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Getting started with AWS serverless - Databases

Pierre Chollet on March 01, 2023

In the last article, I covered the basics of creating Lambda functions on AWS, using the CDK. In this article, I will cover how to store data in a ...
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Todd Sharp • • Edited

Just a small suggestion - when creating an API, it's better to include details as to why validation failed instead of just returning a generic error message. At the very least, this code:

if (userId === undefined || noteId === undefined) {
  return {
    statusCode: 400,
    body: 'bad request',
  };
}
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Would be vastly improved by this simple change:

if (userId === undefined || noteId === undefined) {
  return {
    statusCode: 400,
    body: 'You must pass a userId or noteId to getNote',
  };
}
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Pierre Chollet •

Indeed! I tried to keep it simple in these examples. To go even further, a better typing should be used instead of hard coding the input and output types. I plan to cover the use of contracts one day

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kob.xrd •

Shouldn't the handler function return a promise?

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Pierre Chollet •

Yes, but it does here -> async functions that contain an "await" statement automatically return a promise, even if it ins't stated explicitly.

If you write the code and check the return type, you will see that it's a promise

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Abdeali •

How did you deploy the code in required lambda using cdk code.. would like to know more on those points as well. Thanks

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Pierre Chollet •

I covered the subject with more details in the previous article of the series. Basically the Nodejsfunction construct allows you to write code in a separate file and will handle deployment for you !

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Adèle Gauvrit •

I wished someone had taught me how to partionned a DynamoDB when I started

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Pierre Chollet •

Partitioning a DB is easier said than done 😩

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Alexandre Pernin •

classic use case, it's super valuable to have these code examples, thanks for sharing!

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Pierre Chollet •

Thank you! I’m glad you found this useful 🤗

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Hiram •

Excellent content. I tried the homework, DELETE was actually the same than GET. Update and creation might rely on the existence of noteId to use or create a new uuid 😎