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The internet consists of a vast array of highly-connected devices spanning the entire globe. To ensure that any two devices can communicate, it was necessary to develop a common set of rules - or protocol - to facilitate dependable communication.
Now you might be asking yourself,
why do we need a set of rules for
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two devices to talk to each other?
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Aren't rules limiting?
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Well, think about the way we hold phone
conversations with family or friends.
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The nature of your conversations probably
varies widely from making dinner plans to
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expressing sympathy from a loss,
to catching up after a year or
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two of losing touch.
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However, all of these conversations
probably follow a set of conventions.
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First, there's some sort of greeting.
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Hello?
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Hi Courtney, this is Chris.
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Or some variation of that.
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What follows is a series of comments and
sequence.
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As in, one person talks,
then the other, but
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never at the same time where neither
person is heard by the other.
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And if a question is asked, well,
a response quickly follows.
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Unless there's no response, which can
be unexpected or just plain awkward.
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Both people know the conversation is
over when each person says, goodbye or
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talk to you soon.
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Communication between devices
over the internet is not
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unlike spoken language over the phone.
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Except that there are even more rules,
to make sure machines don't end up
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guessing what question was asked or
what answer was given.
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You might equate this rigid communication
environment to a court room.
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Where the judge won't response
to an attorney shouting, hey or
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no you didn't, but
would respond to a simple objection.
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Likewise, in internet
communication word choice matters.
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If the internet was
going to be successful,
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it required a set of standards for
device communication.
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That is, communication between the devices
that contain the information and
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the devices that wish to interact with it.
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So, when Tim Berners-Lee and his team
proposed the World Wide Web project
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in 1989, what soon followed was
the first published version of HTTP.
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This was HTTP 0.9 in 1991.
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The HyperText Transfer Protocol
is the setup rules that
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governs the messaging between
devices over the Internet.
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It functions mainly as a request-response
cycle between a client and a server.
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That is, a client makes a request and
a server responds.
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Examples of clients are a web browser,
such as Chrome or Safari,
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a native mobile app on iOS or Android
like the Facebook app on your phone.
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Or even a in a desktop weather
application like one written in JavaFX.
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The main example of a server is
a web server such as Apache,
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Nginx and Node.js server or even
a Java enabled web server like Tomcat.
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After a quick break
let's see HTTP in action
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using a simple text-based
tool called Telnet.
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