redis_array

This library provides a way to store Ruby arrays in redis with little fuss. You’re free to store anything that can be converted to a string and other arrays that contain objects that can be converted into a string. Anything else will throw an error because Redis only supports string storage. In addition, if you store a value that is not a string but can be converted into a string, such as an integer, when you access the value it will be a string. A work-around will be developed in the near future to support serialized objects and typecasting, though.

redis_array works by creating a list in redis for each array. Array keys are unique, so you cannot have multiple “test” keys, for example.

“‘ruby list1 = RedisArray.new(“list1”) # Redis key will be redisarray:list1 list2 = RedisMultiList.new(“list2”) # Redis key will be redisarray:list2 list1.push list2 # The value of index 0 in the list redisarray:list1 will be redisarray:~>list2 list1 # Will return a RedisArray object representing the values within redisarray:list2 “`

All retreival actions are done through Redis, so you don’t have to worry about concurrency between processes when accessing a List, or creating a different list instance using the same key.

redis_array attempts to act more like a Ruby Array then a Redis List. For example, LPOP in redis removes the first item within a list, whereas #pop on a RedisArray instance will remove the last.

Configuration

redis_array needs to have a redis connection to work properly. Where ever you open your Redis connection you should set it. For example:

“‘ruby redis = Redis.new(ENV) RedisArray.redis = redis “`

redis_array namespaces the arrays it stores. By default, it uses “redisarray”. Feel free to change it to whatever works and is unique.

Usage

Use RedisArray.new(“list-name”) to create or obtain a list. If the list already exists in Redis this will not create a new one; it will just access the existing. You can also use RedisArray.get(“list-name”), which is just an alias for new. Use this whether the list already exists or not. Nothing will be added into redis until a value is pushed in. You can also call it without a list name, and a random one will be generated for you:

“‘ RedisArray.new

> #<RedisArray:0x007fba4c4503b8 @key=“e5f0dfbfa8fdcf2cef63f4ca6369a98c”>

“‘

Each RedisArray instance supports the following methods, which behave like the Ruby Array class, along with including the Enumerable module: [], all, count, []=, <<, +, push, pop, delete_at, delete, and clear.

Gotchas

Redis doesn’t include a way to delete by index. We’ve implemented a way to handle that process, but it is going to be slow, and there’s a chance of concurrency issues. I’ll work on making a better way to handle the process itself, but until delete-by-index is supported using that method should be avoided. It’s better to delete by value.

Concatenating a List will append the rvalue to the list, rather then make a new one composed of the two values. This is to maintain the key layout, but it is useful to add many items at once by providing them in an array.

Contributing to redis_array