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Learn the basics of cloud-native file handling:
Why serverless needs a new way to distribute files
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How permissions work with signature-based downloads
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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.
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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
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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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Cold starts
Async programming model
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A Practical Guide to AWS IAM free chapters
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Large files can play well with AWS Lambda
Serverless computing is about short functions that run fast and only for a short duration. On the other hand, files can be arbitrarily large, and sending them through ephemeral functions can easily hit a limit of the runtime.
This is the problem S3 signed URLs solve.
Learn how to implement a serverless-friendly, robust, and secure solution to handle files using signed URLs.
Want a sneak peek? Sign up for free chapters here:
Handling files in a serverless environment
Serverless functions are designed to be run for a short duration, handle small amounts of data, then terminate quickly. This is great to provide an HTTP API that users can call to interact with your app but is terrible for large downloads or uploads.
S3 on the other hand is to handle arbitrarily large files and can handle long downloads and uploads and terabytes of data.
URL signing is a mechanism to combine the best parts of the two services. The Lambda function decides who and how can download and upload files, but the actual transfer is handled by the S3 service.
"But a signed URL is just a function call!"
When I started working with signed URLs I quickly realized how easy it is to end up with a solution that is not reliable and not secure. This prompted me to learn how it works and what services are taking part.
Signed URLs change how you think about files and access control.
And the best part is that this knowledge is transferrable between clouds. The services and the details are different, but the underlying mechanism is the same for all providers that offer this functionality.
Learn how to implement a secure and robust file-handling solution
This book is a thorough introduction to signed URLs. You'll learn:
Why serverless needs a new model to handle files
What services work together when you sign a URL
Backend and frontend implementations
How to secure your implementation and what are the usual problems
Solutions to common use-cases
...and more!
Screenshots
Table of contents
Chapter 1: Overview Use cases From servers to serverless 3-tier architecture Serverless architecture Signed URLs for S3 Credentials URL structure Expiration time Security of S3 signed URLs Algorithm Bandwidth control Implementation disclosure Revocation
Chapter 2: Implementation Sample code Infrastructure Bucket Object Function Execution role Backend with Node.js S3 service Sign URLs Frontend
Chapter 3: Specific use-cases Least privilege with dedicated roles CORS Using HTTP redirects How to check if a file exists before signing How to set the filename Integrate with CloudFront Caching Uploading files Handling encrypted data Permanent URLs
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 
