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- # sax js
-
- A sax-style parser for XML and HTML.
-
- Designed with [node](http://nodejs.org/) 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 `<!DOCTYPE`s and `<!ENTITY`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('<xml>Hello, <who name="world">world</who>!</xml>').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](http://www.w3.org/TR/REC-xml/#sec-predefined-ent)
- (`&`, `'`, `>`, `<`, and `"`)
-
- ## 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<eventname>`. 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 `<!DOCTYPE` declaration. Argument: doctype string.
-
- `processinginstruction` - Stuff like `<?xml foo="blerg" ?>`. Argument:
- object with `name` and `body` members. Attributes are not parsed, as
- processing instructions have implementation dependent semantics.
-
- `sgmldeclaration` - Random SGML declarations. Stuff like `<!ENTITY p>`
- 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 `<![CDATA[` block.
-
- `cdata` - The text of a `<![CDATA[` block. Since `<![CDATA[` 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 `<![CDATA[` 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, `<script>` tags trigger a `"script"`
- event, and their contents are not checked for special xml characters.
- If you pass `noscript: true`, then this behavior is suppressed.
-
- ## Reporting Problems
-
- It's best to write a failing test if you find an issue. I will always
- accept pull requests with failing tests if they demonstrate intended
- behavior, but it is very hard to figure out what issue you're describing
- without a test. Writing a test is also the best way for you yourself
- to figure out if you really understand the issue you think you have with
- sax-js.
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