Same name in other branches

1. 7.x modules/search/search.module \search_excerpt()
2. 9 core/modules/search/search.module \search_excerpt()
3. 8.9.x core/modules/search/search.module \search_excerpt()
4. 11.x core/modules/search/search.module \search_excerpt()

Returns snippets from a piece of text, with search keywords highlighted.

Used for formatting search results. All HTML tags will be stripped from $text.

Parameters

string $keys: A string containing a search query.

string $text: The text to extract fragments from.

string|null $langcode: Language code for the language of $text, if known.

Return value

array A render array containing HTML for the excerpt.

Related topics

3 calls to search_excerpt()

HelpSearch::prepareResults in core/modules/help/src/Plugin/Search/HelpSearch.php

Prepares search results for display.

NodeSearch::prepareResults in core/modules/node/src/Plugin/Search/NodeSearch.php

Prepares search results for rendering.

SearchExcerptTest::doSearchExcerpt in core/modules/search/tests/src/Kernel/SearchExcerptTest.php

Calls search_excerpt() and renders output.

File

core/modules/search/search.module, line 134

Code

function search_excerpt($keys, $text, $langcode = NULL) {
    // We highlight around non-indexable or CJK characters.
    $boundary_character = '[' . Unicode::PREG_CLASS_WORD_BOUNDARY . SearchTextProcessorInterface::PREG_CLASS_CJK . ']';
    $preceded_by_boundary = '(?<=' . $boundary_character . ')';
    $followed_by_boundary = '(?=' . $boundary_character . ')';
    // Extract positive keywords and phrases.
    preg_match_all('/ ("([^"]+)"|(?!OR)([^" ]+))/', ' ' . $keys, $matches);
    $keys = array_merge($matches[2], $matches[3]);
    // Prepare text by stripping HTML tags and decoding HTML entities.
    $text = strip_tags(str_replace([
        '<',
        '>',
    ], [
        ' <',
        '> ',
    ], $text));
    $text = Html::decodeEntities($text);
    $text_length = strlen($text);
    // Make a list of unique keywords that are actually found in the text,
    // which could be items in $keys or replacements that are equivalent through
    // \Drupal\search\SearchTextProcessorInterface::analyze().
    $temp_keys = [];
    foreach ($keys as $key) {
        $key = _search_find_match_with_simplify($key, $text, $boundary_character, $langcode);
        if (isset($key)) {
            // Quote slashes so they can be used in regular expressions.
            $temp_keys[] = preg_quote($key, '/');
        }
    }
    // Several keywords could have simplified down to the same thing, so pick
    // out the unique ones.
    $keys = array_unique($temp_keys);
    // Extract fragments of about 60 characters around keywords, bounded by word
    // boundary characters. Try to reach 256 characters, using second occurrences
    // if necessary.
    $ranges = [];
    $length = 0;
    $look_start = [];
    $remaining_keys = $keys;
    while ($length < 256 && !empty($remaining_keys)) {
        $found_keys = [];
        foreach ($remaining_keys as $key) {
            if ($length >= 256) {
                break;
            }
            // Remember where we last found $key, in case we are coming through a
            // second time.
            if (!isset($look_start[$key])) {
                $look_start[$key] = 0;
            }
            // See if we can find $key after where we found it the last time. Since
            // we are requiring a match on a word boundary, make sure $text starts
            // and ends with a space.
            $matches = [];
            if (preg_match('/' . $preceded_by_boundary . $key . $followed_by_boundary . '/iu', ' ' . $text . ' ', $matches, PREG_OFFSET_CAPTURE, $look_start[$key])) {
                $found_position = $matches[0][1];
                $look_start[$key] = $found_position + 1;
                // Keep track of which keys we found this time, in case we need to
                // pass through again to find more text.
                $found_keys[] = $key;
                // Locate a space before and after this match, leaving about 60
                // characters of context on each end.
                $before = strpos(' ' . $text, ' ', max(0, $found_position - 61));
                if ($before !== FALSE && $before <= $found_position) {
                    if ($text_length > $found_position + 60) {
                        $after = strrpos(substr($text, 0, $found_position + 60), ' ', $found_position);
                    }
                    else {
                        $after = $text_length;
                    }
                    if ($after !== FALSE && $after > $found_position) {
                        // Account for the spaces we added.
                        $before = max($before - 1, 0);
                        if ($before < $after) {
                            // Save this range.
                            $ranges[$before] = $after;
                            $length += $after - $before;
                        }
                    }
                }
            }
        }
        // Next time through this loop, only look for keys we found this time,
        // if any.
        $remaining_keys = $found_keys;
    }
    if (empty($ranges)) {
        // We didn't find any keyword matches, so just return the first part of the
        // text. We also need to re-encode any HTML special characters that we
        // entity-decoded above.
        return [
            '#plain_text' => Unicode::truncate($text, 256, TRUE, TRUE),
        ];
    }
    // Sort the text ranges by starting position.
    ksort($ranges);
    // Collapse overlapping text ranges into one. The sorting makes it O(n).
    $new_ranges = [];
    $max_end = 0;
    foreach ($ranges as $this_from => $this_to) {
        $max_end = max($max_end, $this_to);
        if (!isset($working_from)) {
            // This is the first time through this loop: initialize.
            $working_from = $this_from;
            $working_to = $this_to;
            continue;
        }
        if ($this_from <= $working_to) {
            // The ranges overlap: combine them.
            $working_to = max($working_to, $this_to);
        }
        else {
            // The ranges do not overlap: save the working range and start a new one.
            $new_ranges[$working_from] = $working_to;
            $working_from = $this_from;
            $working_to = $this_to;
        }
    }
    // Save the remaining working range.
    $new_ranges[$working_from] = $working_to;
    // Fetch text within the combined ranges we found.
    $out = [];
    foreach ($new_ranges as $from => $to) {
        $out[] = substr($text, $from, $to - $from);
    }
    // Combine the text chunks with "…" separators. The "…" needs to be
    // translated. Let translators have the … separator text as one chunk.
    $ellipses = explode('@excerpt', t('… @excerpt … @excerpt …'));
    $text = (isset($new_ranges[0]) ? '' : $ellipses[0]) . implode($ellipses[1], $out) . ($max_end < strlen($text) - 1 ? $ellipses[2] : '');
    $text = Html::escape($text);
    // Highlight keywords. Must be done at once to prevent conflicts ('strong'
    // and '<strong>').
    $text = trim(preg_replace('/' . $preceded_by_boundary . '(?:' . implode('|', $keys) . ')' . $followed_by_boundary . '/iu', '<strong>\\0</strong>', ' ' . $text . ' '));
    return [
        '#markup' => $text,
        '#allowed_tags' => [
            'strong',
        ],
    ];
}

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