PHP Linkify 内容中的链接

Question

我一直在做一个小项目，我发现自己需要一个 php 函数，它可以链接我数据中的 URL，同时使我能够在我不想链接的链接上设置一些例外.知道如何做到这一点吗？

Answer 1

我在 GitHub 上有一个开源项目：LinkifyURL，您可能想考虑一下。它有一个功能：linkify() 从文本中提取 URL 并将它们转换为链接。请注意，正确完成这不是一项简单的任务！ （请参阅：The Problem With URLs - 并且一定要阅读 cmets 的帖子以掌握所有可能出错的内容。）

如果您确实不需要链接特定域（即 vimeo 和 youtube），这里有一个修改后的 PHP 函数 linkify_filtered（以工作测试脚本的形式），可以满足您的需要：

<?php // test.php 20110313_1200

function linkify_filtered($text) {
    $url_pattern = '/# Rev:20100913_0900 github.com\/jmrware\/LinkifyURL
    # Match http & ftp URL that is not already linkified.
      # Alternative 1: URL delimited by (parentheses).
      (\()                     # $1  "(" start delimiter.
      ((?:ht|f)tps?:\/\/[a-z0-9\-._~!$&\'()*+,;=:\/?#[\]@%]+)  # $2: URL.
      (\))                     # $3: ")" end delimiter.
    | # Alternative 2: URL delimited by [square brackets].
      (\[)                     # $4: "[" start delimiter.
      ((?:ht|f)tps?:\/\/[a-z0-9\-._~!$&\'()*+,;=:\/?#[\]@%]+)  # $5: URL.
      (\])                     # $6: "]" end delimiter.
    | # Alternative 3: URL delimited by {curly braces}.
      (\{)                     # $7: "{" start delimiter.
      ((?:ht|f)tps?:\/\/[a-z0-9\-._~!$&\'()*+,;=:\/?#[\]@%]+)  # $8: URL.
      (\})                     # $9: "}" end delimiter.
    | # Alternative 4: URL delimited by <angle brackets>.
      (<|&(?:lt|\#60|\#x3c);)  # $10: "<" start delimiter (or HTML entity).
      ((?:ht|f)tps?:\/\/[a-z0-9\-._~!$&\'()*+,;=:\/?#[\]@%]+)  # $11: URL.
      (>|&(?:gt|\#62|\#x3e);)  # $12: ">" end delimiter (or HTML entity).
    | # Alternative 5: URL not delimited by (), [], {} or <>.
      (                        # $13: Prefix proving URL not already linked.
        (?: ^                  # Can be a beginning of line or string, or
        | [^=\s\'"\]]          # a non-"=", non-quote, non-"]", followed by
        ) \s*[\'"]?            # optional whitespace and optional quote;
      | [^=\s]\s+              # or... a non-equals sign followed by whitespace.
      )                        # End $13. Non-prelinkified-proof prefix.
      ( \b                     # $14: Other non-delimited URL.
        (?:ht|f)tps?:\/\/      # Required literal http, https, ftp or ftps prefix.
        [a-z0-9\-._~!$\'()*+,;=:\/?#[\]@%]+ # All URI chars except "&" (normal*).
        (?:                    # Either on a "&" or at the end of URI.
          (?!                  # Allow a "&" char only if not start of an...
            &(?:gt|\#0*62|\#x0*3e);                  # HTML ">" entity, or
          | &(?:amp|apos|quot|\#0*3[49]|\#x0*2[27]); # a [&\'"] entity if
            [.!&\',:?;]?        # followed by optional punctuation then
            (?:[^a-z0-9\-._~!$&\'()*+,;=:\/?#[\]@%]|$)  # a non-URI char or EOS.
          ) &                  # If neg-assertion true, match "&" (special).
          [a-z0-9\-._~!$\'()*+,;=:\/?#[\]@%]* # More non-& URI chars (normal*).
        )*                     # Unroll-the-loop (special normal*)*.
        [a-z0-9\-_~$()*+=\/#[\]@%]  # Last char can\'t be [.!&\',;:?]
      )                        # End $14. Other non-delimited URL.
    /imx';
//    $url_replace = '$1$4$7$10$13<a href="$2$5$8$11$14">$2$5$8$11$14</a>$3$6$9$12';
//    return preg_replace($url_pattern, $url_replace, $text);
    $url_replace = '_linkify_filter_callback';
    return preg_replace_callback($url_pattern, $url_replace, $text);
}
function _linkify_filter_callback($m)
{ // Filter out youtube and vimeo domains.
    $pre  = $m[1].$m[4].$m[7].$m[10].$m[13];
    $url  = $m[2].$m[5].$m[8].$m[11].$m[14];
    $post = $m[3].$m[6].$m[9].$m[12];
    if (preg_match('/\b(?:youtube|vimeo)\.com\b/', $url)) {
        return $pre . $url . $post;
    } // else linkify...
    return $pre .'<a href="'. $url .'">' . $url .'</a>' .$post;
}

// Create some test data.
$data = 'Plain URLs (not delimited):
foo http://example.com bar...
foo http://example.com:80 bar...
foo http://example.com:80/path/ bar...
foo http://example.com:80/path/file.txt bar...
foo http://example.com:80/path/file.txt?query=val&var2=val2 bar...
foo http://example.com:80/path/file.txt?query=val&var2=val2#fragment bar...
foo http://example.com/(file\'s_name.txt) bar... (with \' and (parentheses))
foo http://[2001:0db8:85a3:08d3:1319:8a2e:0370:7348] bar... ([IPv6 literal])
foo http://[2001:0db8:85a3:08d3:1319:8a2e:0370:7348]/file.txt bar... ([IPv6] with path)
foo http://youtube.com bar...
foo http://youtube.com:80 bar...
foo http://youtube.com:80/path/ bar...
foo http://youtube.com:80/path/file.txt bar...
foo http://youtube.com:80/path/file.txt?query=val&var2=val2 bar...
foo http://youtube.com:80/path/file.txt?query=val&var2=val2#fragment bar...
foo http://youtube.com/(file\'s_name.txt) bar... (with \' and (parentheses))
foo http://vimeo.com bar...
foo http://vimeo.com:80 bar...
foo http://vimeo.com:80/path/ bar...
foo http://vimeo.com:80/path/file.txt bar...
foo http://vimeo.com:80/path/file.txt?query=val&var2=val2 bar...
foo http://vimeo.com:80/path/file.txt?query=val&var2=val2#fragment bar...
foo http://vimeo.com/(file\'s_name.txt) bar... (with \' and (parentheses))
';
// Verify it works...
echo(linkify_filtered($data) ."\n");

?>

这使用了一个回调函数来进行过滤。是的，正则表达式很复杂（但事实证明这是个问题！）。您可以在此处查看linkify() 的交互式 Javascript 版本：URL Linkification (HTTP/FTP)。

此外，John Gruber 有一个非常好的正则表达式来进行链接。见：An Improved Liberal, Accurate Regex Pattern for Matching URLs。然而，他的正则表达式在某些情况下会遭受灾难性的回溯。 （我已经写信给他，但他还没有回复。）

希望这会有所帮助！ :)

Answer 2

嗯，这很好，但是仍然存在很大的问题，字符串中的现有锚点，我想链接文本而不将它们转换为无意义的 sh.t.

Answer 3

$string = "some text and a link http://www.google.com"
$new_string = ereg_replace("[[:alpha:]]+://[^<>[:space:]]+[[:alnum:]/]","<a href=\"\\0\">\\0</a>", $string)

或使用：

http://code.iamcal.com/php/lib_autolink/