I want to dynamically remove specific tags and their content from an html file and thought of using preg_replace but can't get the syntax right. Basically it should, for example, do something like :
Replace everything between (and including) "" by nothing.
Could anybody help me out on this please ?
Easy dude.
To have a Ungreedy regexpr, use the U modifier
And to make it multiline, use the s modifier.
Knowing that, to remove all paragraphes use this pattern :
#<p[^>]*>(.*)?</p>#sU
Explain :
I use # delimiter to not have to protect my \ characters (to have a more readable pattern)
<p[^>]*> : part detecting an opening paragraph (with a hypothetic style, such as )
(.*)? : Everything (in "Ungreedy mode")
</p> : Obviously, the closing paragraph
Hope that help !
If you are trying to sanitize your data, it is often recommended that you use a whitelist as opposed to blacklisting certain terms and tags. This is easier to sanitize and prevent XSS attacks. There's a well known library called HTML Purifier that, although large and somewhat slow, has amazing results regarding purifying your data.
I would suggest not trying to do this with a regular expression. A safer approach would be to use something like
Simple HTML DOM
Here is the link to the API Reference: Simple HTML DOM API Reference
Another option would be to use DOMDocument
The idea here is to use a real HTML parser to parse the data and then you can move/traverse through the tree and remove whichever elements/attributes/text you need to. This is a much cleaner approach than trying to use a regular expression to replace data within the HTML.
<?php
$doc = new DOMDocument;
$doc->loadHTMLFile('blah.html');
$content = $doc->documentElement;
$table = $content->getElementsByTagName('table')->item(0);
$delfirstTable = $content->removeChild($table);
echo $doc->saveHTML();
?>
If you don't know what is between the tags, Phill's response won't work.
This will work if there's no other tags in between, and is definitely the easier case. You can replace the div with whatever tag you need, obviously.
preg_replace('#<div>[^<]+</div>#','',$html);
If there could be other tags in the middle, this should work, but could cause problems. You're probably better off going with the DOM solution above, if so
preg_replace('#<div>.+</div>#','',$html);
These aren't tested
PSEUDO CODE
function replaceMe($html_you_want_to_replace,$html_dom) {
return preg_replace(/^$html_you_want_to_replace/, '', $html_dom);
}
HTML Before
<div>I'm Here</div><div>I'm next</div>
<?php
$html_dom = "<div>I'm Here</div><div>I'm next</div>";
$get_rid_of = "<div>I'm Here</div>";
replaceMe($get_rid_of);
?>
HTML After
<div>I'm next</div>
I know it's a hack job
Related
I used the following code to remove script, link tags from my string,
$contents='<script>inside tag</script>hfgkdhgjh<script>inside 2</script>';
$ss=preg_replace('#<script(.*?)>(.*?)</script>#is', '', $contents);
echo htmlspecialchars($ss);
it works fine. But can I use anything that similar to html parsing rather than preg_match for this?
Here are few things you can do
htmlspecialchars() can prove those tags useless
striptags() removes all HTML tags
But the technique you are using is the correct one. However here is a improved version for that
echo preg_replace('/<script\b[^>]*>(.*?)<\/script>/is', "", $contents);
HTML Purifier is always a good choice. phpQuery has also come in handy a few times.
If you are sanitizing content, it's very easy to make mistakes with regular expressions... read this post. It just depends what you're trying to achieve.
I'm grabbing data from a published google spreadsheet, and all I want is the information inside of the content div (<div id="content">...</div>)
I know that the content starts off as <div id="content"> and ends as </div><div id="footer">
What's the best / most efficient way to grab the part of the DOM that is inside there? I was thinking regular expression (see my example below) but it is not working and I'm not sure if it that efficient...
header('Content-type: text/plain');
$foo = file_get_contents('https://docs.google.com/spreadsheet/pub?key=0Ahuij-1M3dgvdG8waTB0UWJDT3NsUEdqNVJTWXJNaFE&single=true&gid=0&output=html&ndplr=1');
$start = '<div id="content">';
$end = '<div id="footer">';
$foo = preg_replace("#$start(.*?)$end#",'$1',$foo);
echo $foo;
UPDATE
I guess another question I have is basically about if it is just simpler and easier to use regex with start and end points rather than trying to parse through a DOM which might have errors and then extract the piece I need. Seems like regex would be the way to go but would love to hear your opinions.
Try changing your regex to $foo = preg_replace("#$start(.*?)$end#s",'$1',$foo); , the s modifier changes the . to include new lines. As it is, your regex would have to all the content between the tags on the same line to match.
If your HTML page is any more complex than that, then regex probably won't cut it and you'd need to look into a parser like DOMDocument or Simple HTML DOM
if you have a lot to do, I would recommend you take a look at http://simplehtmldom.sourceforge.net
really good for this sort of thing.
Do not use regex, it can fail.
Use PHP's inbuilt DOM parse :
http://php.net/manual/en/class.domdocument.php
You can easily traverse and parse relevant content .
I want to get the <form> from the site. but between the form part in this situation, there still have mnay other html code. how to remove them? I mean how to use php just regular the and part from the site?
$str = file_get_contents('http://bingphp.codeplex.com');
preg_match_all('~<form.+</form>~iUs', $str, $match);
var_dump($match);
You should not use regular expressions for extracting HTML content. Use a DOM parser.
E.g.
$doc = new DOMDocument();
$doc->loadHTMLFile("http://bingphp.codeplex.com");
$forms = $doc->getElementsByTagName('form');
Update: If you want to remove the forms (not sure if you meant that):
for($i = $forms.length;$i--;) {
$node = $forms->item($i);
$node->parentNode->removeChild($node);
}
Update 2:
I just noticed that they have one form that wraps the whole body content. So this way or another, you will get the whole page actually.
The regex problem lies in the greedyness. For such cases .+? is advisable.
But what #Felix said. While a regular expression is workable for HTML extraction, you often look for something specific, and should thus rather parse it. It's also much simpler if you use QueryPath:
$str = file_get_contents('http://bingphp.codeplex.com');
print qp($str)->find("form")->html();
The best way i can think of is to use the Simple HTML DOM library with PHP to get the form(s) from the HTML page using DOM queries.
It is a little more convenient than using built-in xml parsers like simplexml or domdocument.
You can find the library here.
Normally you should use DOM to parse HTML, but in this case the web site is very far from being standard HTML, with some of the code being modified in place by javascript. It can therefore not be loaded into the DOM object. This might be intentional, a way of obfuscating the code.
In any case, it is not so much your RE (although using a non-greedy match would help), but the design of the site itself which is preventing you from parsing out what you want.
What will be the best way to highligh the Searched pharase within a HTML Document.
I have Complete HTML Document as a Large String in a Variable.
And I want to Highlight the searched term excluding text with Tags.
For example if the user searches for "img" the img tag should be ignored but
phrase "img" within the text should be highlighted.
Don't use regex.
Because regex cannot parse HTML (or even come close), any attempt to mess around with matching words in an HTML string risks breaking words that appear in markup. A badly-implemented HTML regex hack can even leave you with HTML-injection vulnerabilities which an attacker may be able to leverage to do cross-site-scripting.
Instead you should parse the HTML and do the searches on the text content only.
If you can accept a solution that adds the highlighting from JavaScript on the client side, this is really easy because the browser will already have parsed the HTML into a bunch of DOM objects you can manipulate. See eg. this question for a client-side example.
If you have to do it with PHP that's a bit more tricky. The simple solution would be to use DOMDocument::loadHTML and then translate the findText function from the above example into PHP. At least the DOM methods used are standardised so they work the same.
Edit: This was tagged as Java before, so this answer might not be applicable.
This is quick and dirty but it might work for you, or at least be a starting point
private String highlight(String search,String html) {
return html.replaceAll("(>[^<]*)("+search+")([^>]*<)","$1<em>$2</em>$3");
}
This requires testing, and I make no guarantees that its correct but the simplest way to explain how is that you ensure that your term exists between two tags and is thus is not itself a tag or part of a tag parameter.
var highlight = function(what){
var html = document.body.innerHTML,
word = "(" + what + ")",
match = new RegExp(word, "gi");
html = html.replace(match, "<span style='background-color: red'>$1</span>");
document.body.innerHTML = html;
};
highlight('ll');
This would highlight any occurence of 'll'.
Be carefull by calling highlight() with < or > or any tag name, it would also replace those, screwing up your markup. You might workaround that by reading innerText instead of innerHTML, but that way you'll lose the markup information.
Best way probably is to implement a parser routine yourself.
Example: http://www.jsfiddle.net/DRtVn/
there is a free javascript library that might help you out -> http://scott.yang.id.au/code/se-hilite/
You must be using some server side language to render the search results on the webpage.
So the best way I can think of is to highlight the word while rendering it using the server side language itself,which may be php,java or any other language.
This way you would have only the result strings without html and without parsing overhead.
I googled a lot, for those kind of problems have been asked a lot in the past. But I didn't find anything to match my needs.
I have a html formatted text from a form. Just like this:
Hey, I am just some kind of <strong>formatted</strong> text!
Now, I want to strip all html tags, that I don't allow. PHP's built-in strip_tags() Method does that very well.
But I want to go a step further: I want to allow some Tags only inside or not inside of other tags. I also want to define my own XML Tags.
Another example:
I am a custom xml tag: <book><strong>Hello!</strong></book>. Ok... <strong>Hi!</strong>
Now, I want the <strong/> inside of <book/> to be stripped, but the <strong>Hi!</strong> can stay the way it is.
So, I want to define some rules of what I allow or don't allow, and want to have any filter do the rest.
Is there any easy way to do that? Regexp aren't what I'm looking for, for they can't parse html properly.
Regards, Jan Oliver
Don't think there is such a thing, I think not even HTML Purifier does that.
I suggest you parse the XHTML by hand using something like Simple HTML Dom.
Use a second argument to strip_tags, which is allowable tags.
$text = strip_tags($text, '<book><myxml:tag>');
I don't think there's a way to only strip certain tags if they're not inside other tags, without using regex.
Also, regex aren't not good at parsing HTML, but it's slow compared to the options. But that's not what you're doing here, anyways. You're going through the string and removing things you don't want. And for your complex requirement I think your only option is to use regex.
To be completely honest I think you should decide which tags are allowable and which aren't. Whether or not they are inside of other tags shouldn't matter at all. It's markup, not a script.
The second argument shows that you cal allow some tags:
string strip_tags ( string $str [, string $allowable_tags ] )
From php.net
I wrote my own Filter class based on the DOM classes of PHP. Look here: XHTMLFilter class