PHP 解析html文件(file_get_html) | rin部落-web前端开发-主流web技术分享博客

相关用法：

如何创建 HTML DOM 对象?

方法如下:

// Create a DOM object from a string 字符串创建
$html = str_get_html('<html><body>Hello!</body></html>');

// Create a DOM object from a URL URL创建
$html = file_get_html('http://www.google.com/');

// Create a DOM object from a HTML file 文件创建
$html = file_get_html('test.htm');

面向对象的方式:

// Create a DOM object 创建一个DOM对象
$html = new simple_html_dom();

// Load HTML from a string 从字符串中加载HTML
$html->load('<html><body>Hello!</body></html>');

// Load HTML from a URL 从URL中加载HTML
$html->load_file('http://www.google.com/');

// Load HTML from a HTML file 从文件中加载HTML
$html->load_file('test.htm');

如何找到HTML元素?
基本方法:

// Find all anchors, returns a array of element objects 查找所有锚，返回元素对象的数组
$ret = $html->find('a');

// Find (N)th anchor, returns element object or null if not found (zero based) 查找（N）个锚，返回元素对象或null，如果没有发现（从零开始）
$ret = $html->find('a', 0);

// Find all <div> which attribute id=foo 找到所有的<div>哪个属性ID= foo的
$ret = $html->find('div[id=foo]'); 

// Find all <div> with the id attribute
$ret = $html->find('div[id]');

// Find all element has attribute id
$ret = $html->find('[id]');
Advanced:

// Find all element which id=foo
$ret = $html->find('#foo');

// Find all element which class=foo
$ret = $html->find('.foo');

// Find all anchors and images 
$ret = $html->find('a, img'); 

// Find all anchors and images with the "title" attribute
$ret = $html->find('a[title], img[title]');

后代选择器:

// Find all <li> in <ul> 
$es = $html->find('ul li');

// Find Nested <div> tags
$es = $html->find('div div div'); 

// Find all <td> in <table> which class=hello 
$es = $html->find('table.hello td');

// Find all td tags with attribite align=center in table tags 
$es = $html->find(''table td[align=center]');

嵌套选择器:

// Find all <li> in <ul> 
foreach($html->find('ul') as $ul) 
{
       foreach($ul->find('li') as $li) 
       {
             // do something...
       }
}

// Find first <li> in first <ul> 
$e = $html->find('ul', 0)->find('li', 0);

属性过滤器:

支持这些运营商在属性选择:

FilterDescription
[attribute]Matches elements that have the specified attribute.
[attribute=value]Matches elements that have the specified attribute with a certain value.
[attribute!=value]Matches elements that don't have the specified attribute with a certain value.
[attribute^=value]Matches elements that have the specified attribute and it starts with a certain value.
[attribute$=value]Matches elements that have the specified attribute and it ends with a certain value.
[attribute*=value]Matches elements that have the specified attribute and it contains a certain value.
Text & Comments:

// Find all text blocks 
$es = $html->find('text');

// Find all comment (<!--...-->) blocks 
$es = $html->find('comment');
How to access the HTML element's attributes?
Get, Set and Remove attributes:

// Get a attribute ( If the attribute is non-value attribute (eg. checked, selected...), it will returns true or false)
$value = $e->href;

// Set a attribute(If the attribute is non-value attribute (eg. checked, selected...), set it's value as true or false)
$e->href = 'my link';

// Remove a attribute, set it's value as null! 
$e->href = null;

// Determine whether a attribute exist? 
if(isset($e->href)) 
         echo 'href exist!';
Magic attributes:

// Example
$html = str_get_html("<div>foo <b>bar</b></div>"); 
$e = $html->find("div", 0);

echo $e->tag; // Returns: " div"
echo $e->outertext; // Returns: " <div>foo <b>bar</b></div>"
echo $e->innertext; // Returns: " foo <b>bar</b>"
echo $e->plaintext; // Returns: " foo bar"

Attribute NameUsage
$e->tagRead or write the tag name of element.
$e->outertextRead or write the outer HTML text of element.
$e->innertextRead or write the inner HTML text of element.
$e->plaintextRead or write the plain text of element.
Tips:

// Extract contents from HTML 
echo $html->plaintext;

// Wrap a element
$e->outertext = '<div class="wrap">' . $e->outertext . '<div>';

// Remove a element, set it's outertext as an empty string 
$e->outertext = '';

// Append a element
$e->outertext = $e->outertext . '<div>foo<div>';

// Insert a element
$e->outertext = '<div>foo<div>' . $e->outertext;
How to traverse the DOM tree?

Background Konwledge:

// If you are not so familiar with HTML DOM, check this link to learn more... 

// Example
echo $html->find("#div1", 0)->children(1)->children(1)->children(2)->id;
// or 
echo $html->getElementById("div1")->childNodes(1)->childNodes(1)->childNodes(2)->getAttribute('id');
Traverse the DOM tree:

You can also call methods with Camel naming convertions.
MethodDescription
mixed
$e->children ( [int $index] )Returns the Nth child object if index is set, otherwise return an array of children.
element
$e->parent ()Returns the parent of element.
element
$e->first_child ()Returns the first child of element, or null if not found.
element
$e->last_child ()Returns the last child of element, or null if not found.
element
$e->next_sibling ()Returns the next sibling of element, or null if not found.
element
$e->prev_sibling ()Returns the previous sibling of element, or null if not found.
How to dump contents of DOM object?

Quick way:

// Dumps the internal DOM tree back into string 
$str = $html;

// Print it!
echo $html;
Object-oriented way:

// Dumps the internal DOM tree back into string 
$str = $html->save();

// Dumps the internal DOM tree back into a file 
$html->save('result.htm');
How to customize the parsing behavior?
Callback function
// Write a function with parameter "$element"
function my_callback($element) {
        // Hide all <b> tags 
         if ($element->tag=='b')
                 $element->outertext = '';
} 

// Register the callback function with it's function name
$html->set_callback('my_callback');

// Callback function will be invoked while dumping
echo $html;

2014-04-29