[MUSIC] Whenever a client sends a request to a server using HTTP, that request has to have a very specific format. I mean, just think about it, if you're that server receiving all of these requests from all over the place. You have to absolutely make sure that they all have the same format so you can interpret them properly and figure out the right thing to do with them. And that's why HTTP, very strictly specifies what the format and the rules are for sending that request. So let's talk about the Parts of a Request. So we have our HTTP Request. And, each HTTP Request has a number of critical, some mandatory and some optional, parts that have to be sent to the server. One of the first parts that has to be sent to the server is the Request Line. And the Request Line specifies two really important things. The first thing is it specifies the Request Method. And the second thing that it specifies is the Resource. That we want to take action on, which is typically specified as a Path. So these are a request part. Now, this is the key thing. We're going to say, server, please go and take this action. On this particular Resource. But when that server gets that Request there's lots of cases where it may have multiple options for how it goes and completes that request. For example, let's say that we have a webpage on the server, and it's the homepage of that particular web address, so you go to the Equivalent of google.com. Well, sometimes the server needs help knowing some information about the client that can help it to complete that request, things like the language that the client would like to receive the response in. So, the next piece of the request is a series of Headers. And what we can think of these is extra information to help the server. And these were things like the language that we would like the response to come back in. Or the character set that we would like to see the response in, or the content type, what we're sending back to the client so it knows how to interpret it and process it. Or possibly something like the cookies or small pieces of data that were sent from the server to the client in a past request that the client's now providing back to the server to help it figure out. Where it was or who this person is, and associate them with past requests. So the Headers are the second key component of a request, and they provide extra information to help the server figure out the right way to process the request. A final piece of information that can be part of an HTTP Request. Is the Request Body, and the Body is any data that the client is sending to the server, in order to help it complete the request. Now, this an optional part of a request, and not a 100% required, but let's distinguish it a little bit from the Headers. The Headers are meta information, things to help it know the right way to process the request. The Body is core data that is being sent to the server to process the request. Now one way to think about this is in most cases. If you didn't include the Headers, but you did include the Body, the server could still process the Request. It just may not give it back to you in the format that you expected or exactly the way that you expected it. But if you didn't include the Body and the server needed the Body, it wouldn't be able to process the Request. So the Body is the data the client is sending, that the server absolutely has to have in order to complete that Request. The Headers are extra information that the client is giving the server to help it complete that Request.
