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In this video, we are going to developing our lambda function.

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So the first step is we are listing objects into the bucket.

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So that means think about that with the incoming event JSON object, we can get the bucket name and

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after that in the lambda function, we will interact with the Amazon S3 passing the bucket name and

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get the object from the bucket.

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We're using a WS SDK package, so let's get started.

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Please open the index JS file.

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So I'm going to listing objects in the bucket name.

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So that means I have the interaction with the S3 client object.

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And for that purpose we are going to use these list object version two command.

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So you can see the example in here.

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We can come here and see the list object version two command and this is the example we will implement

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this example.

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So let me start to developing first.

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First of all, I'm going to develop try case block.

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We can come here and from the cache block.

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Now in the tribe.

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Look, we basically use a steady client and center list object version to command.

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Let me develop these codes.

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So as you remember that these are the almost the same steps when we have interaction with the client.

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The only difference is we are developing the handle method, which is the lambda function code.

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But the idea is the same.

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We are using the client and sent to this object version to command with the parameters.

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Also, I'm going to create the parameters and after that we are logging the incoming data from the H3.

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Okay, now let me continue with developing the parameters.

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So we should define the parameters in here.

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Basically, in the parameters we should provide the bucket name.

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We can check the list object version to command request.

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The only important object is the bucket.

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I'm placing the bucket name in here in the previous.

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In the next videos we will get this bucket name from the incoming event JSON.

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But this time I would like to show with the hardcoded and give the bucket name and paste the parameters

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in here in the list object command and send the data with S3 client.

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So that means we have performed the first step listing object in the bucket, but please don't forget

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that required package.

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Please come here and import required packets for that purpose I'm going to import one by one.

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Let me go on top of these indexes and import this statement.

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So we will import list, object command and also import client separate Node.js module and don't forget

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to add the JS extension, otherwise it won't be work.

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Okay.

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So now I would like to test this code in my local computer.

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Even we develop the Lambda 100 code before we deploy these methods and these codes into lambda function.

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We can test and verify the codes and into our local computer.

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In order to do that, I'm going to copy this hundred method and.

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At the end of these indexes, I am going to invoke and call these one methods.

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So first of all, I'm calling this handle method and after that I will use note command as we did before.

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So this is the good practice with using the note command.

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With the note command, we can verify that this function is working fine or not.

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And after that, we should command this 100 method and zip this file and deploy the lambda function.

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But since that time we can perform our local test to running the note commands.

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If you open the our.

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Command window.

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You can run the mode, command and paste the indexes.

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So this will be run these indexes and go to 100 method.

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In the handle method, we basically perform that communicating with S3 listing to objects into the bucket,

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which the given name of this one.

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So let's hit enter and try to test these code.

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Yes.

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As you can see that we have successful test.

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Basically request seems either undefined because we don't passing any event JSON, but we can also paste

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this event JSON into our application.

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But after that, we basically get the success response from the S3 client object.

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You can come here and see the service code and see the content in here.

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So in the S3 bucket of this name of the bucket, there is a key index, HTML file and you can see the

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other attributes and there is only one column, one object into this bucket.

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So as you can see that we have successfully performed our local test before deploying this application.

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So this is the our way of working and development of the Lambda development approach.

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First we verify it is working our local computer with the node command and after that we will compress

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and deploy our code to the lambda function and test with the real locations.

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After verify our function code, let's review our function code.

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If you scroll down and see that basically it is returning a response as a subsequent 200.

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So if you look at our one method, you can see that we are returning helo response, which is status

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code of 200, but we don't need to return any code from our function because we are asynchronous function

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that triggers from the Amazon S3 so we don't need to return value for that purpose.

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I'm going to remove these all return statement and come here.

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And we basically covered the cache block and in the case block we can log the error if there is an error,

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and that's all.

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So for our 100 method, we don't need to return any synchronous response because we are triggering from

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S3 asynchronously.

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As you can see that we have only try catch block and log the asynchronous operation that we can understand

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what's happening in this function code.

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So we have already test this code with the node command you can run again and test your index JS and

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see that our objects listed from the bucket name and we are ready for to continue the second operation.

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So in the next video we are going to iterate these bucket objects and write these bucket objects on

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the Dynamo DB table.