I am trying to use regex in php to find all strings that starts with "$" and replacing it with the appropriate variable. For example:
$value = "Some Value";
<b>$value</b>
Where the end result should be:
<b>Some Value</b>
This is what I have tried:
ob_start("tagreplace");
function tagreplace ( $tagreplace )
{
$value1 = "Some Value";
$pattern = '/(?<=\s)(\$[^#\s]+)(?=\s)/';
$tagreplace = preg_replace( $pattern , '<?php echo $0 ?>', $tagreplace);
return $tagreplace;
}
/* html files for combining */
include 'main_content.html';
ob_end_flush();
But this doesn't seem to work... I've tried for loops, while loops, and none of them are working. Basically I am trying to be extremely lazy and use regex to make very shorthand variables that I can put everywhere, replacing the strings like "$value" with whatever corresponding value that the variable $value has assigned to it.
I understand that /e is now deprecated so I can't use that to treat php tags as actual code. I have attempted to use preg_replace_callback but this didn't actually do anything. I'm thinking there probably isn't a way to properly do this.
It's not exactly clear what you're trying to do here, although if you take a slightly different approach with your regex you'll likely have more success. Essentially it's easier to break the pattern up into three capture groups (the start tag, the value, and the end tag)
function tagreplace ( $tagreplace ) {
$replace = "Some Value";
$pattern = '/(.+>)(.+)(<.+)/m';
$tagreplace = preg_replace( $pattern, '$1'.$replace.'$3', $tagreplace);
return $tagreplace;
}
$value = "Old Value";
echo tagreplace("<b>$value</b>");
echo "\n -- Using \$value slightly different-- \n";
$value = "<b>$value</b>";
echo tagreplace($value);
By using a more generic pattern you should be able swap out $value, regardless if it's the entire value, or if it's what is between the < > tags. When in doubt use a regex tester (linked below) and you might be able to eliminate several recursive loops, or going around in circles.
Example:
https://regex101.com/r/rW8lC6/1
Related
I have a source of html, and an array of keywords. I'm trying to find all words which begin with any keyword in the keywords array and wrap it in a link tag.
For example, the keyword array has two values: [ABC, DEF]. It should match ABCDEF, DEFAD, etc. and wrap each word with hyperlink markup.
Here is the code I've got so far:
$_keys = array('ABC', 'DEF');
$text = 'Some ABCDD <strong>HTML</strong> text. DEF';
function search_and_replace(($key,$text)
{
$words = preg_split('/\s+/', trim($text)); //to seprate words in $_text
for($words as $word)
{
if(strpos($word,$key) !== false)
{
if($word.startswith($key))
{
str_replace($word,''.$word.',$_text);
}
}
}
return text;
}
for($_keys as $_key)
{
$text = search_and_replace($key,$text);
}
My questions:
Would this algorithm work?
How would I modify this to work with UTF-8?
How can I recognize hyperlinks in the html and ignore them (don't want to put a hyperlink in a hyperlink).
Is this algorithm safe?
is the algorithm "true"? ( I'm reading "accurate")
No, it is not. Since str_replace functions as follows
a string or an array with all occurrences of search in subject
replaced with the given replace value.
The string you're matching is not the only one being replaced. Using your example, if you ran this function against your data set, you'd end up wrapping each occurrence of ABC in multiple tags ( just run your code to see it, but you'll have to fix syntax errors).
work with UTF-8 Alphabets?
Not sure, but as written, I don't think so. See Preg_Replace and UTF8. PREG functions should be multibyte safe.
I want to igonre all words in each a tag for search operetion
That's awefully hard. You'll have to avoid <a ...>word</a>, which starts to make a big mess fast. Regex matching HTML reliably is a fool's errand.
Probably the best would be to interpret the webpage as XML or HTML. Have you considered doing this in javascript? Why do it on the server side? The advantage of JS is twofold - one, it runs on the client side, so you're offloading / distributing the work, and two, since the DOM is already interpreted, you can find all text nodes and replace them fairly easily. In fact, I was helping a frend working on a chrome extension to to almost exactly what you're describing; you could modify it to do what you're looking for easily.
a better alternative method?
Definitely. What you're showing here is one of the worse methods of doing this. I'd push for you to use preg_replace ( another answer has a good start for the regex you'd want, matching word breaks tather than whitespace) but since you want to avoid changing some elements, I'm thinking now that doing this in JS client-side is far better.
In order to maximize your performance you should look into Trie (same as Retrieval Tree) data structure. (http://en.wikipedia.org/wiki/Trie) If I were you I would first build a Trie containing the words in the HTML page. At this step you could also check if the word is inside an <a> tag and if it this then do not add it to the Trie. You can easily do that with a Regex match
How about regex?
preg_match_all("/\b".$word."\B*\b/",$matches);
foreach($matches as $each) {
print($each[0]);
}
(Sorry, my PHP is a bit rusty)
For a simple task like this PHP regular expressions will serve well. The idea is to find all hyperlinks ( and optionally some other HTML elements ) and replace them with unique tokens. After that we are free to seek and replace desired keywords, and in the end we will restore the removed HTML elements back.
$_keys = array( 'ABC', 'DEF', 'ABČ' );
$text =
'Some <a href="#" >ABC</a> ABCDđD <strong>ABCDEF</strong> text. DEF
<p class="test">
PHP is <em>the</em> most ABCwidely used
langČuage ABC for ABČogr ammDEFing on the webABC DEFABC.
</p>';
// array for holding html items replaced with tokens
$tokens = array();
$id = 0;
// we will replace all links and strong elements (a|strong)
$text = preg_replace_callback( '/<(a|strong)[^>]*>.*?<\/\1\s*>/s',
function( $matches ) use ( &$tokens, &$id )
{
// store matches into the tokens array
$tokens[ '#'.++$id.'#' ] = $matches[0];
// replace matches with the unique id
return '#'.$id.'#';
},
$text
);
echo htmlentities( $text );
/* - outputs: Some #1# ABCDđD #2# text. DEF <p class="test"> #3# is <em>the</em> most ABCwidely used langČuage ABC for pćrogrABCamming on the webABC DEFABC. </p>
- note the #1# #2# #3# tokens
*/
// wrap the words that starts with items in $_keys array ( with u(PCRE_UTF8) modifier )
$text = preg_replace( '/\b('. implode( '|', $_keys ) . ')\w*\b/u', '$0', $text );
// replace the tokens with values
$text = str_replace( array_keys($tokens), array_values($tokens), $text );
echo $text;
Info about UTF-8 strings in PHP regex:
$text = "
<tag>
<html>
HTML
</html>
</tag>
";
I want to replace all the text present inside the tags with htmlspecialchars(). I tried this:
$regex = '/<tag>(.*?)<\/tag>/s';
$code = preg_replace($regex,htmlspecialchars($regex),$text);
But it doesn't work.
I am getting the output as htmlspecialchars of the regex pattern. I want to replace it with htmlspecialchars of the data matching with the regex pattern.
what should i do?
You're replacing the match with the pattern itself, you're not using the back-references and the e-flag, but in this case, preg_replace_callback would be the way to go:
$code = preg_replace_callback($regex,'htmlspecialchars',$text);
This will pass the mathces groups to htmlspecialchars, and use its return value as replacement. The groups might be an array, in which case, you can try either:
function replaceCallback($matches)
{
if (is_array($matches))
{
$matches = implode ('', array_slice($matches, 1));//first element is full string
}
return htmlspecialchars($matches);
}
Or, if your PHP version permits it:
preg_replace_callback($expr, function($matches)
{
$return = '';
for ($i=1, $j = count($matches); $i<$j;$i++)
{//loop like this, skips first index, and allows for any number of groups
$return .= htmlspecialchars($matches[$i]);
}
return $return;
}, $text);
Try any of the above, until you find simething that works... incidentally, if all you want to remove is <tag> and </tag>, why not go for the much faster:
echo htmlspecialchars(str_replace(array('<tag>','</tag>'), '', $text));
That's just keeping it simple, and it'll almost certainly be faster, too.
See the quickest, easiest way in action here
If you want to isolate the actual contents as defined by your pattern, you could use preg_match($regex,$text,$hits);. This will give you an array of hits those bits that were between the paratheses in the pattern, starting at $hits[1], $hits[0] contains the whole matched string). You can then start manipulating these found matches, possibly using htmlspecialchars ... and combine them again into $code.
Basically I need a regex expression to match all double quoted strings inside PHP tags without a variable inside.
Here's what I have so far:
"([^\$\n\r]*?)"(?![\w ]*')
and replace with:
'$1'
However, this would match things outside PHP tags as well, e.g HTML attributes.
Example case:
Here's my "dog's website"
<?php
$somevar = "someval";
$somevar2 = "someval's got a quote inside";
?>
<?php
$somevar3 = "someval with a $var inside";
$somevar4 = "someval " . $var . 'with concatenated' . $variables . "inside";
$somevar5 = "this php tag doesn't close, as it's the end of the file...";
it should match and replace all places where the " should be replaced with a ', this means that html attributes should ideally be left alone.
Example output after replace:
Here's my "dog's website"
<?php
$somevar = 'someval';
$somevar2 = 'someval\'s got a quote inside';
?>
<?php
$somevar3 = "someval with a $var inside";
$somevar4 = 'someval ' . $var . 'with concatenated' . $variables . 'inside';
$somevar5 = 'this php tag doesn\'t close, as it\'s the end of the file...';
It would also be great to be able to match inside script tags too...but that might be pushing it for one regex replace.
I need a regex approach, not a PHP approach. Let's say I'm using regex-replace in a text editor or JavaScript to clean up the PHP source code.
tl;dr
This is really too complex complex to be done with regex. Especially not a simple regex. You might have better luck with nested regex, but you really need to lex/parse to find your strings, and then you could operate on them with a regex.
Explanation
You can probably manage to do this.
You can probably even manage to do this well, maybe even perfectly.
But it's not going to be easy.
It's going to be very very difficult.
Consider this:
Welcome to my php file. We're not "in" yet.
<?php
/* Ok. now we're "in" php. */
echo "this is \"stringa\"";
$string = 'this is \"stringb\"';
echo "$string";
echo "\$string";
echo "this is still ?> php.";
/* This is also still ?> php. */
?> We're back <?="out"?> of php. <?php
// Here we are again, "in" php.
echo <<<STRING
How do "you" want to \""deal"\" with this STRING;
STRING;
echo <<<'STRING'
Apparently this is \\"Nowdoc\\". I've never used it.
STRING;
echo "And what about \\" . "this? Was that a tricky '\"' to catch?";
// etc...
Forget matching variable names in double quoted strings.
Can you just match all of the string in this example?
It looks like a nightmare to me.
SO's syntax highlighting certainly won't know what to do with it.
Did you consider that variables may appear in heredoc strings as well?
I don't want to think about the regex to check if:
Inside <?php or <?= code
Not in a comment
Inside a quoted quote
What type of quoted quote?
Is it a quote of that type?
Is it preceded by \ (escaped)?
Is the \ escaped??
etc...
Summary
You can probably write a regex for this.
You can probably manage with some backreferences and lots of time and care.
It's going to be hard and your probably going to waste a lot of time, and if you ever need to fix it, you aren't going to understand the regex you wrote.
See also
This answer. It's worth it.
Here's a function that utilizes the tokenizer extension to apply preg_replace to PHP strings only:
function preg_replace_php_string($pattern, $replacement, $source) {
$replaced = '';
foreach (token_get_all($source) as $token) {
if (is_string($token)){
$replaced .= $token;
continue;
}
list($id, $text) = $token;
if ($id === T_CONSTANT_ENCAPSED_STRING) {
$replaced .= preg_replace($pattern, $replacement, $text);
} else {
$replaced .= $text;
}
}
return $replaced;
}
In order to achieve what you want, you can call it like this:
<?php
$filepath = "script.php";
$file = file_get_contents($filepath);
$replaced = preg_replace_php_string('/^"([^$\{\n<>\']+?)"$/', '\'$1\'', $file);
echo $replaced;
The regular expression that's passed as the first argument is the key here. It tells the function to only transform strings to their single-quoted equivalents if they do not contain $ (embedded variable "$a"), { (embedded variable type 2 "{$a[0]}"), a new line, < or > (HTML tag end/open symbols). It also checks if the string contains a single-quote, and prevents the replacement to avoid situations where it would need to be escaped.
While this is a PHP solution, it's the most accurate one. The closest you can get with any other language would require you to build your own PHP parser in that language to some degree in order for your solution to be accurate.
I'm trying to give my client the ability to call a function that has various code snippets by inserted a short code in their WYSIWYG editor.
For example, they will write something like...
[getSnippet(1)]
This will call my getSnippet($id) php function and output the appropriate 'chunk'.
It works when I hard code the $id like this...
echo str_replace('[getSnippet(1)]',getSnippet(1),$rowPage['sidebar_details']);
However, I really want to make the '1' dynamic. I'm sort of on the right track with something like...
function getSnippet($id) {
if ($id == 1) {
echo "car";
}
}
$string = "This [getSnippet(1)] is a sentence.This is the next one.";
$regex = '#([getSnippet(\w)])#';
$string = preg_replace($regex, '. \1', $string);
//If you want to capture more than just periods, you can do:
echo preg_replace('#(\.|,|\?|!)(\w)#', '\1 \2', $string);
Not quite working :(
Firstly in your regex you need to add literal parentheses (the ones you have just capture \w but that will not match the parentheses themselves):
$regex = '#(\[getSnippet\((\w)\)\])#';
I also escaped the square brackets, otherwise they will open a character class. Also be aware that this captures only one character for the parameter!
But I recommend you use preg_replace_callback, with a regex like this:
function getSnippet($id) {
if ($id == 1) {
return "car";
}
}
function replaceCallback($matches) {
return getSnippet($matches[1]);
}
$string = preg_replace_callback(
'#\[getSnippet\((\w+)\)\]#',
'replaceCallback',
$string
);
Note that I changed the echo in your getSnippet to a return.
Within the callback $matches[1] will contain the first captured group, which in this case is your parameter (which now allows for multiple characters). Of course, you could also adjust you getSnippet function to read the id from the $matches array instead of redirecting through the replaceCallback.
But this approach here is slightly more flexible, as it allows you to redirect to multiple functions. Just as an example, if you changed the regex to #\[(getSnippet|otherFunction)\((\w+)\)\]# then you could find two different functions, and replaceCallback could find out the name of the function in $matches[1] and call the function with the parameter $matches[2]. Like this:
function getSnippet($id) {
...
}
function otherFunction($parameter) {
...
}
function replaceCallback($matches) {
return $matches[1]($matches[2]);
}
$string = preg_replace_callback(
'#\[(getSnippet|otherFunction)\((\w+)\)\]#',
'replaceCallback',
$string
);
It really depends on where you want to go with this. The important thing is, there is no way of processing an arbitrary parameter in a replacement without using preg_replace_callback.
Would it be possible to make a regex that reads {variable} like <?php echo $variable ?> in PHP files?
Thanks
Remy
The PHP manual already provides a regular expression for variable names:
[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*
You just have to alter it to this:
\{[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*\}
And you’re done.
Edit You should be aware that a simple sequential replacment of such occurrences as Ross proposed can cause some unwanted behavior when for example a substitution also contains such variables.
So you should better parse the code and replace those variables separately. An example:
$tokens = preg_split('/(\{[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*\})/', $string, -1, PREG_SPLIT_DELIM_CAPTURE);
for ($i=1, $n=count($tokens); $i<$n; $i+=2) {
$name = substr($tokens[$i], 1, -1);
if (isset($variables[$name])) {
$tokens[$i] = $variables[$name];
} else {
// Error: variable missing
}
}
$string = implode('', $tokens);
It sounds like you're trying to do some template variable replacement ;)
I'd advise collecting your variables first, in an array for example, and then use something like:
// Variables are stored in $vars which is an array
foreach ($vars as $name => $value) {
$str = str_replace('{' . $name . '}', $value, $str);
}
{Not actually an answer, but need clarification}
Could you expand your question? Are you wanting to apply a regex to the contents of $variable?
The following line should replace all occurences of the string '{variable}' with the value of the global variable $variable:
$mystring = preg_replace_callback(
'/\{([a-zA-Z][\w\d]+)\}/',
create_function('$matches', 'return $GLOBALS[$matches[1]];'),
$mystring);
Edit: Replace the regex used here by the one mentioned by Gumbo to precisely catch all possible PHP variable names.
(in comments) i want to be able to type {variable}
instead of <?php echo $variable ?>
Primitive approach: You could use an external program (e.g. a Python script) to preprocess your files, making the following regex substitution:
"{([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)}"
with
"<?php echo $\g<1> ?>"
Better approach: Write a macro in your IDE or code editor to automatically make the substitution for you.