DiDOM
DiDOM - simple and fast HTML parser.
Contents
- Installation
- Quick start
- Creating new document
- Search for elements
- Verify if element exists
- Search in element
- Supported selectors
- Output
- Working with elements
- 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)');
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->tag;
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 document
$document = new Document($html);
$element = $document->find('input[name=email]')[0];
$document2 = $element->getDocument();
// bool(true)
var_dump($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();
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