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Using PHP substr() and strip_tags() while retaining formatting and without breaking HTML

由 安稳与你 提交于 2019-12-17 05:01:53

问题


I have various HTML strings to cut to 100 characters (of the stripped content, not the original) without stripping tags and without breaking HTML.

Original HTML string (288 characters):

$content = "<div>With a <span class='spanClass'>span over here</span> and a
<div class='divClass'>nested div over <div class='nestedDivClass'>there</div>
</div> and a lot of other nested <strong><em>texts</em> and tags in the air
<span>everywhere</span>, it's a HTML taggy kind of day.</strong></div>";

Standard trim: Trim to 100 characters and HTML breaks, stripped content comes to ~40 characters:

$content = substr($content, 0, 100)."..."; /* output:
<div>With a <span class='spanClass'>span over here</span> and a
<div class='divClass'>nested div ove... */

Stripped HTML: Outputs correct character count but obviously looses formatting:

$content = substr(strip_tags($content)), 0, 100)."..."; /* output:
With a span over here and a nested div over there and a lot of other nested
texts and tags in the ai... */

Partial solution: using HTML Tidy or purifier to close off tags outputs clean HTML but 100 characters of HTML not displayed content.

$content = substr($content, 0, 100)."...";
$tidy = new tidy; $tidy->parseString($content); $tidy->cleanRepair(); /* output:
<div>With a <span class='spanClass'>span over here</span> and a
<div class='divClass'>nested div ove</div></div>... */

Challenge: To output clean HTML and n characters (excluding character count of HTML elements):

$content = cutHTML($content, 100); /* output:
<div>With a <span class='spanClass'>span over here</span> and a
<div class='divClass'>nested div over <div class='nestedDivClass'>there</div>
</div> and a lot of other nested <strong><em>texts</em> and tags in the
ai</strong></div>...";

Similar Questions

  • How to clip HTML fragments without breaking up tags
  • Cutting HTML strings without breaking HTML tags

回答1:


Not amazing, but works.

function html_cut($text, $max_length)
{
    $tags   = array();
    $result = "";

    $is_open   = false;
    $grab_open = false;
    $is_close  = false;
    $in_double_quotes = false;
    $in_single_quotes = false;
    $tag = "";

    $i = 0;
    $stripped = 0;

    $stripped_text = strip_tags($text);

    while ($i < strlen($text) && $stripped < strlen($stripped_text) && $stripped < $max_length)
    {
        $symbol  = $text{$i};
        $result .= $symbol;

        switch ($symbol)
        {
           case '<':
                $is_open   = true;
                $grab_open = true;
                break;

           case '"':
               if ($in_double_quotes)
                   $in_double_quotes = false;
               else
                   $in_double_quotes = true;

            break;

            case "'":
              if ($in_single_quotes)
                  $in_single_quotes = false;
              else
                  $in_single_quotes = true;

            break;

            case '/':
                if ($is_open && !$in_double_quotes && !$in_single_quotes)
                {
                    $is_close  = true;
                    $is_open   = false;
                    $grab_open = false;
                }

                break;

            case ' ':
                if ($is_open)
                    $grab_open = false;
                else
                    $stripped++;

                break;

            case '>':
                if ($is_open)
                {
                    $is_open   = false;
                    $grab_open = false;
                    array_push($tags, $tag);
                    $tag = "";
                }
                else if ($is_close)
                {
                    $is_close = false;
                    array_pop($tags);
                    $tag = "";
                }

                break;

            default:
                if ($grab_open || $is_close)
                    $tag .= $symbol;

                if (!$is_open && !$is_close)
                    $stripped++;
        }

        $i++;
    }

    while ($tags)
        $result .= "</".array_pop($tags).">";

    return $result;
}

Usage example:

$content = html_cut($content, 100);



回答2:


I'm not claiming to have invented this, but there is a very complete Text::truncate() method in CakePHP which does what you want:

function truncate($text, $length = 100, $ending = '...', $exact = true, $considerHtml = false) {
    if (is_array($ending)) {
        extract($ending);
    }
    if ($considerHtml) {
        if (mb_strlen(preg_replace('/<.*?>/', '', $text)) <= $length) {
            return $text;
        }
        $totalLength = mb_strlen($ending);
        $openTags = array();
        $truncate = '';
        preg_match_all('/(<\/?([\w+]+)[^>]*>)?([^<>]*)/', $text, $tags, PREG_SET_ORDER);
        foreach ($tags as $tag) {
            if (!preg_match('/img|br|input|hr|area|base|basefont|col|frame|isindex|link|meta|param/s', $tag[2])) {
                if (preg_match('/<[\w]+[^>]*>/s', $tag[0])) {
                    array_unshift($openTags, $tag[2]);
                } else if (preg_match('/<\/([\w]+)[^>]*>/s', $tag[0], $closeTag)) {
                    $pos = array_search($closeTag[1], $openTags);
                    if ($pos !== false) {
                        array_splice($openTags, $pos, 1);
                    }
                }
            }
            $truncate .= $tag[1];

            $contentLength = mb_strlen(preg_replace('/&[0-9a-z]{2,8};|&#[0-9]{1,7};|&#x[0-9a-f]{1,6};/i', ' ', $tag[3]));
            if ($contentLength + $totalLength > $length) {
                $left = $length - $totalLength;
                $entitiesLength = 0;
                if (preg_match_all('/&[0-9a-z]{2,8};|&#[0-9]{1,7};|&#x[0-9a-f]{1,6};/i', $tag[3], $entities, PREG_OFFSET_CAPTURE)) {
                    foreach ($entities[0] as $entity) {
                        if ($entity[1] + 1 - $entitiesLength <= $left) {
                            $left--;
                            $entitiesLength += mb_strlen($entity[0]);
                        } else {
                            break;
                        }
                    }
                }

                $truncate .= mb_substr($tag[3], 0 , $left + $entitiesLength);
                break;
            } else {
                $truncate .= $tag[3];
                $totalLength += $contentLength;
            }
            if ($totalLength >= $length) {
                break;
            }
        }

    } else {
        if (mb_strlen($text) <= $length) {
            return $text;
        } else {
            $truncate = mb_substr($text, 0, $length - strlen($ending));
        }
    }
    if (!$exact) {
        $spacepos = mb_strrpos($truncate, ' ');
        if (isset($spacepos)) {
            if ($considerHtml) {
                $bits = mb_substr($truncate, $spacepos);
                preg_match_all('/<\/([a-z]+)>/', $bits, $droppedTags, PREG_SET_ORDER);
                if (!empty($droppedTags)) {
                    foreach ($droppedTags as $closingTag) {
                        if (!in_array($closingTag[1], $openTags)) {
                            array_unshift($openTags, $closingTag[1]);
                        }
                    }
                }
            }
            $truncate = mb_substr($truncate, 0, $spacepos);
        }
    }

    $truncate .= $ending;

    if ($considerHtml) {
        foreach ($openTags as $tag) {
            $truncate .= '</'.$tag.'>';
        }
    }

    return $truncate;
}



回答3:


Use PHP's DOMDocument class to normalize an HTML fragment:

$dom= new DOMDocument();
$dom->loadHTML('<div><p>Hello World');      
$xpath = new DOMXPath($dom);
$body = $xpath->query('/html/body');
echo($dom->saveXml($body->item(0)));

This question is similar to an earlier question and I've copied and pasted one solution here. If the HTML is submitted by users you'll also need to filter out potential Javascript attack vectors like onmouseover="do_something_evil()" or <a href="javascript:more_evil();">...</a>. Tools like HTML Purifier were designed to catch and solve these problems and are far more comprehensive than any code that I could post.




回答4:


Use a HTML parser and stop after 100 characters of text.




回答5:


You should use Tidy HTML. You cut the string and then you run Tidy to close the tags.

(Credits where credits are due)




回答6:


I made another function to do it, it supports UTF-8:

/**
 * Limit string without break html tags.
 * Supports UTF8
 * 
 * @param string $value
 * @param int $limit Default 100
 */
function str_limit_html($value, $limit = 100)
{

    if (mb_strwidth($value, 'UTF-8') <= $limit) {
        return $value;
    }

    // Strip text with HTML tags, sum html len tags too.
    // Is there another way to do it?
    do {
        $len          = mb_strwidth($value, 'UTF-8');
        $len_stripped = mb_strwidth(strip_tags($value), 'UTF-8');
        $len_tags     = $len - $len_stripped;

        $value = mb_strimwidth($value, 0, $limit + $len_tags, '', 'UTF-8');
    } while ($len_stripped > $limit);

    // Load as HTML ignoring errors
    $dom = new DOMDocument();
    @$dom->loadHTML('<?xml encoding="utf-8" ?>'.$value, LIBXML_HTML_NODEFDTD);

    // Fix the html errors
    $value = $dom->saveHtml($dom->getElementsByTagName('body')->item(0));

    // Remove body tag
    $value = mb_strimwidth($value, 6, mb_strwidth($value, 'UTF-8') - 13, '', 'UTF-8'); // <body> and </body>
    // Remove empty tags
    return preg_replace('/<(\w+)\b(?:\s+[\w\-.:]+(?:\s*=\s*(?:"[^"]*"|"[^"]*"|[\w\-.:]+))?)*\s*\/?>\s*<\/\1\s*>/', '', $value);
}

SEE DEMO.

I recommend use html_entity_decode at the start of function, so it preserves the UTF-8 characters:

 $value = html_entity_decode($value);



回答7:


Regardless of the 100 count issues you state at the beginning, you indicate in the challenge the following:

  • output the character count of strip_tags (the number of characters in the actual displayed text of the HTML)
  • retain HTML formatting close
  • any unfinished HTML tag

Here is my proposal: Bascially, I parse through each character counting as I go. I make sure NOT to count any characters in any HTML tag. I also check at the end to make sure I am not in the middle of a word when I stop. Once I stop, I back track to the first available SPACE or > as a stopping point.

$position = 0;
$length = strlen($content)-1;

// process the content putting each 100 character section into an array
while($position < $length)
{
    $next_position = get_position($content, $position, 100);
    $data[] = substr($content, $position, $next_position);
    $position = $next_position;
}

// show the array
print_r($data);

function get_position($content, $position, $chars = 100)
{
    $count = 0;
    // count to 100 characters skipping over all of the HTML
    while($count <> $chars){
        $char = substr($content, $position, 1); 
        if($char == '<'){
            do{
                $position++;
                $char = substr($content, $position, 1);
            } while($char !== '>');
            $position++;
            $char = substr($content, $position, 1);
        }
        $count++;
        $position++;
    }
echo $count."\n";
    // find out where there is a logical break before 100 characters
    $data = substr($content, 0, $position);

    $space = strrpos($data, " ");
    $tag = strrpos($data, ">");

    // return the position of the logical break
    if($space > $tag)
    {
        return $space;
    } else {
        return $tag;
    }  
}

This will also count the return codes etc. Considering they will take space, I have not removed them.




回答8:


Here is a function I'm using in one of my projects. It's based on DOMDocument, works with HTML5 and is about 2x faster than other solutions I've tried (at least on my machine, 0.22 ms vs 0.43 ms using html_cut($text, $max_length) from the top answer on a 500 text-node-characters string with a limit of 400).

function cut_html ($html, $limit) {
    $dom = new DOMDocument();
    $dom->loadHTML(mb_convert_encoding("<div>{$html}</div>", "HTML-ENTITIES", "UTF-8"), LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD);
    cut_html_recursive($dom->documentElement, $limit);
    return substr($dom->saveHTML($dom->documentElement), 5, -6);
}

function cut_html_recursive ($element, $limit) {
    if($limit > 0) {
        if($element->nodeType == 3) {
            $limit -= strlen($element->nodeValue);
            if($limit < 0) {
                $element->nodeValue = substr($element->nodeValue, 0, strlen($element->nodeValue) + $limit);
            }
        }
        else {
            for($i = 0; $i < $element->childNodes->length; $i++) {
                if($limit > 0) {
                    $limit = cut_html_recursive($element->childNodes->item($i), $limit);
                }
                else {
                    $element->removeChild($element->childNodes->item($i));
                    $i--;
                }
            }
        }
    }
    return $limit;
}



回答9:


Here is my try at the cutter. Maybe you guys can catch some bugs. The problem, i found with the other parsers, is that they don't close tags properly and they cut in the middle of a word (blah)

function cutHTML($string, $length, $patternsReplace = false) {
    $i = 0;
    $count = 0;
    $isParagraphCut = false;
    $htmlOpen = false;
    $openTag = false;
    $tagsStack = array();

    while ($i < strlen($string)) {
        $char = substr($string, $i, 1);
        if ($count >= $length) {
            $isParagraphCut = true;
            break;
        }

        if ($htmlOpen) {
            if ($char === ">") {
                $htmlOpen = false;
            }
        } else {
            if ($char === "<") {
                $j = $i;
                $char = substr($string, $j, 1);

                while ($j < strlen($string)) {
                    if($char === '/'){
                        $i++;
                        break;
                    }
                    elseif ($char === ' ') {
                        $tagsStack[] = substr($string, $i, $j);
                    }
                    $j++;
                }
                $htmlOpen = true;
            }
        }

        if (!$htmlOpen && $char != ">") {
            $count++;
        }

        $i++;
    }

    if ($isParagraphCut) {
        $j = $i;
        while ($j > 0) {
            $char = substr($string, $j, 1);
            if ($char === " " || $char === ";" || $char === "." || $char === "," || $char === "<" || $char === "(" || $char === "[") {
                break;
            } else if ($char === ">") {
                $j++;
                break;
            }
            $j--;
        }
        $string = substr($string, 0, $j);
        foreach($tagsStack as $tag){
            $tag = strtolower($tag);
            if($tag !== "img" && $tag !== "br"){
                $string .= "</$tag>";
            }
        }
        $string .= "...";
    }

    if ($patternsReplace) {
        foreach ($patternsReplace as $value) {
            if (isset($value['pattern']) && isset($value["replace"])) {
                $string = preg_replace($value["pattern"], $value["replace"], $string);
            }
        }
    }
    return $string;
}



回答10:


try this function

// trim the string function
function trim_word($text, $length, $startPoint=0, $allowedTags=""){
    $text = html_entity_decode(htmlspecialchars_decode($text));
    $text = strip_tags($text, $allowedTags);
    return $text = substr($text, $startPoint, $length);
}

and

echo trim_word("<h2 class='zzzz'>abcasdsdasasdas</h2>","6");


来源：https://stackoverflow.com/questions/2398725/using-php-substr-and-strip-tags-while-retaining-formatting-and-without-break

标签
php
html
substr
strip-tags
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