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src/node_modules/xmlrpc/node_modules/sax/README.md
1 # sax js
2 
3 A sax-style parser for XML and HTML.
4 
5 Designed with [node](http://nodejs.org/) in mind, but should work fine in
6 the browser or other CommonJS implementations.
7 
8 ## What This Is
9 
10 * A very simple tool to parse through an XML string.
11 * A stepping stone to a streaming HTML parser.
12 * A handy way to deal with RSS and other mostly-ok-but-kinda-broken XML
13  docs.
14 
15 ## What This Is (probably) Not
16 
17 * An HTML Parser - That's a fine goal, but this isn't it. It's just
18  XML.
19 * A DOM Builder - You can use it to build an object model out of XML,
20  but it doesn't do that out of the box.
21 * XSLT - No DOM = no querying.
22 * 100% Compliant with (some other SAX implementation) - Most SAX
23  implementations are in Java and do a lot more than this does.
24 * An XML Validator - It does a little validation when in strict mode, but
25  not much.
26 * A Schema-Aware XSD Thing - Schemas are an exercise in fetishistic
27  masochism.
28 * A DTD-aware Thing - Fetching DTDs is a much bigger job.
29 
30 ## Regarding `<!DOCTYPE`s and `<!ENTITY`s
31 
32 The parser will handle the basic XML entities in text nodes and attribute
33 values: `&amp; &lt; &gt; &apos; &quot;`. It's possible to define additional
34 entities in XML by putting them in the DTD. This parser doesn't do anything
35 with that. If you want to listen to the `ondoctype` event, and then fetch
36 the doctypes, and read the entities and add them to `parser.ENTITIES`, then
37 be my guest.
38 
39 Unknown entities will fail in strict mode, and in loose mode, will pass
40 through unmolested.
41 
42 ## Usage
43 
44 ```javascript
45 var sax = require("./lib/sax"),
46  strict = true, // set to false for html-mode
47  parser = sax.parser(strict);
48 
49 parser.onerror = function (e) {
50  // an error happened.
51 };
52 parser.ontext = function (t) {
53  // got some text. t is the string of text.
54 };
55 parser.onopentag = function (node) {
56  // opened a tag. node has "name" and "attributes"
57 };
58 parser.onattribute = function (attr) {
59  // an attribute. attr has "name" and "value"
60 };
61 parser.onend = function () {
62  // parser stream is done, and ready to have more stuff written to it.
63 };
64 
65 parser.write('<xml>Hello, <who name="world">world</who>!</xml>').close();
66 
67 // stream usage
68 // takes the same options as the parser
69 var saxStream = require("sax").createStream(strict, options)
70 saxStream.on("error", function (e) {
71  // unhandled errors will throw, since this is a proper node
72  // event emitter.
73  console.error("error!", e)
74  // clear the error
75  this._parser.error = null
76  this._parser.resume()
77 })
78 saxStream.on("opentag", function (node) {
79  // same object as above
80 })
81 // pipe is supported, and it's readable/writable
82 // same chunks coming in also go out.
83 fs.createReadStream("file.xml")
84  .pipe(saxStream)
85  .pipe(fs.createWriteStream("file-copy.xml"))
86 ```
87 
88 
89 ## Arguments
90 
91 Pass the following arguments to the parser function. All are optional.
92 
93 `strict` - Boolean. Whether or not to be a jerk. Default: `false`.
94 
95 `opt` - Object bag of settings regarding string formatting. All default to `false`.
96 
97 Settings supported:
98 
99 * `trim` - Boolean. Whether or not to trim text and comment nodes.
100 * `normalize` - Boolean. If true, then turn any whitespace into a single
101  space.
102 * `lowercase` - Boolean. If true, then lowercase tag names and attribute names
103  in loose mode, rather than uppercasing them.
104 * `xmlns` - Boolean. If true, then namespaces are supported.
105 * `position` - Boolean. If false, then don't track line/col/position.
106 * `strictEntities` - Boolean. If true, only parse [predefined XML
107  entities](http://www.w3.org/TR/REC-xml/#sec-predefined-ent)
108  (`&amp;`, `&apos;`, `&gt;`, `&lt;`, and `&quot;`)
109 
110 ## Methods
111 
112 `write` - Write bytes onto the stream. You don't have to do this all at
113 once. You can keep writing as much as you want.
114 
115 `close` - Close the stream. Once closed, no more data may be written until
116 it is done processing the buffer, which is signaled by the `end` event.
117 
118 `resume` - To gracefully handle errors, assign a listener to the `error`
119 event. Then, when the error is taken care of, you can call `resume` to
120 continue parsing. Otherwise, the parser will not continue while in an error
121 state.
122 
123 ## Members
124 
125 At all times, the parser object will have the following members:
126 
127 `line`, `column`, `position` - Indications of the position in the XML
128 document where the parser currently is looking.
129 
130 `startTagPosition` - Indicates the position where the current tag starts.
131 
132 `closed` - Boolean indicating whether or not the parser can be written to.
133 If it's `true`, then wait for the `ready` event to write again.
134 
135 `strict` - Boolean indicating whether or not the parser is a jerk.
136 
137 `opt` - Any options passed into the constructor.
138 
139 `tag` - The current tag being dealt with.
140 
141 And a bunch of other stuff that you probably shouldn't touch.
142 
143 ## Events
144 
145 All events emit with a single argument. To listen to an event, assign a
146 function to `on<eventname>`. Functions get executed in the this-context of
147 the parser object. The list of supported events are also in the exported
148 `EVENTS` array.
149 
150 When using the stream interface, assign handlers using the EventEmitter
151 `on` function in the normal fashion.
152 
153 `error` - Indication that something bad happened. The error will be hanging
154 out on `parser.error`, and must be deleted before parsing can continue. By
155 listening to this event, you can keep an eye on that kind of stuff. Note:
156 this happens *much* more in strict mode. Argument: instance of `Error`.
157 
158 `text` - Text node. Argument: string of text.
159 
160 `doctype` - The `<!DOCTYPE` declaration. Argument: doctype string.
161 
162 `processinginstruction` - Stuff like `<?xml foo="blerg" ?>`. Argument:
163 object with `name` and `body` members. Attributes are not parsed, as
164 processing instructions have implementation dependent semantics.
165 
166 `sgmldeclaration` - Random SGML declarations. Stuff like `<!ENTITY p>`
167 would trigger this kind of event. This is a weird thing to support, so it
168 might go away at some point. SAX isn't intended to be used to parse SGML,
169 after all.
170 
171 `opentagstart` - Emitted immediately when the tag name is available,
172 but before any attributes are encountered. Argument: object with a
173 `name` field and an empty `attributes` set. Note that this is the
174 same object that will later be emitted in the `opentag` event.
175 
176 `opentag` - An opening tag. Argument: object with `name` and `attributes`.
177 In non-strict mode, tag names are uppercased, unless the `lowercase`
178 option is set. If the `xmlns` option is set, then it will contain
179 namespace binding information on the `ns` member, and will have a
180 `local`, `prefix`, and `uri` member.
181 
182 `closetag` - A closing tag. In loose mode, tags are auto-closed if their
183 parent closes. In strict mode, well-formedness is enforced. Note that
184 self-closing tags will have `closeTag` emitted immediately after `openTag`.
185 Argument: tag name.
186 
187 `attribute` - An attribute node. Argument: object with `name` and `value`.
188 In non-strict mode, attribute names are uppercased, unless the `lowercase`
189 option is set. If the `xmlns` option is set, it will also contains namespace
190 information.
191 
192 `comment` - A comment node. Argument: the string of the comment.
193 
194 `opencdata` - The opening tag of a `<![CDATA[` block.
195 
196 `cdata` - The text of a `<![CDATA[` block. Since `<![CDATA[` blocks can get
197 quite large, this event may fire multiple times for a single block, if it
198 is broken up into multiple `write()`s. Argument: the string of random
199 character data.
200 
201 `closecdata` - The closing tag (`]]>`) of a `<![CDATA[` block.
202 
203 `opennamespace` - If the `xmlns` option is set, then this event will
204 signal the start of a new namespace binding.
205 
206 `closenamespace` - If the `xmlns` option is set, then this event will
207 signal the end of a namespace binding.
208 
209 `end` - Indication that the closed stream has ended.
210 
211 `ready` - Indication that the stream has reset, and is ready to be written
212 to.
213 
214 `noscript` - In non-strict mode, `<script>` tags trigger a `"script"`
215 event, and their contents are not checked for special xml characters.
216 If you pass `noscript: true`, then this behavior is suppressed.
217 
218 ## Reporting Problems
219 
220 It's best to write a failing test if you find an issue. I will always
221 accept pull requests with failing tests if they demonstrate intended
222 behavior, but it is very hard to figure out what issue you're describing
223 without a test. Writing a test is also the best way for you yourself
224 to figure out if you really understand the issue you think you have with
225 sax-js.