PHP preg_replace error when using on array

Question

We have got web app which does replacing some text with another using str_replace(). Find strings and replace strings are stored in template file.

We what to replace str_replace() function to preg_replace() to have possibility to use regex in find strings (to set them in the same template file).

In original scripts we have such parts of php code.

In one file:

class SiteConfig {

// Strings to search for in HTML before processing begins (used with $replace_string)
public $find_string = array();
// Strings to replace those found in $find_string before HTML processing begins
public $replace_string = array();

// a lot of code goes here

public function append(SiteConfig $newconfig) {
    foreach (array('find_string', 'replace_string') as $var) {
        // append array elements for this config variable from $newconfig to this config
        //$this->$var = $this->$var + $newconfig->$var;
        $this->$var = array_merge($this->$var, $newconfig->$var);
    }
}

// a lot of code goes here

public static function build_from_array(array $lines) {
    $config = new SiteConfig();
    foreach ($lines as $line) {
        $line = trim($line);

        // skip comments, empty lines
        if ($line == '' || $line[0] == '#') continue;

        // get command
        $command = explode(':', $line, 2);
        // if there's no colon ':', skip this line
        if (count($command) != 2) continue;
        $val = trim($command[1]);
        $command = trim($command[0]);
        //if ($command == '' || $val == '') continue;
        // $val can be empty, e.g. replace_string: 
        if ($command == '') continue;

        // strip_attr is now an alias for strip.
        // In FTR 3.8 we can strip attributes from elements, not only the elements themselves
        // e.g. strip: //img/@srcset (removes srcset attribute from all img elements)
        // but for backward compatibility (to avoid errors with new config files + old version of FTR)
        // we've introduced strip_attr and we'll recommend using that in our public site config rep.
        // strip_attr: //img/@srcset
        if ($command == 'strip_attr') $command = 'strip';

        // check for commands where we accept multiple statements
        if (in_array($command, array('title', 'body', 'author', 'date', 'strip', 'strip_id_or_class', 'strip_image_src', 'single_page_link', 'single_page_link_in_feed', 'next_page_link', 'native_ad_clue', 'http_header', 'test_url', 'find_string', 'replace_string'))) {
            array_push($config->$command, $val);
        // check for single statement commands that evaluate to true or false
        } elseif (in_array($command, array('tidy', 'prune', 'autodetect_on_failure', 'insert_detected_image'))) {
            $config->$command = ($val == 'yes');
        // check for single statement commands stored as strings
        } elseif (in_array($command, array('parser'))) {
            $config->$command = $val;
        // special treatment for test_contains
        } elseif (in_array($command, array('test_contains'))) {
            $config->add_test_contains($val);
        // special treatment for if_page_contains
        } elseif (in_array($command, array('if_page_contains'))) {
            $config->add_if_page_contains_condition($val);
        // check for replace_string(find): replace
        } elseif ((substr($command, -1) == ')') && preg_match('!^([a-z0-9_]+)\((.*?)\)$!i', $command, $match)) {
            if (in_array($match[1], array('replace_string'))) {
                array_push($config->find_string, $match[2]);
                array_push($config->replace_string, $val);
            } elseif (in_array($match[1], array('http_header'))) {
                $_header = strtolower(trim($match[2]));
                $config->http_header[$_header] = $val;
            }
        }
    }
    return $config;
}

}

In another file:

public function process($html, $url, $smart_tidy=true) {

    // a lot of code goes before

    // do string replacements
    if (!empty($this->config->find_string)) {
        if (count($this->config->find_string) == count($this->config->replace_string)) {
            $html = str_replace($this->config->find_string, $this->config->replace_string, $html, $_count);
            $this->debug("Strings replaced: $_count (find_string and/or replace_string)");
        } else {
            $this->debug('Skipped string replacement - incorrect number of find-replace strings in site config');
        }
        unset($_count);
    }

    // a lot of code goes after
}

I tried to replace str_replace() with preg_replace(), but while testing it shows an error:

Warning: preg_replace(): No ending matching delimiter '>' found in this line:

            $html = preg_replace($this->config->find_string, $this->config->replace_string, $html, $_count);

Where is the error and how to replace str_replace() function to preg_replace() correctly? I'm very very beginning in php, so any help is badly needed. Big thanks in advance!

With that kind of error, we're going to need to see how you're constructing your regular expression string. `preg_replace` is not a "drop in" replacement for `str_replace`, at minimum you may need `'/'.preg_quote($this->config->find_string).'/'` for non regex based patterns, but then that's just silly and has no benefit over the former. — Scuzzy, Jul 29 '18 at 21:06
This error goes even I have no any regular expression string in template. — Jesty, Jul 29 '18 at 21:11
regex in php expects a leading and trailing character as part of the pattern, eg to match `hello` your expression would be `/hello/` http://php.net/manual/en/regexp.reference.delimiters.php — Scuzzy, Jul 29 '18 at 21:11
Yes, of cause, when I tried to set regular expression in template it was: find_string: /teststing/ — Jesty, Jul 29 '18 at 21:14
You're going to have to us show what's in `$this->config->find_string` and `$this->config->replace_string` i'd say. — Scuzzy, Jul 29 '18 at 21:16
But even when I remove string 'find_string: /teststing/' from template file it shows the same error, so I think that the error in this string construction '$html = preg_replace($this->config->find_string, $this->config->replace_string, $html, $_count);' — Jesty, Jul 29 '18 at 21:19
`Warning: preg_replace(): No ending matching delimiter '>' found in this line:` this error is telling us there's a problem with a particular regular expression, show us it and we can help you. — Scuzzy, Jul 29 '18 at 21:19
Possible duplicate of [PHP regular expressions: No ending delimiter '^' found in](https://stackoverflow.com/questions/4634993/php-regular-expressions-no-ending-delimiter-found-in) — Scuzzy, Jul 29 '18 at 21:20
@Scuzzy, when I delete whole regex from settings, the same error persist, so it is not about my regex. — Jesty, Jul 29 '18 at 21:24
show us the content of `$this->config->find_string` and `$this->config->replace_string` please — Scuzzy, Jul 29 '18 at 21:28
@Scuzzy Using echo? `echo $this->config->find_string;` or how to see that content? — Jesty, Jul 29 '18 at 21:34
With `str_replace()` (as it was in original script) everything is working fine. I just need to set `find_string: teststingtofind` in template file. — Jesty, Jul 29 '18 at 21:51
You can use `var_dump()` or `print_r()` to display the data. — Scuzzy, Jul 29 '18 at 21:55
I used `print_r()`: `Array ( [0] => /test/ [1] => /test/ [2] => [4] => [6] => [8] => ) Array ( [0] => replace_test [1] => replace_test [2] => [4] => [6] => [8] => )` — Jesty, Jul 29 '18 at 21:59
And with `var_dump`: `array(10) { [0]=> string(6) "/test/" [1]=> string(6) "/test/" [2]=> string(8) " string(10) "" [4]=> string(8) " string(10) "" [6]=> string(8) " string(10) "" [8]=> string(8) " string(10) "" } array(10) { [0]=> string(12) "replace_test" [1]=> string(12) "replace_test" [2]=> string(4) " string(16) "" [4]=> string(4) " string(16) "" [6]=> string(4) " string(16) "" [8]=> string(4) " string(16) "" } ` — Jesty, Jul 29 '18 at 22:00
Those empty ones are probably going to be a problem because they are not a valid regular expression pattern. Either way I'm not seeing anything with `>` in it as per that error. Also can you try `preg_replace($this->config->find_string, $this->config->replace_string, $html, -1, $_count);` because the 4th parameter does not align with str_replace's 4th parameter — Scuzzy, Jul 29 '18 at 22:10
Maybe I cannot use `$this->config->find_string` in `preg_replace()` as a parametr? And php thinks that `>` in that statment needs ending delimiter? — Jesty, Jul 29 '18 at 22:16
Tried `preg_replace($this->config->find_string, $this->config->replace_string, $html, -1, $_count);` - the same error... — Jesty, Jul 29 '18 at 22:19
An array of regex is fine https://3v4l.org/hJtRl having empty space is not https://3v4l.org/NO5sd having bad delimiters is not https://3v4l.org/dlo6P — Scuzzy, Jul 29 '18 at 22:25
And none of the examples shows the same error `Warning: preg_replace(): No ending matching delimiter '>' found in` — Jesty, Jul 29 '18 at 22:29
Since preg_replace() is expecting an un-parsed regex string, you have to add delimiters and escape them as necessary. If you were not using arrays, you could construct the regex string dynamically `preg_replace('~' . $astring . '~', 'replace with this' )` But since you're passing an array, you have to include the delimiter when you construct/declare your array. `$rxary = [ '~' . $astring . '~', ...];` And, for safety, it's good practice to escape regex metachars in the variable `preg_quote($astring)` as well as escaping the delimiter your using, in this case, it's the `~`. — , Jul 29 '18 at 23:14
@sln as I said, even if I delete regex string at all, I recieve the same error. — Jesty, Jul 29 '18 at 23:37

Erisan Olasheni · Accepted Answer · 2018-07-30T00:29:07.767

0

Rewrite your process function like this:

public function process($html, $url, $smart_tidy=true) {

    // a lot of code goes before

    // do string replacements
    if (!empty($this->config->find_string)) {
        if (count($this->config->find_string) == count($this->config->replace_string)) {



    $new_config_find_string = array_map(function($new_pattern)
    {
        return '/'.preg_quote($new_pattern).'/';
    },$this->config->find_string);


    $html = preg_replace($new_config_find_string, $this->config->replace_string, $html, $_count);

            $this->debug("Strings replaced: $_count (find_string and/or replace_string)");
        } else {
            $this->debug('Skipped string replacement - incorrect number of find-replace strings in site config');
        }
        unset($_count);
    }

    // a lot of code goes after
}

edited Jul 30 '18 at 00:29

answered Jul 29 '18 at 23:53

Erisan Olasheni

2,395
17
20

@Ersian it gives `Warning: preg_quote() expects parameter 1 to be string, array given in` that string – Jesty Jul 30 '18 at 00:04
after your change now it gives `Warning: preg_replace(): Unknown modifier 'a' in` the same string. And where exactly do I need to place first part of your code? – Jesty Jul 30 '18 at 00:11
please confirm if `$this->config->find_string` and `$this->config->replace_string` are both arrays, and it is better to show us the real values of it – Erisan Olasheni Jul 30 '18 at 00:22
arrays, you can see values in comments above. – Jesty Jul 30 '18 at 00:27
the same `Warning: preg_replace(): Unknown modifier 'a' in` the same string. – Jesty Jul 30 '18 at 00:35
`print_r($new_config_find_string);` gives: `Array ( [0] => /123/ [1] => /123/ [2] => /\ /\/ [4] => /\ /\/ [6] => /\ /\/ [8] => /\ /\/ ) ` Where `123` is find_string value in template file. – Jesty Jul 30 '18 at 00:45
that's according to what's in your $this->config->find_string array – Erisan Olasheni Jul 30 '18 at 07:02
I will still suggest that you give us exactly what is inside the `$this->config->find_string` and the `$this->config->replace_string` arrays – Erisan Olasheni Jul 30 '18 at 07:03
how to do that? – Jesty Jul 30 '18 at 08:01
you can user `var_dump($this->config->find_string);` `var_dump($this->config->replace_string);` And Paste in the results – Erisan Olasheni Jul 30 '18 at 08:28
`array(10) { [0]=> string(3) "123" [1]=> string(3) "123" [2]=> string(8) " string(10) "" [4]=> string(8) " string(10) "" [6]=> string(8) " string(10) "" [8]=> string(8) " string(10) "" }` `array(10) { [0]=> string(13) "replace_test1" [1]=> string(13) "replace_test1" [2]=> string(4) " string(16) "" [4]=> string(4) " string(16) "" [6]=> string(4) " string(16) "" [8]=> string(4) " string(16) "" } ` Where `123` is `find_string` value in template file. – Jesty Jul 30 '18 at 09:13
there are errors in the way these patterns are quoted, in your `$this->config->find_string` why are there empty strings? There should not be. You will have to work on that first, you cannot replace `nothing` with `something` – Erisan Olasheni Jul 30 '18 at 15:32
and why everything works well `str_replace()` and the same array? – Jesty Jul 30 '18 at 16:04

PHP preg_replace error when using on array

1 Answers1