WEBVTT

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Hi and welcome back.

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In our previous lecture,
we talked about what a server is,

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how it serves as a central hub
for storing and sharing data.

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Now we will dive into another essential

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aspect of software development,
which is APIs.

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API stands for application
Programming Interface.

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An API is a set of protocols, routines,

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and tools for building
software applications.

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And simply put, it defines how different
software component should interact

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with each other.

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In the context
of mobile app and server communication.

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APIs are used to allow the mobile app

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to communicate with the server and access

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data and functionality

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provided by the server.

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When a mobile app wants to retrieve data
or perform an action on the server,

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it sends a request through the API and the
server responds with the requested data.

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In addition to defining the interactions
between the mobile app and server,

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APIs also require different
types of requests to be made.

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These requests are typically categorized

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as get, post, put and delete.

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A Get request is used to retrieve
data from the server.

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For example, if we want to retrieve

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information about specific book,
we would make a get request to the server

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through the API asking
for the book information.

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A post request is used
to send data to the server.

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For example, if we wanted to add a new
book to the database,

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we would make a post request
to the server, send the information about

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the new book, and create this
new book using the server.

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A put request is used to update
existing data on the server.

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For example, if we wanted to change

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the price of a book,
we would make a put request to the server

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through the API sending
the updated book data.

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And a delete request is something

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that you probably could guess already.

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It would remove data from the server.

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And for example, if we wanted to delete

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a book from the database,

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we would make delete requests

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to the server through the API,
specifying which book to delete.

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Now that we understand what an API is,
how it works, and the different types

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of requests that APIs use, we can move
on to the practical side of things.

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In this section, we will be learning how
to create APIs using NodeJS and Express.

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We'll learn how to handle different types

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of requests and use them to retrieve, add,
update and delete data from the server.

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By the end of this section,
you'll have the skills necessary to build

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robust, scalable APIs for your
mobile app and server communication.

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Thanks so much for watching,
and I'll see you in the next video.