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feat: convert to async/await #21

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May 17, 2019
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feat: convert to async/await #21

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579311b
feat: convert to async/await
achingbrain Apr 25, 2019
eea8423
chore: readme update
achingbrain Apr 25, 2019
e1334bb
chore: fix linting
achingbrain Apr 25, 2019
1c7456b
feat: convert internals to be async/await
achingbrain Apr 26, 2019
468cdfb
test: increase test coverage
achingbrain Apr 26, 2019
220de8a
chore: remove uncessary await
achingbrain Apr 26, 2019
3679e1d
feat: add export depth and recursive exports
achingbrain May 14, 2019
ef5499b
chore: address PR comments
achingbrain May 15, 2019
747a664
chore: update ipld formats
achingbrain May 15, 2019
a193651
chore: PR comments
achingbrain May 15, 2019
6a73635
chore: standardise error codes
achingbrain May 17, 2019
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276 changes: 149 additions & 127 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -19,13 +19,21 @@

## Table of Contents

- [Install](#install)
- [Usage](#usage)
- [Example](#example)
- [API](#api)
- [exporter(cid, ipld)](#exportercid-ipld-options)
- [Contribute](#contribute)
- [License](#license)
- [ipfs-unixfs-exporter](#ipfs-unixfs-exporter)
- [Lead Maintainer](#lead-maintainer)
- [Table of Contents](#table-of-contents)
- [Install](#install)
- [Usage](#usage)
- [Example](#example)
- [API](#api)
- [`exporter(cid, ipld)`](#exportercid-ipld)
- [UnixFS V1 entries](#unixfs-v1-entries)
- [Raw entries](#raw-entries)
- [CBOR entries](#cbor-entries)
- [`entry.content({ offset, length })`](#entrycontent-offset-length)
- [`exporter.path(cid, ipld)`](#exporterpathcid-ipld)
- [Contribute](#contribute)
- [License](#license)

## Install

Expand All @@ -38,29 +46,41 @@
### Example

```js
// Create an export source pull-stream cid or ipfs path you want to export and a
// <dag or ipld-resolver instance> to fetch the file from
// import a file and export it again
const importer = require('ipfs-unixfs-importer')
const exporter = require('ipfs-unixfs-exporter')
const pull = require('pull-stream/pull')
const { stdout } = require('pull-stdio')

const options = {}

pull(
exporter(cid, ipld, options),
collect((error, files) => {
if (error) {
// ...handle error
}

// Set up a pull stream that sends the file content to process.stdout
pull(
// files[0].content is a pull-stream that contains the bytes of the file
files[0].content,
stdout()
)
})
)

const files = []

for await (const file of importer([{
path: '/foo/bar.txt',
content: Buffer.from(0, 1, 2, 3)
}], ipld)) {
files.push(file)
}

console.info(files[0].cid) // Qmbaz

const entry = await exporter(files[0].cid, ipld)

console.info(entry.cid) // Qmqux
console.info(entry.path) // Qmbaz/foo/bar.txt
console.info(entry.name) // bar.txt
console.info(entry.unixfs.fileSize()) // 4

// stream content from unixfs node
const bytes = []

for await (const buf of entry.content({
offset: 0, // optional offset
length: 4 // optional length
})) {
bytes.push(buf)
}

const content = Buffer.concat(bytes)

console.info(content) // 0, 1, 2, 3
```

#### API
Expand All @@ -69,124 +89,126 @@ pull(
const exporter = require('ipfs-unixfs-exporter')
```

### exporter(cid, ipld, options)
### `exporter(cid, ipld)`

Uses the given [dag API][] or an [ipld-resolver instance][] to fetch an IPFS [UnixFS][] object(s) by their CID.
Uses the given [js-ipld instance][] to fetch an IPFS node by it's CID.

Creates a new pull stream that outputs objects of the form
Returns a Promise which resolves to an `entry`.

```js
#### UnixFS V1 entries

Entries with a `dag-pb` codec `CID` return UnixFS V1 entries:

```javascript
{
path: 'a name',
content: <pull stream>
name: 'foo.txt',
path: 'Qmbar/foo.txt',
cid: CID, // see https://github.com/multiformats/js-cid
node: DAGNode, // see https://github.com/ipld/js-ipld-dag-pb
content: function, // returns an async iterator
unixfs: UnixFS // see https://github.com/ipfs/js-ipfs-unixfs
}
```

#### `offset` and `length`
If the entry is a file, `entry.content()` returns an async iterator that emits buffers containing the file content:
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`offset` and `length` arguments can optionally be passed to the exporter function. These will cause the returned stream to only emit bytes starting at `offset` and with length of `length`.
```javascript
for await (const chunk of entry.content()) {
// chunk is a Buffer
}
```

See [the tests](test/exporter.js) for examples of using these arguments.
If the entry is a directory or hamt shard, `entry.content()` returns further `entry` objects:
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```js
const exporter = require('ipfs-unixfs-exporter')
const pull = require('pull-stream')
const drain = require('pull-stream/sinks/drain')

pull(
exporter(cid, ipld, {
offset: 0,
length: 10
})
drain((file) => {
// file.content is a pull stream containing only the first 10 bytes of the file
})
)
```javascript
for await (const entry of dir.content()) {
console.info(entry.name)
}
```

### `fullPath`
#### Raw entries

If specified the exporter will emit an entry for every path component encountered.
Entries with a `raw` codec `CID` return raw entries:

```javascript
const exporter = require('ipfs-unixfs-exporter')
const pull = require('pull-stream')
const collect = require('pull-stream/sinks/collect')

pull(
exporter('QmFoo.../bar/baz.txt', ipld, {
fullPath: true
})
collect((err, files) => {
console.info(files)

// [{
// depth: 0,
// name: 'QmFoo...',
// path: 'QmFoo...',
// size: ...
// cid: CID
// content: undefined
// type: 'dir'
// }, {
// depth: 1,
// name: 'bar',
// path: 'QmFoo.../bar',
// size: ...
// cid: CID
// content: undefined
// type: 'dir'
// }, {
// depth: 2,
// name: 'baz.txt',
// path: 'QmFoo.../bar/baz.txt',
// size: ...
// cid: CID
// content: <Pull stream>
// type: 'file'
// }]
//
})
)
{
name: 'foo.txt',
path: 'Qmbar/foo.txt',
cid: CID, // see https://github.com/multiformats/js-cid
node: Buffer, // see https://nodejs.org/api/buffer.html
content: function, // returns an async iterator
}
```

`entry.content()` returns an async iterator that emits buffers containing the node content:
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```javascript
for await (const chunk of entry.content()) {
// chunk is a Buffer
}
```

### `maxDepth`
#### CBOR entries
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hmm, interesting...

  • Does it already support this?
  • Does go-ipfs support this?
  • Given that this is a unixfs exporter should we be supporting these IPLD node types?

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Yes, through the object exporter.

I'm not sure what go does.

The name starts to become misleading, true - might be worth turning it into a ipfs-exporter, though it's really an ipld-exporter with some baked in assumptions about dag-pb nodes? Not sure.


If specified the exporter will only emit entries up to the specified depth.
Entries with a `dag-cbor` codec `CID` return JavaScript object entries:

```javascript
const exporter = require('ipfs-unixfs-exporter')
const pull = require('pull-stream')
const collect = require('pull-stream/sinks/collect')

pull(
exporter('QmFoo.../bar/baz.txt', ipld, {
fullPath: true,
maxDepth: 1
})
collect((err, files) => {
console.info(files)

// [{
// depth: 0,
// name: 'QmFoo...',
// path: 'QmFoo...',
// size: ...
// cid: CID
// content: undefined
// type: 'dir'
// }, {
// depth: 1,
// name: 'bar',
// path: 'QmFoo.../bar',
// size: ...
// cid: CID
// content: undefined
// type: 'dir'
// }]
//
})
)
{
name: 'foo.txt',
path: 'Qmbar/foo.txt',
cid: CID, // see https://github.com/multiformats/js-cid
node: Object, // see https://github.com/ipld/js-ipld-dag-cbor
}
```

There is no `content` function for a `CBOR` node.


#### `entry.content({ offset, length })`

When `entry` is a file or a `raw` node, `offset` and/or `length` arguments can be passed to `entry.content()` to return slices of data:

```javascript
const bufs = []

for await (const chunk of entry.content({
offset: 0,
length: 5
})) {
bufs.push(chunk)
}

// `data` contains the first 5 bytes of the file
const data = Buffer.concat(bufs)
```

If `entry` is a directory or hamt shard, passing `offset` and/or `length` to `entry.content()` will limit the number of files return from the directory.
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Suggested change
If `entry` is a directory or hamt shard, passing `offset` and/or `length` to `entry.content()` will limit the number of files return from the directory.
If `entry` is a directory or hamt shard, passing `offset` and/or `length` to `entry.content()` will limit the number of files returned from the directory.


```javascript
const entries = []

for await (const entry of dir.content({
offset: 0,
length: 5
})) {
entries.push(entry)
}

// `entries` contains the first 5 files/directories in the directory
```

### `exporter.path(cid, ipld)`

`exporter.path` will return an async iterator that yields entries for all segments in a path:

```javascript
const entries = []

for await (const entry of exporter('Qmfoo/foo/bar/baz.txt', ipld)) {
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Suggested change
for await (const entry of exporter('Qmfoo/foo/bar/baz.txt', ipld)) {
for await (const entry of exporter.path('Qmfoo/foo/bar/baz.txt', ipld)) {

entries.push(entry)
}

// entries contains 4x `entry` objects
```

[dag API]: https://github.com/ipfs/interface-ipfs-core/blob/master/SPEC/DAG.md
Expand Down
28 changes: 14 additions & 14 deletions package.json
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,8 @@
"release": "aegir release",
"release-minor": "aegir release --type minor",
"release-major": "aegir release --type major",
"coverage": "aegir coverage"
"coverage": "nyc -s npm run test:node && nyc report --reporter=html",
"dep-check": "aegir dep-check"
},
"repository": {
"type": "git",
Expand All @@ -37,29 +38,28 @@
"homepage": "https://github.com/ipfs/js-ipfs-unixfs-exporter#readme",
"devDependencies": {
"aegir": "^18.0.2",
"async-iterator-all": "0.0.2",
"async-iterator-buffer-stream": "0.0.1",
"async-iterator-first": "0.0.2",
"chai": "^4.2.0",
"detect-node": "^2.0.4",
"dirty-chai": "^2.0.1",
"ipld": "~0.21.1",
"ipld": "~0.22.0",
"ipld-dag-pb": "~0.15.2",
"ipld-in-memory": "^2.0.0",
"pull-pushable": "^2.2.0",
"pull-stream-to-stream": "^1.3.4",
"pull-zip": "^2.0.1",
"sinon": "^7.1.0",
"stream-to-pull-stream": "^1.7.2"
"multicodec": "~0.5.1",
"multihashes": "~0.4.14",
"nyc": "^14.0.0",
"sinon": "^7.1.0"
},
"dependencies": {
"async": "^2.6.1",
"async-iterator-last": "0.0.2",
"cids": "~0.5.5",
"err-code": "^1.1.2",
"hamt-sharding": "0.0.2",
"ipfs-unixfs": "~0.1.16",
"ipfs-unixfs-importer": "~0.38.0",
"pull-cat": "^1.1.11",
"pull-defer": "~0.2.3",
"pull-paramap": "^1.2.2",
"pull-stream": "^3.6.9",
"pull-traverse": "^1.0.3"
"ipfs-unixfs-importer": "ipfs/js-ipfs-unixfs-importer#async-await",
"promisify-es6": "^1.0.3"
},
"contributors": [
"Alan Shaw <[email protected]>",
Expand Down
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