Visibility and REST v. Security

Fair warning: Half baked thoughts ahead.

Mark Baker counts as thought leader for me, esp. subtopic REST. He rails on the importance of visibility in internet scale systems in a recent post. So, this is for you, Mr. Baker: What is your opinion on HTTP's Connect and SSL/TLS tunneling in light of the need for visibility as a key enabler of internet scale? Doesn't security (specifically confidentiality) throw a pretty huge monkey wrench into the nice properties visibility affords the architecture? There is a lot of data that can flow cleartext, but businesses don't like it as much in my experience. I know I have seen Mr. Fielding highlighting the issue as something to attend to.

Once you are inside the firewall, is the term "internet-scale" really material anymore? Especially in the sense that the internet is a collection of autonomous but interconnected networks? That is, the relevant bits wrt internet scalability are the messages flowing between the firewalls. It would seem that the majority of the visibility necessary to gain the scale qualities in the architecture exist at the tcp and, more importantly, ip levels rather than the http levels (in spite of the increased semantic visibility provided by a RESTful protocol). I think that web services would benefit from that visibility as much as the REST.

Comments

[Mark Baker]

FWIW, I think CONNECT is good as it makes visible something that without which, wouldn't be; the tunneling of one protocol through another. Of course, the tunneled protocol's semantics aren't visible, but using CONNECT is like asking "Please may I tunnel?". It permits the server to say "No". And remember that REST is just a guide. When you really *do* need to tunnel, as above, it guides you to make that explicit in the messages, which CONNECT does. And yes, visibility is lost, at least to processors of the tunneling protocol. In many cases though, if a server permits a CONNECT to happen, it's because it understands the tunneled protocol - to whatever extent that's possible. I expect that what Roy's talking about in that slide is the that the simple secured-transport approach has won out for now (largely because it's simple, IMO), but we should consider the advantages of swinging back to message-oriented security. "Once you are inside the firewall, is the term "internet-scale" really material anymore?" Good question, but yes, I think it's still important. "Internet-scale" is another way of saying "supports unanticipated forms of integration", which is very good. The larger the company, the more important I think that is, since the higher the probability of unexpected things occuring. Of course, you don't have to get very big for that to happen, which is why I like starting with Internet-scale as my defacto position going into data-centric distributed app.