sax-jsvschopper
sax-js is a streaming XML parser for Node.js that is built on top of the sax C library. It is designed to be fast, low-memory, and easy to use. It is commonly used for parsing large XML files, as it allows you to process the XML data incrementally, rather than loading the entire file into memory at once.
sax-js is a low-level html tree parser and does not provide html query capabilities (like CSS selectors) though it can be useful in HTML tree parsing and serialization.
Chopper is a tool to extract elements from HTML by preserving ancestors and CSS rules.
Compared to other HTML parsers Chopper is designed to retain original HTML tree but eliminate elements that do not match parsing rules. Meaning, we can parse HTML elements and keep thei structure for machine learning or other tasks where data structure is needed as well as the data value.
Example Use
const fs = require("fs");
const sax = require("sax");
const xmlStream = fs.createReadStream("example.xml");
const saxParser = sax.createStream(true, {});
saxParser.on("opentag", function(node) {
console.log(`<${node.name}>`);
});
saxParser.on("closetag", function(nodeName) {
console.log(`</${nodeName}>`);
});
saxParser.on("text", function(text) {
console.log(text);
});
xmlStream.pipe(saxParser);
HTML = """
<html>
<head>
<title>Test</title>
</head>
<body>
<div id="header"></div>
<div id="main">
<div class="iwantthis">
HELLO WORLD
<a href="/nope">Do not want</a>
</div>
</div>
<div id="footer"></div>
</body>
</html>
"""
CSS = """
div { border: 1px solid black; }
div#main { color: blue; }
div.iwantthis { background-color: red; }
a { color: green; }
div#footer { border-top: 2px solid red; }
"""
extractor = Extractor.keep('//div[@class="iwantthis"]').discard('//a')
html, css = extractor.extract(HTML, CSS)
# will result in:
html
"""
<html>
<body>
<div id="main">
<div class="iwantthis">
HELLO WORLD
</div>
</div>
</body>
</html>"""
css
"""
div{border:1px solid black;}
div#main{color:blue;}
div.iwantthis{background-color:red;}
"""