Class: Seahorse::Client::HandlerList

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
gems/aws-sdk-core/lib/seahorse/client/handler_list.rb

Instance Method Summary collapse

Instance Method Details

#add(handler_class, options = {}) ⇒ Class<Handler>

Note:

There can be only one :send handler. Adding an additional send handler replaces the previous.

Registers a handler. Handlers are used to build a handler stack. Handlers default to the :build step with default priority of 50. The step and priority determine where in the stack a handler will be.

Handler Stack Ordering

A handler stack is built from the inside-out. The stack is seeded with the send handler. Handlers are constructed recursively in reverse step and priority order so that the highest priority handler is on the outside.

By constructing the stack from the inside-out, this ensures that the validate handlers will be called first and the sign handlers will be called just before the final and only send handler is called.

Steps

Handlers are ordered first by step. These steps represent the life-cycle of a request. Valid steps are:

  • :initialize
  • :validate
  • :build
  • :sign
  • :send

Many handlers can be added to the same step, except for :send. There can be only one :send handler. Adding an additional :send handler replaces the previous one.

Priorities

Handlers within a single step are executed in priority order. The higher the priority, the earlier in the stack the handler will be called.

  • Handler priority is an integer between 0 and 99, inclusively.
  • Handler priority defaults to 50.
  • When multiple handlers are added to the same step with the same priority, the last one added will have the highest priority and the first one added will have the lowest priority.

Parameters:

Options Hash (options):

  • :step (Symbol) — default: :build —

    The request life-cycle step the handler should run in. Defaults to :build. The list of possible steps, in high-to-low priority order are:

    • :initialize
    • :validate
    • :build
    • :sign
    • :send

    There can only be one send handler. Registering an additional :send handler replaces the previous one.

  • :priority (Integer) — default: 50 —

    The priority of this handler within a step. The priority must be between 0 and 99 inclusively. It defaults to 50. When two handlers have the same :step and :priority, the handler registered last has the highest priority.

  • :operations (Array<Symbol,String>) —

    A list of operations names the handler should be applied to. When :operations is omitted, the handler is applied to all operations for the client.

Returns:

  • (Class<Handler>) —

    Returns the handler class that was added.

Raises:

  • (InvalidStepError)
  • (InvalidPriorityError) 


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# File 'gems/aws-sdk-core/lib/seahorse/client/handler_list.rb', line 105

def add(handler_class, options = {})
  @mutex.synchronize do
    add_entry(
      HandlerListEntry.new(options.merge(
        handler_class: handler_class,
        inserted: next_index
      ))
    )
  end
  handler_class
end

#copy_from(source_list, &block) ⇒ void

This method returns an undefined value.

Copies handlers from the source_list onto the current handler list. If a block is given, only the entries that return a true value from the block will be copied.

Parameters:



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# File 'gems/aws-sdk-core/lib/seahorse/client/handler_list.rb', line 129

def copy_from(source_list, &block)
  entries = []
  source_list.entries.each do |entry|
    if block_given?
      entries << entry.copy(inserted: next_index) if yield(entry)
    else
      entries << entry.copy(inserted: next_index)
    end
  end
  add_entries(entries)
end

#each(&block) ⇒ Object

Yields the handlers in stack order, which is reverse priority.



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# File 'gems/aws-sdk-core/lib/seahorse/client/handler_list.rb', line 151

def each(&block)
  entries.sort.each do |entry|
    yield(entry.handler_class) if entry.operations.nil?
  end
end

#entries ⇒ Array<HandlerListEntry>

Returns:



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# File 'gems/aws-sdk-core/lib/seahorse/client/handler_list.rb', line 22

def entries
  @mutex.synchronize do
    @entries.values
  end
end

#for(operation) ⇒ HandlerList

Returns a handler list for the given operation. The returned will have the operation specific handlers merged with the common handlers.

Parameters:

  • operation (String) —

    The name of an operation.

Returns:



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# File 'gems/aws-sdk-core/lib/seahorse/client/handler_list.rb', line 146

def for(operation)
  HandlerList.new(index: @index, entries: filter(operation.to_s))
end

#remove(handler_class) ⇒ Object

Parameters:



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# File 'gems/aws-sdk-core/lib/seahorse/client/handler_list.rb', line 118

def remove(handler_class)
  @entries.each do |key, entry|
    @entries.delete(key) if entry.handler_class == handler_class
  end
end

#to_stack ⇒ Handler

Constructs the handlers recursively, building a handler stack. The :send handler will be at the top of the stack and the :validate handlers will be at the bottom.

Returns:



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# File 'gems/aws-sdk-core/lib/seahorse/client/handler_list.rb', line 161

def to_stack
  inject(nil) { |stack, handler| handler.new(stack) }
end