Flash Messages

Flash provides temporary message storage that persists for exactly one request, then auto-clears. Useful for notifications like "Saved successfully" or "Invalid credentials".

How It Works

Flash uses two internal hashes:

• next -- Messages set during the current request, available in the next request

• now -- Messages from the previous request, available for reading in the current request

At the start of each request, rotate! moves next into now and clears next. This happens automatically when Store#load_from is called.

Basic Usage

# Set a message (available next request)
store.flash["notice"] = "Saved successfully"

# In the next request, read it
store.flash["notice"]  # => "Saved successfully"

Same-Request Messages

To display a message in the current request (e.g., validation errors on form re-render):

store.flash.now["error"] = "Validation failed"

Convenience Accessors

Accessor	Getter	Setter
notice	flash.notice	flash.notice = "msg"
alert	flash.alert	flash.alert = "msg"
error	flash.error	flash.error = "msg"
success	flash.success	flash.success = "msg"
warning	flash.warning	flash.warning = "msg"
info	flash.info	flash.info = "msg"

Lifecycle Control

Method	Description
keep(key)	Preserve a message for one more request
keep_all	Preserve all messages for one more request
discard(key)	Remove a message from the next request
discard_all	Clear all messages from the next request

# Keep a notice around for an extra request (e.g., after redirect)
store.flash.keep("notice")

Utility Methods

Method	Return	Description
[key]	String?	Get message (checks now first, then next)
[key]?	String?	Same as []
has_key?(key)	Bool	Check if message exists
empty?	Bool	True if no messages in either hash
keys	Array(String)	All unique keys across both hashes

See Also

• Session Lifecycle

• Quick Start