pbf

A low-level, lightweight protocol buffers implementation in JavaScript for Node and browsers.

Designed to be a building block for writing a customized, lazy decoder for a stable protobuf schema. If you need an easy-to-use, all-purpose protobuf JS library that does most of the work for you, take a look at protocol-buffers.

Install

Node and Browserify:

npm install pbf

Making a browser build:

npm install
npm run build-dev # pbf-dev.js (development build)
npm run build-min # pbf.js (minified production build)

Example

Reading:

var pbf = new Pbf(buffer),
    name, version, layerName;

pbf.readFields(function(tag) {
    if (tag === 1) name = pbf.readString();
    else if (tag === 2) version = pbf.readVarint();
    else if (tag === 3) {
        pbf.readMessage(function(tag) {
            if (tag === 1) layerName = pbf.readString();
        });
    }
    return result;
});

Writing:

var pbf = new Pbf();

pbf.writeStringField(1, 'Hello world');
pbf.writeVarintField(2, 300);

var layer = new Pbf();
layer.writeStringField(1, 'foobar');

pbf.writeMessage(3, layer);

var buffer = pbf.finish();

API

Create a buffer:

var pbf = Protobuf(/*Buffer*/ buf);

Get buffer length:

pbf.length;

Reading

Read a sequence of fields:

pbf.readFields(function (tag) {
    if (tag === 1) pbf.readVarint();
    else if (tag === 2) pbf.readString();
    else ...
});

To read an embedded message, use pbf.readMessage(fn) (in the same way as read).

Read values:

var value = pbf.readVarint();
var packed = pbf.readPacked('UInt32');

Basic reading methods:

• readVarint()
• readSVarint()
• readFixed32()
• readFixed64()
• readBoolean()
• readFloat()
• readDouble()
• readString()
• readBytes()
• readPacked(type)
• skip(value)

Writing

Write values:

pbf.writeVarint(123);
pbf.writeString("Hello world");

Writing methods:

• writeVarintField(tag, val)
• writeSVarintField(tag, val)
• writeFixed32Field(tag, val)
• writeFixed64Field(tag, val)
• writeBooleanField(tag, val)
• writeFloatField(tag, val)
• writeDoubleField(tag, val)
• writeStringField(tag, val)
• writeBytesField(tag, buffer)
• writePacked(type, tag, items)
• writeVarint(val)
• writeSVarint(val)
• writeFixed32(val)
• writeFixed64(val)
• writeFloat(val)
• writeDouble(val)
• writeString(val)
• writeBytes(buffer)
• writeMessage(tag, pbf)

Misc methods:

• realloc(minBytes) - pad the underlying buffer size to accommodate the given number of bytes
• finish() - make the current buffer ready for reading and return the data as a buffer slice
• destroy() - disposes the buffer

For an example of a real-world usage of the library, see vector-tile-js.