Blendris

DESCRIPTION

Blendris is a Ruby interface to a Redis database. It performs no caching, causing all reads and writes to interact directly with Redis.

FEATURES/PROBLEMS

BLENDRIS IS IN VERY EARLY ALPHA!!!

PLEASE DON'T USE IT FOR ANYTHING IMPORTANT YET!!!

Blendris provides a way to create an object hierarchy within Redis, a key-value database. It provides very little in the way of indexing or querying that data. It is up to the user to maintain objects representing the query in which they are interested.

REQUIREMENTS

Blendris uses the redis gem.

INSTALL

gem install blendris

EXAMPLES

Let's say we want to maintain a list of employers and employees.

class Employer < Blendris::Model
  key "employer", :name

  string :name
  string :address

  refs :employees, :class => "Employee", :reverse => :employer
end

class Employee < Blendris::Model
  key "employee", :name

  string :name
  string :address
  set :family_members

  ref :employer, :class => "Employer", :reverse => :employees
end

And now some examples of using them:

>> captain = Employee.create("Captain Amazing")
=> #<Employee:0x45d18084 @key="employee:Captain_Amazing">

>> captain.address = "123 Fake Street"
=> "123 Fake Street"

>> guild = Employer.create("The Really Fantastic Guild of Heroes")
=> #<Employer:0x476e46f5 @key="employer:The_Really_Fantastic_Guild_of_Heroes">

>> guild.employees << captain
=> #<Blendris::RedisReferenceSet:0x500150a0 @key="employer:The_Really_Fantastic_Guild_of_Heroes:employees", ...>

>> guild.employees.first.address
=> "123 Fake Street"

>> guild.employees.count
=> 1

>> guild.employees.first.employer.employees.first.name
=> "Captain Amazing"

key

Key sets the base key for this object.

Any strings in the key will be used as literal strings.
Any symbols in the key will be set to the value of that field in this object.
In the case of the employer "37 Signals" it would create a key "employer:37_Signals" and set its value to "Employer".
Note that spaces are converted to underscores, as spaces are not allowed in Redis keys. This could cause problems in some data sets.
Also note that the value assigned to the base key is the class name of the model being used.
Only strings and integers should be used as key values.

Examples of keys in use:

>> employer = Employer.create("37 Signals")
=> #<Employer:0x169da74 @key="employer:37_Signals">

>> employer.key
=> "employer:37_Signals"

>> employer.name
=> "37 Signals"

>> employer[:name]
=> #<Blendris::RedisString:0x20dbd794 @key="employer:37_Signals:name", ...>

>> employer[:name].key
=> "employer:37_Signals:name"

string

String creates a string key named for the first parameter given to it. This means that it would generate a key "employer:37_Signals:name" with a value of "37 Signals".

ref and refs

Refs maintain references to other objects.

:class will limit objects in this reference set to the given class. If a string is specified as a class, it will be constantized before comparing.
:reverse will cause the given field to be updated on the object when it is added to or removed from this set.

new vs create

Calling the create method will build a new object, generating a new base key based upon the parameters. The parameter list should be the same as the list of symbols in your key field.

Calling the new method will instantiate an existing object using the given key as the base key.

Calling create on an object key that already exists is perfectly acceptable and only results in new Ruby objects being instantiated. They will all read and write to the same Redis data. Calling new however must be done on a Redis key that already exists and is set to the name of the requested model.

>> Employer.create("Giant Faceless Corporation")
=> #<Employer:0x45a84b38 @key="employer:Giant_Faceless_Corporation">

>> Employer.create("Giant Faceless Corporation")
=> #<Employer:0x12b8501d @key="employer:Giant_Faceless_Corporation">

>> Employer.create("Giant Faceless Corporation")
=> #<Employer:0x742136c6 @key="employer:Giant_Faceless_Corporation">

>> Employer.new("Anything")
TypeError: Anything does not exist, not a Employer - you may want create instead of new
        from .../blendris/lib/blendris/model.rb:25:in `initialize'
        from (irb):32:in `new'
        from (irb):32

>> Employer.new("employer:Giant_Faceless_Corporation")
=> #<Employer:0x73cb4cae @key="employer:Giant_Faceless_Corporation">

>> Employee.create("Invisible Woman")
=> #<Employee:0x5f27a49c @key="employee:Invisible_Woman">

>> Employer.new("employee:Invisible_Woman")
TypeError: employee:Invisible_Woman is a Employee, not a Employer
        from /Users/amchale/Dropbox/Projects/blendris/lib/blendris/model.rb:26:in `initialize'
        from (irb):36:in `new'
        from (irb):36

on_change

This keyword allows you to execute a block when one or more fields on the object change. The block is executed within the context of the object.

class Dog < Blendris::Model
  key "dog", :name

  string  :name
  string  :color
  integer :attention
  integer :food

  on_change do
    puts "Bark, bark!"
  end

  on_change :attention, :food do
    puts "Woof, woof!"
  end
end

>> d = Dog.create("Spot")
Bark, bark!
=> #<Dog:0x000001011739e8 @key="dog:Spot">

>> d.attention = 0
Bark, bark!
Woof, woof!
=> 0

>> d.color = "brown"
Bark, bark!
=> "brown"

>> d[:attention].increment
Bark, bark!
Woof, woof!
=> 1

LICENSE

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.