Learn S3 signed URLs from our free email-based course
Learn the basics of cloud-native file handling:
Why serverless needs a new way to distribute files
How to implement signed URLs on the backend and the frontend
How permissions work with signature-based downloads
Tamás Sallai
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Learn how to use CloudFront from our free email-based course
Learn the basics of CloudFront configuration and:
Take advantage of AWS's global distribution network
Use path-based routing to add an entry point to your cloud infrastructure
Utilize caching on the edge locations
Tamás Sallai
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Learn how to use async functions in Javascript from our free email-based course
Learn the basics of async/await and master asynchronous workflows in Javascript.
Learn:
How async functions work and how to use the await keyword
How to use the Promise constructor
How to implement proper error handling in an async environment
Tamás Sallai
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Learn the basics of serverless computing on AWS from our free email-based course
Learn the parts that are needed to make a serverless API on AWS:
Write a Lambda function and add IAM permissions to it
Add API Gateway for an HTTP endpoint
Use DynamoDB to store data
Tamás Sallai
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AWS S3 Signed URLs Handbook free chapters
Thank you for your interest in the book! By signing up to the free chapters you'll receive 4 emails, each with a different part of the book.
The included chapters:
Introduction and use cases
The architecture of signed URLs
Backend implementation with Node.js
Least privilege with dedicated roles
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Javascript on AWS Lambda free chapters
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The included chapters:
Introduction and the Lambda execution model
Cold starts
Async programming model
Storing secrets in SSM Parameter Store
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A Practical Guide to AWS IAM free chapters
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The included chapters:
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Asynchronous Programming Patterns in Javascript free chapters
Thank you for your interest in the book! By signing up to the free chapters you'll receive 4 emails, each with a different part of the book.
The included chapters:
Introduction
Getting started with async/await
Error propagation in Promise chains
The async disposer pattern
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Master async/await
Almost everything new in Javascript is built on Promises and async functions, and even the existing features of the language are starting to migrate to the new structure.
But they are not just keywords that magically make something async work with the rest of the program. It changes how the function work and that can lead to errors without proper understanding.
From this book, you'll learn the basics of async/await and you'll be familiar with the common problems with it and their solutions.
Want a sneak peek? Sign up for free chapters here:
Javascript has no multithreading and synchronous waiting.
Instead, it has Promises and async/await.
Javascript started as a scripting language with the aim to make things as easy as possible. This resulted in its single-threaded model that has consequences for asynchronous operations. Without the ability to wait for a later result, callbacks became ubiquitous in frontend programming.
But callbacks are the past now as they lead to a cluttered program structure. Instead, Promises and now async/await is the mainstream way to handle asynchronous results.
Async functions are everywhere
When a function provides its result later, it has to be an async function. and every function that calls it needs to be async too. Modern Javascript programs are mostly made of async functions.
The async/await addition to the language makes using async functions a lot easier. You no longer need to interpret complicated Promise chains and use an unfamiliar error handling scheme. The complexity is hidden behind two keywords.
From the first steps to mastery
This book helps you understand how async functions works and how to use them. And with the more advanced patterns, no async/await problem will be beyond you. You'll learn:
How to use async functions
How Promises work and how they relate to async/await
The intricate workings of asynchronicity in Javascript and common problems
...and more!
Screenshots
Table of contents
Getting started with async/await Async functions How to use the Promise The benefits of Promises The await keyword Async function examples Chaining Promises Promises Callbacks The Promise constructor Promise states Result value Error handling Error callback in the Promise constructor Rejecting a Promise Detecting errors Error propagation in Promise chains
Parallel and sequential processing Parallel processing with Promise.all Results Errors in Promise.all Early init
Returning multiple values
Convert between Promises and callbacks Callback styles Node-style callbacks Convert callbacks to Promises Promise constructor Promisified functions util.promisify Usual problems Handle this function.length Convert Promises to callbacks
Paginating with async generators Pagination A solution with async generators Breaking it down Making it generic
Using async functions with postMessage Request-response communication Response identification MessageChannel Error handling Using Promises
Collection processing with async functions Async for iteration Async functions with reduce Asynchronous reduce Timing await memo last await memo first When parallelism matters Async functions with map Concurrency Batch processing Parallel processing Sequential processing Async functions with forEach Controlling the timing Waiting for finish Sequential processing Async functions with filter Async filter with map Concurrency Async filter with reduce Sequential processing Async functions with some/every Using an async filter Short-circuiting Async some Async every Parallel processing
Common errors Not propagating errors Missing await in try..catch Not checking the return value Not closing resources in case of a rejection Using both the rejection and resolve handlers in one then function Not waiting for an async forEach
Glossary About the author
About the author
Tamás Sallai
Hey, I'm Tamás! I co-author the advancedweb.hu blog and if you're here there is a good chance you've already read some of my articles.
I'm a software developer focusing mostly on cloud computing and web technologies. I'm especially interested in how to handle edge cases to end up with dependable software.
One of my main focus is security and how each part affects the whole system. I'm an AWS-certified security specialist.
Tamás Sallai 
