sax js

A sax-style parser for XML and HTML.

Designed with node in mind, but should work fine in
the browser or other CommonJS implementations.

What This Is

- A very simple tool to parse through an XML string.
- A stepping stone to a streaming HTML parser.
- A handy way to deal with RSS and other mostly-ok-but-kinda-broken XML
docs.

What This Is (probably) Not

- An HTML Parser - That's a fine goal, but this isn't it. It's just
XML.
- A DOM Builder - You can use it to build an object model out of XML,
but it doesn't do that out of the box.
- XSLT - No DOM = no querying.
- 100% Compliant with (some other SAX implementation) - Most SAX
implementations are in Java and do a lot more than this does.
- An XML Validator - It does a little validation when in strict mode, but
not much.
- A Schema-Aware XSD Thing - Schemas are an exercise in fetishistic
masochism.
- A DTD-aware Thing - Fetching DTDs is a much bigger job.

Regarding s and s

The parser will handle the basic XML entities in text nodes and attribute
values: & < > ' ". It's possible to define additional
entities in XML by putting them in the DTD. This parser doesn't do anything
with that. If you want to listen to the ondoctype event, and then fetch
the doctypes, and read the entities and add them to parser.ENTITIES, then
be my guest.

Unknown entities will fail in strict mode, and in loose mode, will pass
through unmolested.

Usage

``javascript
var sax = require('./lib/sax'),
strict = true, // set to false for html-mode
parser = sax.parser(strict)

parser.onerror = function (e) {
// an error happened.
}
parser.ontext = function (t) {
// got some text. t is the string of text.
}
parser.onopentag = function (node) {
// opened a tag. node has "name" and "attributes"
}
parser.onattribute = function (attr) {
// an attribute. attr has "name" and "value"
}
parser.onend = function () {
// parser stream is done, and ready to have more stuff written to it.
}

parser.write('Hello, world!').close()

// stream usage
// takes the same options as the parser
var saxStream = require('sax').createStream(strict, options)
saxStream.on('error', function (e) {
// unhandled errors will throw, since this is a proper node
// event emitter.
console.error('error!', e)
// clear the error
this._parser.error = null
this._parser.resume()
})
saxStream.on('opentag', function (node) {
// same object as above
})
// pipe is supported, and it's readable/writable
// same chunks coming in also go out.
fs.createReadStream('file.xml')
.pipe(saxStream)
.pipe(fs.createWriteStream('file-copy.xml'))
`

Arguments

Pass the following arguments to the parser function. All are optional.

strict - Boolean. Whether or not to be a jerk. Default: false.

opt - Object bag of settings regarding string formatting. All default to false.

Settings supported:

- trim - Boolean. Whether or not to trim text and comment nodes.
- normalize - Boolean. If true, then turn any whitespace into a single
space.
- lowercase - Boolean. If true, then lowercase tag names and attribute names
in loose mode, rather than uppercasing them.
- xmlns - Boolean. If true, then namespaces are supported.
- position - Boolean. If false, then don't track line/col/position.
- strictEntities - Boolean. If true, only parse predefined XML
entities
(&, ', >, <, and ")
- unquotedAttributeValues - Boolean. If true, then unquoted
attribute values are allowed. Defaults to false when strict
is true, true otherwise.

Methods

write - Write bytes onto the stream. You don't have to do this all at
once. You can keep writing as much as you want.

close - Close the stream. Once closed, no more data may be written until
it is done processing the buffer, which is signaled by the end event.

resume - To gracefully handle errors, assign a listener to the error
event. Then, when the error is taken care of, you can call resume to
continue parsing. Otherwise, the parser will not continue while in an error
state.

Members

At all times, the parser object will have the following members:

line, column, position - Indications of the position in the XML
document where the parser currently is looking.

startTagPosition - Indicates the position where the current tag starts.

closed - Boolean indicating whether or not the parser can be written to.
If it's true, then wait for the ready event to write again.

strict - Boolean indicating whether or not the parser is a jerk.

opt - Any options passed into the constructor.

tag - The current tag being dealt with.

And a bunch of other stuff that you probably shouldn't touch.

Events

All events emit with a single argument. To listen to an event, assign a
function to on. Functions get executed in the this-context of
the parser object. The list of supported events are also in the exported
EVENTS array.

When using the stream interface, assign handlers using the EventEmitter
on function in the normal fashion.

error - Indication that something bad happened. The error will be hanging
out on parser.error, and must be deleted before parsing can continue. By
listening to this event, you can keep an eye on that kind of stuff. Note:
this happens _much_ more in strict mode. Argument: instance of Error.

text - Text node. Argument: string of text.

doctype - The declaration. Argument: doctype string.

processinginstruction - Stuff like . Argument:
object with name and body members. Attributes are not parsed, as
processing instructions have implementation dependent semantics.

sgmldeclaration - Random SGML declarations. Stuff like
would trigger this kind of event. This is a weird thing to support, so it
might go away at some point. SAX isn't intended to be used to parse SGML,
after all.

opentagstart - Emitted immediately when the tag name is available,
but before any attributes are encountered. Argument: object with a
name field and an empty attributes set. Note that this is the
same object that will later be emitted in the opentag event.

opentag - An opening tag. Argument: object with name and attributes.
In non-strict mode, tag names are uppercased, unless the lowercase
option is set. If the xmlns option is set, then it will contain
namespace binding information on the ns member, and will have a
local, prefix, and uri member.

closetag - A closing tag. In loose mode, tags are auto-closed if their
parent closes. In strict mode, well-formedness is enforced. Note that
self-closing tags will have closeTag emitted immediately after openTag.
Argument: tag name.

attribute - An attribute node. Argument: object with name and value.
In non-strict mode, attribute names are uppercased, unless the lowercase
option is set. If the xmlns option is set, it will also contains namespace
information.

comment - A comment node. Argument: the string of the comment.

opencdata - The opening tag of a block.

cdata - The text of a block. Since blocks can get
quite large, this event may fire multiple times for a single block, if it
is broken up into multiple write()s. Argument: the string of random
character data.

closecdata - The closing tag (]]>) of a block.

opennamespace - If the xmlns option is set, then this event will
signal the start of a new namespace binding.

closenamespace - If the xmlns option is set, then this event will
signal the end of a namespace binding.

end - Indication that the closed stream has ended.

ready - Indication that the stream has reset, and is ready to be written
to.

noscript - In non-strict mode,