DiDOM

Simple and fast HTML and XML parser

Monthly Downloads: 39,900

Programming language: PHP

License: MIT License

Tags: Scraping     HTML     Parser     XML     Composer Repositories     Didom    

Latest version: v2.0

README

DiDOM

DiDOM - simple and fast HTML parser.

• [README на русском](README-RU.md)
• DiDOM 1.x documentation. To upgrade from 1.x please checkout the [changelog](CHANGELOG.md).

Contents

• Installation
• Quick start
• Creating new document
• Search for elements
• Verify if element exists
• Search in element
• Supported selectors
• Changing content
• Output
• Working with elements
  • Creating a new element
  • Getting the name of an element
  • Getting parent element
  • Getting sibling elements
  • Getting the child elements
  • Getting document
  • Working with element attributes
  • Comparing elements
  • Adding a child element
  • Replacing element
  • Removing element
• Working with cache
• Miscellaneous
• Comparison with other parsers

Installation

To install DiDOM run the command:

composer require imangazaliev/didom

Quick start

use DiDom\Document;

$document = new Document('http://www.news.com/', true);

$posts = $document->find('.post');

foreach($posts as $post) {
    echo $post->text(), "\n";
}

Creating new document

DiDom allows to load HTML in several ways:

With constructor

// the first parameter is a string with HTML
$document = new Document($html);

// file path
$document = new Document('page.html', true);

// or URL
$document = new Document('http://www.example.com/', true);

The second parameter specifies if you need to load file. Default is false.

Signature:

__construct($string = null, $isFile = false, $encoding = 'UTF-8', $type = Document::TYPE_HTML)

$string - an HTML or XML string or a file path.

$isFile - indicates that the first parameter is a path to a file.

$encoding - the document encoding.

$type - the document type (HTML - Document::TYPE_HTML, XML - Document::TYPE_XML).

With separate methods

$document = new Document();

$document->loadHtml($html);

$document->loadHtmlFile('page.html');

$document->loadHtmlFile('http://www.example.com/');

There are two methods available for loading XML: loadXml and loadXmlFile.

These methods accept additional options:

$document->loadHtml($html, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD);
$document->loadHtmlFile($url, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD);

$document->loadXml($xml, LIBXML_PARSEHUGE);
$document->loadXmlFile($url, LIBXML_PARSEHUGE);

Search for elements

DiDOM accepts CSS selector or XPath as an expression for search. You need to path expression as the first parameter, and specify its type in the second one (default type is Query::TYPE_CSS):

With method find():

use DiDom\Document;
use DiDom\Query;

...

// CSS selector
$posts = $document->find('.post');

// XPath
$posts = $document->find("//div[contains(@class, 'post')]", Query::TYPE_XPATH);

If the elements that match a given expression are found, then method returns an array of instances of DiDom\Element, otherwise - an empty array. You could also get an array of DOMElement objects. To get this, pass false as the third parameter.

With magic method __invoke():

$posts = $document('.post');

Warning: using this method is undesirable because it may be removed in the future.

With method xpath():

$posts = $document->xpath("//*[contains(concat(' ', normalize-space(@class), ' '), ' post ')]");

You can do search inside an element:

echo $document->find('nav')[0]->first('ul.menu')->xpath('//li')[0]->text();

Verify if element exists

To verify if element exist use has() method:

if ($document->has('.post')) {
    // code
}

If you need to check if element exist and then get it:

if ($document->has('.post')) {
    $elements = $document->find('.post');
    // code
}

but it would be faster like this:

if (count($elements = $document->find('.post')) > 0) {
    // code
}

because in the first case it makes two queries.

Search in element

Methods find(), first(), xpath(), has(), count() are available in Element too.

Example:

echo $document->find('nav')[0]->first('ul.menu')->xpath('//li')[0]->text();

Method findInDocument()

If you change, replace, or remove an element that was found in another element, the document will not be changed. This happens because method find() of Element class (a, respectively, the first () and xpath methods) creates a new document to search.

To search for elements in the source document, you must use the methods findInDocument() and firstInDocument():

// nothing will happen
$document->first('head')->first('title')->remove();

// but this will do
$document->first('head')->firstInDocument('title')->remove();

Warning: methods findInDocument() and firstInDocument() work only for elements, which belong to a document, and for elements created via new Element(...). If an element does not belong to a document, LogicException will be thrown;

Supported selectors

DiDom supports search by:

• tag
• class, ID, name and value of an attribute
• pseudo-classes:
  • first-, last-, nth-child
  • empty and not-empty
  • contains
  • has

// all links
$document->find('a');

// any element with id = "foo" and "bar" class
$document->find('#foo.bar');

// any element with attribute "name"
$document->find('[name]');
// the same as
$document->find('*[name]');

// input field with the name "foo"
$document->find('input[name=foo]');
$document->find('input[name=\'bar\']');
$document->find('input[name="baz"]');

// any element that has an attribute starting with "data-" and the value "foo"
$document->find('*[^data-=foo]');

// all links starting with https
$document->find('a[href^=https]');

// all images with the extension png
$document->find('img[src$=png]');

// all links containing the string "example.com"
$document->find('a[href*=example.com]');

// text of the links with "foo" class
$document->find('a.foo::text');

// address and title of all the fields with "bar" class
$document->find('a.bar::attr(href|title)');

Changing content

Change inner HTML

$element->setInnerHtml('<a href="#">Foo</a>');

Change inner XML

$element->setInnerXml(' Foo <span>Bar</span><!-- Baz --><![CDATA[
    <root>Hello world!</root>
]]>');

Change value (as plain text)

$element->setValue('Foo');
// will be encoded like using htmlentities()
$element->setValue('<a href="#">Foo</a>');

Output

Getting HTML

With method html():

$posts = $document->find('.post');

echo $posts[0]->html();

Casting to string:

$html = (string) $posts[0];

Formatting HTML output

$html = $document->format()->html();

An element does not have format() method, so if you need to output formatted HTML of the element, then first you have to convert it to a document:

$html = $element->toDocument()->format()->html();

Inner HTML

$innerHtml = $element->innerHtml();

Document does not have the method innerHtml(), therefore, if you need to get inner HTML of a document, convert it into an element first:

$innerHtml = $document->toElement()->innerHtml();

Getting XML

echo $document->xml();

echo $document->first('book')->xml();

Getting content

$posts = $document->find('.post');

echo $posts[0]->text();

Creating a new element

Creating an instance of the class

use DiDom\Element;

$element = new Element('span', 'Hello');

// Outputs "<span>Hello</span>"
echo $element->html();

First parameter is a name of an attribute, the second one is its value (optional), the third one is element attributes (optional).

An example of creating an element with attributes:

$attributes = ['name' => 'description', 'placeholder' => 'Enter description of item'];

$element = new Element('textarea', 'Text', $attributes);

An element can be created from an instance of the class DOMElement:

use DiDom\Element;
use DOMElement;

$domElement = new DOMElement('span', 'Hello');

$element = new Element($domElement);

Using the method createElement

$document = new Document($html);

$element = $document->createElement('span', 'Hello');

Getting the name of an element

$element->tagName();

Getting parent element

$document = new Document($html);

$input = $document->find('input[name=email]')[0];

var_dump($input->parent());

Getting sibling elements

$document = new Document($html);

$item = $document->find('ul.menu > li')[1];

var_dump($item->previousSibling());

var_dump($item->nextSibling());

Getting the child elements

$html = '<div>Foo<span>Bar</span><!--Baz--></div>';

$document = new Document($html);

$div = $document->first('div');

// element node (DOMElement)
// string(3) "Bar"
var_dump($div->child(1)->text());

// text node (DOMText)
// string(3) "Foo"
var_dump($div->firstChild()->text());

// comment node (DOMComment)
// string(3) "Baz"
var_dump($div->lastChild()->text());

// array(3) { ... }
var_dump($div->children());

Getting owner document

$document = new Document($html);

$element = $document->find('input[name=email]')[0];

$document2 = $element->ownerDocument();

// bool(true)
var_dump($document->is($document2));

Working with element attributes

Creating/updating an attribute

With method setAttribute:

$element->setAttribute('name', 'username');

With method attr:

$element->attr('name', 'username');

With magic method __set:

$element->name = 'username';

Getting value of an attribute

With method getAttribute:

$username = $element->getAttribute('value');

With method attr:

$username = $element->attr('value');

With magic method __get:

$username = $element->name;

Returns null if attribute is not found.

Verify if attribute exists

With method hasAttribute:

if ($element->hasAttribute('name')) {
    // code
}

With magic method __isset:

if (isset($element->name)) {
    // code
}

Removing attribute:

With method removeAttribute:

$element->removeAttribute('name');

With magic method __unset:

unset($element->name);

Comparing elements

$element  = new Element('span', 'hello');
$element2 = new Element('span', 'hello');

// bool(true)
var_dump($element->is($element));

// bool(false)
var_dump($element->is($element2));

Appending child elements

$list = new Element('ul');

$item = new Element('li', 'Item 1');

$list->appendChild($item);

$items = [
    new Element('li', 'Item 2'),
    new Element('li', 'Item 3'),
];

$list->appendChild($items);

Adding a child element

$list = new Element('ul');

$item = new Element('li', 'Item 1');
$items = [
    new Element('li', 'Item 2'),
    new Element('li', 'Item 3'),
];

$list->appendChild($item);
$list->appendChild($items);

Replacing element

$element = new Element('span', 'hello');

$document->find('.post')[0]->replace($element);

Waning: you can replace only those elements that were found directly in the document:

// nothing will happen
$document->first('head')->first('title')->replace($title);

// but this will do
$document->first('head title')->replace($title);

More about this in section Search for elements.

Removing element

$document->find('.post')[0]->remove();

Warning: you can remove only those elements that were found directly in the document:

// nothing will happen
$document->first('head')->first('title')->remove();

// but this will do
$document->first('head title')->remove();

More about this in section Search for elements.

Working with cache

Cache is an array of XPath expressions, that were converted from CSS.

Getting from cache

use DiDom\Query;

...

$xpath    = Query::compile('h2');
$compiled = Query::getCompiled();

// array('h2' => '//h2')
var_dump($compiled);

Cache setting

Query::setCompiled(['h2' => '//h2']);

Miscellaneous

preserveWhiteSpace

By default, whitespace preserving is disabled.

You can enable the preserveWhiteSpace option before loading the document:

$document = new Document();

$document->preserveWhiteSpace();

$document->loadXml($xml);

count

The count () method counts children that match the selector:

// prints the number of links in the document
echo $document->count('a');

// prints the number of items in the list
echo $document->first('ul')->count('li');

matches

Returns true if the node matches the selector:

$element->matches('div#content');

// strict match
// returns true if the element is a div with id equals content and nothing else
// if the element has any other attributes the method returns false
$element->matches('div#content', true);

isElementNode

Checks whether an element is an element (DOMElement):

$element->isElementNode();

isTextNode

Checks whether an element is a text node (DOMText):

$element->isTextNode();

isCommentNode

Checks whether the element is a comment (DOMComment):

$element->isCommentNode();

Comparison with other parsers

Comparison with other parsers