class Line::Message::Builder::Context

The Context class is a crucial component of the Line::Message::Builder DSL, enabling a flexible and dynamic environment for message construction. It acts as a wrapper around an optional user-provided context object and manages a separate hash of assigns (local variables for the DSL).

The primary purposes of the Context are:

To provide access to helper methods: If a user passes a context object (e.g., a Rails view context, a presenter, or any custom object) during builder initialization, methods defined on that object become directly callable within the DSL blocks.
To allow local data storage: The assigns hash allows for setting and retrieving temporary data that can be shared across different parts of a complex message construction block, without needing to pass it explicitly or pollute the user-provided context.

Method calls within the DSL that are not defined on the builder objects themselves are resolved by Context in the following order:

First, it checks if the method name corresponds to a key in the assigns hash.
If not found in assigns, it checks if the wrapped user-context object responds to the method.
If neither, the call proceeds up the normal Ruby method lookup chain.

This mechanism allows for a clean and powerful way to integrate external logic and data into the message building process.

Example: Using a custom context

class MyContext
  def current_user_name
    "Alice"
  end
end

context = MyContext.new
Line::Message::Builder.with(context) do
  # current_user_name is resolved from context by Context
  text "Hello, #{current_user_name}!"
end

Attributes

assigns [RW]

A hash for storing arbitrary data that can be accessed within the builder DSL. This is useful for temporary variables or shared state during message construction.

Example

context.assigns[:user_id] = 123
puts context.assigns[:user_id] # => 123

mode [R]

The mode in which the builder is operating. This affects how messages are formatted in the final output. Either :api for direct LINE Messaging API format or :sdkv2 for LINE Bot SDK v2 compatible format.

Public Class Methods

new (context, mode: :api)

Source

# File lib/line/message/builder/context.rb, line 80
def initialize(context, mode: :api)
  @context = context
  @assigns = {}
  @mode = mode
end

Initializes a new Context object.

context: An optional object whose methods will be made available within the DSL. If nil, only assigns and standard builder methods will be available.
mode: The mode of the context, which can be :api (default) for direct LINE Messaging API format or :sdkv2 for LINE Bot SDK v2 compatible format.

Example

# With a custom context object
my_context = MyHelpers.new
context = Line::Message::Builder::Context.new(my_context, mode: :api)

Example: Without context

# Without context, using only assigns
context = Line::Message::Builder::Context.new(nil)
context.assigns[:user_name] = "Alice"

Public Instance Methods

sdkv2? ()

Source

# File lib/line/message/builder/context.rb, line 111
def sdkv2?
  mode == :sdkv2
end

Checks if the current mode is set to SDK v2 compatibility.

Returns true if the mode is :sdkv2, false otherwise.

Example

if context.sdkv2?
  # Format message for LINE Bot SDK v2
else
  # Format message for direct API use
end