blob-slicer

Read all or part of the content in a Blob or File as a Buffer or Stream

Install

npm install blob-slicer

Usage

var BlobSlicer = require('blob-slicer')
 
var reader = new BlobSlicer(getBlobOrFileSomehow())
 
// Read as Buffer
reader.read(start, end, function (error, buffer) {
  if (error) {
    // handle error
  }
  // handle data
})
 
// Read as Stream
reader.createReadStream()
  .on('data', function (chunk) { ... })
  .on('error', function (error) { ... })
  .on('end', function () { ... })

blob-slicer depends on buffer v4.x . Therefore, if you are using browserify v14 and higher, you must include buffer v4 instead of the default v5 by either doing :

browserify -r buffer/:buffer main.js -o bundle.js

or

browserify().require(require.resolve('buffer/'), { expose: 'buffer' })

API

Class: BlobSlicer

new BlobSlicer(blob)
Throws error if blob is not an instance of Blob or File.

blobSlicer.read([start], [end], callback)
Read a range of bytes delimited by start(inclusive) and end(exclusive).
If end is not specified, it reads all bytes from start to the end of blob.
If start and end are not specified, it reads all data in the blob.
The callback is passed two arguments (err: Error, buf: Buffer).

blobSlicer.createReadStream([options])
options may be omitted, the default is {highWaterMark: 64 * 1024, start: 0, end: blob.size}.
options.start is inclusive, options.end is exclusive.
Return an instance of ReadStream.

Class: ReadStream

An implementation of Readable Streams.

readStream.readableLength: number
same as in stream_readable_readablelength

readStream.ended: boolean
true if reached the end of blob (there may be still some bytes in the queue ready to be consumed).

License

MIT. Copyright (c) Hoummad Merzouqi.