RegularExpressionstoremoveorreplace
Solution Title:
regular Expressions to remove or replaceAuthor:
pmengalPoints: 500 Grade: ADate: 05/12/2003 01:18AM PDT Hello,I want to use a regular expression to replace or remove some texts.Replace-------I want to be able to replace > by &;amp;gt; in the following HTML text :"<p><strong>Superman is greater > than Spiderman</strong></p>"The same code should work also for this text without any change :"<span class="thisname<isinvalid"><b>a > b ?</b></span>"You understood, it's to use with a custom Html Encoder.Remove------I want to remove all (tags included) that is between <script></script> like :"<script> some malicious code </script>"The same code (without any change, but different that the replace one of course) should work on this too :"<script language="javascript"> some malicious code </script>"and this one"<script language='javascript'> some malicious code </script>"and this one too"<script dull="dull" language="javascript"> some malicious code</script>"and this one too ..."<SCRIPT Language="JavaScript"> some malicious code </ScripT>"Sorry to be so complete, but I posted some 500 and 250 questions and got incomplete answers due to the non complete enough question.Thanks in advance ! Comment from
pmengal
Date: 05/12/2003 01:19AM PDT Author Comment Forgot to say :Can you provide ALL the code to achieve this ? Giving me just the regular expression will not help me. I'm not familiar with regular expressions at all...If you have time, giving me some
website to learn is welcome ;) Comment from
AvonWyss
Date: 05/12/2003 05:22AM PDT Comment I will.... stay tuned. Comment from
testn
Date: 05/12/2003 06:37AM PDT Comment Hi,my previous regex should work with >pattern = "((?<!(<([^>])*))(>))|((?<=((<(\/)?[^A-Z,a-z,/,]){1}([^>,<])*))(>))"About tutorials,
http://www.c-sharpcorner.com/3/RegExpPSD.asp
http://www.wellho.net/regex/dotnet.html
http://windows.oreilly.com/news/csharp_0101.html
If you want a comprehensive book, you might consider buying pdf from amazon
http://www.amazon.com/exec/obidos/tg/detail/-/B0000632ZU/102-4200309-1247344?vi=glance
Accepted Answer from
testn
Date: 05/12/2003 06:42AM PDT Accepted Answer This is the code for removing malicious code.using System.Text.RegularExpressions;public string removeMaliciousCode(string oldStr) { string pattern = @"(?i)<script([^>])*>(\w|\W)*</script([^>])*>"; string newStr = Regex.Replace(oldStr,pattern,""); return newStr;}This function will return the string that contains no malicious code. Comment from
testn
Date: 05/12/2003 06:47AM PDT Comment Explain the function......(?i) means case-insensitive string matching<script([^>])*> means finding any string starting with "<script" and contains 0 or more characters before ending with >(\w|\W)* means may having some string in between <Script> and </script> (0 or more characters of anything)</script([^>])*>" means finding any string starting with "</script" and contains 0 or more characters before ending with >However, this one may be too extreme since it will also match the whole string of <SCRIPT Language="JavaScript"> some malicious code</ScripT> Hello <script ></script> without leaving Hello Comment from
testn
Date: 05/12/2003 07:22AM PDT Comment You can make it better by putting<script[^>]*>.*?</script[^>]*>It will screen<SCRIPT Language="JavaScript"> some malicious code</ScripT> Hello <script ></script> without to Hellosince .*? mean non-greedy matching it will try to match up least possible characters of the pattern Comment from
testn
Date: 05/12/2003 07:33AM PDT Comment Please also keep testing when this applies to multiple lines dataYou might need to change it to<script[^>]*>(\w|\W)*?</script[^>]*>or to(?m)<script[^>]*>(\w|\W)*?</script[^>]*> Comment from
AvonWyss
Date: 05/12/2003 09:39PM PDT Comment private string ReplaceMatch(Match match) { if (match.Groups["script"].Success) return ""; else if (match.Groups["gt"].Value==">") return "&;amp;gt;"; else return match.Value; } public string CleanupHtml(string html) { return Regex.Replace(html, @"(?<script><script[^>]*>.*?</script[^>]*>)|(?<gt>(<(""[^""]""|'[^']'|[^>]) )?>)", new MatchEvaluator(ReplaceMatch), RegexOptions.ExplicitCapture|RegexOptions.IgnoreCase|RegexOptions.Singleline); }This Regex will do both your tasks and at the same time. The first part is pretty similar to testn's suggestion, but I also provide the code to find single > chars (with no matching < before). Comment from
osxmaster
Date: 02/23/2004 02:19PM PST Comment Hi do you know how I can clean this page from HTML and script tags?
http://www.wipo.org
Seems to be very complicated.thanks Comment from
AvonWyss
Date: 02/24/2004 09:59PM PST Comment Yes I do. Just a few days ago I answered a very similar question; have a look at recent posts in C#
http:Q_20892954.html
Or you can of course also post a new Q.From:http://www.experts-exchange.com/Programming/Programming_Languages/C_Sharp/Q_20613142.html#8508997 (2005-9-13:03:46)
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