Dependencies and build!

Any blueprint can have dependencies. Dependencies mean that that building one blueprint will also build another. Note that each blueprint can only be built once.

Defining dependencies

There are several ways to define dependencies:

Hash

First way is similar to what rake uses - passing dependencies as values of hash key (which then becomes name of blueprint).

# define blueprint :fruits which depends on :apple and :orange
blueprint :fruits => [:apple, :orange]

# define blueprint :apple_tree which depends on :apple
blueprint :apple_tree => :apple do
  # Note that we have @apple defined from :apple blueprint, since we defined it as a dependency
  Tree.blueprint :fruit => @apple
end

Depends on

Another way is using depends_on method which. This can be used in three different forms: prefix, postfix and block.

blueprint(:fruits).depends_on(:apple, :orange)

depends_on(:apple, :orange).blueprint(:fruits)

depends_on(:apple, :orange) do
  # Any blueprints we define inside this block will depends on :apple and :orange
  blueprint :fruits
  blueprint :round_fruits
end

Method `d`

Method d is a bit special case in a way that not only it defined dependency but also assigns it to some attribute.

# Define blueprint named :apple_tree which when built will build :apple and assign
# :fruit with @apple
Tree.blueprint :apple_tree, :fruit => d(:apple)

# Define blueprint named :apple_tree which when built will build :apple with options
# {:color => 'red'} and assign :fruit with @apple_fruit
Tree.blueprint :apple_tree, :fruit => d(:apple, :apple_fruit, :color => 'red')

# Define blueprint name :apple_tree which when built will build :apple and assign
# :fruit_name with @apple.name
Tree.blueprint :apple_tree, :fruit => d(:apple).name

Building multiple times

Sometimes you need same blueprint build multiple times (eg. testing pagination). For that you can use build method. Note that any dependencies of those blueprints will only be built once.