Nokogiri VS gopacket

release planning: v1.16.0 · Issue #2897 · sparklemotion/nokogiri

What's holding me back from going all in with Crystal is I have a lot of pre-existing Ruby code, and porting Ruby code to Crystal can be tricky. For example, Crystal lacks an Enumerator class (aka generators) due to captured block semantics. I also wish the shards ecosystem was a little more mature; for example there's multiple HTML parsing libraries, but none have all of the features that Ruby's Nokogiri has. For new greenfield backend projects, I would totally use Crystal.

Welcome! Ruby isn't exactly "dying", but the hype/popularity is definitely fading. This is primarily because Ruby is no longer "new", most of Ruby's popularity came from Rails, and now Rails is no longer the "new hotness". However, Ruby still has lots of awesome features and lots of awesome other libraries and frameworks, such as the new fancy irb gem that uses reline, nokogiri, chunky_png, the async gems, Dragon Ruby, SciRuby, Ronin, and the new Hanami web framework.

great for hacking at xml

Mike has worked hard over the years to have Nokogiri come with its dependencies. It does come with libxml and all that is required.

From https://nokogiri.org

> These dependencies are met by default by Nokogiri's packaged versions of the libxml2 and libxslt source code, but a configuration option --use-system-libraries is provided to allow specification of alternative library locations.

Some authors work hard to have their tools do the right thing and consistently.

If the page is rendered as html you can use Nokogiri. It has great support and is pretty easy to get started with too.

And even now, pulling in a Java-based HTML5 parser is still probably easier than re-implementing in FFI, which is why I created https://github.com/sparklemotion/nokogiri/issues/2227 and would love to have this the conversation there if possible.

I have seen pcap but not packetz, thanks. Pcap looks unfinished and packetz has not been updated in a long time, but they might be able to make a working capture program. However the popularity and features available in Go regarding packet capture makes it very hard to beat. E.g. the Google gopacket library has 5.6k stars on github and as pretty much every feature you'd want for this sort of stuff built in.

eCapture implements the feature of saving a pcapng file by eBPF TC, and supports TLS Master Secret Key capturing by eBPF Uprobe. Also, gopacket's DSB feature is supported, based on Decryption Secrets Block (DSB)

Well, there is https://github.com/google/gopacket/, you have a package that uses CGo, `pcap`, and then there is `pcapgo`, native Go implementation. Doesn't have all the features but in my case, I was able to use it and remove CGo.

I will capturing TCP packets by gopacket/pcap.

For example, gopacket uses libpcap by default for capturing the traffic. Libpcap doesn't support network namespaces and we can't ask it to listen to traffic on a different namespace. However, we can change the network namespace of the calling thread and then start libpcap to see the traffic on a different namespace.

https://pkg.go.dev/github.com/google/gopacket/routing - Linux only and not working correctly and not actively maintained