The folk at apigee have distilled everything they’ve learned about Web API design over the last few years into a new free eBook called “Web API Design: Crafting Interfaces that Developers Love.” This collates many of the details from their various blog posts into a single reference, covering topics such as REST, handling errors, versioning, authentication, complementary SDKs, and many others. If you’re writing a Web API for your platform this is a great read.

• http://blog.apigee.com/detail/announcement_new_ebook_on_web_api_design

This website presents an interactive architecture diagram of the Linux kernel. The diagram breaks the kernel into a grid of functionality and layers with the ability to pan and zoom the map. You can then click on a specific item to look it up in the Linux source code.

One of the problems of providing documentation for a large project such as the Linux kernel is how to make the information manageable to navigate. This interactive diagram is a great way to provide an overview of all the available APIs and gives developers a jumping off point into the API documentation (although in this case it is an index to the actual code, rather than a documentation index).

• http://www.makelinux.net/kernel_map.shtml

Brady Booch is chief scientist and fellow at IBM Research and is known for co-developing the Unified Modeling Language (UML). He has been doing a regular podcast for IEEE Software called “On Architecture”, where he discusses various topics on developing software architectures. These are more than general than API specific concerns, but it’s still a really interest set of podcasts for you to listen to.

• http://www.computer.org/portal/web/computingnow/onarchitecture

This article by Markus Ewald guides you through the design of a simple C++ plugin architecture based upon Factory classes. He also includes a fully working example implementation of his plugin system for you to download.

• http://www.nuclex.org/articles/cxx/4-building-a-better-plugin-architecture

Markus presents a number of benefits of using plugins:

1. Increased clarity and uniformity of code
2. Improved modularization of code
3. Shorter compile times
4. Replacing/adding components

He also lists a further benefit of being able to use GPL code in a closed source project, although I do not believe that the GPL license allows this. The GPL FAQ states:

“If the program uses fork and exec to invoke plug-ins, then the plug-ins are separate programs, so the license for the main program makes no requirements for them. So you can use the GPL for a plug-in, and there are no special requirements. If the program dynamically links plug-ins, and they make function calls to each other and share data structures, we believe they form a single program, which must be treated as an extension of both the main program and the plug-ins. This means that combination of the GPL-covered plug-in with the non-free main program would violate the GPL.”