🛠️ About This Fork

This is a fork of avsc created to improve Content Security Policy (CSP) compliance for secure web environments.

🚨 Why Fork?

The original package builds its record constructors, checkers, readers, writers, resolvers, and RPC message handlers at runtime using dynamic code generation (new Function()), which is blocked under CSP unless unsafe-eval is allowed. This presents security concerns for browser-based applications that enforce strict CSP rules.

✅ What Was Changed

• 🔁 Replaced every use of new Function() in lib/types.js and lib/services.js with plain closures.
• 🧪 Added a newSlowBuffer helper in lib/utils.js (using Buffer.allocUnsafeSlow, with a fallback to SlowBuffer) and explicit Buffer imports, so buffers work consistently in browser bundles.
• 🔒 Schema parsing, encoding, decoding, and schema resolution can now run in environments with strict CSP.

Avsc

Pure JavaScript implementation of the Avro specification.

Features

• Blazingly fast and compact serialization! Typically faster than JSON with much smaller encodings.
• All the Avro goodness and more: type inference, schema evolution, and remote procedure calls.
• Support for serializing arbitrary JavaScript objects.
• Unopinionated 64-bit integer compatibility.

Installation

$ npm install avsc-csp-compatibility

avsc is compatible with all versions of node.js since 0.11.

Documentation

• Home
• API
• Quickstart
• Advanced usage
• Benchmarks

Examples

Inside a node.js module, or using browserify:

const avro = require('avsc-csp-compatibility');

• Encode and decode values from a known schema:

  const type = avro.Type.forSchema({
    type: 'record',
    name: 'Pet',
    fields: [
      {
        name: 'kind',
        type: {type: 'enum', name: 'PetKind', symbols: ['CAT', 'DOG']}
      },
      {name: 'name', type: 'string'}
    ]
  });
  
  const buf = type.toBuffer({kind: 'CAT', name: 'Albert'}); // Encoded buffer.
  const val = type.fromBuffer(buf); // = {kind: 'CAT', name: 'Albert'}

• Infer a value's schema and encode similar values:

  const type = avro.Type.forValue({
    city: 'Cambridge',
    zipCodes: ['02138', '02139'],
    visits: 2
  });
  
  // We can use `type` to encode any values with the same structure:
  const bufs = [
    type.toBuffer({city: 'Seattle', zipCodes: ['98101'], visits: 3}),
    type.toBuffer({city: 'NYC', zipCodes: [], visits: 0})
  ];

• Get a readable stream of decoded values from an Avro container file compressed using Snappy (see the BlockDecoder API for an example including checksum validation):

  const snappy = require('snappy'); // Or your favorite Snappy library.
  const codecs = {
    snappy: function (buf, cb) {
      // Avro appends checksums to compressed blocks, which we skip here.
      return snappy.uncompress(buf.slice(0, buf.length - 4), cb);
    }
  };
  
  avro.createFileDecoder('./values.avro', {codecs})
    .on('metadata', function (type) { /* `type` is the writer's type. */ })
    .on('data', function (val) { /* Do something with the decoded value. */ });

• Implement a TCP server for an IDL-defined protocol:

  // We first generate a protocol from its IDL specification.
  const protocol = avro.readProtocol(`
    protocol LengthService {
      /** Endpoint which returns the length of the input string. */
      int stringLength(string str);
    }
  `);
  
  // We then create a corresponding server, implementing our endpoint.
  const server = avro.Service.forProtocol(protocol)
    .createServer()
    .onStringLength(function (str, cb) { cb(null, str.length); });
  
  // Finally, we use our server to respond to incoming TCP connections!
  require('net').createServer()
    .on('connection', (con) => { server.createChannel(con); })
    .listen(24950);