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Hey everybody, welcome back.

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REST APIs this lesson.

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API, it's an acronym that stands for Application Programming Interface.

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It's an interface that lets one computer program interact with

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another computer program and rest.

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Not rest as in take a deep breath and relax.

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It's another acronym that stands for

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Representational State Transfer which actually isn't all that helpful either.

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Purists will be happy to explain to you at length

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the more abstract meaning for Representational State Transfer.

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But in everyday parlance,

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a REST API just means a website that produces

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data intended for another computer program to consume,

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rather than something intended to be displayed to people in a browser.

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A REST API will respond to requests in

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a particular format and some things are common across many APIs about the format,

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but some things are specific to the particular API.

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This week, you'll learn how to write programs in Python that interact with REST APIs.

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You'll learn to read the documentation in order to figure out

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the specific format that the API is expecting,

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and you'll learn how to use the Python request module to make the API calls.

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Finally, you'll learn about caching as a way to

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reduce the total number of calls that you have to make to the APIs.

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Before we dive into details of request APIs though,

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we're going to take a little detour to give you some background on what

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goes on behind the scenes when two computers talk to each other over the Internet.

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It'll give you a mental model of what's going

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on so that if things don't work perfectly the first time,

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and they never do, you'll know how to think about

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what might be going wrong and have a good path toward fixing it.

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At the end of this lesson,

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you'll be able to parse a URL into its component parts,

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the protocol HTTP or HTTPS,

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the host, typically a domain name, and the path.

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You'll also be able to use the Python request module to fetch the contents of a URL.

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Let's get started. I'll see you at the end.