Redis Database Session Grails Plugin

Summary

Stores HTTP sessions in a Redis.

Requirements

Database Session Plugin 1.2.1+
Redis Plugin 1.5.2+

Description

This plugin lets you store HTTP session data in a redis store using Database Session Plugin.

Artifacts

This contains a RedisPersistentService.groovy with the persistence logic and RedisSessionCleanupService.groovy for cleanup sessions.

It registers two aliases inside the doWithSpring closure if the plugin is enabled. With this, it can work with the existing Proxy Session Filter, SessionFilters (for flash scope) and DatabaseCleanupJob

springConfig.addAlias 'gormPersisterService', 'redisPersistentService'
springConfig.addAlias 'databaseCleanupService', 'redisSessionCleanupService'

Usage

For configuring, please refer to the Database Session Plugin documents.

To set the session timeout to something other than the default of 30 minutes, set the sessionTimeout flag in your application's config.groovy as follows:

grails.plugin.redisdatabasesession.sessionTimeout = 60

Json Serialization

By default objects are serialized as byte[], but JSON serialization is also available.

To enable JSON serialization set the useJson flag to true in your application's config.groovy as follows:

grails.plugin.redisdatabasesession.useJson = true

To store the grails flash scope in the Redis, rather than the default of the request, set storeFlashScopeWithRedis to true as follows:

grails.plugin.redisdatabasesession.storeFlashScopeWithRedis = true

Warning: While serialization for some commonly needed classes has been taken care of, it is possible that you may need to implement your own type adapters depending on what you are storing in your session.

Custom type adapters will need to produce JSON that has both a type field and a value field. Additionally, the type adapter is a gson type adapter and must implement com.google.gson.JsonSerializer and/or com.google.gson.JsonDeserializer

type should be the canonical name of the class for which you are registering a type adapter.
value should be the data stored for the object.

An example of a type adapter for a Double is as follows:

class DoubleSerializer implements JsonSerializer<Double>, JsonDeserializer<Double> {

    JsonElement serialize(Double aDouble, Type type, JsonSerializationContext context) {
        JsonObject result = new JsonObject()
        result.addProperty("type", "java.lang.Double")
        result.addProperty("value", aDouble.toString())
        return result
    }
    
    Double deserialize(JsonElement json, Type type, JsonDeserializationContext context) {
        JsonObject jsonObject = json.getAsJsonObject()
        return jsonObject.get("value").getAsDouble()
    }
}

The type adapter must then be registered with the registerTypeAdapter method on the plugin's GsonService.

The recommend place to register the type adapter is from your applications's BootStrap.groovy. To register our Double serializer, we would do as follows within BootStrap.groovy:

def redisDatabaseSessionGsonService //autowires our plugin's GsonService

redisDatabaseSessionGsonService.registerTypeAdapter(Double.class, new DoubleSerializer())

Contributors

Roberto Perez Alcolea

Brit Indrelie

Daniel Mhlbachler

Raj Govindarajan

grails-redis-session