There are times where you need to store user related variables in some kind of permanent storage then relocate the user into another section of your application, be able to retrieve the data, use it and then clean it. All of these tedious operations are definitely doable but why reinvent the wheel if we can have the platform give us a tool for maintaing conversation variables across requests. The key point for Flash RAM is where will the data be stored so that it is unique per user. ColdFusion gives us several persistent scopes that we can use and we have also created several flash storages for this purpose. Since the ColdBox flash scope is based on an interface, the flash scope storage can be virtually anywhere. You will find all of these implementations in the following package: coldbox.system.web.flash. In order to choose what implementation to use in your application you need to tell the ColdBox.cfc which one to use via flash configuration structure:

Configuration

// flash scope configuration
flash = {
scope = "session,client,cluster,cache,or full path",
properties = {}, // constructor properties for the flash scope implementation
inflateToRC = true, // automatically inflate flash data into the RC scope
inflateToPRC = false, // automatically inflate flash data into the PRC scope
autoPurge = true, // automatically purge flash data for you
autoSave = true // automatically save flash scopes at end of a request and on relocations.
};

Below is a nice chart of all the keys in this configuration structure so you can alter behavior of the Flash RAM objects:

Key

Type

Required

Default

Description

scope

string or instantiation path

false

session

Determines what scope to use for Flash RAM. The available aliases are: session, client, cluster, cache or a custom instantiation path

properties

struct

false

{}

Properties that can be used inside the constructor of any Flash RAM implementation

inflateToRC

boolean

false

true

Whatever variables you put into the Flash RAM, they will also be inflated or copied into the request collection for you automatically.

inflateToPRC

boolean

false

false

Whatever variables you put into the Flash RAM, they will also be inflated or copied into the private request collection for you automatically

autoPurge

boolean

false

true

This is what makes the Flash RAM work, it cleans itself for you. Be careful when setting this to false as it then becomes your job to do the cleaning

autoSave

boolean

false

true

The Flash RAM saves itself at the end of requests and on relocations via setNextEvent(). If you do not want auto-saving, then turn it off and make sure you save manually

Core Flash Implementations

The included flash implementations for ColdBox are:

Name

Class

Description

Session

coldbox.system.web.flash.SessionFlash

Persists variables in session scope

Cluster

coldbox.system.web.flash.ClusterFlash

Persists variables in cluster scope via Railo only

Client

coldbox.system.web.flash.ClientFlash

Persists variables in client scope

Mock

coldbox.system.web.flash.MockFlash

Mocks the storage of Flashed variables. Great for unit/integration testing.

Cache

coldbox.system.web.flash.ColdboxCacheFlash

Persists variables in the ColdBox Cache

Configuration Properties

Each RAM implementation can also use properties in order to alter its behavior upon construction via the properties configuration struct. Below are the properties our core implementations can use:

Session Flash Settings

  • none

Cluster Flash Settings

  • none

Client Flash Settings

  • none

Mock Flash Settings

  • none

Cache Flash Settings

  • cacheName : The cache provider name declared in CacheBox

// flash scope configuration
flash = {
scope = "cache",
properties = { cacheName="cluster" }
};