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Requesting data with https
6:27We'll use one of Node.js' built-in modules `https` to go out and make a GET request.
In JavaScript, we can handle
events using callback functions.
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There are two types of events that occur,
user events and system events.
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User events are triggered by user input,
or
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system events are triggered
by the machine.
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Examples of user events are mouse clicks,
hovering and scrolling.
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An example of a system event
is the set timeout method.
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The callback function supplied
will run after a given time.
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The developer may define the time
when the callback is executed, but
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the system is what triggers it.
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When we make requests in Node,
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different types of system events occur
throughout the cycle of the request.
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These include data events,
when data is received.
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Completion events,
when a request is finished.
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And error events, and when an error
occurs our first step in handling
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the data in our app
will be to retrieve it.
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Or watch for data and run a callback
to handle the data once it's received.
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To do this,
we need to connect to the Treehouse API.
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Let's go to the Node docs and
check out the https module.
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Go to node.org, docs, API reference
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documentation, find https.
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And get method, we're using https because
we want to connect to a secure site.
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The get method takes a string of
the URL we want to connect to and
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a callback function that lets us
work with the response object.
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Let's create a folder called profileSearch
to house this project.
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I'll use the mkdir command
followed by profileSearch,
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And change into that directory.
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And now I'll open my text editor
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Inside of this folder,
I create a file named app.js.
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That we'll later execute
using node in the terminal.
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I'll paste some comments in here
that will help us complete the app,
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Remind us of our plan.
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One thing that may be new,
in order to use a module like https,
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we need to indicate that
our code requires it.
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In the docs there's a variable
defined as require ('https').
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The require function in JavaScript allows
us to include modules that exist in
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separate files.
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At the top,
we'll store https in a variable named
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https with the require method.
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And https as a string. We will continue
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by creating a function to hold our data
retrieving code and defining a request.
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Let's name the function getProfile.
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Next, I'll create a variable
to store the request.
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And use the https.get method,
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With the string of the URL we went
to connect to, the Treehouse URL.
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Now follow that with a callback function.
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That takes the response object.
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There we go.
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Node comes with a console.dir method
that's similar to console log.
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When console.dir is given
an object as an argument,
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it displays that object's
properties in a list.
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Let's use console.dir to
log out the response.
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Then in the console,
we'll run our file with node app.js.
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We'll add a call to our getProfile
function to make sure it's executed, save.
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Now run Node app.js.
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The terminal prints out a long list of
properties from the response object.
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Remember that restaurant
I mentioned earlier?
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Our current response object feels like
the kitchen cooked the entire menu and
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brought it to our table.
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We weren't too specific about
the response we wanted.
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So they brought out a bit of everything.
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One of these properties is
the statusMessage of OK,
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which indicates the request went well.
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We get more detail about the status
of our request from the statusCode.
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Our statusCode is 200, which indicates
a successful connection to the API.
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Let's try selecting or
accessing a single piece of this response.
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We'll use dot notation to access
the statusCode property of
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the response object.
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Rerunning the application shows again
that the statusCode is 200, which
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means that the request was successful and
we've connected to the API URL, nice!
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We can interact with objects returned
from API's just like other objects and
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access specific properties
like statusCode.
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Great work so far, you've successfully
requested data from an API and
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received it.
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Next, we'll learn how to convert this
data to a format we can work with.
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