Cookbook

The Yesod Cookbook

The Yesod Cookbook contains small snippets of code for solving practical problems with Yesod. If you have some code to share, please create a wiki page and link to it in the appropriate section.

If you're looking for a comprehensive guide to learning Yesod, please consider reading the book.

For non-Yesod code, see also Snippets.

Basics

• Adding CSS and JS
• JSON Object Create and Append

Forms

• Change the order of form fields
• Require input for Maybe field
• Custom form layout
• Password confirm field
• Multi-field validation
• Select field populated from database
• Multi-select field populated from database
• Multi-select field populated from database (esqueleto) - this is the optimized version
• File upload
• File upload saving files to server

Persistence

• Run raw MongoDB
• Run raw SQL
• Sphinx Search
• Non scaffolded MongoDB App
• Using Database.Persist.runPool without Foundation
• Using runDB in IO with SQL
• Database Views and Non-Migrated Entities
• Lens for existing site
• Connecting to an additional existing database
• Activate foreign key checking in Sqlite
• Adding Seed data to Scaffolded Site

State

• Keeping (in-memory) state with warp
• Keeping (in-memory) state with yesod

HTML5 and Yesod

• Basic ServerEvent example
• Allowing WOFF fonts to be accessed from other domains (CORS)

Auth

• Use HashDB in a scaffolded site
• Abstracting user roles & permissions

Internationalization

• Internationalization of forms

Routing

• Hierarchical routes and breadcrumbs
• Domain-based routing
• subdomain (www) redirect
• Static file subsite Hello World
• Pure-Haskell static subdomains
• Slugs
• Using type-safe URLs from inside Javascript

Ajax

• Using Ajax with a Scaffolded Site
• Convert Get Params into a haskell record

Testing

• Testing Yesod App
• Performing Authentication during Testing
• Flushing Database Between Tests

Template Haskell

• Creating string based enums using Template Haskell

Conduit

• Consume a webpage with http-conduit and print progress along the way