Spud

Lead Maintainer: Aria Stewart

Load and convert content bundles to and from different formats, including .properties, .json, etc.

API

spud.registerSerializer(name, serializer)

Register a custom serializer. See the "Plugins" section below for more information on custom serializers

var mySerializer = require('node-mySerializer');
require('spud').registerSerializer('mySerializer', mySerializer);

spud.convert(source, sourceType, targetType, [writeStream], [callback])

Deserializes the source (file, buffer, or Read Stream) of type sourceType and serializes to targetType, writing the results to the optional writeStream, or providing them to the optional callback. The callback should have the signature function (err, data);

var spud = require('spud'),
	fs = require('fs'),
	readStream = fs.createReadStream('./config.json'),
	writeStream = fs.createWriteStream('./config.properties');

spud.convert(readStream, 'json', 'properties', writeStream, function (err) {
	console.log('Conversion complete.');
});

spud.deserialize(source, sourceType, callback)

Deserializes the source (file, buffer, or Read Stream) of type sourceType and invokes the provided callback with the result or any error that occurred. The callback should have the signature function (err, data);

var spud = require('spud'),
	fs = require('fs'),
	readStream = fs.createReadStream('./config.json');

spud.deserialize(readStream, 'json', function (err, data) {
	console.log(err || data);
	console.log('Conversion complete.');
});

spud.serialize(source, targetType, [writeStream], [callback])

Serializes the source (String) to targetType and invokes the provided callback with the result or any error that occurred. The callback should have the signature function (err, data);

var spud = require('spud'),
	fs = require('fs'),
	writeStream = fs.createWriteStream('./config.json');

var settings = {
	host: "www.paypal.com",
	port: 8080
};

spud.serialize(settings, 'json', writeStream, function (err) {
	console.log('Conversion complete.');
});

Serializers supported out of the box

properties: Java-style properties files, treated as UTF-8. Some effort is made build a richer object model from structured keys.

value=A Value
array[0]=First Entry
array[1]=Second Entry
map[US]=United States
map[GB]=United Kingdom
include=../file.properties

json: A simple, direct output of the data structure as JSON

{
    "value": "A Value",
    "array": [
        "First Entry",
        "Second Entry"
    ],
    "map": {
        "US": "United States",
        "GB": "United Kingdom"
    },
    "include": "../file.json"
}

Includes are processed at load time, using paths resolved relative to the source files, just like paths in require(modulename). Which serializer is used is controlled by the file extension.

Plugins

Writing serializers is easy. It's just 3 steps:

1. Make sure your module exports an object with a property called 'Reader' and one called 'Writer' whose values are the constructors for your deserializer and serialzer, respectively:

// index.js
module.exports = {
	Reader: MyReader,
	Writer: MyWriter
};

2. Build out your deserializer implementation. It merely needs to implement a method called _doDeserialize that accepts data (in the form of a string) and callback arguments, and invokes the callback with error and deserialized data.

function MyReader() {
    MyReader.super_.call(this);
}

util.inherits(MyReader, spud.AbstractReader);

MyReader.prototype._doDeserialize = function(input, callback) {
    // TODO: Implement
    var data = null;
    // ...
    callback(null, data);
};

3. Build out your serializer implementation and a Read Stream for outputting the serialized data.

function MyWriter() {
    MyWriter.super_.call(this);
}

util.inherits(MyWriter, spud.AbstractWriter);

MyWriter.prototype._doCreateReadStream = function (data) {
    return new CustomReadStream(data);
};

The stream must accept a data object in its constructor and implement the NodeJS Read Stream interface. It is likely that this where your serialization implementation will go. When chunks of data are availble/serialized, write them out using the 'data' event.

var util = require('util');

function CustomReadStream(data) {
	Stream.call(this);
	this._data = data;
}
util.inherits(ReadStream, Stream);

MyStream.prototype._read = function (size) {
	var serialized = null;
	// TODO: Serialize this._data
	this.push(serialized);
};