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    digest-stream

    2.0.0 • Public • Published

    digest-stream

    Simple node.js pass-through stream (RW) which calculates the a crypto digest (sha/md5 hash) of a stream and also the length. Pipe your stream through this to get digest and length. (streams2)

    Build Status

    Installation

    npm install digest-stream

    Usage

    Provide a the digest algorithm, optional input encoding, digest encoding, and a listener function when you construct the stream. The listener will be called with the resultant digest and length of the stream just prior to end being emitted.

    Since this uses the node.js crypto package, refer to http://nodejs.org/api/crypto.html for the specific options available.

    • digestStream(algorithm, [inputEncoding,] digestEncoding, [options], listenerFn) - constructs a new stream instance, the listenerFn will be called prior to the end event being emitted. inputEncoding is optional and defaults to binary if not provided.
    • options - optional streams options
    • listenerFn function signature is fn(digest, dataLength) - digest is the digest for the stream data in the digest encoding format specified when instance was created. dataLength is the length of the data in the stream (provided for convenience). If listenerFn returns an object that is an instance of Error, then the error will be signaled in the stream.
    var digestStream = require('digest-stream');
    var digest;
    var dataLength;
    function listenerFn(resultDigest, length) {
      digest = resultDigest;
      dataLength = length;
    }
    var dstream = digestStream('sha1', 'hex', listenerFn); // create instance
    readstream
      .pipe(dstream) // digest and length calculated as it passes through
      .pipe(...)

    Goals

    • Easy to use pass-through stream which calculates the digest and length of string or Buffer streamlength of the string
    • Builds on pass-stream to have all the normal pass-through functionality for a spec compliant stream
    • works with node 0.10+ streams2 but is also compatible with 0.8

    Why

    By making this simple pass-through stream which calculates the digest and length of a stream, it becomes really easy to add this functionality to a streaming workflow, just by piping it through this stream, the digest and length will be available prior to end being fired.

    Changes

    • v1.0.0 - listenerFn can return an instance of Error and it will be signaled to the stream

    Get involved

    If you have input or ideas or would like to get involved, you may:

    License

    Install

    npm i digest-stream

    DownloadsWeekly Downloads

    7,833

    Version

    2.0.0

    License

    none

    Last publish

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