<? Php
/*************************************** *****************************
* Process description:
* When the required parameters are passed to the filter function, the filter () function first
* Use preg_match_all () to filter all tags in the string ()
* Obtain it, And then loop through the match array of preg_match_all, through preg_split ()
* The function splits each label into the form of "Left attribute" = "right value", and
* Loop in the left attribute array. The preg_split () Matching content is retrieved to form
* Value that can be replaced, and then the corresponding tag in the string is replaced by str_replcae ()
* Function list:
* Function filter (& $ str, $ tag, $ keep_attribute)
* Function match ($ reg, & $ str, $ arr)
* Function show ($ str, $ title =, $ debug = True)
* Example:
* // Obtain the homepage of Sohu news
* $ Str = @ file_get_content ("http://news.sohu.com ");
* // Filter
* Filter ($ str, a, href, target, alt );
* Filter ($ str, p, align );
* Show ($ str, filtered content );
**************************************** ****************************/
$ Start_time = array_sum (explode ("", microtime ()));
$ Str = <HTML
<A style = "a" target = _ blank href = http://www.bkjia.com xxx = xadsfa alt = "a" style = "aa"> site a </a>
<A alt = B xxx = xadsfa target = _ blank href = http://www. B .com style = "B" style = "bb"> site B </A>
<A xxx = xadsfa style = "c" href = http://www.php100.net target = _ blank alt = c style = "cc"> site c </A>
<A style = "d" href = http://www.d.com xxx = xadsfa alt = d target = _ blank style = "dd"> site d </A>
<A target = _ blank style = "e" xxx = xadsfa style = "ee" alt = e href = http://www.e.com> site e </A>
<P align = right style = "font-size: 10px"> adasdfasdf </p>
<P style = "font-color: red;" align = left> asdfasdfasdfasdf </p>
<P align = left right center> asdfasdfasdf </p>
<Font color = "red" alt = adasd adsasd> asdfadsfasdf </font>
<Font align = left color = red> asdfasdfadf </font>
<Font align = left right color = red black> asdfasdf </font>
HTML;
// Display the original string
Show ($ str, Html );
/*************************************** **************************************** **************************************** **************************************** ********/
// Filter
Filter ($ str, a, href, target, alt );
Filter ($ str, p, align );
Filter ($ str, font, color, alt );
// Display the filtered content
Show ($ str, Result );
// Script running time
$ Run_time = array_sum (explode ("", microtime ()-$ start_time;
Echo (<center> Script Run Time:. $ run_time. </center> );
/**
* Description: filters HTML strings.
* Parameters:
* $ Str: the HTML string to be filtered
* $ Tag: the type of the filtered tag.
* $ Keep_attribute:
* Attributes to be retained. The parameter format is
* Href
* Href, target, alt
* Array (href, target, alt)
*/
Function filter (& $ str, $ tag, $ keep_attribute ){
// Check the parameter transfer method of the attribute to be retained
If (! Is_array ($ keep_attribute )){
// When the array is not passed in, determine whether the parameter contains, no.
If (strpos ($ keep_attribute ,,)){
// Contains, number, splitting parameter string as an array
$ Keep_attribute = explode (, $ keep_attribute );
} Else {
// A pure string to construct an array
$ Keep_attribute = array ($ keep_attribute );
}
}
Echo ("· filter [$ tag] tags, retain attributes:". implode (, $ keep_attribute). <br> );
// Obtain all tags to be processed
$ Pattern = "/<$ tag (. *) </$ tag>/I ";
Preg_match_all ($ pattern, $ str, $ out );
// Process each tag cyclically
Foreach ($ out [1] as $ key => $ val ){
// Several =
$ Cnt = preg_split (/* =/I, $ val );
$ Cnt = count ($ cnt)-1;
// Construct a regular expression
$ Pattern =;
For ($ I = 1; $ I <= $ cnt; $ I ++ ){
$ Pattern. = (. * = .*);
}
// Complete regular expression formation, such as/(<a) (. * =. *) (. * =. *) (>. * </a>/I style
$ Pattern = "/(<$ tag) $ pattern (>. * </$ tag>)/I ";
// Get reserved attributes
$ Replacement = match ($ pattern, $ out [0] [$ key], $ keep_attribute );
// Replace
$ Str = str_replace ($ out [0] [$ key], $ replacement, $ str );
}
}
/**
* Description: Creates tags and retains the attributes to be retained.
* Parameter: $ reg: Expression of pattern and preg_match
* $ Str: string, html string
* $ Arr: array, the attribute to be retained
* Return value:
* Return the retained tag, as shown in figure
* <A href = http://www.e.com target = _ blank alt = e> e.com </A>
*/
Function match ($ reg, & $ str, $ arr ){
// Match
Preg_match ($ reg, $ str, $ out );
// Retrieve the reserved attributes
$ Keep_attribute =;
Foreach ($ arr as $ k1 => $ v1 ){
// Defines the array of attributes to be retained
Foreach ($ out as $ k2 => $ v2 ){
// Matching = Array
$ Attribute = trim (substr ($ v2, 0, strpos ($ v2, = )));
// = Previous
If ($ v1 = $ attribute ){
// The attributes to be retained are the same as those before = of the matched values.
$ Keep_attribute. = $ v2;
// Save the value of this matching part
}
}
}
// Construct the return value. The structure is as follows: <a href = xxx target = xxx class = xxx> aadd </a>
$ Keep_attribute = $ out [1]. $ keep_attribute. ($ out [count ($ out)-1]);
// Return Value
Return $ keep_attribute;
}
/**
* Display string content
*/
Function show ($ str, $ title =, $ debug = True ){
If ($ debug ){
If (is_array ($ str )){
$ Str = print_r ($ str, True );
}
$ TxtRows = count (explode ("", $ str) + 1;
Echo ($ title.: <br> <textarea name = "txt" ROWS = ". $ txtRows. "COLS =" 130 ">. $ str. </TEXTAREA> <br> );
}
}
?>
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