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We've now spent a pretty good amount of time learning about gnats and I would say that you pretty much

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know the basics of what you need to know to really make use of it inside of some application.

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Now at this point I can't take a look at the code that we've written now inside this listener file and

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the publisher file and I just want to point out that there is a lot of boilerplate inside of here to

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just get to the point where we can actually receive a message and do something with it.

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So in total we essentially a forty two lines of code.

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We're only just about one line.

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Really just this right here has some logic related to really running some information or processing

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some incoming event.

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This line really is the only one where we receive some event data and do something with it.

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So it took us 41 lines to get one line of essentially business logic put together.

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Now eventually we're going to have a lot of listeners inside of application.

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There are going to be many different kinds of events we have to listen to.

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And as you can imagine we do not want to write out this entire 41 lines of setup for every different

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event that we're going to try to deal with.

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So with that in mind starting this video we're going to try to refactor a lot of this logic around publishing

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and receiving messages to make it a lot easier to publish and receive.

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We're going to write out an initial implementation to make all this stuff a lot easier.

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Inside of this test project that we're currently working on and eventually we're going to move all this

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logic over to our common module so we can use it across all of our different services let's first begin

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by getting a better idea of exactly how we're going to make this stuff more usable in nature.

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So we're going to first begin on the listener side of things.

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We're going to create a class called listener.

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This is going to be an abstract class.

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Remember abstract classes are not meant to be used directly.

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Instead we're going to subclass them in order to use them.

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I'll show you more on what that means in just a moment.

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Right now let's just take a look at the properties are going to define inside this class.

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The entire goal the class is to essentially automate as much of all this stuff as possible so inside

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this class we're going to have a property called subject.

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There's gonna be a string that's gonna be the name of the channel that we're going to listen to.

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We're going to have an on message function.

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This is where we're going to actually run our business logic or implement the business logic we're going

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to make sure that our class listener receives a stay on client to use to listen for incoming events

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and whatnot.

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We're gonna make sure this thing has a Q group name.

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We're going to make sure that it has an equate property.

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We discussed the goal of this manual act mode right here and as we saw there was that automatic 30 second

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time out but it turns out that when we create the subscription we can also customize that 30 seconds.

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So we might for some listeners want to customize that equate down to maybe five seconds or so.

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So we'll make sure that we add in some properties just to allow ourselves to customize that window of

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how long we have to acknowledge an incoming message we'll make a method that's going to make it a lot

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easier to create these options right here.

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So essentially just wrap up those lines of code.

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We'll have a listen method which is where we're going to actually set up our subscription.

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And then finally a helper method that will call pass message that is going to take a look at the incoming

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message.

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Figure out what kind of data is inside there and pass it in some way.

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So essentially like this right here more or less where we pulled out the data and then we figured out

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whether or not that data was a string or a buffer.

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And eventually pass that data into actual object from the string or the Jason that is some very purposefully

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just going through these properties very quickly right now.

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Because once we start writing some code they will all make a lot more sense lasting on mentioned is

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what we really mean by abstract class and why these two properties are labeled as abstract.

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So the real idea here is that we're not going to use class of listener directly.

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Instead we are going to subclass this listener into things like ticket create a listener and order updated

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listener and then inside these subclasses we're going to put together some different options to make

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sure that it listens specifically for say a ticket created event or in order updated event.

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So in other words we're gonna customize the subject we're listening to the subclass and we're also going

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to customize the on message method inside the subclass as well to make sure that when we receive some

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event inside of a ticket created versus order updated we can do some business logic or do some appropriate

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processing for a ticket created event or in order updated event.

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So that's the general idea.

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So right now really just going to focus on creating class listener will then take a look at how we can

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somehow subclass it into something that's more usable.

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OK.

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Quick pause right here.

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Let's start putting the thing together in just a moment.