {
dweb.joinNetwork()
dweb.network.on('connection', function () {
console.log('I connected to someone!')
})
})
`

#### Downloading Files

Remember, if you are downloading - metadata and file downloads will happen automatically once you join the network!

DWeb runs on a peer to peer network, sometimes there may not be anyone online for a particular key. You can make your application more user friendly by using the callback in joinNetwork:

`js
// Downloading with joinNetwork callback
DWeb('/my-dir', {key: ''}, function (err, dweb) {
dweb.joinNetwork(function (err) {
if (err) throw err

// After the first round of network checks, the callback is called
// If no one is online, you can exit and let the user know.
if (!dweb.network.connected || !dweb.network.connecting) {
console.error('No users currently online for that key.')
process.exit(1)
}
})
})
`

##### Download on Demand

If you want to control what files and metadata are downloaded, you can use the sparse option:

`js
// Downloading with sparse option
DWeb('/my-dir', {key: '', sparse: true}, function (err, dweb) {
dweb.joinNetwork()

// Manually download files via the dwebfs API:
dweb.archive.readFile('/cat-locations.txt', function (err, content) {
console.log(content) // prints cat-locations.txt file!
})
})
`

DWeb will only download metadata and content for the parts you request with sparse mode!

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There are many ways to get files imported into an archive! DWeb node provides a few basic methods. If you need more advanced imports, you can use the archive.createWriteStream() methods directly.

By default, just call dweb.importFiles() to import from the directory you initialized with. You can watch that folder for changes by setting the watch option:

`js
DWeb('/my-data', function (err, dweb) {
if (err) throw err

var progress = dweb.importFiles({watch: true}) // with watch: true, there is no callback
progress.on('put', function (src, dest) {
console.log('Importing ', src.name, ' into archive')
})
})
`

You can also import from another directory:

`js
DWeb('/my-data', function (err, dweb) {
if (err) throw err

dweb.importFiles('/another-dir', function (err) {
console.log('done importing another-dir')
})
})
`

That covers some of the common use cases, let us know if there are more to add! Keep reading for the full API docs.

API

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Initialize a DWeb Archive in dir. If there is an existing DWeb Archive, the archive will be resumed.

#### Storage

* dir (Default) - Use dweb-storage inside dir. This stores files as files, sleep files inside .dweb, and the secret key in the user's home directory.
* dir with opts.latest: false - Store as SLEEP files, including storing the content as a content.data file. This is useful for storing all history in a single flat file.
* dir with opts.temp: true - Store everything in memory (including files).
* storage function - pass a custom storage function along to dwebfs, see dweb-storage for an example.

Most options are passed directly to the module you're using (e.g. dweb.importFiles(opts). However, there are also some initial opts can include:

`js
opts = {
key: '', // existing key to create archive with or resume
temp: false, // Use random-access-memory as the storage.

// DWebFs options
sparse: false // download only files you request
}
`

The callback, cb(err, dweb), includes a dweb object that has the following properties:

* dweb.key: key of the dweb (this will be set later for non-live archives)
* dweb.archive: DWebFs archive instance.
* dweb.path: Path of the DWeb Archive
* dweb.live: archive.live
* dweb.writable: Is the archive writable?
* dweb.resumed: true if the archive was resumed from an existing database
* dweb.options: All options passed to DWeb and the other submodules

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dwebs-core provides an easy interface to common DWeb modules for the created DWeb Archive on the dweb object provided in the callback:

#### var network = dweb.joinNetwork([opts], [cb])

Join the network to start transferring data for dweb.key, using dweb-discovery-swarm. You can also use dweb.join([opts], [cb]).

If you specify cb, it will be called when the first round of discovery has completed. This is helpful to check immediately if peers are available and if not fail gracefully, more similar to http requests.

Returns a network object with properties:

* network.connected - number of peers connected
* network.on('listening') - emitted with network is listening
* network.on('connection', connection, info) - Emitted when you connect to another peer. Info is an object that contains info about the connection

##### Network Options

opts are passed to dweb-discovery-swarm, which can include:

`js
opts = {
upload: true, // announce and upload data to other peers
download: true, // download data from other peers
port: 6620, // port for discovery swarm
utp: true, // use utp in discovery swarm
tcp: true // use tcp in discovery swarm
}

//Defaults from datland-swarm-defaults can also be overwritten:

opts = {
dns: {
server: // DNS server
domain: // DNS domain
}
dht: {
bootstrap: // distributed hash table bootstrapping nodes
}
}
`

Returns a dweb-discovery-swarm instance.

#### dweb.leaveNetwork() or dweb.leave()

Leaves the network for the archive.

#### var importer = dweb.importFiles([src], [opts], [cb])

Archive must be writable to import.

Import files to your DWeb Archive from the directory using mirror-folder.

* src - By default, files will be imported from the folder where the archive was initiated. Import files from another directory by specifying src.
* opts - options passed to mirror-folder (see below).
* cb - called when import is finished.

Returns a importer object with properties:

* importer.on('error', err)
* importer.on('put', src, dest) - file put started. src.live is true if file was added by file watch event.
* importer.on('put-data', chunk) - chunk of file added
* importer.on('put-end', src, dest) - end of file write stream
* importer.on('del', dest) - file deleted from dest
* importer.on('end') - Emits when mirror is done (not emitted in watch mode)
* If opts.count is true:
* importer.on('count', {files, bytes}) - Emitted after initial scan of src directory. See import progress section for details.
* importer.count will be {files, bytes} to import after initial scan.
* importer.putDone will track {files, bytes} for imported files.

##### Importer Options

Options include:

`js
var opts = {
count: true, // do an initial dry run import for rendering progress
ignoreHidden: true, // ignore hidden files (if false, .dweb will still be ignored)
ignoreDirs: true, // do not import directories (dwebfs does not need them and it pollutes metadata)
useDatIgnore: true, // ignore entries in the .datignore file from import dir target.
ignore: // (see below for default info) anymatch expression to ignore files
watch: false, // watch files for changes & import on change (archive must be live)
}
`

##### Ignoring Files

You can use a .datignore file in the imported directory, src, to ignore any the user specifies. This is done by default.

dwebs-core uses dweb-ignore to provide a default ignore option, ignoring the .dweb folder and all hidden files or directories. Use opts.ignoreHidden = false to import hidden files or folders, except the .dweb directory.

It's important that the .dweb folder is not imported because it contains a private key that allows the owner to write to the archive.

#### var stats = dweb.trackStats()

##### stats.on('update')

Emitted when archive stats are updated. Get new stats with stats.get().

##### var st = dweb.stats.get()

dweb.trackStats() adds a stats object to dweb. Get general archive stats for the latest version:

`js
{
files: 12,
byteLength: 1234,
length: 4, // number of blocks for latest files
version: 6, // archive.version for these stats
downloaded: 4 // number of downloaded blocks for latest
}
`

##### stats.network

Get upload and download speeds: stats.network.uploadSpeed or stats.network.downloadSpeed. Transfer speeds are tracked using dwebfs-network-speed.

##### var peers = stats.peers

* peers.total - total number of connected peers
* peers.complete - connected peers with all the content data

#### var server = dweb.serveHttp(opts)

Serve files over http via dwebfs-http. Returns a node http server instance.

`js
opts = {
port: 8080, // http port
live: true, // live update directory index listing
footer: 'Served via DWeb.', // Set a footer for the index listing
exposeHeaders: false // expose dweb key in headers
}
`

#### dweb.pause()

Pause all upload & downloads. Currently, this is the same as dweb.leaveNetwork(), which leaves the network and destroys the swarm. Discovery will happen again on resume().

#### dweb.resume()

Resume network activity. Current, this is the same as dweb.joinNetwork().

#### dweb.close(cb)

Stops replication and closes all the things opened for dwebs-core, including:

* dweb.archive.close(cb)
* dweb.network.close(cb)
* dweb.importer.destroy()` (file watcher)

License

MIT

[0]: https://img.shields.io/npm/v/dwebs-core.svg?style=flat-square
[1]: https://npmjs.org/package/dwebs-core
[2]: https://img.shields.io/travis/datproject/dwebs-core/master.svg?style=flat-square
[3]: https://travis-ci.org/datproject/dwebs-core
[4]: https://img.shields.io/codecov/c/github/datproject/dwebs-core/master.svg?style=flat-square
[5]: https://codecov.io/github/datproject/dwebs-core