First my general issue is that I want to string replace question marks in a string, but only when they are not quoted. So I found a similar answer on SO (link) and began testing out the code. Unfortunately, of course, the code does not take into account escaped quotes.
For example: $string = 'hello="is it me your are looking for\\"?" AND test=?';
I have adapted a regular expression and code from that answer to the question: How to replace words outside double and single quotes, which is reproduced here for ease of reading my question:
<?php
function str_replace_outside_quotes($replace,$with,$string){
$result = "";
$outside = preg_split('/("[^"]*"|\'[^\']*\')/',$string,-1,PREG_SPLIT_DELIM_CAPTURE);
while ($outside)
$result .= str_replace($replace,$with,array_shift($outside)).array_shift($outside);
return $result;
}
?>
So I have attempted to adjust the pattern to allow for it to match anything that is not a quote " and quotes that are escaped \":
<?php
$pattern = '/("(\\"|[^"])*"' . '|' . "'[^']*')/";
// when parsed/echoed by PHP the pattern evaluates to
// /("(\"|[^"])*"|'[^']*')/
?>
But this does not work as I had hoped.
My test string is: hello="is it me your are looking for\"?" AND test=?
And I am getting the following matches:
array
0 => string 'hello=' (length=6)
1 => string '"is it me your are looking for\"?"' (length=34)
2 => string '?' (length=1)
3 => string ' AND test=?' (length=11)
Match index two should not be there. That question mark should be considered part of match index 1 only and not repeated separately.
Once resolved this same fix should also correct the other side of the main alternation for single quotes/apostrophes as well '.
After this is parsed by the complete function it should output:
echo str_replace_outside_quotes('?', '%s', 'hello="is it me your are looking for\\"?" AND test=?');
// hello="is it me your are looking for\"?" AND test=%s
I hope that this makes sense and I have provided enough information to answer the question. If not I will happily provide whatever you need.
My current (complete) code sample is on codepad for forking as well:
function str_replace_outside_quotes($replace, $with, $string){
$result = '';
var_dump($string);
$pattern = '/("(\\"|[^"])*"' . '|' . "'[^']*')/";
var_dump($pattern);
$outside = preg_split($pattern, $string, -1, PREG_SPLIT_DELIM_CAPTURE);
var_dump($outside);
while ($outside) {
$result .= str_replace($replace, $with, array_shift($outside)) . array_shift($outside);
}
return $result;
}
echo str_replace_outside_quotes('?', '%s', 'hello="is it me your are looking for\\"?" AND test=?');
In: hello="is it me your are looking for\\"?" AND test=? AND hello='is it me your are looking for\\'?' AND test=? hello="is it me your are looking for\\"?" AND test=?' AND hello='is it me your are looking for\\'?' AND test=?
Out: hello="is it me your are looking for\\"?" AND test=%s AND hello='is it me your are looking for\\'?' AND test=%s hello="is it me your are looking for\\"?" AND test=%s AND hello='is it me your are looking for\\'?' AND test=%s
In: my_var = ? AND var_test = "phoned?" AND story = 'he said \'where is it?!?\''
Out: my_var = %s AND var_test = "phoned?" AND story = 'he said \'where is it?!?\''
The following tested script first checks that a given string is valid, consisting solely of single quoted, double quoted and un-quoted chunks. The $re_valid regex performs this validation task. If the string is valid, it then parses the string one chunk at a time using preg_replace_callback() and the $re_parse regex. The callback function processes the unquoted chunks using preg_replace(), and returns all quoted chunks unaltered. The only tricky part of the logic is passing the $replace and $with argument values from the main function to the callback function. (Note that PHP procedural code makes this variable passing from the main function to the callback function a bit awkward.) Here is the script:
<?php // test.php Rev:20121113_1500
function str_replace_outside_quotes($replace, $with, $string){
$re_valid = '/
# Validate string having embedded quoted substrings.
^ # Anchor to start of string.
(?: # Zero or more string chunks.
"[^"\\\\]*(?:\\\\.[^"\\\\]*)*" # Either a double quoted chunk,
| \'[^\'\\\\]*(?:\\\\.[^\'\\\\]*)*\' # or a single quoted chunk,
| [^\'"\\\\]+ # or an unquoted chunk (no escapes).
)* # Zero or more string chunks.
\z # Anchor to end of string.
/sx';
if (!preg_match($re_valid, $string)) // Exit if string is invalid.
exit("Error! String not valid.");
$re_parse = '/
# Match one chunk of a valid string having embedded quoted substrings.
( # Either $1: Quoted chunk.
"[^"\\\\]*(?:\\\\.[^"\\\\]*)*" # Either a double quoted chunk,
| \'[^\'\\\\]*(?:\\\\.[^\'\\\\]*)*\' # or a single quoted chunk.
) # End $1: Quoted chunk.
| ([^\'"\\\\]+) # or $2: an unquoted chunk (no escapes).
/sx';
_cb(null, $replace, $with); // Pass args to callback func.
return preg_replace_callback($re_parse, '_cb', $string);
}
function _cb($matches, $replace = null, $with = null) {
// Only set local static vars on first call.
static $_replace, $_with;
if (!isset($matches)) {
$_replace = $replace;
$_with = $with;
return; // First call is done.
}
// Return quoted string chunks (in group $1) unaltered.
if ($matches[1]) return $matches[1];
// Process only unquoted chunks (in group $2).
return preg_replace('/'. preg_quote($_replace, '/') .'/',
$_with, $matches[2]);
}
$data = file_get_contents('testdata.txt');
$output = str_replace_outside_quotes('?', '%s', $data);
file_put_contents('testdata_out.txt', $output);
?>