How do I substitute characters around a string in Ruby?

Question

I'm trying to write a ruby script to turn a small markup language I wrote into HTML, but I can't figure out how to parse links. It's basically a trimmed down version of BBCode, so for example, if someone enters [i]{text}[/i], I use [i]{text}[/i].gsub('[i]','<i>').gsub('[/i]','</i>'. I can't figure out how to parse links, though. How would I turn [url=website.com]site[/url] into <a href="website.com">site</a>? I'm not using a premade BBCode parser because there are a few tags that are different, and I don't want people to use some of the tags such as [img][/img].

[bb-ruby](http://bb-ruby.rubyforge.org/) seems to allow you to specify only certain tags to use, why not use that? — Andrew Marshall, May 29 '12 at 20:15

score 0 · Answer 1 · edited May 23 '17 at 12:11

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Very naïvely:

s.gsub(/\[url=(.*?)\](.*?)\[\/url\]/) { "<a href='#{$1}'>#{$2}</a>" }

HTML injection would be quite easy. The point here (write a proper parser) still applies to what you're doing.

edited May 23 '17 at 12:11

Community

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answered May 29 '12 at 20:19

kch

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score 0 · Answer 2 · answered May 29 '12 at 20:37

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I agree with kch by using a regular expression but if you want to wrap your head around it using gsub() like you've been doing...

s = "[url=website.com]site[/url]"
s2 = s.gsub('[url=','<a href="').gsub('[/url]','</a>').gsub(']','">')

answered May 29 '12 at 20:37

rbnewb

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How do I substitute characters around a string in Ruby?

2 Answers2