node-expat

Motivation

You use Node.js for speed? You process XML streams? Then you want the fastest XML parser: libexpat!

Install

npm install node-expat

Usage

Important events emitted by a parser:

(function () {
  "use strict";

  var expat = require('node-expat')
  var parser = new expat.Parser('UTF-8')

  parser.on('startElement', function (name, attrs) {
    console.log(name, attrs)
  })

  parser.on('endElement', function (name) {
    console.log(name)
  })

  parser.on('text', function (text) {
    console.log(text)
  })

  parser.on('error', function (error) {
    console.error(error)
  })

  parser.write('<html><head><title>Hello World</title></head><body><p>Foobar</p></body></html>')

}())

API

#on('startElement' function (name, attrs) {})
#on('endElement' function (name) {})
#on('text' function (text) {})
#on('processingInstruction', function (target, data) {})
#on('comment', function (s) {})
#on('xmlDecl', function (version, encoding, standalone) {})
#on('startCdata', function () {})
#on('endCdata', function () {})
#on('entityDecl', function (entityName, isParameterEntity, value, base, systemId, publicId, notationName) {})
#on('error', function (e) {})
#stop() pauses
#resume() resumes

Error handling

We don't emit an error event because libexpat doesn't use a callback either. Instead, check that parse() returns true. A descriptive string can be obtained via getError() to provide user feedback.

Alternatively, use the Parser like a node Stream. write() will emit error events.

Namespace handling

A word about special parsing of xmlns: this is not necessary in a bare SAX parser like this, given that the DOM replacement you are using (if any) is not relevant to the parser.

Benchmark

npm run benchmark

module	ops/sec	native	XML compliant	stream
sax-js	99,412	☐	☑	☑
node-xml	130,631	☐	☑	☑
libxmljs	276,136	☑	☑	☐
node-expat	322,769	☑	☑	☑

Higher is better.

Testing

npm install -g standard
npm test

Windows

If you fail to install node-expat as a dependency of node-xmpp, please update node-xmpp as it doesn't use node-expat anymore.

Dependencies for node-gyp https://github.com/TooTallNate/node-gyp#installation

See https://github.com/astro/node-expat/issues/78 if you are getting errors about not finding nan.h.

expat.vcproj

VCBUILD : error : project file 'node-expat\build\deps\libexpat\expat.vcproj' was not found or not a valid proj
ect file. [C:\Users\admin\AppData\Roaming\npm\node_modules\node-expat\build\bin
ding.sln]

Install Visual Studio C++ 2012 and run npm with the --msvs_version=2012 flag.

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