![]() ![]() Because if you do user can affect speed of your code by supplying different regex withing wildcard string - this could be used in DoS attacks.Įxample to show execution speeds of similar patterns: seq 1 50000000 > ~/1 You should avoid passing unescaped regex to any other parts of application and only use to filter data retrieved by other means. This can be done by adding ? after * or + like this: \S*? and \S*+?Ĭonsider security: user will send you code to run (because regex is kind of a code too, and user string is used as the regex). \S - stand for non-space character, which happens zero or more times.Ĭonsider using reluctant (non-greedy) quantifiers if you have characters to match after * or +. Optionally: append $ to pattern - this will enforce exact match with the end. Optionally: prepend pattern with ^ - this will enforce exact match with the beginning.Also you could enclose it within \Q (which starts the quote) and \E (which ends it). ![]() Prepend all special characters ([).+ with \ - so they are matched as characters and don't make user experience unexpected.Here is a way to transform wildcard into regex: I know how powerful they can be, but I also know they can be very hard to learn. PS: I'm totally new to regular expressions. However, I have no idea what to replace * with.Īny help would be greatly appreciated. I searched the web (obviously including this website) and all I could find were tutorials that tried to teach me too much or questions that were somewhat similar, but not enough as to provide an answer to my own problem.Īll I could figure out was that I have to replace ? with. My questions is: How do I convert what the user types ( m?st* for example) to a regular expression ? I absolutely want to build my search feature based on this. Now, most users (especially the ones who are not familiar with regular expressions) know that ? is a replacement for exactly 1 character, while * is a replacement for 0, 1 or more characters. if the user searches for *ind (any word ending in ind), it would match wind or bind or blind or grind. ![]()
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