May 23rd, 2014

Mapping the API Landscape

Mapping the API LandscapeThis week, I had the opportunity to deliver a “lightning talk” at the APIStrat Tech Un-Workshop at Gluecon 2014. The event was focused on two key topics: IoT and service description/discovery. I was in the service track and delivered a talk called Mapping the API Landscape. I won’t cover the entire talk here (BTW, the text has lots of links to information I could not discuss on stage this week) but did want to hit some key points.

What Google’s Self-Driving Car Tells Us
The Google car has been in the news again and a key point that was discussed at some length in these articles was the fact that the car depends on a very detailed map of the roadways. Right now, the car can only drive in the Mountain View, CA area since that is the only landscape mapped well enough for the car to navigate.

So, the Google car does not “discover” anything while driving. It actually recognizes intersections, traffic lights, etc. through a special representation of the landscape that contains all the right annotations. This reliance on a known map allows the car to navigate successfully between two points within that landscape – which is no simple feat, of course. Reacting to surroundings “at speed” takes serious computing power and that’s one of the reasons the Google implementation is so amazing.

Norman’s Action Lifecycle
The process of navigating from A to B is a goal-driven process that we see very often in nature. Ants, micro-organisms etc. all do this. Human-computer interaction expert Donald Norman calls this process the “action lifecycle” or “seven stages of action”.

This is how we learned to write GUI interfaces, too. Wait for a keystroke or button-click, process that action, affect the UI, then allow the user to evaluate the changes and decide if another action is needed. We also build Web servers this way. Wait for a request, process it, modify the backend (if needed) and reflect results back to the requestor. Game programming works like this, as well. But it’s rare to see the Web and mobile client applications that leverage enterprise APIs written in this way. They continue to look like single-minded bots that just go from A to B and ignore landmarks, incapable of actually reacting to surroundings.

Client Apps & Web Maps
Why are most client apps one-off implementations that are likely to break over time? It’s because client developers don’t have decent “maps” of the online landscape. And good maps are not just “photos” of the surroundings but heavily-annotated representations with recognizable symbols and landmarks. Most servers today just belch out JSON or XML with almost no recognizable symbols or signage (e.g. hypermedia controls).

So, what we need to do is create maps for devs to use so that they can build their own client applications against our APIs and solve their own problems. Client apps should be free to follow whatever route they wish within the maps – they shouldn’t be limited to following the path that server developers decide upon.

Let’s Make Maps!
Things like service description formats and discovery protocols are all ways to start creating more maps for client devs to rely upon. Using hypermedia in responses provides the symbols and signs client apps can use at runtime (like the Google car) in order to navigate in real time.

There are several description formats (see my paper Hold Your Nose vs. Follow Your Nose for more on this). In the book RESTful Web APIs, Leonard Richardson and I list close to 20 options for expressing hypermedia in Web responses. And more have come online since the book was published last year.

We have all the tools we need. We just need to use those tools to make more maps!

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