doubt on reliability of Java REGEX

[sukatoa]

Good day

Is it safe to use java regex to extract links and email addresses of a specific webpage?(this is not intended for malicious activity)

We are on the final stage in college, and we have already proposed a project that needs an extraction tool, we decided to create our own(we still have 3 weeks to decide whether to hardcode it or to use 3rd party libraries for parsing html)

Im doubt to choose whether to use the java regular expression or other 3rd party html parsers due to some articles like this one.

[JosAH]

@sukatoa
Regular expressions in Java are reliable but limited to regular languages. HTML isn't a regular language. I use the word 'regular' in a theoretical way. One of the limitations is that regular languages (and so regular expressions) can not find nested structures easily. You need full fledged parsers for that. The SAX parser implemented in Java is such a parser. Email addresses don't contain nested structures and can be parsed by regular expressions. Google for some of them, there are a lot around on the net.

My advice would be to use a SAX parser to retrieve the possible pieces of text out of an HTML text and parse those pieces with a regular expression to determine whether or not it actually can be a valid email address.

kind regards,

Jos

[sukatoa]

Thanks for your advice Jos :)

[JosAH]

@sukatoa
You're welcome of course and good luck with your project.

kind regards,

Jos