Download - Web APIs: The future of software
In the Beginning, There were Ones and Zeroes.
Software• Software is the magical collection of instructions
that control a computer
• At the end of the day, we know that there are ones and zeroes in there.
• No matter what language you use, the programs you write are turned into ones and zeroes when they are executed.
Abstraction
• So, why not just use ones and zeroes?
• Abstraction: One of the most important concepts in computer science!
• Abstraction lets you think big thoughts, not worrying about the underlying infrastructure or implementation
High level• The greatest abstractions happen in "high-level"
languages, such as Python, Ruby, JavaScript, and Lisp
• In low-level languages, I work hard to suit the computer.
• But in high-level languages, the computer works hard to suit me, by black-boxing the details!
Repetition• No matter what language you use, you'll eventually
find yourself repeating code.
• How can you deal with this problem?
• Put the code in a common place, and then use it again and again.
• Write it once, and then use it — ignoring the implementation
Programmer virtues
• "The three virtues of a programmer: laziness, impatience, and hubris" — Larry Wall
• Laziness: Write it once, and then reuse it many times!
DRY
• This leads directly to the idea of DRY — write code only once.
• Don't repeat yourself!
• Don't repeat yourself!
Libraries of code
• Writing libraries of code, which can then be used by many different programs, is an extremely common programming task.
• With a library, we can concentrate on the most important things to our business, rather than focus on infrastructure.
API• "Application Programming Interface"
• What is the interface to a library of code?
• Function/method names
• Effects (what each function does)
• Parameters expected by each function
• Return value(s) from each function
• What happens if there was an error?
Modern operating systems• What is an operating system? A bunch of libraries
that abstract away the hardware and many other aspects of computers:
• Networking
• Printing
• Running multiple programs
• Drawing to the screen
Operating systems
• In other words, an operating system is just a collection of APIs!
• You can write your own printing system, but why bother? Just use the printing API that the operating system provides.
From Wikipedia• Win32 (Windows)
• The Windows API, informally WinAPI, is Microsoft's core set of application programming interfaces (APIs) available in the Microsoft Windows operating systems.
• Cocoa (Mac OS X)
• Cocoa is Apple's native object-oriented application programming interface (API) for the OS X operating system.
RPC• "Remote procedure call"
• Don't invoke a library on the local computer — rather, invoke it on another computer!
• Abstraction #1: The software library does some task for me
• Abstraction #2: I don't have to know how that things are executing remotely
What is the Web?
• URLs — what I want, where it's located, and how I get there
• HTTP — a great way to get there
• HTML — a type of content
The entire Web, explained
• A browser sends an HTTP request to a server.
• The server sends a response (perhaps content, perhaps an error message, perhaps a redirect), and hangs up.
What if machines browsed, and not humans?
• The Web was designed for people.
• But you know, the combination of URLs, HTTP, and HTML could be used by computers, too.
• And then you wouldn't need to have a "browser" sending a request. It could be any program, right?
XML
• "Extensible markup language"
• Not a markup language, but rather a way to define new markup languages!
• Now computers can send requests and get results not in human-centric HTML, but in machine-centric XML.
XML-RPC• Dave Winer suggested that we could use a
combination of XML and HTTP for RPC!
• Works across the Internet
• Works across programming languages
• Used libraries (XML, HTTP) that already existed
• Set up a client or server in minutes!
• But is this really RPC? Actually, yes!
SOAP
• Simple Object Access Protocol
• Officially: A more modern, well-defined version of XML-RPC
• Realistically: Massive overhead and complexity
"Web Services"• Both XML-RPC and SOAP are protocols that let you
advertise Web services
• In other words: APIs against which we can make calls from anywhere on the Internet!
• There's a whole alphabet soup of standards that were written to address this problem.
• But today, APIs are often cleaner and leaner than this, implemented in different ways
REST• Representational State Transfer (Roy Fielding)
• URLs should be nouns, and different HTTP actions should describe the actions on those nouns
• Not a lot of documentation is needed, because REST standardizes how things look on the outside
• Wait, how does it look on the inside? What does the implementation look like?
JSON• JavaScript is everywhere!
• And JavaScript syntax is easy to understand
• So Douglas Crockford created "JSON" — JavaScript Object Notation — which makes XML-RPC look clunky and fat by comparison
• A huge number of programming languages support JSON
REST + JSON
• Modern APIs are thus standardized via REST, and exchange data using JSON
• Many frameworks, such as Ruby on Rails, make it trivially easy to create RESTful JSON APIs
Um. OK.• Web APIs let programs talk to other programs.
• And? Why should I care? And how is this the future of software?
• Two reasons:
• All software is moving online, and
• The entire Internet is becoming our OS!
If an OS is a collection of APIs you can call, then the Internet is becoming a
massively distributed OS!
In other words
• Build the parts of your application that are special and specific for you.
• The rest of your application should leverage APIs on the Web
• And by the way, your application can offer APIs as well, leading to a complex web of API calls!
Example: FedEx• One of the first companies to offer an API
• (Yes, beyond the Web site!)
• Benefit to your company: Create custom software that handles all of your package needs, with the appropriate permissions and reporting
• Benefit to FedEx: Lock-in, customer satisfaction
Example: Payment• It used to be difficult to deal with payment and e-
commerce — because you implemented it yourself
• But now we have APIs that make it easier to deal with. PayPal, Strip, Dwolla, Amazon, PayByGroup.
• How can we simplify the API? Simple: Offer a library that wraps up those APIs.
• Charging credit cards becomes a one-line task!
Example: Authentication• Why store usernames and passwords?
• People don't trust you
• Users need to remember another password
• You're vulnerable
• Solution: Let people log in via Facebook, LinkedIn, Google, etc.
Example: New York Times
What does this mean?
• The New York Times is not only a source for news.
• It's now a source for data that people can use to inform others.
• It becomes a platform on which you can create new content, and do meta-reporting
Weather APIs
• wunderground.com offers APIs to current weather data
• Get weather data, and integrate it into your app
• Location-aware apps on your phone can use this to show weather wherever you are!
Amazon Web Services
• Everything is available via an API!
• Start new servers, shut down existing servers, and monitor servers — all via APIs
• Your application can thus spin up (and spin down) entire servers whenever it needs, using nothing more than URLs and JSON!
Amazon?!?
• Yes, they make billions off of their cloud servers
• You can manage those servers via various APIs
• Want to manage buying, selling, and management of products on Amazon? Sure, there are APIs for those, too…
Geocoding
• Have a street address, and want to know its longitude and latitude?
• Have an IP address, and want to know its country?
• There are APIs for this, generally from mapping companies (e.g., Google, Bing, MapQuest)
Geocoding IP address
def geocoder_decode(ip_address)
Geocoder.search(ip_address).location rescue nil
end
A/B Testing
• optimize.ly lets you do A/B ("split") testing on your Web site by including a snippet of JavaScript
• How does it work? By accessing Optimizely's API
• How can you modify its behavior? By accessing Optimizely's API from your own program!
Storage
• Dropbox and Google Drive offer APIs!
• Store and retrieve Dropbox documents from within your program
• Use Dropbox for storage, and it automatically replicates!
Facebook• Get access to a user's personal information —
name, address, and interests
• You also get information about the person's friends!
• This is potentially a huge privacy issue! So users need to agree to add Facebook API applications, and specifically see what capabilities apps want
• (The same is true for LinkedIn, of course.)
• Twitter has long offered an API, allowing anyone to tweet from within a program
• (You can also read and search through tweets)
Using the API
def tweet_person
Twitter.update("Welcome, #{fullname}, to the #NetLogo Modeling Commons, our #{ActiveSupport::Inflector::ordinalize(Person.count)} user!")
end
SOA• Service-Oriented Architecture
• Instead of a big Web application, write many small ones that talk to each other via APIs!
• Each service can then be created, updated, and maintained by different teams. Or companies. Or individuals.
• Easier to create, maintain, scale, and understand
SaaS APIs
• SaaS — software as a service
• Applications that run on a server somewhere; they may have a browser-side, as well.
• A growing number of SaaS companies offer APIs. This turns the application into something beyond what you use it for in your browser.
Example API: Harvest• "Harvest," time-tracking and invoicing software, has
an API
• The time-tracking API lets you keep track of your time. Build a new widget or app that starts and stops your clock, for example.
• The extended API lets you edit your clients, projects, and tasks!
Example API: Job seeking
• Looking to hire people? You can use an API to post jobs (on monster.com, linkedin.com, and elsewhere)
• Looking for work? You can search via an API!
• Trying to match jobs and people? You can use these APIs, and build a company on top of them!
Example API: Search
• Run searches against your favorite search engine
• (Or run searches against multiple search engines, and compare the results!)
• All search engines provide APIs that let you build on top of what they offer
ProgrammableWeb.com• Not sure what's out there?
• ProgrammableWeb.com lists as many APIs as it can, categorized by topic, protocol and data format.
• Don't reinvent the wheel — find one that has already been rolling for a while, and integrate it!
• (Let someone else do the hard work of implementing things. Laziness wins again!)
Connecting• IFTTT ("If this, then that")
• It's an connector for APIs!
• You can say, "When I'm tagged in a photo on Facebook, post a note to my blog."
• Once a company is part of the IFTTT family, you can connect APIs for added
Mobile apps• Mobile apps all use APIs!
• They usually talk to Web sites via XML or JSON
• In other words, a mobile app has two parts
• Client (running on the device)
• Server (offering a JSON API)
• Support iOS and Android? Two clients, one API!
Single-page apps• As browsers get smarter, more of the app is being
pushed onto the client, running in JavaScript
• So instead of each click being a new HTTP request, you can create a whole application in the browser that occasionally syncs with a server
• How does it sync? APIs, of course!
• Google Docs work just like this
Even the browser…
• How do programs talk to the browser? Via APIs!
• DOM — API for us to read and update a Web page
• Call APIs from the browser, to talk to lots of servers
• e.g., Disqus, Facebook, LiveFyre — add discussion to any page!
APIs on the server
• Consume:
• Logging, payment, analytics, authentication
• Offer:
• Authentication, read/write your unique data, aggregation, analytics
Make a fortune!
• The path to startup success:
1. Come up with an idea
2. ???
3. Profit!
What's stage 2?
• The path to startup success:
1. Come up with an idea
2. Offer an API to information or analysis that no one else can offer
3. Profit!
$
Opportunities in your work?
• An API doesn't have to be big or complex
• It can often solve simple problems — saving you money and making you more efficient
• Don't e-mail Excel files to one another. Rather, create an API on a local server!
Thanks! Any questions?
• You can always find me at:
• http://www.lerner.co.il/
• Get my newsletter, with articles and insights like this!
• 054-496-8405
• “reuvenlerner” on Skype
• @reuvenmlerner on Twitter
