# cabs

> content addressable blob store for node

Latest version **0.10.1** (published 2014-02-18) · MIT license · 0 weekly downloads

## Install

```sh
npm install cabs
pnpm add cabs
yarn add cabs
bun add cabs
```

Provides the command `cabs`.

## Health

**Score 15/100 (F)** — status: abandoned.

Positive: no vulnerabilities.

Warnings: low downloads; no types; no esm support; pre 1.0.

Negative: abandoned; low maintenance score.

## Facts

| | |
|---|---|
| Version | 0.10.1 |
| Published | 2014-02-18 |
| First published | 2014-02-14 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | none |
| Module format | CommonJS |
| Dependencies | 7 |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 6 |
| Author | Calvin Metcalf |
| Maintainers | cwmma |

## Links

- npm: https://www.npmjs.com/package/cabs
- Repository: git@github.com:calvinmetcalf/cabs
- Homepage: https://github.com/calvinmetcalf/cabs
- Issues: https://github.com/calvinmetcalf/cabs/issues
- npm.io page: https://npm.io/package/cabs

## Dependencies (7)

- [mkdirp](https://npm.io/package/mkdirp.md) ~0.3.5
- [rimraf](https://npm.io/package/rimraf.md) ~2.2.6
- [duplexer](https://npm.io/package/duplexer.md) ~0.1.1
- [through2](https://npm.io/package/through2.md) ~0.4.1
- [ldjson-stream](https://npm.io/package/ldjson-stream.md) ~0.0.1
- [readable-stream](https://npm.io/package/readable-stream.md) ~1.1.10
- [stream-combiner](https://npm.io/package/stream-combiner.md) ~0.0.4

## Recent versions

- 0.10.1 (latest) — 2014-02-18
- 0.10.0 — 2014-02-18
- 0.9.2 — 2014-02-18
- 0.9.1 — 2014-02-18
- 0.9.0 — 2014-02-17
- 0.8.2 — 2014-02-17
- 0.8.1 — 2014-02-16
- 0.8.0 — 2014-02-16
- 0.7.0 — 2014-02-16
- 0.6.1 — 2014-02-15
- 0.6.0 — 2014-02-15
- 0.5.4 — 2014-02-14
- 0.5.3 — 2014-02-14
- 0.5.2 — 2014-02-14
- 0.5.0 — 2014-02-14
- … 6 more at https://npm.io/package/cabs/versions

## README

cabs
====

A [Content Addressable Blob Store](https://en.wikipedia.org/wiki/Content-addressable_storage) for Node.

[![NPM](https://nodei.co/npm/cabs.png)](https://nodei.co/npm/cabs/)

This implements something similar to the object store from `git` (the `.git/objects` folder). By default blobs stored by cabs are `sha256` hashed and stored in subdirectories to avoid putting too many files in a single directory. The hashing algorithm and depth of the directories are configurable.

write
====

```js
Cabs.write(path[, hashFunction, limit]);
```

Pipe in a blob stream (e.g. fs.createReadStream), get back objects for the various pieces stored. Each object has a hash of the block, as well as the starting and ending locations within the stream. You may optionally pass a string representing the hash function to use (default `sha256`) and number representing the block size (defaults to 5 MB).

To learn more about hashing algorithm tradeoffs read the comments on [this issue](https://github.com/calvinmetcalf/cabs/pull/4).

read
====

```js
Cabs.read(path);
```

Pipe in the objects from write, returns a readable stream of the blob.

example
====

```js
var fs = require('fs')
var Cabs = require('cabs')

/** stream a movie into cabs, store hashes in hashes.json **/
fs.createReadStream('movie.avi')
  .pipe(Cabs.write('./storage'))
  .pipe(fs.createWriteStream('hashes.json'));
  
/** later, to retrieve the movie, stream the hashes into cabs **/
fs.createReadStream('hashes.json')
  .pipe(Cabs.read('./storage))
  .pipe(fs.createWriteStream('movie-copy.avi'));
```

Low Level Class
=====

you also have access to the base Cabs class located at `cabs.Cabs`, initialize it with a location and optionally an options object wtih a string representing the hash function to use (Defaults to sha256), the block size limit (defaults to 5 MB) and the depth of folders to use.

```javascript
var store = new Cabs('./location');
// or
var store = new Cabs({
  path: './location',
  hashFunction: 'sha256',
  limit: 5 * 1024 *1024
  depth: 3
});

store.write(buffer, callback);
//stores buffer, callback is called with the hash

store.read(hash, callback);
//calls the callback with the blob

store.rm(hash, callback);
//removes the file with the given hash

store.destroy(callback);
//deletes all the files related to the store, just a shortcut to rimraf so beware.

store.readStream();
//same as Cabs.read

store.writeStream();
//same as Cabs.write

store.has(hash, callback);
//calls callback with true if it exists, otherwise false

store.check(hash, callback);
//similar to has but throws an error if the file doesn't exist
//or it's hash doesn't match it's address hash

store.writeFile();
//write to a single file on disc.  Will only ever emit a single string
//the hash for the combined file you streamed in.
//unlike writeStream which chunks a big file into multiple smaller ones
//which can be handled in memory, this method buffers to disk.
```

---
_Source: https://npm.io/package/cabs · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._