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Ruby core language, v3.0.2

Arrays     Classes     Continuations     File directories     Exceptions     Fibers     File IO Operations     Hashes     IO Primitives     Numerics     Objects     Procs     Queues     Random Numbers     Ranges     Regular expressions     Strings     Structs     Symbols     Thread     Time    

Rails Guides

Data Models

Definition     Naming     Schemas     Creating a Model     Custom Naming     create     read     update     delete    

Model Validators

Basics     Helpers     Options     Strict Validation     :if, :unless     Custom     Error Handlers     Error Displays    

Callbacks

Setup     Options     Execution     Skipping     Halting Execution     Relationals     :if, :unless     Classes     DB Transactions    

DB Queries

Get 1 Object     Get Multiple Objects (Batching)     Where     Ordering     Specific Fields     Limit, Offset     Grouping     Having     Override Conditions     Null Relations     Read-Only     DB Locking     Table Joins     Eager Loading     Scopes     find_by_     Enums     Method Chains     Find-or-Build     find_by_sql     exists?     Calculations     Explain    

Generating (Rendering) Views

Defaults     render     redirect_to     head     Asset Tags     yield     content_for     Partials     Nested Layouts    

View Helpers

(partial list. Many more listed here in the API.)     Asset Tag     Atom Feed     Benchmark     Cache     Capture     Date     Debug    

Routing

Intro     Resources     Non-Resource Routing     Custom Resources     Inspect/Test    

Ruby Core Extensions

How to Load     All Objects     Module     Class     String     Symbol     Numeric     Integer     BigDecimal     Enumerable     Array     Hash     Regexp     Range     Date     DateTime     Time     File     Marshal     NameError     LoadError    

Email

Intro     Build     Headers     Methods     Views     Layouts     Previews     Generating URLs     Adding Images     Multipart Emails     Dynamic Delivery     Without Template Rendering     Callbacks     Helpers     Config     Testing     Intercept & Observe    

Background Jobs (Active Job)

Create     Execute     Queues     Callbacks     Email     Internationalization     Supported Arguments     Exceptions     Testing    

File Attachments (Active Storage)

Setup     Attaching     Removing     Linking     Downloading     Analyzing     Images     Previewing     Uploads     System Tests     Integration Tests     Other Cloud Services    

WebSockets (Action Cable)

Terminology     Server-Side     Client-Side     Streams     Broadcasting     Subscriptions     Params & Channels     Re-Broadcasting     Examples     Configuration     Standalone Cable Servers     Dependencies     Deployment     Testing    

Internationalization API

Intro     Setup     Localization     API Features     Custom Translations     Custom Setup     Translating Model Content    

CLI (command line)

new     server     generate     console     dbconsole     runner     destroy     about     assets     db     notes     routes     test     tmp     miscellaneous     custom rake tasks     advanced topics    

Autoloading & Reloading Constants (Zeitwerk mode (Rails 6+))

Intro     Enabling     Structure     Autoload Paths     $LOAD_PATH     Reloading     Eager Loading     Single Table Inheritance (STI)     Inflections     Troubleshooting     Rails.autoloaders     Vs Classic Mode    

API-only Applications

Definition     Why Rails?     Setup     Middleware     Controller Modules