The Dark Sky API

When we're working with APIs, we care a lot about the interface itself. 0:00 It's an understanding between the user, us, and the service, Dark Sky. 0:04 It's much like a contract. 0:10 It tells us what we need to provide to the service. 0:12 In exchange, it tells us what the service will return. 0:16 The rest of the details, like where they get the weather information, 0:20 how they manage it,etc, is hidden from us, which is fine. 0:24 Let's take a look at the Dark Sky API, and see how to use their latest version. 0:29 We care about this one here, the Forecast Request. 0:33 The Forecast Request returns current weather data, along with forecast date for 0:37 the next hour, 48 hours, and the next week. 0:41 This is more or less the interface we will be using for our Stormy app. 0:45 We'll need to do a bit of work, of course, but don't worry, 0:50 it isn't going to stretch us too much, and I'll walk you through it step by step. 0:53 Essentially, we are going to make a request at this URL and 0:57 then handle the response Dark Sky provides. 1:01 We'll dive into that in more detail soon. 1:04 The Dark Sky API is a web API that follows the common RESTful programming pattern. 1:08 REST stands for 1:14 Representational State Transfer, which in it of itself may not mean much. 1:16 In our context, it means that when an API adheres to the principles of REST, 1:22 it doesn't require us, the client, to know anything about the specific 1:26 structure of the API, it's another black box, if you will. 1:31 A RESTful API provides whatever information 1:36 the client needs to interact with by means of an identifier. 1:39 In most cases, this is a URL. 1:43 A URL is a reference to a resource like 1:47 http://www.google.com, or 1:51 in our case here, the special URL that will give us a specific weather forecast. 1:56 RESTful programming isn'tt necessarily restricted to the web, but 2:02 most web-based APIs are built following the RESTful pattern. 2:06 In our case, our client, the Stormy app, 2:11 doesn't know anything at all about the Dark Sky API. 2:14 We simply request the data we need through an exposed URL 2:18 with certain keywords that specify what data we want back. 2:22 The API then returns this data to our client in a specified format, XML, 2:26 JSON, or some other data format. 2:31 In the case of Dark Sky, we see JSON data, 2:34 which is part of the contract the API establishes with the client. 2:37 With a RESTful API, that's the only real restriction. 2:41 The client and server need to agree on the data format being used. 2:45 JSON data is very common for web APIs to provide. 2:49 And that's what we'll use in this course. 2:53 Returning to the Dark Sky API documentation, if we look at this URL 2:56 under Forecast Request, we see how we need to construct the request to the API. 3:00 The URL has this base component of api.darksky.net/forecast, 3:04 and then needs specific identifiers, such as a private API key, 3:10 and the longitude and latitude coordinates, for our location. 3:15 But wait, a private API key? 3:20 What's that all about? 3:23 We'll need to register for a Dark Sky developer account so 3:25 we can get an API key and use this service. 3:28 We click on the Sign Up button up at the top of the page, we can register. 3:31 It's super simple, and all you need to provide is an email address and password. 3:35 I'll put the link in the Teacher's Notes, if you need it as well. 3:40 Once you're registered, you'll see a request to provide billing information. 3:43 We can ignore that because we'll utilize their free service tier. 3:47 The free tier allows 1,000 requests a day. 3:51 This will be plenty for our purposes. 3:54 If you decide to publish your app on the Play Store, 3:56 you'll probably want to upgrade to the paid tier. 3:59 Great, once you've register with Dark Sky, 4:02 join me in the next video where we'll start our project. 4:05