How do I linkify urls in a string with php?
You can use the following:
$string = "Look on http://www.google.com";
$string = preg_replace(
"~[[:alpha:]]+://[^<>[:space:]]+[[:alnum:]/]~",
"<a href=\"\\0\">\\0</a>",
$string);
PHP versions < 5.3 (ereg_replace) otherwise (preg_replace)
Linkify URLs with PHP, trim outputted urls length
Create a capture group after the protocol:
$string = preg_replace(
"~[[:alpha:]]+://([^<>[:space:]]+[[:alnum:]/])~",
"<a href=\"\\0\">\\1</a>",
$string
);
then \1
will be the URL without the protocol. For the text limiting I'd recommend using CSS, Setting a max character length in css.
PHP Linkify Links In Content
I have an open source project on GitHub: LinkifyURL which you may want to consider. It has a function: linkify()
which plucks URLs from text and converts them to links. Note that this is not a trivial task to do correctly! (See: The Problem With URLs - ands be sure to read the thread of comments to grasp all the things that can go wrong.)
If you really need to NOT linkify specific domains (i.e. vimeo and youtube), here is a modified PHP function linkify_filtered
(in the form of a working test script) that does what you need:
<?php // test.php 20110313_1200
function linkify_filtered($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");
?>
This employs a callback function to do the filtering. Yes, the regex is complex (but so it the problem as it turns out!). You can see the interactive Javascript version of linkify()
in action here: URL Linkification (HTTP/FTP).
Also, John Gruber has a pretty good regex to do linkification. See: An Improved Liberal, Accurate Regex Pattern for Matching URLs. However, his regex suffers catastrophic backtracking under certain circumstances. (I've written to him about this, but he has yet to respond.)
Hope this helps! :)
PHP: How do I linkify all links inside a given text?
That's the kind of thing best left to a 3rd party library (which you're doing, so kudos). I'd recommend trying another one before you roll your own. purl is an excellent alternative.
Related Topics
PHP Glob - Scan in Subfolders For a File
Read Each Line of Txt File to New Array Element
Jquery - Call Ajax Every 10 Seconds
How to Execute PHP That Is Stored in a MySQL Database
How to Create Virtual Host on Xampp
Does MySQL_Real_Escape_String() Fully Protect Against SQL Injection
Decode Gzipped Web Page Retrieved Via Curl in PHP
Fastest Way to Convert String to Integer in PHP
PHP Setcookie "Samesite=Strict"
PHP X86 How to Get Filesize of ≫ 2 Gb File Without External Program
How to Change Maximum Number of Post Variable in PHP
PHP: If Internet Explorer 6, 7, 8 , or 9
Mongodb Duplicate Documents Even After Adding Unique Key
How to Get First 5 Characters from String
How to Best Configure PHP to Handle a Utf-8 Website
Array_Splice() For Associative Arrays
Why I'M Getting 500 Error When Using File_Get_Contents(), But Works in a Browser