DOM_QUERY is a flexible Rust crate that simplifies HTML parsing, DOM querying and manipulation by providing a high-level jQuery-like API. It uses the html5ever crate for HTML parsing and the selectors crate for efficient DOM traversal and element selection.
- Parse HTML documents and fragments
- Query DOM elements using CSS selectors
- Traverse the DOM tree (ancestors, parents, children, siblings)
- Manipulate elements and their attributes:
- Add/remove/modify attributes
- Change element content
- Add/remove elements
- Rename elements
- Move elements within the DOM tree
Note
This crate is a significantly enhanced fork of nipper, featuring expanded CSS selector support, enhanced DOM traversal and improved DOM manipulation capabilities.
Parsing a document
use dom_query::Document;
use tendril::StrTendril;
// Document may consume &str, String, StrTendril
let contents_str = r#"<!DOCTYPE html>
<html><head><title>Test Page</title></head><body></body></html>"#;
let doc = Document::from(contents_str);
let contents_string = contents_str.to_string();
let doc = Document::from(contents_string);
let contents_tendril = StrTendril::from(contents_str);
let doc = Document::from(contents_tendril);
// The root element for the `Document` is a Document
assert!(doc.root().is_document());
// if the source has DocType, then the Document will also have one
// as a first child.
assert!(doc.root().first_child().unwrap().is_doctype());
//both of them are not elements.Parsing a fragment
use dom_query::Document;
use tendril::StrTendril;
// fragment can be created with Document::fragment(), which accepts &str, String, StrTendril
let contents_str = r#"<!DOCTYPE html>
<html><head><title>Test Page</title></head><body></body></html>"#;
let fragment = Document::fragment(contents_str);
let contents_string = contents_str.to_string();
let fragment = Document::fragment(contents_string);
let contents_tendril = StrTendril::from(contents_str);
let fragment = Document::fragment(contents_tendril);
// The root element for the fragment is not a Document but a Fragment
assert!(!fragment.root().is_document());
assert!(fragment.root().is_fragment());
// and when it parses a fragment, it drops Doctype
assert!(!fragment.root().first_child().unwrap().is_doctype());Selecting elements
use dom_query::Document;
let html = r#"<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Test Page</title>
</head>
<body>
<h1>Test Page</h1>
<ul>
<li>One</li>
<li><a href="/2">Two</a></li>
<li><a href="/3">Three</a></li>
</ul>
</body>
</html>"#;
let document = Document::from(html);
// select a single element
let a = document.select("ul li:nth-child(2)");
let text = a.text().to_string();
assert!(text == "Two");
// selecting multiple elements
document.select("ul > li:has(a)").iter().for_each(|el| {
assert!(el.is("li"));
})
// there is also `try_select` which returns an Option
let no_sel = document.try_select("p");
assert!(no_sel.is_none());Selecting a single match and multiple matches
use dom_query::Document;
let doc: Document = r#"<!DOCTYPE html>
<html lang="en">
<head></head>
<body>
<ul class="list">
<li>1</li><li>2</li><li>3</li>
</ul>
<ul class="list">
<li>4</li><li>5</li><li>6</li>
</ul>
</body>
</html>"#
.into();
// if you need to select only the first, single match, you can use following:
let single_selection = doc.select_single(".list");
// access is only for the first matching:
assert_eq!(single_selection.length(), 1);
assert_eq!(single_selection.inner_html().to_string().trim(), "<li>1</li><li>2</li><li>3</li>");
// simple selection contains all matches:
let selection = doc.select(".list");
assert_eq!(selection.length(), 2);
// but if you call inner_html() on it, you will get the inner_html of the first match:
assert_eq!(selection.inner_html().to_string().trim(), "<li>1</li><li>2</li><li>3</li>");
//this approach is using the first node from nodes vec and `select_single` consumes one iteration instead.
let first_selection = doc.select(".list").first();
assert_eq!(first_selection.length(), 1);
assert_eq!(first_selection.inner_html().to_string().trim(), "<li>1</li><li>2</li><li>3</li>");
// this approach is consuming all nodes into vec at first, and then you can call `iter().next()` to get the first one.
let next_selection = doc.select(".list").iter().next().unwrap();
assert_eq!(next_selection.length(), 1);
assert_eq!(next_selection.inner_html().to_string().trim(), "<li>1</li><li>2</li><li>3</li>");
// currently, to get data from all matches you need to iterate over them, either:
let all_matched: String = selection.iter().map(|s| s.inner_html().trim().to_string()).collect();
assert_eq!(
all_matched,
"<li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li>"
);
// or:
let all_matched: String = selection.nodes().iter().map(|s| s.inner_html().trim().to_string()).collect();
/ which is more efficient.
assert_eq!(
all_matched,
"<li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li>"
);Selecting descendent elements
use dom_query::Document;
let html = r#"<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Test Page</title>
</head>
<body>
<h1>Test Page</h1>
<ul class="list-a">
<li>One</li>
<li><a href="/2">Two</a></li>
<li><a href="/3">Three</a></li>
</ul>
<ul class="list-b">
<li><a href="/4">Four</a></li>
</ul>
</body>
</html>"#;
let document = Document::from(html);
// select a parent element
let ul = document.select("ul");
// selecting multiple elements
ul.select("li").iter().for_each(|el| {
assert!(el.is("li"));
});
// also descendant selector may be specified starting from the parent elements
let el = ul.select("body ul.list-b li").first();
let text = el.text();
assert_eq!("Four", text.to_string());Selecting ancestors
use dom_query::Document;
let doc: Document = r#"<!DOCTYPE html>
<html>
<head>Test</head>
<body>
<div id="great-ancestor">
<div id="grand-parent">
<div id="parent">
<div id="child">Child</div>
</div>
</div>
</div>
</body>
</html>
"#.into();
// selecting an element
let child_sel = doc.select("#child");
assert!(child_sel.exists());
let child_node = child_sel.nodes().first().unwrap();
// getting all ancestors
let ancestors = child_node.ancestors(None);
let ancestor_sel = Selection::from(ancestors);
// or just: let ancestor_sel = child_sel.ancestors(None);
// in this case ancestors includes all ancestral nodes including html
// the root html element is presented in the ancestor selection
assert!(ancestor_sel.is("html"));
// also the direct parent of our starting node is presented
assert!(ancestor_sel.is("#parent"));
// `Selection::is` matches only the current selection without descending down the tree,
// so it won't match the #child node.
assert!(!ancestor_sel.is("#child"));
// if you don't require all ancestors, you can specify a number of ancestors you need -- `max_limit`
let ancestors = child_node.ancestors(Some(2));
let ancestor_sel = Selection::from(ancestors);
// in this case ancestors includes only two ancestral nodes: #grand-parent and #parent
assert!(ancestor_sel.is("#grand-parent #parent"));
assert!(!ancestor_sel.is("#great-ancestor"));Selecting with precompiled matchers (for reuse)
use dom_query::{Document, Matcher};
let html1 = r#"<!DOCTYPE html><html><head><title>Test Page 1</title></head><body></body></html>"#;
let html2 = r#"<!DOCTYPE html><html><head><title>Test Page 2</title></head><body></body></html>"#;
let doc1 = Document::from(html1);
let doc2 = Document::from(html2);
// create a matcher once, reuse on different documents
let title_matcher = Matcher::new("title").unwrap();
let title_el1 = doc1.select_matcher(&title_matcher);
assert_eq!(title_el1.text(), "Test Page 1".into());
let title_el2 = doc2.select_matcher(&title_matcher);
assert_eq!(title_el2.text(), "Test Page 2".into());
// selecting a single match
let title_single = doc1.select_single_matcher(&title_matcher);
assert_eq!(title_single.text(), "Test Page 1".into());Selecting with pseudo-classes (:has, :has-text, :contains, :only-text)
use dom_query::Document;
let html = include_str!("../test-pages/rustwiki_2024.html");
let doc = Document::from(html);
// searching list items inside a `tr` element which has a `a` element
// with title="Programming paradigm"
let paradigm_selection =
doc.select(
r#"table tr:has(a[title="Programming paradigm"]) td.infobox-data ul > li"#
);
println!("Rust programming paradigms:");
for item in paradigm_selection.iter() {
println!(" {}", item.text());
}
println!("{:-<50}", "");
//since `th` contains text "Paradigms" without sibling tags, we can use `:has-text` pseudo class
let influenced_by_selection =
doc.select(r#"table tr:has-text("Influenced by") + tr td ul > li > a"#);
println!("Rust influenced by:");
for item in influenced_by_selection.iter() {
println!(" {}", item.text());
}
println!("{:-<50}", "");
// Extract all links from the block that contains certain text.
// Since `foreign function interface` located in its own tag,
// we have to use `:contains` pseudo class
let links_selection =
doc.select(
r#"p:contains("Rust has a foreign function interface") a[href^="/"]"#
);
println!("Links in the FFI block:");
for item in links_selection.iter() {
println!(" {}", item.attr("href").unwrap());
}
println!("{:-<50}", "");
// :only-text selects an element that contains only a single text node,
// with no child elements.
// It can be combined with other pseudo-classes to achieve more specific selections.
// For example, to select a <div> inside an <a>
//that has no siblings and no child elements other than text.
println!("Single <div> inside an <a> with text only:");
for el in doc.select("a div:only-text:only-child").iter() {
println!("{}", el.text().trim());
}Serializing to HTML
use dom_query::Document;
let html = r#"<!DOCTYPE html>
<html>
<head><title>Test</title></head>
<body><div class="content"><h1>Test Page</h1></div></body>
</html>"#;
let doc = Document::from(html);
let heading_selector = doc.select("div.content");
// serializing including the outer html tag
let content = heading_selector.html();
assert_eq!(content.to_string(), r#"<div class="content"><h1>Test Page</h1></div>"#);
// serializing without the outer html tag
let inner_content = heading_selector.inner_html();
assert_eq!(inner_content.to_string(), "<h1>Test Page</h1>");
// there is also `try_html()` method, which returns an `Option<StrTendril>`,
// and if there is no matching selection it returns None
let opt_no_content = doc.select("div.no-content").try_html();
assert_eq!(opt_no_content, None);
//`html()` method will return an empty `StrTendril` if there is no matching selection
let no_content = doc.select("div.no-content").html();
assert_eq!(no_content, "".into());
//Same things works for `inner_html()` and `try_inner_html()` method.
assert_eq!(doc.select("div.no-content").try_inner_html(), None);
assert_eq!(doc.select("div.no-content").inner_html(), "".into());Accessing descendent text
use dom_query::Document;
let html = r#"<!DOCTYPE html>
<html>
<head><title>Test</title></head>
<body><div><h1>Test <span>Page</span></h1></div></body>
</html>"#;
let doc = Document::from(html);
let body_selection = doc.select("body div").first();
let text = body_selection.text();
assert_eq!(text.to_string(), "Test Page");Accessing immediate text
use dom_query::Document;
let html = r#"<!DOCTYPE html>
<html>
<head><title>Test</title></head>
<body><div><h1>Test <span>Page</span></h1></div></body>
</html>"#;
let doc = Document::from(html);
let body_selection = doc.select("body div h1").first();
// accessing immediate text without descendants
let text = body_selection.immediate_text();
assert_eq!(text.to_string(), "Test ");Manipulating the attribute of an HTML element
use dom_query::Document;
let html = r#"<!DOCTYPE html>
<html>
<head><title>Test</title></head>
<body><input hidden="" id="k" class="important" type="hidden" name="k" data-k="100"></body>
</html>"#;
let doc = Document::from(html);
let mut input_selection = doc.select("input[name=k]");
// get the value of attribute "data-k"
let val = input_selection.attr("data-k").unwrap();
assert_eq!(val.to_string(), "100");
// remove the attribute "data-k" from the element
input_selection.remove_attr("data-k");
// get the value of attribute "data-k", if missing, return default value
let val_or = input_selection.attr_or("data-k", "0");
assert_eq!(val_or.to_string(), "0");
// remove a list of attributes from the element
input_selection.remove_attrs(&["id", "class"]);
// set a attribute "data-k" with value "200"
input_selection.set_attr("data-k", "200");
assert_eq!(input_selection.html(), r#"<input hidden="" type="hidden" name="k" data-k="200">"#.into());
// check if attribute "hidden" exists on the element
let is_hidden = input_selection.has_attr("hidden");
assert!(is_hidden);
let has_title = input_selection.has_attr("title");
assert!(!has_title);
// remove all attributes from the element
input_selection.remove_all_attrs();
assert_eq!(input_selection.html(), r#"<input>"#.into());Manipulating the DOM
use dom_query::Document;
let html_contents = r#"<!DOCTYPE html>
<html>
<head><title>Test</title></head>
<body>
<div class="content">
</div>
<div class="remove-it">
Remove me
</div>
<div class="replace-it">
<div>Replace me</div>
</div>
</body>
</html>"#;;
let doc = Document::from(html_contents);
let mut content_selection = doc.select("body .content");
// append a new html node to the selection
content_selection.append_html(r#"<div class="inner">inner block</div>"#);
assert!(doc.select("body .content .inner").exists());
// set a new content to the selection, replacing existing content
let mut set_selection = doc.select(".inner");
set_selection.set_html(r#"<p>1,2,3</p>"#);
assert_eq!(doc.select(".inner").html(), r#"<div class="inner"><p>1,2,3</p></div>"#.into());
// remove the selection
doc.select(".remove-it").remove();
assert!(!doc.select(".remove-it").exists());
// replace the selection with a new html, current selection will not change.
let mut replace_selection = doc.select(".replace-it");
replace_selection.replace_with_html(r#"<div class="replaced">Replaced</div>"#);
assert_eq!(replace_selection.text().trim(), "Replace me");
//but the document will change
assert_eq!(doc.select(".replaced").text(),"Replaced".into());
//instead of appending content, you can prepend it
let mut content_selection = doc.select_single("body .content");
// you can prepend one element or,
content_selection.prepend_html(r#"<p class="third">3</p>"#);
// more:
content_selection.prepend_html(r#"<p class="first">2</p><p class="second">2</p>"#);
// now the added paragraphs standing in front of `div`
assert!(doc.select(r#".content > .first + .second + .third + div:has-text("1,2,3")"#).exists());Node manipulations: Creating an empty element, adding a single element to a single node
use dom_query::Document;
let doc: Document = r#"<!DOCTYPE html>
<html lang="en">
<head></head>
<body>
<div id="main">
<p id="first">It's</p>
</div>
</body>
</html>"#.into();
// selecting a node we want to attach a new element
let main_sel = doc.select_single("#main");
let main_node = main_sel.nodes().first().unwrap();
// if you need just to create a simple element, then you can use the following:
let el = doc.tree.new_element("p");
// you still able to deal with element's attributes:
el.set_attr("id", "second");
// and set text
el.set_text("test");
main_node.append_child(&el);
// also main_node.append_child(&el);
assert!(doc.select(r#"#main #second:has-text("test")"#).exists());
// because this method doesn't parse anything it is much more cheaper than following approaches.
// if you need to add a more complex element, you can use `node.append_html`,
// which is much more convenient, then previous approach:
main_node.append_html(r#"<p id="third">Wonderful</p>"#);
assert_eq!(doc.select("#main #third").text().as_ref(), "Wonderful");
// There is also a `prepend_child` and `prepend_html` methods which allows
// to insert content to the begging of the node.
main_node.prepend_html(r#"<p id="minus-one">-1</p><p id="zero">0</p>"#);
assert!(doc.select("#main > #minus-one + #zero + #first + #second + #third").exists());
// if we need to replace existing element content inside a node with a new one, then use `node.set_html`.
// It changes the inner html contents of the node.
main_node.set_html(r#"<p id="the-only">Wonderful</p>"#);
assert_eq!(doc.select("#main #the-only").text().as_ref(), "Wonderful");
assert!(!doc.select("#first").exists());
// To completely replace contents of the node,
// including itself use `node.replace_with_html`.
// Also we can specify more than one element in the string for methods
// like `replace_with_html`, `set_html` and `append_html`.
main_node.replace_with_html(r#"<span>Tweedledum</span> and <span>Tweedledee</span>"#);
assert!(!doc.select("#main").exists());
assert_eq!(doc.select("span + span").text().as_ref(), "Tweedledee");Renaming selected elements without changing the contents
use dom_query::Document;
let doc: Document = r#"<!DOCTYPE html>
<html>
<head><title>Test</title></head>
<body>
<div class="content">
<div>1</div>
<div>2</div>
<div>3</div>
<span>4</span>
</div>
<body>
</html>"#
.into();
let mut sel = doc.select("div.content > div, div.content > span");
// before renaming, there are 3 `div` and 1 `span`
assert_eq!(sel.length(), 4);
sel.rename("p");
// after renaming, there are no `div` and `span` elements
assert_eq!(doc.select("div.content > div, div.content > span").length(), 0);
// but there are four `p` elements
assert_eq!(doc.select("div.content > p").length(), 4);hashbrown— optional, standard hashmaps and hashsets will be replacedhashbrownhashmaps and hashsets;
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