pauls-dat-api

A library of functions that make working with dat / hyperdrive easier.
Includes common operations, and some sugars.
These functions were factored out of beaker browser's internal APIs.

All async methods work with callbacks and promises. If no callback is provided, a promise will be returned.

Any time a hyperdrive archive is expected, a scoped-fs instance can be provided, unless otherwise stated.

``js
var hyperdrive = require('hyperdrive')
var ScopedFS = require('scoped-fs')

var archive = hyperdrive('./my-hyperdrive')
var scopedfs = new ScopedFS('./my-scoped-fs')

await pda.readFile(archive, '/hello.txt') // read the published hello.txt
await pda.readFile(scopedfs, '/hello.txt') // read the local hello.txt
`

NOTE: this library is written natively for node 7 and above.

To use with node versions lesser than 7 use:
`js
var pda = require('pauls-dat-api/es5');
`


- Lookup
- [stat(archive, name[, cb])](#statarchive-name-cb)
- Read
- [readFile(archive, name[, opts, cb])](#readfilearchive-name-opts-cb)
- [readdir(archive, path[, opts, cb])](#readdirarchive-path-opts-cb)
- [readSize(archive, path[, cb])](#readsizearchive-path-cb)
- Write
- [writeFile(archive, name, data[, opts, cb])](#writefilearchive-name-data-opts-cb)
- [mkdir(archive, name[, cb])](#mkdirarchive-name-cb)
- [copy(archive, sourceName, targetName[, cb])](#copyarchive-sourcename-targetname-cb)
- [rename(archive, sourceName, targetName[, cb])](#renamearchive-sourcename-targetname-cb)
- Delete
- [unlink(archive, name[, cb])](#unlinkarchive-name-cb)
- [rmdir(archive, name[, opts, cb])](#rmdirarchive-name-opts-cb)
- Network
- [download(archive, name[, cb])](#downloadarchive-name-cb)
- Activity Streams
- [watch(archive[, path])](#watcharchive-path)
- createNetworkActivityStream(archive)
- Exporters
- [exportFilesystemToArchive(opts[, cb])](#exportfilesystemtoarchiveopts-cb)
- [exportArchiveToFilesystem(opts[, cb])](#exportarchivetofilesystemopts-cb)
- [exportArchiveToArchive(opts[, cb])](#exportarchivetoarchiveopts-cb)
- Manifest
- [readManifest(archive[, cb])](#readmanifestarchive-cb)
- [writeManifest(archive, manifest[, cb])](#writemanifestarchive-manifest-cb)
- [updateManifest(archive, manifest[, cb])](#updatemanifestarchive-manifest-cb)
- generateManifest(opts)
- Diff/Merge
- [diff(srcArchive, srcPath, dstArchive, dstPath[, opts, cb])](#diffsrcarchive-srcpath-dstarchive-dstpath-opts-cb)
- [merge(srcArchive, srcPath, dstArchive, dstPath[, opts, cb])](#mergesrcarchive-srcpath-dstarchive-dstpath-opts-cb)
- Helpers
- findEntryByContentBlock(archive, block)

`js
const pda = require('pauls-dat-api')
`

Lookup

$3

- archive Hyperdrive archive (object).
- name Entry name (string).
- Returns a Hyperdrive Stat entry (object).
- Throws NotFoundError

`js
// by name:
var st = await pda.stat(archive, '/dat.json')
st.isDirectory()
st.isFile()
console.log(st) /* =>
Stat {
dev: 0,
nlink: 1,
rdev: 0,
blksize: 0,
ino: 0,
mode: 16877,
uid: 0,
gid: 0,
size: 0,
offset: 0,
blocks: 0,
atime: 2017-04-10T18:59:00.147Z,
mtime: 2017-04-10T18:59:00.147Z,
ctime: 2017-04-10T18:59:00.147Z,
linkname: undefined } */
`

Read

$3

- archive Hyperdrive archive (object).
- name Entry path (string).
- opts. Options (object|string). If a string, will act as opts.encoding.
- opts.encoding Desired output encoding (string). May be 'binary', 'utf8', 'hex', or 'base64'. Default 'utf8'.
- Returns the content of the file in the requested encoding.
- Throws NotFoundError, NotAFileError.

`js
var manifestStr = await pda.readFile(archive, '/dat.json')
var imageBase64 = await pda.readFile(archive, '/favicon.png', 'base64')
`

$3

- archive Hyperdrive archive (object).
- path Target directory path (string).
- opts.recursive Read all subfolders and their files as well?
- Returns an array of file and folder names.

`js
var listing = await pda.readdir(archive, '/assets')
console.log(listing) // => ['profile.png', 'styles.css']

var listing = await pda.readdir(archive, '/', { recursive: true })
console.log(listing) /* => [
'index.html',
'assets',
'assets/profile.png',
'assets/styles.css'
]*/
`

$3

- archive Hyperdrive archive (object).
- path Target directory path (string).
- Returns a number (size in bytes).

This method will recurse on folders.

`js
var size = await pda.readSize(archive, '/assets')
console.log(size) // => 123
`

Write

$3

- archive Hyperdrive archive (object).
- name Entry path (string).
- data Data to write (string|Buffer).
- opts. Options (object|string). If a string, will act as opts.encoding.
- opts.encoding Desired file encoding (string). May be 'binary', 'utf8', 'hex', or 'base64'. Default 'utf8' if data is a string, 'binary' if data is a Buffer.
- Throws ArchiveNotWritableError, InvalidPathError, EntryAlreadyExistsError, ParentFolderDoesntExistError, InvalidEncodingError.

`js
await pda.writeFile(archive, '/hello.txt', 'world', 'utf8')
await pda.writeFile(archive, '/profile.png', fs.readFileSync('/tmp/dog.png'))
`

$3

- archive Hyperdrive archive (object).
- name Directory path (string).
- Throws ArchiveNotWritableError, InvalidPathError, EntryAlreadyExistsError, ParentFolderDoesntExistError, InvalidEncodingError.

`js
await pda.mkdir(archive, '/stuff')
`

$3

- archive Hyperdrive archive (object).
- sourceName Path to file or directory to copy (string).
- targetName Where to copy the file or folder to (string).
- Throws ArchiveNotWritableError, InvalidPathError, EntryAlreadyExistsError, ParentFolderDoesntExistError, InvalidEncodingError.

`js
// copy file:
await pda.copy(archive, '/foo.txt', '/foo.txt.back')
// copy folder:
await pda.copy(archive, '/stuff', '/stuff-copy')
`

$3

- archive Hyperdrive archive (object).
- sourceName Path to file or directory to rename (string).
- targetName What the file or folder should be named (string).
- Throws ArchiveNotWritableError, InvalidPathError, EntryAlreadyExistsError, ParentFolderDoesntExistError, InvalidEncodingError.

This is equivalent to moving a file/folder.

`js
// move file:
await pda.rename(archive, '/foo.txt', '/foo.md')
// move folder:
await pda.rename(archive, '/stuff', '/things')
`

Delete

$3

- archive Hyperdrive archive (object).
- name Entry path (string).
- Throws ArchiveNotWritableError, NotFoundError, NotAFileError

`js
await pda.unlink(archive, '/hello.txt')
`

$3

- archive Hyperdrive archive (object).
- name Entry path (string).
- opts.recursive Delete all subfolders and files if the directory is not empty.
- Throws ArchiveNotWritableError, NotFoundError, NotAFolderError, DestDirectoryNotEmpty

`js
await pda.rmdir(archive, '/stuff', {recursive: true})
`

Network

$3

- archive Hyperdrive archive (object). Can not be a scoped-fs object.
- name Entry path (string). Can point to a file or folder.

Download an archive file or folder-tree.

`js
// download a specific file:
await pda.download(archive, '/foo.txt')
// download a specific folder and all children:
await pda.download(archive, '/bar/')
// download the entire archive:
await pda.download(archive, '/')
`

Activity Streams

$3

- archive Hyperdrive archive (object).
- path Entry path (string) or anymatch pattern (array of strings). If falsy, will watch all files.
- Returns a Readable stream.

Watches the given path or path-pattern for file events, which it emits as an emit-stream. Supported events:

- ['invalidated',{path}] - The contents of the file has changed, but may not have been downloaded yet. path is the path-string of the file.
- ['changed',{path}] - The contents of the file has changed, and the new version is ready to read. path is the path-string of the file.

An archive will emit "invalidated" first, when it receives the new metadata for the file. It will then emit "changed" when the content arrives. (A local archive will emit "invalidated" immediately before "changed.")

`js
var es = pda.watch(archive)
var es = pda.watch(archive, 'foo.txt')
var es = pda.watch(archive, ['/.txt', '/.md'])

es.on('data', ([event, args]) => {
if (event === 'invalidated') {
console.log(args.path, 'has been invalidated')
pda.download(archive, args.path)
} else if (event === 'changed') {
console.log(args.path, 'has changed')
}
})

// alternatively, via emit-stream:

var emitStream = require('emit-stream')
var events = emitStream(pda.watch(archive))
events.on('invalidated', args => {
console.log(args.path, 'has been invalidated')
pda.download(archive, args.path)
})
events.on('changed', args => {
console.log(args.path, 'has changed')
})
`

$3

- archive Hyperdrive archive (object). Can not be a scoped-fs object.
- Returns a Readable stream.

Watches the archive for network events, which it emits as an emit-stream. Supported events:

- ['network-changed',{connections}] - The number of connections has changed. connections is a number.
- ['download',{feed,block,bytes}] - A block has been downloaded. feed will either be "metadata" or "content". block is the index of data downloaded. bytes is the number of bytes in the block.
- ['upload',{feed,block,bytes}] - A block has been uploaded. feed will either be "metadata" or "content". block is the index of data downloaded. bytes is the number of bytes in the block.
- ['sync',{feed}] - All known blocks have been downloaded. feed will either be "metadata" or "content".

`js
var es = pda.createNetworkActivityStream(archive)

es.on('data', ([event, args]) => {
if (event === 'network-changed') {
console.log('Connected to %d peers', args.connections)
} else if (event === 'download') {
console.log('Just downloaded %d bytes (block %d) of the %s feed', args.bytes, args.block, args.feed)
} else if (event === 'upload') {
console.log('Just uploaded %d bytes (block %d) of the %s feed', args.bytes, args.block, args.feed)
} else if (event === 'sync') {
console.log('Finished downloading', args.feed)
}
})

// alternatively, via emit-stream:

var emitStream = require('emit-stream')
var events = emitStream(es)
events.on('network-changed', args => {
console.log('Connected to %d peers', args.connections)
})
events.on('download', args => {
console.log('Just downloaded %d bytes (block %d) of the %s feed', args.bytes, args.block, args.feed)
})
events.on('upload', args => {
console.log('Just uploaded %d bytes (block %d) of the %s feed', args.bytes, args.block, args.feed)
})
events.on('sync', args => {
console.log('Finished downloading', args.feed)
})
`

Exporters

$3

- opts.srcPath Source path in the filesystem (string). Required.
- opts.dstArchive Destination archive (object). Required.
- opts.dstPath Destination path within the archive. Optional, defaults to '/'.
- opts.ignore Files not to copy (array of strings). Optional. Uses anymatch.
- opts.inplaceImport Should import source directory in-place? (boolean). If true and importing a directory, this will cause the directory's content to be copied directy into the dstPath. If false, will cause the source-directory to become a child of the dstPath.
- opts.dryRun Don't actually make changes, just list what changes will occur. Optional, defaults to false.
- Returns stats on the export.

Copies a file-tree into an archive.

`js
var stats = await pda.exportFilesystemToArchive({
srcPath: '/tmp/mystuff',
dstArchive: archive,
inplaceImport: true
})
console.log(stats) /* => {
addedFiles: ['fuzz.txt', 'foo/bar.txt'],
updatedFiles: ['something.txt'],
removedFiles: [],
addedFolders: ['foo'],
removedFolders: [],
skipCount: 3, // files skipped due to the target already existing
fileCount: 3,
totalSize: 400 // bytes
}*/
`

$3

- opts.srcArchive Source archive (object). Required.
- opts.dstPath Destination path in the filesystem (string). Required.
- opts.srcPath Source path within the archive. Optional, defaults to '/'.
- opts.ignore Files not to copy (array of strings). Optional. Uses anymatch.
- opts.overwriteExisting Proceed if the destination isn't empty (boolean). Default false.
- opts.skipUndownloadedFiles Ignore files that haven't been downloaded yet (boolean). Default false. If false, will wait for source files to download.
- Returns stats on the export.

Copies an archive into the filesystem.

NOTE

- Unlike exportFilesystemToArchive, this will not compare the target for equality before copying. If overwriteExisting is true, it will simply copy all files again.

`js
var stats = await pda.exportArchiveToFilesystem({
srcArchive: archive,
dstPath: '/tmp/mystuff',
skipUndownloadedFiles: true
})
console.log(stats) /* => {
addedFiles: ['fuzz.txt', 'foo/bar.txt'],
updatedFiles: ['something.txt'],
fileCount: 3,
totalSize: 400 // bytes
}*/
`

$3

- opts.srcArchive Source archive (object). Required.
- opts.dstArchive Destination archive (object). Required.
- opts.srcPath Source path within the source archive (string). Optional, defaults to '/'.
- opts.dstPath Destination path within the destination archive (string). Optional, defaults to '/'.
- opts.ignore Files not to copy (array of strings). Optional. Uses anymatch.
- opts.skipUndownloadedFiles Ignore files that haven't been downloaded yet (boolean). Default false. If false, will wait for source files to download.

Copies an archive into another archive.

NOTE

- Unlike exportFilesystemToArchive, this will not compare the target for equality before copying. It copies files indescriminately.

`js
var stats = await pda.exportArchiveToArchive({
srcArchive: archiveA,
dstArchive: archiveB,
skipUndownloadedFiles: true
})
console.log(stats) /* => {
addedFiles: ['fuzz.txt', 'foo/bar.txt'],
updatedFiles: ['something.txt'],
fileCount: 3,
totalSize: 400 // bytes
}*/
`

Manifest

$3

- archive Hyperdrive archive (object).

A sugar to get the manifest object.

`js
var manifestObj = await pda.readManifest(archive)
`

$3

- archive Hyperdrive archive (object).
- manifest Manifest values (object).

A sugar to write the manifest object.

`js
await pda.writeManifest(archive, { title: 'My dat!' })
`

$3

- archive Hyperdrive archive (object).
- manifest Manifest values (object).

A sugar to modify the manifest object.

`js
await pda.writeManifest(archive, { title: 'My dat!', description: 'the desc' })
await pda.writeManifest(archive, { title: 'My new title!' }) // preserves description
`

$3

- opts Manifest options (object).

Helper to generate a manifest object. Opts in detail:

`
{
url: String, the dat's url
title: String
description: String
type: Array
author: String | Object{name: String, url: String}
links: Object
web_root: String
fallback_page: String
}
`

See: https://github.com/datprotocol/dat.json

Diff/Merge

$3

- srcArchive Source archive (object). Required.
- srcPath Source path within the source archive (string). Required.
- dstArchive Destination archive (object). Required.
- dstPath Destination path within the destination archive (string). Required.
- opts.shallow Don't descend into changed folders (bool). Optional, default false.
- opts.compareContent. Compare the content of the files, rather than the mtime and size. Optional, default false.
- opts.paths Whitelist of files to diff (array). Optional.
- opts.ops Whitelist of operations to include in the diff (array). Optional. Valid values are 'add', 'mod', and 'del'.
- Returns diff data.

Get a list of differences between the two archives at the given paths.

`js
await pda.diff(archiveA, '/', archiveB, '/')
await pda.diff(archiveA, '/', archiveB, '/', {shallow: false, compareContent: true})
await pda.diff(archiveA, '/', archiveB, '/', {paths: ['/foo', '/bar']})
await pda.diff(archiveA, '/', archiveB, '/', {ops: ['add']}) // additions only
`

Output looks like:

`
[
{change: 'mod', type: 'file', path: '/hello.txt'},
{change: 'add', type: 'dir', path: '/pics'},
{change: 'add', type: 'file', path: '/pics/kitty.png'},
{change: 'del', type: 'file', path: '/backup/hello.txt'},
{change: 'del', type: 'dir', path: '/backup'},
{change: 'del', type: 'file', path: '/hello.txt'},
]
`

$3

- srcArchive Source archive (object). Required.
- srcPath Source path within the source archive (string). Required.
- dstArchive Destination archive (object). Required.
- dstPath Destination path within the destination archive (string). Required.
- opts.shallow Don't descend into changed folders (bool). Optional, default false.
- opts.compareContent. Compare the content of the files, rather than the mtime and size. Optional, default false.
- opts.paths Whitelist of files to diff (array). Optional.
- opts.ops Whitelist of operations to include in the diff (array). Optional. Valid values are 'add', 'mod', and 'del'.
- Returns the changes applied.

Merges the source archive into the destinatio archive at the given paths, causing dstArchive content to match srcArchive.

`js
await pda.merge(archiveA, '/', archiveB, '/')
await pda.merge(archiveA, '/', archiveB, '/', {shallow: false, compareContent: true})
await pda.merge(archiveA, '/', archiveB, '/', {paths: ['/foo', '/bar']})
await pda.merge(archiveA, '/', archiveB, '/', {ops: ['add']}) // additions only
`

Output looks like:

`
[
{change: 'mod', type: 'file', path: '/hello.txt'},
{change: 'add', type: 'dir', path: '/pics'},
{change: 'add', type: 'file', path: '/pics/kitty.png'},
{change: 'del', type: 'file', path: '/backup/hello.txt'},
{change: 'del', type: 'dir', path: '/backup'},
{change: 'del', type: 'file', path: '/hello.txt'},
]
`

Helpers

$3

- archive Hyperdrive archive (object).
- block Content-block index
- Returns a Promise for {name:, start:, end:}

Runs a binary search to find the file-entry that the given content-block index belongs to.

`js
await pda.findEntryByContentBlock(archive, 5)
/* => {
name: '/foo.txt',
start: 4,
end: 6
}*/
``