I’m in the throes of composition. My presentation for STC Summit 2014 is in good shape, and I’m working on the proceedings paper right now. I got to thinking about why I put myself up for speaking at conferences. It’s a lot of work! Is it worth it? I also saw a post from Neal Kaplan, who doesn’t get conferences. So I decided to blog my thoughts.
If you’d told me five years ago that you’d seen me speaking at a conference, my reaction would have been
Ha ha, nope, that must have been some other Sarah.
Public speaking scared me to death. (Actually, it still does.) I never thought I’d be able to do it. Simply standing in front of a handful of peers turned me into a blob of jelly on a roller coaster.
Then Joe Welinske asked me to speak at WritersUA in Seattle in 2009. Of course, I said “Eek, no.” But Joe’s sweet persistence persuaded me to think about it. After all, he said, I knew a lot about what was then an emerging technology for technical writing: wikis. A few days later, Joe asked me again. To my utter horror, I said yes. My thinking went along these lines: I know no-one in the US. I’ve never even been to the US. If I make a total fool of myself, it doesn’t matter. No-one I know will ever know.
I survived WritersUA 2009. And now, five years later, I’ve spoken at twelve conferences.
Oft-discussed benefits of attending conferences include:
- Peers: Meeting other tech writers has been hugely rewarding. It’s especially great to meet in person the people I’ve bumped into on blogs, Twitter, and other online meeting spots.
- Learning: Conferences seed ideas. I see what other people are up to, get a glimpse of new technologies, peer at different products. A while later, an idea pops up about something I can use in my own environment.
What’s the benefit of speaking yourself?
Getting funding to attend the conference is a big one. For me, living in Australia, the travel costs are too big to cover personally.
But for me, the biggie is this: Putting together a presentation makes me think about how others see what I’m doing. It makes me look at my own work, and that of my team, in a new light. It gives me a wider perspective. It firms up my own opinions on what are good procedures to follow, and what could do with tweaking.
So, a call to all conference speakers: why do you do it?
I’m putting together a list of the various types of API we might encounter. This is primarily a resource for technical writers, who may need to know what type of thing they could be asked to document if they take on the role of API tech writer.
A Google search didn’t reveal much material about API types. The best source of information is the Wikipedia page on APIs.
I tried searching for “API classification” and received plenty of information about engine oil.
So here goes… my attempt at an API classification.
Before we start: What is an API?
API stands for “application programming interface”. Put briefly, an API consists of a set of rules describing how one application can interact with another, and the mechanisms that allow such interaction to happen.
What is an interaction between two applications? Typically, an interaction occurs when one application would like to access the data held by another application, or send data to that app. Another interaction might be when one application wants to request a service from another.
A key thing to note: An API is (usually) not a user interface. It provides software-to-software interaction, not user interactions. Sometimes, though, an API may provide a user interface widget, which an app can grab and display.
There are two primary benefits that an API brings:
- Simplification, by providing a layer that hides complexity.
- Microsoft Word asks the active printer to return its status. Microsoft Word does not care what kind of printer is available. The API worries about that.
- Bloggers on WordPress can embed their Twitter stream into their blog’s sidebar. WordPress uses the Twitter API to enable this.
Web service APIs
A web service is a piece of software, or a system, that provides access to its services via an address on the World Wide Web. This address is known as a URI, or URL. The key point is that the web service offers its information in a format that other applications can “understand”, or parse.
A web service uses HTTP to exchange information. (Or HTTPS, which is an encrypted version of HTTP.)
When an application, the “client”, wants to communicate with the web service, the application sends an HTTP request. The web service then sends an HTTP response.
In the request, much of the required information is passed in the URL itself, as paths in the URL and/or as URL parameters.
In addition to the URL, HTTP requests and responses will include information in the header and the body of the message. Request and response “headers” include various types of metadata, such as the browser being used, the content type, language (human, not software), and more.
The body includes additional data in the request or response. Common data formats are XML and JSON. The process of converting data from internal format (for example, a database or a class) to the transferrable format is called “data serialization”.
Most often-used types of web service:
SOAP (Simple Object Access Protocol)
SOAP is a protocol that defines the communication method, and the structure of the messages. The data transfer format is XML.
A SOAP service publishes a definition of its interface in a machine-readable document, using WSDL – Web Services Definition Language.
XML-RPC is an older protocol than SOAP. It uses a specific XML format for data transfer, whereas SOAP allows a proprietary XML format. An XML-RPC call tends to be much simpler, and to use less bandwidth, than a SOAP call. (SOAP is known to be “verbose”.) SOAP and XML-RPC have different levels of support in various libraries. There’s good information in this Stack Overflow thread.
JSON-RPC is similar to XML-RPC, but uses JSON instead of XML for data transfer.
REST (Representational state transfer)
REST is not a protocol, but rather a set of architectural principles. The thing that differentiates a REST service from other web services is its architecture. Some of the characteristics required of a REST service include simplicity of interfaces, identification of resources within the request, and the ability to manipulate the resources via the interface. There are a number of other, more fundamental architectural requirements too.
Looked at from the point of view of a client application, REST services tend to offer an easy-to-parse URL structure, consisting primarily of nouns that reflect the logical, hierarchical categories of the data on offer.
For example, let’s say you need to get a list of trees from an API at example-tree-service.com. You might submit a request like this:
Perhaps you already know the scientific name of a tree family, Leptospermum, and you need to know the common name. You request might look like this:
The tree service might then send a response containing a bunch of information about the Leptospermum family, including a field “common-name” containing the value “teatrees”.
An example of a REST API: The JIRA REST APIs from Atlassian.
The most commonly-used data format is JSON or XML. Often the service will offer a choice, and the client can request one or the other by including “json” or “xml” in the URL path or in a URL parameter.
A REST service may publish a WADL document describing the resources it has available, and the methods it will accept to access those resources. WADL stands for Web Application Description Language. It’s an XML format that provides a machine-processable description of an HTTP-based Web applications. If there’s no WADL document available, developers rely on documentation to tell them what resources and methods are available. Most web services still rely on documentation rather than a machine-readable description of their interface.
In a well-defined REST service, there is no tight coupling between the REST interface and the underlying architecture of the service. This is often cited as the main advantage of REST over RPC (Remote Procedure Call) architectures. Clients calling the service are not dependent on the underlying method names or data structures of the service. Instead, the REST interfaces merely represent the logical resources and functionality available. The structure of the data in the message is independent of the service’s data structure. The message contains a representation of the data. Changes to the underlying service must not break the clients.
To use this type of API, an application will reference or import a library of code or of binary functions, and use the functions/routines from that library to perform actions and exchange information.
TWAIN is an API and communications protocol for scanners and cameras. For example, when you buy an HP scanner you will also get a TWAIN software library, written to comply with the TWAIN standard which supports multiple device types. Applications will use TWAIN to talk to your scanner.
The Oracle Call Interface (OCI) consists of a set of C-language software APIs which provide an interface to the Oracle database.
Class-based APIs (object oriented) – a special type of library-based API
These APIs provide data and functionality organised around classes, as defined in object-oriented languages. Each class offers a discrete set of information and associated behaviours, often corresponding to a human understanding of a concept.
The Java programming community offers a number of good examples of object oriented, or classed-based, APIs. For example:
- The Java API itself. This is a set of classes that come along with the Java development environment (JDK) and which are indispensable if you’re going to program in Java. The Java language includes the basic syntax and primitive types. The classes in the Java API provide everything else – things like strings, arrays, the renowned Object, and much much more.
- The Android API.
- The Google Maps Android API.
Functions or routines in an OS
Operating systems, like Windows and UNIX, provide many functions and routines that we use every day without thinking about it. These OSes offer an API too, so that software programs can interact with the OS.
Examples of functionality provided by the API: Access to the file system, printing documents, displaying the content of a file on the console, error notifications, access to the user interface provided by the OS.
Object remoting APIs
These APIs use a remoting protocol, such as CORBA – Common Object Request Broker Architecture. Such an API works by implementing local proxy objects to represent the remote objects, and interacting with the local object. The same interaction is then duplicated on the remote object, via the protocol.
As far as I can tell, most of these APIs are now considered legacy. Another example is .NET Remoting.
Hardware APIs are for manipulating addressable pieces of hardware on a device – things like video acceleration, hard disk drives, PCI buses.
Other developer products
There’s more to life than APIs, of course. A technical writer may be called upon to document other developer-focused products:
- SDKs – software development kits, which typically contain a set of tools that developers use to interact with, and develop on top of, your product.
- IDE plugins – custom additions to standard development environments, which give developers the extra tools they need to interact with your product from within a development environment like Eclipse, IntelliJ IDEA, or Visual Studio.
- Code libraries that developers can import into their projects.
- Other frameworks that support software development in a specific environment, such as custom XML specifications, templates, UI guidelines.
There’s more than one way to can has a cat
Your turn. What have I missed, and are there more useful ways of classifying APIs?
I’m curious to see how things have changed since I last asked this question, back in March 2012: What’s your favourite API documentation, and why?
Part of the reason for asking is that I’ll soon present a session at STC Summit 2014 on API technical writing. I want to give examples of excellent documentation. I have some favourite documentation sets myself, but it’s great to get the opinions of developers and other technical writers too.
So, have at it! Please comment on this post.
What’s your favourite API documentation, and why?
I’ll also collect any suggestions that people send via Twitter, Google+, and other channels, and add the links to this post.
OT: This has to be the world’s best bird. Well, it’s my current favourite anyway. This is a Tawny Frogmouth, spotted on an early morning walk. Tawny Frogmouths are night birds, about the size of a large owl (34-52 centimetres). During the day, they pretend to be old tree branches.
I’ll be speaking about API technical writing at STC Summit 2014. Part of the presentation is about useful tools for API technical writers. Since there are already some great resources on the Web about editors and IDEs, I plan to focus on a motley collection of “other” tools. Those that do a specific job very well. Those of which you’d say, “When I need it, I really need it.”
There are plenty of blog posts and articles about tools for documentation and code, including open source tools. Particularly when talking about editors and IDEs (Integrated Development Environments) most people have their favourites. The debates about which tool is best can get quite fiery!
Here are some useful links:
- Mike McCallister’s presentation, Open Source Tools for User Assistance. It’s well worth following Mike’s blog too.
- Chantel Brathwaite, writing on the TechWhirl blog about Technical Writing on a Shoestring.
- From Bret McGowen on the Rackspace blog, My Text Editor Final Four.
So, aren’t you going to talk about editors at all?
My favourite IDE is Eclipse. I like to dabble in Android Studio and IntelliJ IDEA, just to see what’s happening.
Now that’s out of the way, let’s look at some super-useful and less-talked-about tools for API tech writers in particular.
Syntax highlighter for code samples
I frequently need to add a code sample to an HTML page, or include a slice of code in a presentation. Code is much easier to understand if the text is highlighted to indicate method names, variable declarations, and other syntactical essentials. And it just looks prettier too.
hilite.me converts a code snippet into styled HTML, which you can copy and paste into your page. Paste in your code, and select the coding language, to get the appropriate highlighting. Then click “Highlight!” to see the result. You can grab the HTML and CSS code, or copy and paste the highlighted text itself. You can even choose from a number of styles, such as “colorful”, “friendly”, “fruity”, and so on.
For example, I pasted in a Java “hello world” class, and asked for “tango” style highlighting. The “Preview” box at the bottom of this screenshot shows the result:
Testing web services and REST APIs
There’s an add-on for Chrome browser, called the Advanced REST Client, which I find very useful for getting examples of web service requests and responses. You can craft an HTTP request, then submit the request and see the response. This is a nice GUI alternative to a command-line tool like cURL.
Let’s say I want to use the Google Geocoding API to get a human-readable address for a pair of latitude/longitude coordinates. My URL would look like this:
I’ve pasted the above URL into the Advanced REST Client tab in Chrome, then used the add-on to expand the URL parameters, making it easy to see the composition of the HTTP request:
Now press the “Send” button to see the response. This is a partial screenshot:
Very handy indeed.
Chrome Developer Tools
The Chrome Developer Tools are a little tricky to grok, but once you’ve figured out what’s going on, they’re coolth personified. To find them, click the three-barred icon at top right of the Chrome window (the tooltip says “Customize and control Google Chrome”) then choose “Tools” > “Developer Tools”. The keyboard shortcut is Ctrl+Shift+I or Cmd+Shift+I.
A panel opens at the bottom of the page. It’s pretty busy, so take your time getting used to it. You can click an option to undock the panel and see it as a separate window, if you prefer that. In this screenshot, the DevTools panel is open at the bottom of the screen, and is showing the “Elements” tab:
There are many many things you can do with the DevTools. The Chrome DevTools documentation is a good guide. These are the functions I use most often:
- Check which CSS style is in effect on a particular block of HTML. This is particularly useful when there are a number of stylesheets at play. Sometimes the cascading effect of CSS doesn’t seem to follow the laws of gravity!
- Watch the error messages scrolling past on the “Console” tab.
- Edit HTML on the spot, to see the effect live on a web page before putting my changes into the source code.
Open Device Labs – Access to real devices and platforms for test-driving an app
It can be very difficult to try out an application on every supported device or platform. Especially for those of us dealing with mobile apps, there are just way too many devices out there for it to be feasible to have an example of each one.
One solution is to use emulators. But here’s an exciting initiative that I heard about recently: Open Device Labs.
The idea is that people may have last year’s mobile phone lying around, that they’d be willing to allow other people to use for testing. Some people may even want to donate new devices to the cause. Smart, enthusiastic people have set up hubs of Internet-connected devices at various locations around the world, and made them available to us all to use. For free!
I haven’t yet used a device from one of these labs, but the idea is awesome. What a great way to test an app, get screenshots, figure out the “how to” instructions you need to write, and just see how the user experience feels.
Mobile emulator in Chrome browser
With Chrome’s mobile emulation, you can make your desktop browser pretend that it’s something else. It can masquerade as an iPhone, Kindle, Blackberry, Nexus, and more. This is very useful for taking screenshots, and for seeing how responsive an app is to different device sizes and resolutions. The emulator is available via a fairly obscure setting in the Chrome Developer Tools panel.
Online source repositories are good for sharing code. In a tutorial, it works well to include code snippets and point readers to the complete source in a repo. Bitbucket and GitHub are very popular. I have accounts on both, because I’ve worked with teams on both. GitHub works with Git, while Bitbucket supports both Git and Mercurial.
That’s my list so far. If I find any more tools before the STC Summit in May, I’ll add them to the list I’m creating for my presentation. It will be fun to share them with the tech writers at the conference. Can you think of any super-useful tools to add to the list?