Practical FP in Scala: A hands-on approach
This book is 100% complete
Completed on 2020-05-11
About the Book
Practical FP in Scala: A hands-on approach, is a book for intermediate to advanced Scala developers. Aimed at those who understand functional effects, referential transparency and the benefits of functional programming to some extent but who are missing some pieces to put all these concepts together to build a large application in a time-constrained manner.
Throughout the chapters we will design, architect and develop a complete stateful application serving an API via HTTP, accessing a database and dealing with cached data, using the best practices and best functional libraries available in the Cats ecosystem.
You will also learn about common design patterns such as managing state, error handling and anti-patterns, all accompanied by clear examples. Furthermore, at the end of the book, we will dive into some advanced concepts such as MTL, Classy Optics and Typeclass derivation.
The book is supplemented by two Scala projects:
- Shopping Cart application: https://github.com/gvolpe/pfps-shopping-cart
- Standalone examples: https://github.com/gvolpe/pfps-examples
Got some feedback? Please email the author here: pfpscala at gmail dot com.
About the Author
Table of Contents
- Preface
- Acknowledgments
- Dependency version
- Prerequisites
-
How to read this book
- Conventions used in this book
-
1. Chapter 1: Shopping Cart project
-
1.1 Business requirements
- 1.1.1 Third-party Payments API
- 1.1.2 Identifying the domain
- 1.1.3 Identifying Http endpoints
- 1.2 Architecture
-
1.3 Technical stack
- 1.3.1 A note on Cats Effect
-
1.1 Business requirements
-
2. Chapter 2: Design patterns
-
2.1 Strongly-typed functions
- 2.1.1 Value classes
- 2.1.2 Newtypes
- 2.1.3 Refinement types
-
2.2 Encapsulating state
- 2.2.1 In-memory counter
-
2.3 Sequential vs concurrent state
- 2.3.1 State Monad
- 2.3.2 Atomic Ref
-
2.4 Shared state
- 2.4.1 Regions of sharing
- 2.4.2 Leaky state
-
2.5 Anti-patterns
- 2.5.1 Seq: a base trait for sequences
- 2.5.2 About Monad Transformers
-
2.6 Error handling
- 2.6.1 MonadError and ApplicativeError
- 2.6.2 Either Monad
- 2.6.3 Classy prisms
-
2.1 Strongly-typed functions
-
3. Chapter 3: Tagless final encoding
-
3.1 Algebras
- 3.1.1 Naming conventions
-
3.2 Interpreters
- 3.2.1 Building interpreters
- 3.3 Programs
-
3.4 Implicit vs explicit parameters
- 3.4.1 Achieving modularity
- 3.4.2 Implicit convenience
-
3.1 Algebras
-
4. Chapter 4: Business logic
- 4.1 Identifying algebras
- 4.2 Data access and storage
-
4.3 Defining programs
- 4.3.1 Checkout
- 4.3.2 Retrying effects
-
5. Chapter 5: HTTP layer
- 5.1 A server is a function
- 5.2 HTTP Routes #1
-
5.3 Authentication
- 5.3.1 JWT Auth
- 5.4 HTTP Routes #2
- 5.5 Composing routes
-
5.6 Middlewares
- 5.6.1 Compositionality
- 5.7 Running server
-
5.8 Entity codecs
- 5.8.1 JSON codecs
- 5.8.2 Validation
-
5.9 HTTP Client
- 5.9.1 Payment client
- 5.9.2 Creating a client
-
6. Chapter 6: Persistent layer
-
6.1 Skunk & Doobie
- 6.1.1 Session Pool
- 6.1.2 Queries
- 6.1.3 Commands
- 6.1.4 Interpreters
- 6.1.5 Streaming & Pagination
-
6.2 Redis for Cats
- 6.2.1 Connection
- 6.2.2 Interpreters
- 6.3 Blocking operations
- 6.4 Health check
-
6.1 Skunk & Doobie
-
7. Chapter 7: Testing
- 7.1 Functional test suite
- 7.2 Generators
-
7.3 Business logic
- 7.3.1 Happy path
- 7.3.2 Empty cart
- 7.3.3 Unreachable payment client
- 7.3.4 Recovering payment client
- 7.3.5 Failing orders
- 7.3.6 Failing cart deletion
- 7.4 Http routes
-
7.5 Integration tests
- 7.5.1 Resource allocation
- 7.5.2 Postgres
- 7.5.3 Redis
-
8. Chapter 8: Assembly
- 8.1 Logging
- 8.2 Configuration
- 8.3 Modules
- 8.4 Resources
- 8.5 Main
-
9. Chapter 9: Deploying
-
9.1 Docker image
- 9.1.1 Optimizing image
- 9.1.2 Run it locally
-
9.2 Continuous Integration
- 9.2.1 Dependencies
- 9.2.2 CI build
- 9.2.3 Furthermore
- 9.3 Summary
-
9.1 Docker image
-
10. Chapter 10: Advanced techniques
- 10.1 Tagless Final plugin
-
10.2 MTL (Monad Transformers Library)
- 10.2.1 Managing state
- 10.2.2 Accessing context
-
10.3 Classy optics
- 10.3.1 Lenses
- 10.3.2 Prisms
- 10.3.3 Classy lenses
- 10.3.4 Classy prisms
-
10.4 Typeclass derivation
- 10.4.1 Kinds
- 10.4.2 Concrete types
- 10.4.3 Higher-kinded types
- 10.4.4 Higher-order functors
-
10.5 Effectful streams
- 10.5.1 Concurrency
- 10.5.2 Resource safety
- 10.5.3 Interruption
Authors have earned$8,948,210writing, publishing and selling on Leanpub,
earning 80% royalties while saving up to 25 million pounds of CO2 and up to 46,000 trees.
Learn more about writing on Leanpub
The Leanpub 45-day 100% Happiness Guarantee
Within 45 days of purchase you can get a 100% refund on any Leanpub purchase, in two clicks.
See full terms
Free Updates. DRM Free.
If you buy a Leanpub book, you get free updates for as long as the author updates the book! Many authors use Leanpub to publish their books in-progress, while they are writing them. All readers get free updates, regardless of when they bought the book or how much they paid (including free).
Most Leanpub books are available in PDF (for computers), EPUB (for phones and tablets) and MOBI (for Kindle). The formats that a book includes are shown at the top right corner of this page.
Finally, Leanpub books don't have any DRM copy-protection nonsense, so you can easily read them on any supported device.
Learn more about Leanpub's ebook formats and where to read them
