如何从文本中删除特定用户的所有 bbcode 引用块？

Question

我想删除在 PHP 中用 BBCode 制作的引号，就像这个例子：

[quote=testuser]
[quote=anotheruser]a sdasdsa dfv rdfgrgre gzdf vrdg[/quote]
sdfsd fdsf dsf sdf[/quote]
the rest of the post text

我正在考虑建立一个屏蔽系统，这样用户就不必看到他们不想看到的内容。所以说 "testuser" 被阻止了，他们不想要整个引用部分，包括嵌套在里面的第二个引用，因为它是主引用的一部分。

所以 post 将只剩下：

the rest of the post text

我想知道这样做的最佳方法。我希望正则表达式，但它比我想的更复杂，我有这个尝试：

/\[quote\=testuser\](.*)\[\/quote\]/is

但是，这会捕获所有结束引号标记。

是否有其他快速的替代方法，或者可以很好地修复我的正则表达式？

总而言之：删除被阻止用户的初始报价以及该报价内的所有内容，但除此之外别无其他。

Answer 1

使用单个正则表达式无法实现您想要的。我建议扫描文件，直到找到 [quote=testuser]。找到它后，设置一个布尔值以开始过滤，并将计数器设置为 1。在布尔值为真后，为您遇到的每个 [quote=...] 标记增加计数器。为遇到的每个 [/quote] 标记递减计数器。当计数器达到 0 时，将用于过滤的布尔值更改为 false。

这是一些sudocode。您可能需要根据您的应用程序对其进行一些修改，但我认为它显示了要使用的一般算法。

filtering = false
counter = 0
for each line:
    if line contains "[quote=testuser]"
        filtering = true
        counter = 0
    if line contains "[quote="
        counter += 1
    if line contains "[/quote]
        counter -= 1
    if counter = 0
        filtering = false
    if not filtering
        print line

Answer 2

据我所知，这不是一个简单的过程。这是我的步骤...

使用preg_split() 将输入字符串分成 3 种方式：左引号标签、右引号标签和其他。我在开始和结束标签上分开，但使用 DELIM_CAPTURE 将它们保存在输出数组和原始 position/order 中。使用 NO_EMPTY 是为了在 foreach 循环中没有无用的迭代。
遍历生成的数组并搜索要省略的用户名。
当找到目标用户的引用时，存储该元素的起始索引，并将 $open 设置为 1。
每当找到新的开头引号标签时，$open 就会递增。
每当找到新的结束引号标记时，$open 就会递减。
一旦 $open 达到 0，$start 和 end 索引将被馈送到 range() 以生成一个数组，其中包含两点。
array_flip()，当然，将值移动到键。
array_diff_key() 从 preg_split().
如果一切顺利，implode() 会将子字符串粘合在一起，只保留所需的组件。

函数声明：(Demo)

/*
This function DOES NOT validate the $bbcode string to contain a balanced number of opening & closing tags.
This funcion DOES check that there are enough closing tags to conclude a targeted opening tag.
*/
function omit_user_quotes($bbcode, $user) {
    $substrings = preg_split('~(\[/?quote[^]]*\])~', $bbcode, 0, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
    $opens = 0;  // necessary declaration to avoid Notice when no quote tags in $bbcode string
    foreach ($substrings as $index => $substring) {
        if (!isset($start) && $substring == "[quote={$user}]") {  // found targeted user's first opening quote
            $start = $index;  // disqualify the first if statement and start searching for end tag
            $opens = 1;  // $opens counts how many end tags are required to conclude quote block
        } elseif (isset($start)) {
            if (strpos($substring, '[quote=') !== false) {  // if a nested opening quote tag is found
                ++$opens;  // increment and continue looking for closing quote tags
            } elseif (strpos($substring, '[/quote]') !== false) {  // if a closing quote tag is found
                --$opens;  // decrement and check for quote tag conclusion or error
                if (!$opens) {  // if $opens is zero ($opens can never be less than zero)
                    $substrings = array_diff_key($substrings, array_flip(range($start, $index)));  // slice away unwanted elements from input array
                    unset($start);  // re-qualify the first if statement to allow the process to repeat
                }
            }
        }
    }
    if ($opens) {  // if $opens is positive
        return 'Error due to opening/closing tag imbalance (too few end tags)';
    } else {
        return trim(implode($substrings));  // trims the whitespaces on either side of $bbcode string as feature
    }    
}

测试输入：

/* Single unwanted quote with nested innocent quote: */
/*$bbcode='[quote=testuser]
[quote=anotheruser]a sdasdsa dfv rdfgrgre gzdf vrdg[/quote]
sdfsd fdsf dsf sdf[/quote]
the rest of the test'; */
/* output: the rest of the test */

/* Complex battery of unwanted, wanted, and nested quotes: */
$bbcode = '[quote=mickmackusa]Keep this[/quote]
[quote=testuser]Don\'t keep this because 
    [quote=mickmackusa]said don\'t do it[/quote]
    ... like that\'s a good reason
    [quote=NaughtySquid] It\'s tricky business, no?[/quote]
    [quote=nester][quote=nesty][quote=nested][/quote][/quote][/quote]
[/quote]
Let\'s remove a second set of quotes
[quote=testuser]Another quote block[/quote]
[quote=mickmackusa]Let\'s do a third quote inside of my quote...
[quote=testuser]Another quote block[/quote]
[/quote]
This should be good, but
What if [quote=testuser]quotes himself [quote=testuser] inside of his own[/quote] quote[/quote]?';

/* No quotes: */
//$bbcode='This has no bbcode quote tags in it.';
/* output: This has no bbcode quote tags in it. */

/* Too few end quote tags by innocent user:
(No flag is raised because the targeted user has not quoted any text) */
//$bbcode='This [quote=mickmackusa] has not end tag.';
/* output: This [quote=mickmackusa] has not end tag. */

/* Too few end quote tags by unwanted user: */
//$bbcode='This [quote=testuser] has not end tag.';
/* output: Error due to opening/closing tag imbalance (too few end tags) */

/* Too many end quote tags by unwanted user: 
(No flag is raised because the function does not validate the bbcode text as fully balanced) */
//$bbcode='This [quote=testuser] has too many end[/quote] tags.[/quote]';
/* output: This  tags.[/quote] */

函数调用：

$user = 'testuser';

echo omit_user_quotes($bbcode, $user);  // omit a single user's quote blocks

/* Or if you want to omit quote blocks from multiple users, you can use a loop:
$users = ['mickmackusa', 'NaughtySquid'];
foreach ($users as $user) {
    $bbcode = omit_user_quotes($bbcode, $user);
}
echo $bbcode;
*/

如何从文本中删除特定用户的所有 bbcode 引用块？

How to remove all bbcode quote blocks by a specific user from a text?

php

regex

filtering

substring

bbcode